Nobel Project: Physics

1901: Wilhelm Conrad Rontgen

"in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him".

Rontgen discovered X-rays, which are a form of high-energy electromagnetic radiation. He discovered X-rays in 1895 and the first X-ray was of his wife's hand.

You can produce X-rays by accelerating a beam of electrons with high voltage into a metal target. In LC Physics, we learned that X-rays are produced then when one of the electrons has such high energy that it knocks an electron from an inner energy level of a metal atom in the anode. An electron falls from an outer level to replace the inner one, releasing a photon of energy equivalent to the difference in energy levels. This is an X-ray photon. However, according to HyperPhysics, that's just one type of X-ray (characteristic X-rays); there's also Brehmsstrahlung or "braking radiation", because accelerating charges give off electromagnetic radiation. I had no idea what this was, so I looked it up on Physics Stack Exchange and, um, still didn't understand it, so I looked it up on Quora and I now understand it a bit. I may ask my friendly neighbourhood physicist (Laurie) for help yet, but according to the Quora answer the reason an accelerating charge emits radiation is that the accelerating charge has a changing magnetic and changing electric field at right angles to each other which is electromagnetic radiation.

(I could totally be wrong. Also, I didn't expect to have to get into that for X-rays.)

Other things Rontgen studied: specific heats of gases, thermal conductivity in crystals, influence of pressure on refractive indices of liquids, oil drops spreading on water and more. 



1902: Hendrik Lorentz & Pieter Zeeman

"in recognition of the extraordinary service they rendered by their researches into the influence of magnetism upon radiation phenomena"

Okay, so I had a pretty good idea what Rontgen did because it was on the Leaving Cert curriculum. These guys, though? No clue. Time for some Googling.

Zeeman discovered the splitting of spectral lines in a static magnetic field, and Lorentz worked to extend Maxwell's theory of electricity.

I find the title "Lorenz-Lorentz formula" funny but yes, anyway, Lorentz is important because, among other things, he conceived of the electron and led to Einstein's theory of relativity.

1903: Marie & Pierre Curie, Antoine Henri Becquerel

My favourite part of this project: when I come across stuff we've already covered in the Leaving Cert ;) We actually covered this one in both Chemistry and Physics.

In 1896, Henri Becquerel was studying X-rays, which had been discovered the year before by the 1901 Laureate. He put potassium uranyl sulfate in sunlight and then put it on photographic plates wrapped in black paper. He thought the uranium absorbed energy from the sun and then re-emitted it as X-rays, but that turned out to wrong when they still made images on an overcast day. Clearly the uranium was emitting something spontaneously. To prove that these mysterious rays weren't X-rays, which are neutral, he showed that the new radiation was bent by a magnetic field. There was negative, positive and neutral radiation - what we'd now call beta-, alpha and gamma radiation.

The Curies then discovered two materials more radioactive than uranium, plutonium and radium, by extracting uranium from ore and finding that the leftover ore actually showed more activity than the pure uranium. 


1904: Lord Rayleigh

First impression: I've heard of Rayleigh scattering when reading about Raman spectroscopy, but that's about all I know. Plus something about bringing potatoes to Ireland? Let's find out!

He was Professor of Experimental Physics and Head of the Cavendish Laboratory at Cambridge. He won the Nobel prize for discovering argon and measuring the densities of various gases. I've just read his Nobel lecture and man, he was so cool. I'm not entirely sure, but it seems that he was trying to measure the density of nitrogen from two different sources, air and ammonia, and found a discrepancy. So he got rid of the oxygen (and had copper staying red in the tube to prove no oxygen present) and found a slightly different number between air and nitrogen. The thing filling in the gap was totally unreactive and he called it argon (it was later discovered that there were other things, like helium, there too). 

He also did a bunch of other cool stuff, including "optics and vibrating systems [...] sound, wave theory, colour vision, electrodynamics, electromagnetism, light scattering, flow of liquids, hydrodynamics, density of gases, viscosity, capillarity, elasticity, and photography". Plus, he was apparently a great teacher.

So cool. 

1905: Philipp Lenard

This dude is also incredibly cool.

I'm enjoying how many of these things I've already covered some of in Leaving Cert Chem and Phys. While we didn't cover this guy, we did learn about cathode rays, which are beams of electrons emitted in a discharge tube. 

Lenard showed, by having a small plate of aluminium interrupting all the glass of the tube, that cathode rays could exist outside the discharge tube. He got the idea from his teacher, Hertz, who showed that the rays could pass through metal plates inside the tube. He knew that the rays outside the tube were the same as the ones inside because they also caused fluorescence and were affected by magnetic fields. He also showed that electrons (i.e. cathode rays) ozonize air, ionise gases and cause impressions on photographic plates. They were affected by electric as well as magnetic fields, were carriers of negative electricity everywhere and were subject to diffusion related to density of the gas they were travelling through.

Reading this is hilarious with the advantage of 111 years of hindsight, for the fact that the Nobel committee so tentatively talks about electrons and everything we take for granted was so new. Also, ether was still thought to be a thing. It also talks about differences between the German school of thought, which saw electrons as a wave, and the English, which saw them as particles. Now we have that annoying particle-wave duality. Unfortunately.

Also, it was fascinating to see the ultraviolet light on negatively charged objects mentioned, because of course that's the photo-electric effect even though it's not named there.


1906: JJ Thomson

Yes! Someone we extensively covered in LC Chemistry. This is going wonderfully.

From what we learned in Chemistry, JJ Thomson did stuff with cathode rays, came up with the plum-pudding model of the nucleus and, uh, sugar. I've forgotten a ton. Let's go relearn!

The prize was awarded "in recognition of the great merits of his theoretical and experimental investigations on the conduction of electricity by gases"."

Okay, so I've just started reading the Award Ceremony Speech and I have to comment on how cute this is. "Every day that passes witnesses electricity obtaining an ever-increasing importance in practical life." Imagine something so fundamental to us being so new to them! Also, instead of waves, the dude said "undulatory movements". Also, "problematical".

Anyway! Thomson managed to calculate the electrical charge-to-mass on a hydrogen atom (I presume of the electron?). This document does heavily imply he found the actual charge...although obviously the atom itself would be neutral... maybe just the proton? 

"The actual existing electricity is negative electricity, according to Thomson", and positive electricity is just the loss of electron(s). Thomson seemed to believe that electrons have no actual mass, that it just seems so because of their charge, which is wrong according to modern physics. He showed that a moving charge has "electromagnetic energy" which adds mass. All I can say to that is F = Bqv. 

Anyway, as for how he found the e/m ratio, he measured the charge of a certain quantity of air, then expanded the air, which was saturated with steam (because charged particles condense steam around them, according to Helmholtz) and calculated the size of the particles from the velocity at which they fell. He calculated the size of each drop because he knew how many there were and the size of the overall thing, and thus got the value 3.4 E-10.

1907: Michelson

I'm finding the Nobel award ceremony speech utterly incomprehensible, so I'm going to read something else on it, something that's calling the Michelson-Morley experiment the greatest failed experiment in the history of Physics, I think because it disproved the luminiferous ether. 

Fun fact: Michelson was the first American to win the Nobel Prize.

Okay, so if there really was an ether, which carried light through the air, you'd expect an ether wind and for the speed of light to change in different places. But Michelson built an interferometer, which worked by splitting a beam of light into beams travelling at right angles to each other, then recombined them using mirrors. If their speeds differed, the interference fringes would be shifted. But they weren't! At least, not nearly as much as they should have been if the ether was real.

Bamalamkebang, goodbye ether. (I've heard that a lot of scientists still hung onto the precious idea of an ether for a long time). 


1908: Gabriel Lippman

Okay, I've absolutely never heard of this guy so let's look him up. He won "for his method of reproducing colours photographically based on the phenomenon of interference".

Another interference winner!

Lippman enabled ... colour photography? Apparently? He was the first person to get the colours to stay. That seems like a weird thing to give a Nobel Prize in Physics for. To do this, he spread "gelatine emulsion, silver nitrate and potassium bromide" on plane glass (the photosensitive layer), then added a layer of mercury. Light passing through the glass and photosensitive layer and being reflected by the mercury mirror creating a standing wave, which supported the wave theory of light.


1909: Guglielmo Marconi & Karl Ferdinand Braun

I heard of Marconi when doing my historical research on Tesla, because apparently Tesla disputed Marconi's claim to have invented radio... or something. Anyway, they won in recognition of their contributions to the development of wireless telegraphy"

So, important people did work on waves before Marconi - Faraday, Maxwell, Hertz - but Marconi succeeded in getting the waves to travel long distances (10s of kilometers, later extending to thousands) but the signals were messed up at the receiving station and "damped", and Braun fixed that by modifying the circuit used to transmit the radio waves. Something unclear about resonance and damping is also mentioned.

Most of the piece just waxes lyrical about the importance of radio in the world.


1910: Johannes Diderik Van der Waals

I've heard a lot about Van der Waals' forces in Chemistry, which are intermolecular forces between non-polar molecules caused by temporary dipoles. He won the Nobel prize for figuring out relationships between gases and liquids of the same materials, although it only worked for non-polar things. He calculated the strength of intermolecular forces in water. He showed that there's a continuum from gas to liquid. He allowed for the production of liquid hydrogen and helium and did stuff on critical temperatures and an equation of state. 

I like the tone of this letter/speech - the last paragraph is very sweet. 


