# What are the most important discoveries/breakthroughs in physics recently?

Can you provide a list of the most important discoveries/breakthroughs in physics recently? By recent, I mean the past decade or so. All branches of physics are welcome.

Basically, I am interested in major physics breakthroughs/discoveries which haven't become well-known yet outside their narrow specialties. Most breakthroughs in the 90s like string dualities and the accelerating universe have already become common knowledge.

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Trying to judge the importance of "breakthroughs" that "haven't become well known" is a fools errand. Time will tell. In the mean time, all the credible suggestions I see below have become well known outside the sub discipline that gave rise to them. –  dmckee Feb 6 '11 at 15:40

Iron-based high-Tc superconductors

The cuprate high-Tc superconductors completely revolutionised the field of superconductivity in the late 80's but proved very difficult to understand and over 20 years later the problem still stands. A new class of high-Tc materials, the iron-pnictides, were discovered in 2008 which have provided a whole new set of system to study.

Iron-pnictides are generally much simpler in structure than the cuprates meaning the crystal growers can generally make larger, better crystals and the theorists have an easier time of it as well.

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One of the biggest recent developments in high-energy physics is the confirmation of neutrino oscillations and the consequent realization that neutrinos must have some non-zero mass.

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The connection between mass and oscillation was known before any observational evidence (include Ray Davis' Homestake Mine experiment), so I take issue with "subsequent". –  dmckee Feb 6 '11 at 15:43
@dmckee: yes, but you still need to know that there is oscillation to deduce there is mass. So while the implication $A \to B$ came before $A$, the confirmation of $B$ came only after $A$ and so David is right :) –  Marek Feb 6 '11 at 16:29
@Marek: No. People the people who ran Kamiokande, SNO, Super-K and the rest said "if these experiments see a positive signal that means neutrinos are massive". The realization was simultaneous with the measurement of oscillations. "Consequent" would be fine. –  dmckee Feb 6 '11 at 21:21
@dmckee: Marek has identified my meaning correctly. I very much doubt that all those scientists were capable of making two realizations simultaneously, and it should be clear which one had to come first. –  David Z Feb 6 '11 at 22:24

The isolation of a graphene --- a single layer of graphite --- was another breakthrough. 2D graphene has many unusual properties, all related to a highly delocalized and strongly entangled band of electrons.

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In theoretical side, I think Witten's discovery that all five string theories are different limits of one unique theory and in experimental side it has to be the surprising discovery that the universe is expanding in an accelerating manner.

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Witten's achievement is in the mathematical physics. –  Vladimir Kalitvianski Feb 6 '11 at 21:36
@Vladimir: last time I checked, mathematical physics had physics in the name :) –  Marek Feb 6 '11 at 22:24
@Vladimir: besides, mathematical physics is usually concerned with providing proofs. This is hardly the case with any of this stringy stuff. So it's definitely theoretical physics anyway. –  Marek Feb 6 '11 at 22:28
No, the theoretical physics is different from the mathematical physics. Not all our fantasies, however beautiful, reach, and "promising" they are, correspond to reality. Especially those that are not based on experimental data. –  Vladimir Kalitvianski Feb 6 '11 at 22:29
@Vladimir: seems you don't have the slightest idea about what either mathematical or theoretical physics is. Mathematical physics is field of math. There is no guessing, just proofs. Theoretical physics (whether it concerns itself with tested theories or just new untested models) is physics where proofs are not required (and indeed usually not done at all). Whether it connects with experiment or not is completely irrelevant. That's what the name theory is about... –  Marek Feb 12 '11 at 14:58

I know this was more than a decade ago, but the discovery and formulation of the AdS/CFT correspondence stating that a conformal field theory in d dimensions without gravity is equivalent to a theory of quantum gravity over an anti de Sitter background one dimension higher was a major breakthrough.

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It's a mathematical physics. –  Vladimir Kalitvianski Feb 6 '11 at 21:35

This also happened more than a decade ago, but the discovery of anisotropies in the cosmic microwave background of the order of $10^{-5}$ by the COBE satellite was also groundbreaking. Subsequent measurements by WMAP have shown the power spectrum is approximately scale-invariant and Gaussian.

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The discovery of a landscape of compactifications in string theory with exponentially many KKLT compactifications is another recent groundbreaking discovery. The landscape made the strong anthropic principle respectable for the first time, and solved fine-tuning problems like the cosmological constant problem.

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It's a mathematical physics. –  Vladimir Kalitvianski Feb 6 '11 at 21:36
Everyone knew there was a landscape already in the late 1970s, when Scherk and Schwarz studied toroidal compactification. The only reason this is considered a recent discovery is because Ed Witten and Ed Witten only either believed that there is a mechanism to select a unique solution, or told people this so that they would be motivated to study string theory. It's hard to tell. Following Witten, many people in the 1980s said there would be only one solution to string theory, although every graduate student knew there was a landscape even then. –  Ron Maimon Sep 19 '11 at 0:01

There are many fantastic discoveries slightly outside your time-horizon, like the discovery of a cosmological constant or the AdS/CFT correspondence, but I'll respect your time-horizon:

1. LHC - the main discovery so far was that LHC is working ;-), which is highly non-trivial; the real discoveries will come this decade, like Higgs or, if it exists at the TeV scale, new physics (like SUSY)

2. Carbon - nanotubes and graphene will keep physicists and engineers busy for at least a decade (engineers probably much longer)

3. WMAP - the WMAP data are very accurate and allow to put relevant bounds on the cosmological parameters, thereby already ruling out some speculative modesl of our Universe

4. Quark Gluon Plasma - LHC converts lead into quark gluon plasma; RHIC has been converting gold into quark gluon plasma; this has tremendously enhanced our understanding about the QCD phase diagram and also allowed applications of the AdS/CFT correspondence, like the famous shear viscosity over entropy density calculation

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1) Black hole radiation (Hawking radiation) 2) Discovery of the dark energy 3) Evaluation of the BH entropy from string theory.

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1) not recent (theoretically) and unconfirmed (experimentally) 2) discovery, really? Would you be so kind and provide a reference? –  Marek Feb 6 '11 at 8:27
@Marek some would say that an accelerating expansion of the cosmos implies the existence of dark energy. Obviously such indirect inference is not the same as direct observation. I think you could easily find dozens of references on BH entropy from string theory on arXiv. –  user346 Feb 6 '11 at 15:07
@space_cadet: I know the distinction between indirect evidence and discovery. This answer claims the latter. As for the last sentence: what are you referring to? I've never mentioned part 3) of this answer. –  Marek Feb 6 '11 at 16:27
@Marek I know you know the difference and I'm sure @James knows the difference. I was just pointing out that @James had likely just made a semantic error - not something I would down-vote. And yes you didn't refer to part 3. My mistake. –  user346 Feb 6 '11 at 17:33
@space_cadet: well, it renders the answer invalid. As soon as everything is fixed I'll remove my down-vote (and perhaps will even up-vote). I think I could edit the answer myself but I am still reluctant, even in the CW mode, to change other people's stuff :) –  Marek Feb 6 '11 at 18:59