1911: Wilhelm Wien

"for his discoveries regarding the laws governing the radiation of heat"

Never heard of this guy. According to the Encyclopaedia Britannica he was a German physicist who studied perfect blackbodies (which absorb all energy radiated onto them). Wien found that the wavelength at which the maximum amount of radiation is emitted from the black body is inversely proportional to its absolute temperature.


1912: Nils Gustaf Dalen

These are such funny names.

"for his invention of automatic regulators for use in conjunction with gas accumulators for illuminating lighthouses and buoys"

This seems weird, like the photography one.

Dalen worked on containing and storing acetylene gas (aka ethyne) and became known as "the benefactor of sailors" for revolutionising maritime navigation.


1913: Heike Kamerlingh Onnes

What a  name!

"for his investigations on the properties of matter at low temperatures which led, inter alia, to the production of liquid helium"

Onnes discovered superconductivity, which is where materials lose electrical resistance at extremely low temperatures, through his work near absolute zero. He liquefied helium in 1908.


1914: Max von Laue

Heard the name but nothing else.

"for his discovery of the diffraction of X-rays by crystals"

This discovery was important because it meant people could now study the structure of crystals, beginning the field of solid-state physics. von Laue's demonstration of the diffraction of X-rays by crystals showed two things: (a) X-rays were electromagnetic radiation like light (b) crystals were regular and repeating at the atomic level.


1915: William Henry Bragg and William Lawrence Bragg

The father-son physics duo received the Nobel prize for "their services in the analysis of crystal structure by means of X-rays"

The father thought in 1907 that X-rays and gamma rays could have be particulate. He established a crystallographic research school at UCL and was apparently altogether a lovely man. Funny how similar the 1914 and 1915 prizes were. 

1916: No Prize

1917: Charles Glover Barkla

Never heard of this dude. He got the prize for "his discovery of the characteristic Rontgen radiation of the elements". Let's go see what that's all about.

Firstly, this is weird. In 1917, the Nobel committee decided none of the nominations merited a Nobel prize, so they reserved the 1917 prize for Barkla and gave it to him in 1918.

I'm having difficulty understanding the presentation speech, which seems to be saying he discovered two different types of X-ray radiation from elements, one corpuscular (i.e. particulate, presumably) and one in waves. It also says he estimated the number of electrons in atoms.

Oh, something I understand - he discovered that X-rays could be polarised, showing them to be like light. He did something to do with line spectra and secondary X-radiation. 

He discovered characteristic X-rays, which occur in heavy elements when electrons fall from higher energy levels to replace ones in lower energy levels. Hang on, this is where brehmsstrahlung radiation mentioned earlier comes from! Thanks, HyperPhysics.

Fun fact: Barkla worked in the Cavendish lab in Cambridge (I swear to God that is a Nobel factory) and was a big JJ Thomson fanboy.


1918: Max Planck

Ooh, I've heard of Planck. I know vaguely of Planck time (a time very very close to the start of the universe when, uh, something important happened) (I just checked - the something important was the first of the four symmetry breaks, when gravity separated from the other four fundamental forces. The Planck era was 10E-43 seconds after the Big Bang, in the model). I also know the Planck constant, which is the h in E = hf.

The weird thing happened again this year - Planck received the Prize in 1919 because the committee didn't think any were good enough in 1918. 

He won the prize for his discovery of "energy quanta". Let's go see exactly what they mean by that.

The product hv, he said, is the smallest amount of heat energy that can be released by a radiation, with h Planck's constant (presumably) and v the frequency of vibration of the wave (or as they call it radiation - probably could also be written hf). Some pieces of evidence for Planck's revolutionary work on radiation were Einstein's photoelectric effect and the specific heat of substances.

Planck also found an accurate value for Avogadro's constant (6.023E23, rounded). 

The Academy loved this dude, calling his discoveries "epoch-making" and speaking very reverentially in the presentation. Nice. 


1919: Johannes Stark

"for his discovery of the Doppler effect in canal rays and the splitting of spectral lines in electric fields"

I sense that this is going to be unpleasant, since I don't know what canal rays are and I'm unfamiliar with splitting spectral lines.

Going by the presentation speech, canal rays are "a new kind of rays in discharge tubes containing rarefied gas", with positive charge. Protons? Cations? Ah, mostly made up of cations of the atoms in the gas moving at high speeds.

Stark detecting the moving particles colliding with gas molecules and emitting light, which were tinted violet (well, their spectrum was) because they were approaching. This was the Doppler effect.


1920: Charles Edouard Guillaume

"in recognition of the service he has rendered to precision measurements in Physics by his discovery of anomalies in nickel steel alloys"

Guillaume was, it turns out, an eminent metrologist in the Bureau of Weights and Measures in Paris. He was preoccupied with the metre and kilogram and making sure they were consistent internationally. When I say the kilogram, I mean the physical thing that defines the kilogram. Anyway, the problem was that things change volume with temperature. So Guillaume studied the extensibility etc of lots and lots of different metals and alloys for a long time until eventually he found one, invar, a steel-nickel alloy with a temperature coefficient of nearly zero.


1921: Albert Einstein

Okay, I think we all know this dude. I'm very glad his Nobel Prize was awarded for the photoelectric effect and what it meant for quantum physics (well, the prize specification also mentions "services to Theoretical Physics", but I have elected to presume that's in relation to quantum as opposed to special or general relativity because I do not understand those.

The Presentation Speech starts on a high note: "There is probably no physicist alive today whose name has become so widely known as that of Albert Einstein". It then talks about Einstein's work on Brownian motion (the random movement of particles). The article also mentions his theory of relativity and says it basically pertains to epistemology but does have some astrophysical implications.

Various people, notably Hertz, Hallwachs and Lenard, discovered the photoelectric effect and found that when trying to make a negatively-charged thing neutral or positively-charged, it didn't matter how intense the light was, what mattered was the frequency (UV was best). Einstein came up with a law for this, which as taught to us in LC Physics was:

h f = Φ + 1/2 m v2

where hf is the frequency of the incident photon, phi is the work function of the metal (Planck's constant*threshold frequency) and the last term is the kinetic energy of the electron.

If hf is equal to the work function, the electron will leave the metal but will have no kinetic energy. If hf is greater, it will and if hf is less it won't be emitted at all. This was evidence for Planck's quantum theory, and was proven by Millikan. According to the speech, it formed the basis for quantitative photo chemistry.


1922: Niels Henrik David Bohr

for his services in the investigation of the structure of atoms and of the radiation emanating from them

I think this is referring to the hydrogen spectrum and the idea of energy levels and light being released when an electron returns to a lower energy level, but let's go check out the speech and see. Shoutout to LC Chemistry.

Okay, so at first it's just talking about spectral analysis, and calls the "Rydberg constant" very important. I've never heard of it before so I just looked it up and apparently it's "in the formula for wave numbers of lines in atomic spectra and is a function of the rest mass and charge of the electron, the speed of light, and Planck's constant" (thanks, Google). 

Okay, so now it's saying a bunch of things we would not now consider to be true, for example that the only force acting in the atom is electrical, and that the nucleus and electron are like a Sun and planet. So it's saying the electron would be expected to spiral into the nucleus and thus there is a conflict between Rutherford's model of the atom and Maxwell's classical theory (of what??? Electrodynamics/electromagnetism I think). 

So Bohr was going with the whole energy levels things and introduced the "principle of correspondence", which apparently states that some energy level transitions are impossible. 

(Also, it mentioned orthohelium and parahelium, which are cool) 

The ending is cute: "Your great success has shown that you have found the right roads to fundamental truths, and in so doing you have laid down principles which have led to the most splendid advances, and promise abundant fruit for the work of the future. May it be vouchsafed to you to cultivate for yet a long time to come, to the advantage of research, the wide field of work that you have opened up to Science."

1923: Robert Andrews Millikan

I know this guy well! Because (a) we covered him lightly in LC Chemistry, and (b) I did a PowerPoint on his oil drop experiment in February as part of my Experimental Design monthly project. Thanks, February me.

So he won the prize for "his work on the elementary charge of electricity and on the photoelectric effect". 

Instead of explaining all this now I'm just going to link you to the presentation I made on it. Here. 

Interestingly, as well as proving that electrons all have the same charge and measuring that charge, his work on the photoelectric effect backed up both Einstein and Bohr, and without him they would not have received Nobel Prizes.

Sources: My PowerPoint has sources at the end

1924: Manne Siegbahn

OK, definitely never heard of this guy.

He won "for his discoveries and research in the field of X-ray spectroscopy". As far as I can gather, he spent ten years meticulously refining X-ray technology until wavelengths could be measured with accuracy a "thousand times greater than that attained by Mosely".

His research was very important for probing the inner structure of atoms.I think he discovered M and N levels, which enabled others to discover that there were 5 M and 7 N (sounds very like d and f orbitals...). He also managed to refract X-rays in a prism and make qualitative analyses of substances with X-rays to find out what elements were in them (between sodium and uranium on the periodic table). 

1925: Gustav Ludwig Hertz, James Franck

"for their discovery of the laws governing the impact of an electron upon the atom"

Hm, sounds interesting. Also, these guys received their prize in 1926 because none of the 1925s were good enough. This keeps happening.

Okay, so the work of these guys verified Bohr's hypotheses about atoms existing in different states with different energy levels, which determine how spectra happen.

1926: Jean Baptiste Perrin

"for his work on the discontinuous structure of matter, and especially on his discovery of sedimentation equilibrium"

Not a clue what this means. Let's go digging. 

So apparently the aim of his research was to prove that molecules were, y'know, real. He wanted to show that if equally heavy small particles are distributed in a liquid, they won't all sink to the bottom even if they're heavier than the liquid. He did this using gamboge obtained from vegetable sap and succeeded in determining Avogadro's number in agreement with the kinetic theory of gases (within limits of experimental error).


1927: Charles Thomson Rees Wilson & Arthur Holly Compton

Compton "for his discovery of the effect named after him" and Wilson "for his method of making the paths of electrically charged particles visible by condensation of vapour". 

Apparently Compton made "exact spectrometrical investigation" (what a lovely phrase) of the secondary X-radiation on matter with small atomic weights.

The Compton effect is an increase in wavelength of X-rays and gamma rays when they're scattered. The shift in wavelength increases with the angle of scattering. 

Wilson invented cloud chambers to track charged particles. The Academy made a big deal of how much time had elapsed between his work and the award of the prize, saying that the value of his work had been verified through its use for later research.


1928: Owen Williams Richardson

Never heard of this guy. Also have you noticed what a sausagefest this is?! I think I've written about maybe one woman so far (Marie Curie). Apparently the only other woman to have received a Nobel prize in physics is Maria Goeppert-Mayer, in 1963. Disgraceful. 

*fumes* Anyway, back to Owen. He got his Prize for "his work on the thermionic phenomenon and especially for the discovery of the law named after him"

Lovely sexism in the presentation speech. "enabling two men to converse in whatever part of the world each may be". From reading the speech, I think he discovered/gave a law for thermionic emission.


1929: Louis de Broglie

I've heard of this guy. Something to do with atomic theory or waves? Let's go see.

Ooh, I was close! "for his discovery of the wave nature of electrons"

His full name is funny: Prince Louis-Victor Pierre Raymond de Broglie.

So basically, with no evidence he asserted that electrons were waves and they'd act like light in situations such as being passed through a very small hole in an opaque screen. He used beams of electrons being reflected from crystalline sheets to show the wave nature. 

So yeah. Electrons. Waves. 

1930: Chandrasekhara Venkata Raman

Ooh I wonder if this is the guy behind Raman spectroscopy! Because I used that for my nanotech Young Scientist project.

"for his work on the scattering of light and for his discovery of the effect named after him" Ooh I think it is this guy.

So reading the presentation speech I've learned that the Tyndall effect says that if white light is passed through a medium blue light is scattered more than yellow and red. 

Apparently Raman found that scattered monochromatic light contained wavelengths other than the original wavelength of the light. Ooh I sense the phrase "Raman shift" coming. Hopefully I can finally understand that, two years later. So apparently this happened in every medium he tried, there was always this shift, this change in wavelength. Apparently this enabled ultrared oscillations to be studied (I assume this is like infrared) because the ultrared was shifted up to the part to which the photographic plate was sensitive. The UV spectrum could also be studied in this way, enabling closer studies of molecules. 


1931: No prize

1932: Werner Heisenberg

Ooh, in LC Chemistry we learned that the Heisenberg Uncertainty Principle goes "It is impossible to determine at the same time the exact position and velocity of an electron". I've also heard it expressed as, the more precise your measurement of the position, the less precise your measurement of the velocity, and vice versa.

He got the prize "for the creation of quantum mechanics, the application of which has, inter alia, led to the discovery of the allotropic forms of hydrogen".

To look up: inter alia, allotropic - among other things, structurally different form of element 

1933: Erwin Schrodinger & Paul Dirac

Heisenberg and these guys actually got their award in the same year, because the committee didn't think the 1932 nominations were good enough. 

Schrodinger came up with a wave equation for electrons. In LC chemistry we learned that atomic orbitals were places where an electron was relatively likely to be found, but an alternative answer was "an approximate solution to the Schrodinger equation". So.

Dirac set up wave mechanics with relativity as a prerequisite. He divided "the equation" (presumably Schrodinger's) into two simpler ones and thus posited the existence of the positron, which was good evidence for his theory when it was discovered.


1934: No prize

1935: James Chadwick

Ooh I think this is the guy who discovered the neutron with beryllium and paraffin wax. 

Yup! Awarded "for the discovery of the neutron". It's hard to believe that quantum mechanics was invented before the discovery of the neutron. We're always taught classical physics first in school. 

So it had already been found that when beryllium was bombarded by alpha particles, a stream of penetrating, non-ionising radiation was released. And then Curie and Joliot showed that when this radiation hit paraffin, it realeased protons. Not really sure what Chadwick's role in the whole thing was. He proved that the radiation could not be photons by bombarding things like nitrogen and argon with it, and determined the mass of the neutron.


1936: Carl David Anderson & Victor Francis Hess
Hess's Law - something to do with heat and routes of reaction? 

Hess - discovery of cosmic radiation

Cosmic radiation was suspected because there was radiation everywhere, despite thick lead casings, and even up on the Eiffel tower (I like the idea of people scaling the Eiffel tower to measure this). Hess used balloons to find out that at 5000 m, radiation was twice as intense as it was on Earth's surface. He determined that it didn't come from the sun because there was no difference between night and day and solar eclipses didn't affect it either. A slight variation dependent on the galaxy's motion led them to believe taht it was from sources beyond the galaxy. Hess couldn't figure out where exactly it was coming from, but he did get that it was extremely powerful and from outer space (beyond the galaxy somewhere). 

Anderson - discovery of the positron

The discovery of the positron was done when studying cosmic radiation. Particles were found that, in a cloud chamber, deviated at the same magnitude but in the opposite direction to electrons (i.e. they were positively charged electrons, or positrons). They also mention pair annihilation. 


1937: George Paget Thomson & Clinton Davisson

"for their experimental discovery of the diffraction of electrons by crystals". 

This sounds like some electron-wave stuff. Wonder if I'm gonna understand it. Let's go. 

So yeah, they proved de Broglie's wave theory. Davisson did it first and then four months later, Thomson did it independently using a different method. They arranged them at different intervals to get destructive and constructive interference, measured the wavelengths and compared them to the known electron velocities and thus checked de Broglie's equation. That's what Davisson and Germer did, using low voltage.

Thomson, on the other hand, used high voltage and very thin films of celluloid/gold/platinum/aluminium. He had a fluorescent screen behind the film, on which he could examine the diffraction pattern when the electrons fell perpendicularly onto the film. The diameter of a ring on the screen corresponded to the wavelengths of mechanical waves.


1938: Enrico Fermi

I've heard of Fermi - there's a particle accelerator somewhere called Fermilab, I'm pretty sure. 

He won "for his demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of nuclear reactions brought about by slow neutrons". 

Okay so this just sounds like nuclear fission, which we learned about in LC Physics. 

So Fermi found that slow neutrons (e.g. that had been passed through parraffin) were actially more effective for causing fission. Also, apparently he and his teaam managed to produce radioactive isotopes of every element except hydrogen and helium?! Fermi produced two new elements with atomic numbers 93 and 94, which he called Ausenium and Hesperium. 


1939: No prize

1940: No prize

1941: No prize

1942: No prize

1943: Otto Stern

"for his contribution to the development of the molecular ray method and his discovery of the magnetic moment of the proton"

Oh dear ... I don't know what any of this means. What is a magnetic moment? Molecular ray method?

Okay so apparently Stern (with Walter Gerlach) bored a tiny hole in a steam furnace and vapour flowed through it in a heterogenous magnetic field, which should've disaligned the particles if they were magnetic. A diffuse beam was expected but instead they got a number of well-defined rays, confirming the "space-quantization hypothesis". I just looked that up, and it's ..... something to do with angular momentum and magnetic intensity? limited number of angles? I'll have to ask about that in college, or ask a physicist friend. I don't really know what angular momentum is, to be honest. Anyway, Stern found the magnetic moment of the proton and that it was significantly bigger than predicted.


1944: Isidor Isaac Rabi

What a cool name. Isidor Rabi! 

"for his resonance method for recording the magnetic properties of atomic nuclei"

Okay, if I had to guess, I'd guess this was NMR? Nuclear magnetic resonance? Let's go see. 

Okay, well it doesn't seem to have been Rabi who invented NMR, but I did guess what it stood for right. Yay.

So, Rabi was looking at how atoms react to magnetic fields. He put a loop of wire attached to an oscillating frequency circuit in a magnetic field. An atomic beam was passed through the field and only affected if it "precessed" (?) in time with the electric current.

The influence caused quantum jumps, so the atoms didn't reach the detector and minima of marked resonance were noted. Can't say I understand this one well. 


1945: Wolfgang Pauli

I've definitely heard of this guy. I think the Pauli exclusion principle states that no more than two electrons may occupy an orbital at the same time and they must have opposite spins?

Oh, look! It was awarded "for his discovery of the Exclusion Principle". Isn't that great. He discovered it in 1925 apparently. The princple is also valid for protons and neutrons, it seems. And it was found because four quantum numbers (quantum number = energy corresponding to an electron orbit) were needed to define the energy state of an electron, three of which are related to the electron's revolution around the nucleus and one is the electron's own spin. Pauli's principle was important in quantum physics also. No two electrons in an atom could have identical sets of quantum numbers. 

Interestingly, Pauli didn't receive the Nobel prize himself and sent someone else to do it. Why? I don't know. Google is being unhelpful.
Oh this is funny. According to Wikipedia (I know), the Pauli effect is the "apparently mysterious, anecdotal failure of technical equipment in the presence of Austrian theoretical physicist Wolfgang Pauli". 


1946: Percy Williams Bridgman

"for the invention of an apparatus to produce extremely high pressures, and for the discoveries he made therewith in the field of high pressure physics"

So previously the highest pressure people had created was 3000 kg/cm squared but Bridgman got it up to 500,000 kg/cm squared. He did it by stopping leakage while playing with what was left of his apparatus after part broke so that the pressure available then just depended on the strength of the material. 

He made a bunch of discoveries, including different forms of ice and phosphorous and stuff about viscosity and elasticity of solid bodies under pressure. 


1947: Edward Victor Appleton

for his investigations of the physics of the upper atmosphere especially for the discovery of the so-called Appleton layer"

So basically they thought that there must be a conducting layer above the earth because there was interference between radio waves along the surface. He discovered the ionisphere and then three years later discovered another conducting layer above the one previously known.


1948: Patrick Blackett

for his development of the Wilson cloud chamber method, and his discoveries therewith in the fields of nuclear physics and cosmic radiation

Fun fact: Lord Rutherford once called the Wilson cloud chamber "the most original and wonderful instrument in scientific history". Which is nice. Anyway. 

In 1925, Blackett got the first photos of an alpha particle at high velocity barrelling into a nitrogen nucleus. He verified that collisions between atomic nuclei follow the laws of conservation of matter-energy and momentum. He made an automatic cloud chamber to register cosmic rays way better. Blackett and collaborators discovered pairs of electrons and positrons in cosmic rays, and also proved that these pairs came from hard gamma rays. This was proof of pair annihilation and pair production. 

So that's pretty cool...but the sass in this presentation speech! "These fascinating variations in the appearance of energy, which sometimes manifests itself as light, sometimes as matter, have stimulated the distinguished French physicist Auger to exclaim enthusiastically, in a monograph on cosmic radiation: "Who has said that there is no poetry in modern, exact and complicated science? Consider only the twin-birth of two quick and lively electrons of both kinds when an overenergetic light quantum brushes too closely against an atom of matter! And think of their death together when, tired out and slow, they meet once again and fuse, sending out into space as their last breath two identical grains of light, which fly off carrying their souls of energy!" (As a memory aid Auger's metaphor is excellent; its poetical value is perhaps open to dispute.)"


1949: Hideki Yukawa

for his prediction of the existence of mesons on the basis of theoretical work on nuclear forces

Yukawa discovered a simple relationship between the range of the nuclear forces and the mass of the particles. Experimental data from other people allowed him to estimate the range affecting the new particles and thus calculate that they should be about 200x heavier than electrons. Yukawa theorized that the nuclear forces are caused by the transmission of mesons. He said mesons should be found in cosmic radiation but not in normal nuclear radiation. Anderson, Neddermayer and others found evidence of mesons in cosmic rays in 1937. Yukawa was only 27 when he predicted the existence of mesons, which is cool. 


1950: Cecil Powell

for his development of the photographic method of studying nuclear processes and his discoveries regarding mesons made with this method

Photographic plates had been used for measuring radiation since the early 1900s, but Powell greatly improved their quality so they could be used for cosmic radiation and were used to detect mesons. Photographic plates register continuously (unlike the Wilson cloud chamber), so it's easier to catch tracks of radiation. Powell's lab found that the primary meson was 1.35 times heavier than the secondary meson, which agreed well with Berkeley's measurements of artificial mesons. (Powell's mesons were from photographic plates on a mountain 2800 metres above sea level, with some 5500 metres above sea level). He also discovered a neutral meson in cosmic radiation. Lots of mesons. 

1731 exercise
1645 microsoft


1951: Cockcroft & Walton

Walton, Ireland's only Nobel Physics laureate, went to the college I'm currently writing this in. Which is cool. We covered this in LC Physics - AFAIK, they built a linear accelerator and split an atom into two helium nuclei, which then flew off in opposite directions and caused fluorescence on a screen. I think the atom was lithium, which was hit by...something. A proton, I think. They got it up to high speed using a constant voltage of around 600,000 V and built a discharge tube where the hydrogen nuclei (i.e. protons) were accelerated.


1952: Felix Block and Edward Mills Purcell

for their development of new methods for nuclear magnetic precision measurements and discoveries in connection therewith

Okay so first of all, apparently there are four kinds of magnetism: ferromagnetic things (e.g. iron, nickel, cobalt), paramagnetic things (e.g. crystals, fluids), diamagnetics (all things) and nuclear magnetism. The magnetic field from the nucleus is very weak and thus hard to detect, but Bloch and Purcell measured it "with a precision exceeding almost all other measurements in Physics". They adapted Rabi's molecular-ray method for analysing nuclear magnetic moments by making it applicable to solids, liquids and gases. Since all substances have a characteristic nuclear frequency, this could be used to identify all atoms and isotopes in an object between the poles of an electromagnet, without affecting the object in any discernible way.


1953: Frits Zernike

for his demonstration of the phase contrast method, especially for his invention of the phase contrast microscope

So, the problem was that even with good microscopes it was impossible/too difficult to study the many things that are transparent. Dyes were problematic with living things and darkfield illumination gave dodgy results, so this is where Zernike stepped in. It turned out that there is a change when light goes through something translucent; a phase difference of a quarter-wavelength compared to a direct ray of light. Zernike inserted a phase-plate which either increased the difference to half a wavelength or decreased it to no difference, creating either destructive or constructive interference and creating a patch of either dark or light where the object was. The phase plate also had other applications, like detecting flaws in mirrors and telescopes.


1954: Max Born & Walter Bothe

Born - for his fundamental research in quantum mechanics, especially for his statistical interpretation of the wavefunction

Bothe - for the coincidence method and his discoveries made therewith

Fun fact related to Born: I was at Physoc committee's weekly meeting today and we decided to go to Edinburgh on our trip, where Born was a professor.

So yeah. Born worked alongside Heisenberg, Schrodinger, those people. It must have been so exciting to be working in quantum physics at that particular time, with all those incredible minds and new discoveries coming out all the time.

Anyway, Born put maths on Heisenberg's theory and figured out how to make statements about electrons based on the wave describing their motion (the answer: determinism is dead, it's all about statistics now). He did ... other things, too. But mainly mathsing quantum mechanics.

Bothe used the coincidence method (of combining two counter tubes, which give out a current when a charged particle passes through them, so that they would only register simultaneous collisions. He used it to investigate whether the energy rule/impulse rule (admittedly I don't know what this is, and looking it up turned up nothing useful) was true for every collision between a photon and an electron (a la Einstein and Compton) or whether it was only true on average for large numbers of collisions, a la Bohr. Turned out Einstein and Compton were right. The coincidence method was also useful in studying cosmic radiation.

1955: Willis Eugene Lamb & Polykarp Kusch

Lamb - for his discoveries concerning the fine structure of the hydrogen spectrum

Lamp found a flaw in Dirac's theory of the fine electronic structure of the hydrogen atom - he found that two levels (energy sublevels?) which Dirac said should coincide were actually shifted apart, and measured the shift which was then called the Lamb shift.

Kusch - for his precision determination of the magnetic moment of the electron

How cool is the name Polykarp?! Anyway, Kusch found that the magnetic moment of the electron is about 0.1% larger than what was thought (called the Bohr magneton).

Also apparently their discoveries were made independently in the same lab in the same year as heads of two different research groups, which is kinda cool. 


1956: William B Shockley, John Bardeen, Walter Houser Brattain

for their researches on semiconductors and their discovery of the transistor effect

Semiconductors are made of materials like silicon and germanium; they have fewer free charges than conductors and more than insulators, and their number of free charges can  be increased by doping e.g. with phosphorous/boron. These guys figured out how to manipulate semiconductors using transistors..and I don't think I need to say how important transistors are. 


1957:  Chen Ning Yang & Tsung-Dao Lee

for their penetrating investigation of the so-called parity laws whic has led to important discoveries regarding the elementary particles

I think I heard of parity laws in A Brief History of Time by Stephen Hawking. So let's learn a bit more about them/this.So apparently the parity laws refer to the left-right symmetry of nature. 

So, it had been assumed that elementary particles didn't distinguish between left and right, but then weird observations with K mesons led Yang and Lee to question the symmetry. They looked at past experiments and found that there was zero experimental evidence for left-right symmetry, and the reason it hadn't been disproven before was that experiments had been arranged not to distinguish between it being true/false. So they had experiments done by other people, including Chinese physicist Mrs Wu. It was found that left-right symmetry was broken using an experiment with low temperature atomic nuclei of a radioisotope of cobalt where they had a direction as magnets. The electrons were shown to be preferentially facing downwards.


1958: Pavel Aleksevevich Cherenkov, Ilja Mikhailovich Frank, Igor Yevgenyevich Tamm

for the discovery and the interpretation of the Cherenkov effect

Cherenkov was looking at radiation in fluids and reasoned that the popularly-accepted explanation, fluorescence, couldn't be right because the bluish light happened even in doubly distilled water where there couldn't be any impurities to fluoresce. He found that the radiation was polarised along the incoming direction and that secondary electrons were responsible mostly for the colour. The Cherenkov/Cerenkov effect happens when an electron moves faster than light in a medium (IN A MEDIUM). Frank and Tamm explained the phenomenon and put it in mathematical form.


1959: Emilio Gino Segré & Owen Chamberlain

for their discovery of the antiproton

The first antiparticle (positron) was discovered by Anderson in 1931, then these guys used the Bevatron in Berkeley to discover the antiproton using very high energy collisions, and the antineutron was discovered shortly after. Yup.


1960: Donald Glaser

for the invention of the bubble chamber

Glaser invented the bubble chamber, like Wilson's cloud chamber but for studying higher-energy reactions. A chamber is filled with liquid near boiling point. When charged particles pass through it at high speed, they ionise nearby atoms. The pressure in the chamber is then lowered and bubbles form around the charged atoms so they can be photographed. 


1961: Robert Hofstadter & Rudolf Mossbauer

Hofstadter - for his pioneering studies of electron scattering in atomic nuclei and for his thereby achieved discoveries concerning the structure of the nucleons

Hofstadter studied the distribution of electrical charge and magnetic moments inside nucleons by bombarding them with high-energy electrons and then measuring the scattering of the electrons on the other side. 

Mossbauer - for his researches concerning the resonance absorption of gamma radiation and his discovery in this connection of the effect which bears his name

Mossbauer got the prize for his doctorate work studying the emission of gamma radiation from one nucleus and its absorption by another nucleus of the same type, leading to resonance. He found a way to do this with a significant portion of the radiation not having a frequency change for atoms in a solid, which made it easier to study resonance absorption.

1963: Maria Goeppert-Mayer & Hans Jensen, Eugene Wigner

Wigner - for his contributions to the theory of the atomic nucleus and the elementary particles, particularly through the discovery and application of fundamental symmetry principles 

Wigner studied left-right symmetry and time symmetry, finding that for elementary particles forward time is equivalent to backward time (backwards, presumably....). He found that the forces between nucleons are very weak unless they're extremely close together, but nevertheless they're a million times stronger than the forces between electrons in the electron cloud. He made a general theory of nuclear reactions and worked to improve practical use of nuclear physics as well.

Goeppert-Mayer & Jensen - for their discoveries concerning nuclear shell structure

Finally, after 50 years, another female Nobel laureate in physics! Except, wait, she only got 25% of a Nobel prize. Damnit. 

It had previously been found that atoms had a stable configuration when there were 2, 8, 20, 28, 50, 82 or 126 of either protons or neutrons in the nucleus. Goeppert-Mayer and Jensen (independently and then together) set out to explain this. They provided evidence for the existence of higher "magic numbers" and said that a nucleon would have different energies according to its spin. They predicted phenomena regarding the ground state and lower excited states of nucleons. This work gave greater credence to the shell model.


1964: Charles Townes, Nikolay Basov & Alexander Prokhorov

for fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle

The prize was given for the invention on LASERs and MASERs, lasers being Light Amplification by Stimulated Emission of Radiation and masers being Microwave Amplification by Stimulated Emission of Radiation. So basically, what they needed to make use of the effect Einstein discovered was to have way more atoms in a higher energy state than in a lower one aka "inverted population". Masers were used for radio astronomy because they were very sensitive receivers for short radio waves. Then came lasers, or optical masers, which had much higher energies. Light bounces off two lasers a ton of times and because the stimulated and stimulating radiation are in phase so by resonance one strong wave is formed (constructive interference, no?). Lasers are coherent sources, which is why they're so valuable. I'm sure I don't need to say why lasers are useful but one reason is their huge power density per unit area. Also, at the end of the speech they caution that death rays are not real. Seriously, they say "death rays."


1965: Sin-Itiro Tomonaga, Julian Schwinger, Richard Feynman

for their fundamental work in quantum electrodynamics, with deep-ploughing consequences for the physics of elementary particles 

There were issues with quantum electrodynamics. For example, when you tried to calculate the effect the electromagnetic field of an electron had on its mass, you got a infinite value. Bethe calculated the Lamb shift and Tomonaga read his paper and then substituted the experimental value for the presumed value, necessitating the addition of extra terms which cancelled out the infinities. Feynman came up with Feynman diagrams, which are useful.


1966: Alfred Kastler

for the discovery and development of optical methods for studying Hertzian resonances in atoms

He proposed that electrons can be elevated using light/other electromagnetic radiation to certain higher fixed energy levels and then fall down to lower fixed ones. This helped in the development of the laser and enabled the precise measurement of energy levels.


1967: Hans Bethe

for his contributions to the theory of nuclear reactions, especially his discoveries concerning the energy production in stars

He proved that nuclear fusion powers stars, giving two processes for hydrogen fusing with helium nuclei. 

Ooh his speech is interesting (his Nobel lecture) -- for one thing, he says the Sun's lifespan is "5 milliards" of years, which is a very French way to say billions, and I'm enjoying the previous idea of a gravitational source of energy for the sun (which wouldn't work because it would only last 30 million years which was shorter than evolution would've taken). 

Reading this is really cool, although I will readily admit I don't understand all of it - I mean, look at two of the equations: [OI] = 7.8~10~~ (Z, Z,/A)‘/J S,ff eTb-“‘3 e-r 
 t = 42.487 (W/T6)‘/3


1968: Luis Walter Alvarez

for his decisive contributions to elementary particle physics, in particular the discovery of a large number of resonance states, made possible through his development of the technique of using hydrogen bubble chamber and data analysis

He improved Glaser's bubble chamber using liquid hydrogen (so the hydrogen would boil whenever a high-energy particle passed through it) and came up with computerized data analysis methods. He proved that K-electron capture (where an electron combines with a proton to form a neutron, forming a different element) actually exists and that helium-3 is stable.


1969: Murray Gell-Mann

for his contributions and discoveries concerning the classification of elementary particles and their interactions

He proposed that presumed-fundamental particles like protons and neutrons are composite and made up of quarks and was legitimised when the omega minus particle was discovered. He proposed the concept of "strangeness", when a subatomic particle interacts via the strong force.


1970: Hannes Alfvén & Louis Néel

Alfvén - for fundamental work and discoveries in magnetohydro-dynamics with fruitful applications in different parts of plasma physics

He developed a theory about aurora borealis (an example of plasma) which led him to work on magnetohydrodynamics. He was interested in the formation of stars and the origin of the solar system and epically dissed theoreticians who did elegant maths with theories that were demonstrably false but were so nice mathematically. Things called Alfven waves and Alfven velocity exist. Google is not being forthcoming on this guy.


Néel - for fundamental work and discoveries concerning antiferromagnetism and ferrimagnetism which have led to important applications in solid state physics

He described antiferromagnetism, in which nearby magnetic moments in a material are oriented in opposite directions. In ferrimagnetism, they're in opposite directions but not the same magnitudes. This was useful for computer memory.


1971: Dennis Gabor

for his invention and development of the holographic method

Gabor used a reference wave (on which the object has had no effect) which fell on the plate along with the wave from the object. The two waves are superimposed and interfere, producing constructive and destructive interference/more and less intense fringes. A laser and electron microscopy were used and bam 3D hologram.


1972: Leon Cooper, John Robert Schrieffer, John Bardeen

for their jointly developed theory of superconductivity, usually called the BCS-theory

Materials are superconducting when they exhibit zero resistance. Bardeen, Cooper and Schrieffer came up with a comprehensive theory of how superconduction is related to groups of electrons' coupling to the vibrations of the crystal lattice. A large fraction of the conduction electrons ended up being coupled so you couldn't just break apart one pair, you had to reach a certain critical value to break up loads of them to make anything happen.


1973: Leo Esaki & Ivar Giaever, Brian David Josephson

Esaki & Giaever - for their experimental discoveries regarding tunneling phenomena in semiconductors and superconductors, respectively

In 1958, Esaki demonstrated a previously unknown type of tunneling in a semiconductor while working with heavily-doped germanium and silicon, a discovery used in tunnel diodes, the first quantum electron device.

In 1960, Giaever showed that electrons could tunnel through a sheet of oxide between two sheets of metal, normal or superconducting.

Josephson - for his theoretical predictions of the properties of a supercurrent through a tunnel barrier, in particular these phenomena which are generally known as Josephson effects 

Josephson effects are supercurrents flowing without voltage between two superconductors coupled by a "weak link". He looked at whether normal currents through an insulated barrier might be related to/modified by the phase difference. Read his lecture, it's interesting.


1974: Sir Martin Ryle & Antony Hewish

for their pioneering work in radio astrophysics; Ryle for his observations and inventions, in particular of the aperture synthesis technique, and Hewish for his decisive role in the discovery of pulsars

Ryle used radio astrophysics to detect elements of the sun including the corona surrouding it, and disproved doubts that you'd need massive dishes to study further away stars by combining lots of smaller dishes pointing in the same direction, a technique called aperture synthesis. Ryle was the 100th Nobel Laureate in Physics.

I attended a talk by Dame Jocelyn Bell Burnell about how she discovered pulsars, and I'm pretty sure this is the Nobel prize she got left out of. She is mentioned at the speech, though, as having noticed the strange signals not behaving like a normal star, with it saying that Hewish is the one who suggested the signal could be caused by the dense, burnt-out remains of supernovae, neutron stars.


1975: Aage Niels Bohr, Ben Mottelson, Leo James Rainwater

for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection

Bohr and Rainwater near-simultaneously and independently sent in papers for publication saying that valence nucleons and inner nucleons influenced each other and deformed the "walls" of the nucleus from a spherical shape. Experimentally in 1952 and 1953, Bohr and Mottelson found that the position of energy levels in certain nuclei could be explained by their forming a rotation spectrum. The experimental data they found agreed perfectly with theory so good times.


1976: Burton Richter & Samuel CC TIng

for their pioneering work in the discovery of a heavy elementary particle of a new kind

Richter used a linear accelerator with high-speed positrons and electrons crashing into each other and creating a heavy elementary particle which then decayed to other particles, but had a lifespan a thousand times what was expected. They called this particle psi. Ting fired high-speed protons at a beryllium target, which created a heavy particle which then decayed into daughter electrons and positrons, which they then measured.


1977: Philip Warren Anderson, Sir Nevill Francis Mott, John Hasbrouck van Vleck

for their fundamental theoretical investigations of the electronic structure of magnetic and disordered systems

Anderson explained how magnetic moments can occur in copper and silver, which in pure form are not magnetic. He explained how an electron can move through a disordered system. He figured out whether an electron in an increasingly disorganised system would have its mean free path decrease continuously or whether there'd be some abrupt change using the concept of electron localization. Mott explained how certain crystals can alternate between being conductors and insulators and worked with electrons in glass. Ooh his lecture contains a diagram of something I worked with in my Young Scientist! Something that is refusing to paste... Van Vleck is seen as the Father of Modern Magnetism, apparently. He established the quantum mechanical field of magnetism, and also worked on military stuff including radar and the Manhattan project.

1978: Arno Allan Penzias & Robert Woodrow Wilson, Pyotr Leonidovich Kapitsa

Kapitsa - for his basic inventions and discoveries in the area of low-temperature physics

In 1934, Kapitsa invented a way of making liquid hydrogen that didn't require the prior use of liquid hydrogen. He showed that Helium just above absolute zero (He II) is a "superfluid"/"quantum fluid", that has zero entropy and negligible viscosity and perfect atomic order. 

Penzias & Wilson - for their discovery of cosmic microwave background radiation

Ooh I actually understood this one when I read about it in Stephen Hawking's A Brief History of Time So, Penzias and Wilson were using this instrument with low noise, tuned to a 7-cm wavelength, where it was expected that not much would be heard. But they found it was much higher than expected and through loads of tests made sure it wasn't coming from the instrument or the atmosphere. They showed that it came from outer space and was the same in all directions. Their discovery allowed study of absolute distances in space because the distribution of the radiation reflects the distribution of matter in the universe, and offered a peek into the beginnings of the universe.


1979: Abdus Salam, Sheldon Lee Glashow, Steven Weinberg

for their contributions to the theory of the theory of the unified weak and electromagnetic interaction between elementary particles, including, inter alia, the prediction of the weak nuclear current

Fun fact: the weak force distinguishes between left and right. This had been seen as a link between the weak force and electromagnetic interactions, but the prevailing theory only worked for low energies. These guys found a theory that worked at high energies and unified the forces into the electroweak force. Their theory predicted the weak neutral current (current that doesn't change anything's charge), and this was later discovered at CERN, validating the theory. The theory goes that the reason the weak force is so short range is that its particles are way heavier than photons, about the mass of 100 protons. (I say goes - I mean went in 1979). 


1980: Val Logsdon Fitch & James Cronin

for the discovery of violations in fundamental symmetry principles in the decay of neutral K-mesons

I think I remember reading about this in A Brief History of Time. Before this, people were happy because any violations in symmetry cancelled each other out (time symmetry and mirror symmetry). But the symmetry principle saying that the laws of nature are exactly the same for matter as for antimatter was broken with this experiment using neutral K-mesons, which according to this can be considered half matter and half antimatter (one quark and one antiquark, I now realise). CP symmetry is violated if a particle is replaced with its antiparticle and its spatial coordinates are inverted and it doesn't act the same. The experiment involved two particle species with lifetimes two orders of magnitude apart that showed something weird; traces of the more short-lived one were still found at the end of the long tube. 


1981: Kai Siegbahn, Arthur Leonard Schawlow, Nicolaas Bloembergen

Siegbahn - for his contribution to the development of high-resolution electron spectroscopy

Using high resolution spectroscopy, Siegbahn and collaborators found in electron spectra some new, strong and very narrow bands that were not previously visible, which came from electrons that had left the sample without losing energy. They used this technique to study electron energies in element binding. It turned out that electron energies in an atom depended slightly on which crystal or molecule it was bound to, so that was useful for identification and classification purposes. Very chemistry. Electron Spectroscopy for Chemical Analysis was cool because it was way easier to interpret that using shifts from X-ray spectroscopy.
Schawlow & Bloembergen - for their contribution to the development of laser spectroscopy

Schawlow was instrumental in the invention of the laser but didn't get the original Nobel prize for it. Luckily for him, after a few decades the Nobel committee decided that there'd been so much great stuff done with lasers that the field needed more prizes. Schawlow and co worked with lasers at super high energies so they could use Doppler-free spectroscopy and get a really accurate value for the Rydberg constant (function of Planck's constant, electron rest mass, charge and speed of light). Bloembergen worked on light interference, with three coherent light waves combining to create a fourth wave. 

1982: Kenneth Wilson

for his theory for critical phenomena in connection with phase transitions

The issue with critical points in phase transitions were that systems showed lots of different fluctuations on many different scales, which were different to measure or explain. Wilson showed that critical phenomena depend mostly on the dimensionality of the system and on the dimensionality of the order parameter (degree of order around phase transition e.g. hotter object less ordered than cooler object). 


1983: William Fowler & Subrahmanyan Chandrasekhar

I've definitely heard of Chandrasekhar. 

Fowler - for his theoretical and experimental studies of the nuclear reactions of importance in the formation of the chemical elements in the universe

Oh I remember loving reading a description of this process in Brian Cox's Wonders of the Universe! Fowler showed how the hydrogen and helium in stars, through nuclear fusion in the very high temperatures inside stars, all the elements up to iron can be formed. The elements after that, up to uranium, can be formed in supernovae which then scatter the elements across the universe, landing them on planets like our own. 

Chandrasekhar - for his theoretical studies of the physical processes of importance to the structure and evolution of the stars

Chandrasekhar showed that not all stars just fade and become white dwarfs; instead, the fate of a star depends on its mass. Above the Chandrasekhar limit (1.4 solar masses), they collapse under their own weight. They explode in supernovae and stars 2-3 solar masses become neutron stars while stars >3 solar masses become black holes.


1984: Carlo Rubbia & Simon van der Meer

for their decisive contributions to the large project, which led to the discovery of the field particles W and Z, communicators of weak interaction

The weak force governs beta decay and other processes inside atoms and until this work, the particles carrying it were hypothetical. Carlo Rubbia proposed converting an existing accelerator to crash protons and antiprotons together, and van der Meer made it feasible by inventing a way to densely pack and store protons. Electroweak theory contains four carriers - two heavy charged ones, W+ and W-, one massless neutral (photon) and one heavy neutral (Z0). The expected success rate was very low - 10 communicator particles per billion collisions. 


1985: Klaus von Klitzing

for the discovery of the quantized Hall effect

The Hall effect is when electrons in an electric current travelling across a metal strip are deflected to the side by a perpendicular magnetic field. von Klitzing showed that in 2D electron systems (like a very thing layer between a metal and a semiconductor) the conductivity changes step-wise (=quantized) rather than continuously, in integer values multiplied by a fundamental physical constant deviating less that 0.0000001 from the integer values.


1986: Ernst Ruska, Heinrich Rohrer, Gerd Binnig

Ruska - for his fundamental work in electron optics, and for the design of the first electron microscope

He used magnetic coils to lens electrons, creating an image. He coupled two lenses to make his first electron microscope, later refining it. It works because a short coil carrying a current can deflect electrons like normal lenses deflect light. Electrons have a much smaller wavelength than light, so this was a huge leap in resolution and atoms and proteins could finally be seen.

Rohrer & Binnig - for their design of the scanning tunnelling microscope

The scanning tunnelling microscope has a tip just one atom thick and works by travelling very closely above the surface so that a potential difference between the tip and the atoms causes a current that can tell you where atoms are on a very fine level.


1987: K Alex Muller & Georg Bednorz

for their important breakthrough in the discovery of superconductivity in ceramic materials

Superconducting materials show no electrical resistance and magnetic fields have great difficulty penetrating them (Meissner effect). Previously, the hottest temperature at which a material (an alloy) had been made at was -250 C. These guys got a "high temperature" one (12 C higher) by using unusual materials, copper oxides with a rare earth metal. Barium was added to crystals of lanthanum-copper-oxide to make a stable ceramic material.


1988: Jack Steinberger, Leon Lederman, Melvin Schwartz

for the neutrino beam method and the demonstration of the doublet structure of the leptons through the discovery of the muon lepton

The researchers developed a way to research the weak force at high energies and showed that there are at least two kinds of neutrino. Neutrinos are cool - they travel at near the speed of light, can penetrate a sheet of lead a light year long, and they have no charge. So obviously they were difficult to discover. Interestingly, the material they used for their experiment came from scrapped warships. Protons were accelerated and directed at beryllium, creating charged pi-mesons, which decayed into a muon and a neutrino. A muon or electron produced by a neutrino would have its sparks photographed. If neutrinos were like the normal ones in beta decay, fast electrons and muons would be seen at the same rate. If there were two different kinds of neutrino, only muons would be seen, and that is indeed what happened. 


1989: Hans Dehmelt, Wolfgang Paul & Norman Ramsey

Ramsey - for the invention of the separated oscillatory fields method and its use in the hydrogen maser and other atomic clocks

Ramsey's hydrogen maser was used for studying the fine structure of hydrogen, and as a secondary clock to check cesium on small time scales. It was improved by covering the walls in superfluid helium below 1 K, and also used to test gravitational redshift (influence of gravity on electromagnetic waves) and measure continental drift. 

Dehmelt & Paul - for the development of the ion trap technique

Paul showed that ions of different masses could be separate using a four-pole magnetic field with a superimposed radio-frequency field. Dehmelt developed a similar trap and then used it to study the ratio of an electron's magnetic and angular momentums.


1990: Richard Taylor, Jerome Isaac, Friedman, Henry Kendall

for their pioneering investigations concerning deep inelastic scattering electrons on protons and bound neutrons, which have been of essential importance for the development of the quark model in particle physics

The research team found that in inelastic collisions between electrons and protons, there was actually a much higher probability than expected of electrons being deflected at high angles, echoing the Rutherford experiment 80 years previously and providing evidence for quarks.


1991: Pierre-Gilles de Gennes

for discovering that methods developed for studying order phenomena in simple systems can be generalized to more complex forms of matter, in particular to liquid crystals and polymers

de Gennes came up with mathematical formulations for the formation of magnetic dipoles in complicated structures like long molecules, and figured out what happens when they go from an ordered to a less ordered state and vice versa. He found that magnets, superconductors, liquid crystals and polymer solutions all undergo these processes fairly similarly. Yay for generality.


1992: Georges Charpak

for his invention and development of particle detectors, in particular the multiwire proportional chamber

Charpak invented a variation on the Geiger Muller tube. Instead of just one wire that only allowed spatial resolution of about a centimetre, he used two 0.1 mm wires about a millimetre apart, which eventually gave resolution of about 0.1 mm once drift time between the wires was accounted for. 


1993: Russell Hulse & Joseph Taylor Jr

for the discovery of a new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation

These guys provided evidence for gravitational waves by finding a binary system of pulsars which were losing energy through the emission of gravitational radiation and thus spiralling towards each other as Einstein had predicted - even at almost exactly the rate he had predicted.


1994: Clifford Shull & Bertram Brockhouse

for pioneering contributions to the development of neutron scattering techniques for studies of condensed matter

Shull - for the development of the neutron diffraction technique

Shull would select a certain neutron wavelength then send a beam of these neutrons into a crystal to determine its atomic structure. Neutrons are (obviously) neutral and do elastic scattering leaving the energy of the sample unchanged, but they do leave the sample's atoms with directional preferences (diffraction).

Brockhouse - for the development of neutron spectroscopy

Brockhouse used a three-axis spectrometer. Neutrons penetrated a sample and could cause or cancel out the oscillations of atoms in the sample. When neutrons excited phonons, they lost energy in inelastic scattering. The neutrons then left the sample and their energy was measured in a detector to study the dynamics/inner movements of the sample. 


1995: Martin Lewis Perl & Frederick Reines

for pioneering experimental contributions to lepton physics

Perl - for the discovery of the tau lepton

Perl had been unsuccessfully looking for new charged leptons for a while when he got to use SPEAR, with a top energy in the range of 5 GeV. He eventually found an anomalous lepton which he called tau, from the first Greek letter of triton for the third charged lepton (after electron and muon). The tau lepton is 3500 times as heavy as the electron. Another group found that a third charged lepton would have to be heavier than 1400 MeV/c squared. Researchers had trouble directly detecting the taus so they looked for violations of charge and momentum conservation.

Reines - for the detection of the neutrino

Pauli hypothesized the existence of the neutrino to conserve charge/momentum/etc as a particle that interacted very weakly with matter. Enrico Fermi then used this concept to formulate a theory of weak interactions. Bethe and others had figured out that you'd need a target of lead multiple light years thick to catch a neutrino, so you'd need a powerful source of neutrinos and a heavy target. Nuclear reactors are super high-flux sources of neutrinos. 

To find a neutrino, Reines and Cowan came up with the following experiment. A neutrino would be captured by a proton, spitting out a proton and a positron, which are much easier to detect. They were registered thus: the neutrino would hit a proton in water, making a positron which would then be annihilated by an electron creating photons which were detected by scintillation detectors. There was then a delay before a neutron combined with a cadmium nucleus, sending out gamma radiation. Underground mines also registered neutrinos from supernovae. 


1996: Robert Richardson, David Lee, Douglas Osheroff

for their discovery of superfluidity in helium-3

There's helium-4, a boson which has an even number of nucleons and follows Bose-Einstein rules, and helium-3, a fermion with an odd number of nucleons that follows Fermi-Dirac rules. Helium-4 had already been made a superfluid at 2 K in the 1930s, but these guys in the 1970s showed that Helium-3 could be made a superfluid at thousandths of a Kelvin. Fermions were not supposed to be able to condense in the lowest energy states like bosons could according to the old theory. But perhaps they could do as the BCS theory (Nobel Prize 1972) had electrons (fermions) do, coupling to other electrons, And bamshamalam.


1997: William Phillips, Claude Cohen-Tannoudji, Steven Chu

for development of methods to cool and trap atoms with laser light

Something interesting: even at the low temperature of -270 C (about 3 K),  atoms move at around 111 m/s -- it's only once you get down to a microkelvin away from absolute zero that they slow down to 0.25 m/s.

Anyway. Phillips got the temperature of atoms down to 40 microKelvins, a sixth of the thought Doppler limit. Cohen-Tannoudji slowed atoms by tuning lasers so that only the fastest atoms would absorb laser light head on, and then atoms will re-emit photons in random directions, causing a net slowing. Cohen-Tannoudji put helium into a "dark" state meaning that they couldn't absorb any additional light and were super cold. This is interesting because they used lasers to cool atoms down, whereas usually putting light on something heats it up. Chu used lasers to do this and built a trap to hold the atoms in place. Now neutral atoms could be controlled as electrically charged ones had been for ages.


1998: Robert Laughlin, Daniel Tsui, Horst Stormer

for their discovery of a new form of quantum fluid with fractionally charged excitations

In 1879, Edwin Hall discovered that a thin gold plate with an electric current flowing along it in a perpendicular magnetic field will exhibit a potential drop at right angles to both the direction of the current and the magnetic field. Near absolute zero and in very strong magnetic fields, the Hall resistance does not vary linearly with magnetic field strength but actually stepwise aka quantized. These guys found lots of steps that von Klitzing (the guy who discovered the Hall resistance was quantized) hadn't found, so this was called the fractional quantum Hall effect. Laughlin said that in these extreme conditions the electron gas condensed to a quantum fluid by forming bosons with three flux quanta. When an electron was added to this, little excitations would be seen from the formation of quasiparticles, which were later experimentally verified. 


1999: Martinus Veltman & Gerard 't Hooft

for elucidating the quantum structure of electroweak interactions in physics

These guys gave mathematical form to the standard model and improved the prediction of properties of new particles. Using Veltman's computer program, the two came up with a non-Abellian (i.e. order mattered) gauge theory for electroweak interactions. Their prediction for physical properties of parties like the W and Z bosons and the mass of the top quark agreed well with experiment, and they predicted a particle called the Higgs boson.


2000: Zhores Alferov, Jack Kilby, Herbert Kroemer

for basic work in information and communication theory

Alferov & Kroemer - for developing semiconductor heterostructures used in high-speed and opto-electronics

Kroemer published a paper in 1957 with theoretical work showing that a heterotransistor was superior to an ordinary transistor for current amplification and high frequency work (heterotransistors could work at a frequency 100 times as high as that of normal transistors, 600 GHz). Alferov and Kroemer independently proposed the principal for a heterostructure laser, and Alferov made it first, with an AlGaAs/GaAs heterostructure. Around 1970, heterostructure lasers started working continuously at room-temperature, making fibre optic cables practical.

Kilby - for his part in the invention of the integrated circuit

Kilby made the chip, with transistors, resistors and condensers in one composite semiconductor block. Noyce was doing this at the same time, but Kilby filed the patent first and Noyce knew this when he filed his.


2001: Carl Wieman, Wolfgang Ketterle, Eric Allin Cornell

for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates

Wieman and Cornell made a condensate of 2000ish rubidium atoms at the temperature of 20 nanoKelvins. Independently, Ketterle made a similar Bose-Einstein condensate of sodium atoms and let them expand into each other showing interference patterns and acting like waves from coherent sources.


2002: Masatoshi Koshiba, Riccardo Giacconi, Raymond Davis Jr

Davis & Koshiba - for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos

Davis captured 2000 neutrinos from the Sun over 30 years, proving that the Sun is powered by nuclear fusion. Koshiba confirmed Davis' results and captured neutrinos from a distant supernova.

Giacconi - for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources

Giacconi developed X-ray astronomy by creating the first X-ray telescope. He found X-rays from outside the solar system and from bodies thought to be black holes, and showed that the universe contains background X-ray radiation.


2003: Alexei Alexeyovich, Vitaly Ginzburg, Anthony Leggett

for pioneering contributions to the theory of superconductors and superfluids

There are two types of superconductors. Type I superconductors are metals and show the Meissner effect: when superconducting they counteract a magnetic field as long as it's below a certain strength, whereas Type II superconductors accommodate the magnetic fields. The properties of type II superconductors (made of metal alloys or copper-nonmetal compounds which retain their superconductivity in strong magnetic fields) can't be described by the BCS theory. Abrikosov showed how the magnetic field could get through vortices in the Type II superconductive condensate, using the density of the condensate and mathematically describing with an order parameter how the magnetic field would get through. Also, the number of vortices grows as the magnetic field strength increases, and the superconductivity stops if the cores of the vortices.

Ginzburg and collaborator Landau showed that an order parameter (wavefunction) was required to understand the interplay between the superconductor and the magnetic field. From their calculations, it was clear that there would be two types of superconductor and a breakpoint at 0.71 (can't tell you what that means, honestly). Mercury has a value of 0.16 (no idea the units), and Abrikosov showed that type-II superconductors had exactly the values required.

Leggett formulated a theory for the anisotropic (different properties in different directions) superfluid He-3, which consists of pairs of atoms.


2004: Hugh Politzer, David Gross, Frank Wilczek

for the discovery of asymptotic freedom in the theory of the strong interaction

Apparently these guys made it impossible to complete the Standard Model of Particle Physics, which is a big commendation. Also what about the Higgs? Let's see.

The strong/colour force acts between quarks. It's very short range but it's the strongest of the four fundamental forces. The theory explains how quarks seem to act nearly like free particles at high energies, and lays the ground for quantum chromodynamics. I just saw why the Standard Model is so beloved -- it takes into account both Einstein's theory of relativity and quantum mechanics. Also, I just found out the amazing fact that the electromagnetic force is 10^41 times stronger than gravity. 

As well as electric charges, quarks have colour charges - either red, blue or green. Antiquarks are antired, antiblue or antigreen. Freely existing quark-aggregates are colour neutral. Gluons lack mass but have a colour and an anticolour. 

Physicists were struggling with calculating the effects of the strong interaction between quarks because they couldn't use Feynman's maths because the coupling constant, as opposed to being, say, 1/137, was greater than one. At higher energies, since the derivative or beta function was positive, the problem would get even worse and the maths would become impossible. But the three Laureates, in back-to-back papers in Physical Review Letters, showed that there was an example in which the beta function was negative. They came up with asymptotic freedom, which means that gluons interact with each other and that the closer quarks come to each other, the weaker the quark colour charge and the weaker the interaction. And since quarks come closer to each other as energy increases, interaction strength is inversely proportional to energy.  Thus the beta function is negative. At very high energies, the small distance interaction for quarks and gluons could now be calculated and calculations could be made that agreed with experiment. 


2005: Roy Glauber, Theodor Hansch, John Hall

Glauber - for his contribution to the quantum theory of optical coherence

Hansch & Hall - for their contributions to the development of laser-based precision spectroscopy, including the optical frequency comb technique

Information about photons is indirect, because in the process of observing a photon it is absorbed. We instead measure photoelectrons. Glauber formulated a quantum theory to describe the detection process, with the formalisms of quantum electrodynamics. Correlating several detectors absorbing photons shows the characteristic features of quantum radiation.

Precision optical measurements are highly important for a number of reasons; they permit measurement of fundamental physical constants, show any asymmetries between matter and antimatter, facilitate better atomic clocks...

Hall and others developed frequency stabilization schemes for lasers by locking them to sharp interference fringes of passive interferometers using electric feedback to make fundamental measurements. The laser could be confined to a 1 Hz range. Hansch and Schawlow made measurements of hydrogen like this and resolved the Lamb shift in an excited state.


2006: George Smoot, John Mather

for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation

These guys worked on the COBE project. Mather coordinated the whole thing and was primarily responsible for the measurement of the blackbody nature of the cosmic microwave background radiation. Smoot was the main person responsible for measuring the small variations in temperature of the radiation. COBE was launched by NASA in 1989. After 9 minutes of observations, COBE had recorded a perfect blackbody spectrum.


2007: Peter Grunberg, Albert Fert

"for the discovery of Giant Magnetoresistance"

Magnetoresistance is the slight change in electric properties of metals when they're in a magnetic field, and is used to read computer memories. In 1988, Fert and Grunberg independently demonstrated a quantum mechanical effect they termed Giant Magnetoresistance. They used stacks of alternating thin layers of iron and chromium. In a magnetic field, the electrons in atoms in one layer had opposite spins to those in alternate layers. This increased resistance in an unprecedented way, while using the magnetic fields to align the electron spins in alternate layers increased current and decreased resistance. Applications lay in miniaturizing electrical devices and selectively separating genetic material.


2008: Yoichiro Nambu, Toshihide Maskawa, Makato Kobayashi

Broken symmetry is a good thing because if the universe were perfectly symmetrical, antimatter and matter would've annihilated each other at the beginning of the universe and we wouldn't exist. 

Nambu - for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics

Nambu was working assymetries in relation to superconductivity in the 1960s. Wow. He modelled how broken symmetry can occur spontaneously at the subatomic level, improving the Standard Model.

Maskawa & Kobayashi - for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature

They figured that there weren't enough types of particles known about to explain broken symmetry, proposed a third family of quarks and then were later proven right.


2009: George Smith, Willard Boyle, Charles Kao

Kao - for groundbreaking achievements concerning the transmission of light in optical fibres for optical communication

In 1970, Kao demonstrated that the previous bad transmissibility of light in optical fibres was due to impurities in the glass, and showed that great results could be attained using pure glass. 

Boyle & Smith - for the invention of an imaging semiconductor circuit - the CCD sensor

Another thing we studied in LC physics! This was invented at Bell Labs. It uses Einstein's photoelectric effect, with the amount of current emitted proportional to the intensity of incoming light. This led to the digital camera.


2010: Andre Geim & Konstantin Novoselov

Yes! This is one I'm very familiar with, because I've done research with graphene. 

for groundbreaking experiments regarding the two-dimensional material graphene

Graphene is a 2D "wonder material" made of carbon. It's very strong (well, for its thickness -- it certainly wasn't strong when it kept ruining my experiments by tearing), highly electrically conductive and all surface area. They discovered it during their Friday evening playtimes, by exfoliating a graphite crystal with Sellotape. 


2011: Adam Riess, Brian Schmidt, Saul Perlmutter

for the discovery of the accelerating expansion of the universe 

These guys studied type 1a supernovae, which are as heavy as the Sun, as small as the Earth and can emit as much light as a whole galaxy. They found that 50 of these supernovae had weaker light than expected, which was evidence that the universe is accelerating its expansion. This implies that the answer to "will the world end in ice or fire" is ice. The acceleration is thought to be driven by dark energy.


2012: Serge Haroche & David Wineland

I've met Haroche! I attended a lecture he gave in DCU in late 2013 and he chose my question about quantum cryptography as the best and gave me a Samsung tablet.

for ground-breaking experimental methods that allow measuring and manipulation of individual quantum systems

Usually, it's impossible to manipulate/measure individual quantum-scale systems without them losing their quantum mechanical properties. Wineland and Haroche took opposite approaches; Wineland controlled ions with photons, whereas Haroche controlled photons with with trapped atoms. 


2013: Peter Higgs & Francois Englert

for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN's Large Hadron Collider.

The Higgs particle is connected to the Higgs field, which is everywhere in the universe and gives mass to electrons and quarks. The standard model depends on the mechanism Higgs, Englert and Brout came up with in 1964. Englert, Higgs and Brout showed that the Higgs could break the symmetry of the Standard Model without destroying the model and this got their theory accepted. This solved a big issue with the Standard Model, namely the unified electroweak force -- electromagnetism is mediated by photons, which are massless, but the weak force is mediated by massie W and Z bosons. The Higgs boson gave a way for particles to attain mass. The particle was then discovered in CERN (announced July 2012) at a 5 sigma significance level. 


2014: Shuji Nakamura, Hiroshi Amano, Isamu Akasaki

for the invention of efficient light-emitting blue diodes which has enabled bright and energy-saving white light sources

Red and green LEDs had been around for ages, but blue ones were needed to make white light. LEDs are made by creating a gap between positively- and negatively- doped semicoducting materials. Development went from infrared to red, green and yellow. Blue LEDS were difficult because it requires a very high energy gap. But these researchers managed to grow gallium nitride crystals on a sapphire substrate to create a p-type layer. He used heating to remove hydrogen. You can now even make ultraviolet LEDs when you add doping with aluminium and indium. A modern white LED consumes only 5% of the power an incandescent lightbulb does with the same lighting effect. 


2015: Takaaki Kajita & Arthur McDonald

for the discovery of neutrino oscillations, which shows that neutrinos have mass

One of our new lecturers mentioned this! Neutrinos are electrically neutral, weakly interacting particles posited by Pauli to explain a disappearance of energy in beta decay. Only about a third of the neutrinos predicted to be emitted from the Sun to earth seemed present. 

Ooh I just found out about Cherenkov light, when a particle moves faster than the speed of light, which is possible because the limit is speed of light in vacuum but this was in water where the light was slowed down to 75% of its maximum speed. 

In one experiment, a detector called Super-Kamiokande caught muon neutrinos from above (from the atmosphere) and below (having travelled through the earth). Because of how weakly-interacting neutrinos are, the earth shouldn't really stop them so the fact that there were fewer muon neutrinos from the bottom than from the top implied that the neutrinos with more travel time had changed into tau neutrinos.

In a second experiment, scientists counted neutrinos from the Sun. They could measure the number of electron neutrinos and the number of all three types (electron, muon, tau) combined. They found that there were only a third as many electron neutrinos as expected, but the right number of all three combined. Since only electron neutrinos come from the Sun. Thus some of the electron neutrinos had changed into muon and tau neutrinos on the way.


2016: Duncan Haldane, David Thouless and Michael Kosterlitz

for theoretical discoveries of topological phase transitions and topological phases of matter

Just found out that are multiple forms of resistance disappearance near 0 K - obviously superconductivity, but also a vortex spinning in a superfluid forever without slowing. Also, the reason many materials become magnetic when cooled is that all the small atomic magnets then point in the same direction, contributing to a strong magnetic field. 

Topology describes the properties of a material that remain if it is stretched, twisted or deformed but not torn. Topological objects are defined by their integer number of holes, so topology was useful in describing the quantum Hall effect which changes in integer steps, which do not depend on temperature, magnetic field or degree of impurity. Topological quantum fluids can, it turns out, form near absolute zero even without a magnetic field. 


No comments:

Post a Comment