There's no real way to "confirm" the number of quarks. Quark number is not a conserved quantum number, so every particle exists as a superposition of different quark numbers. This is particularly problematic if you probe a particle at very high energies; at sufficiently high energies, every hadron (including the humble proton) appears to be a soup of quark-antiquark pairs bubbling out of the vacuum. However, you should be able to make predictions of what the particle's properties will be if it's mostly like a particle that has 4 quarks (really 2 quarks and 2 antiquarks) versus if it's mostly like a particle that is 2 loosely bound mesons (1 quark and 1 antiquark plus 1 quark and 1 antiquark). But there's no definitive way to distinguish between the two.

It's also noteworthy that neither tetraquarks nor mesonic molecules have been previously seen in two experiments. So no matter which it turns out to be mostly like, it's still a discovery.

Anyone interested in the D-wave story should be reading this article where Scott Aaronson explains the meaning of D-Wave's current results.

The takeaway points are:

1. D-Wave's machine does demonstrate entanglement and quantum annealing
2. There is no speed advantage whatsoever for quantum annealing over classical simulated annealing
3. A correctly optimized version of classical annealing is actually faster than D-wave's solution
4. D-Wave will only be able to make this machine work as a quantum computer (with the attendant speed gains) by implementing error-correction and other improvements that D-Wave have been loudly deriding for their entire history

Skritter is a game where you draw Chinese characters. Like anything you do repeatedly, they will burrow into your brain and take up residence. Result: you have learned Chinese on your lunch breaks.

I used a landline phone just recently. It made an excellent chew-toy, rattle, hammer, button pushing toy and number lesson for my baby daughter. It worked much better than my cell phone for these purposes too!

Well, it's just cool because it probes new regions of the parameter space (temperature and density) of quantum chromodynamics (the fundamental theory of the strong nuclear force). Knowing what nuclear matter does under extreme conditions teaches us new things about what kinds of matter that might exist in the cores of neutron stars, whether there could be more compact kinds of stars between neutron stars and black holes and what conditions were like during the first moments after the Big Bang. It also gives us more data to compare against the predictions of quantum chromodynamics, which will help us make sure that that's actually the correct theory of the nuclear forces. I can't think of any practical applications (say, to fission cross-sections or something) off the top of my head, but that doesn't imply they don't exist.

Back in my grad student days, we saved the early hardware for our supercomputer (a BlueGene precursor) by programming and soldering an EEPROM to every daughterboard. On a massively parallel machine, that was quite an undertaking, and given that we were all *theoretical* physicists, it was kind of a miracle that the thing worked when we were done.

According to TFA, the MgSiO3 dissociates into SiO2 and MgO under Jovian core conditions. They don't calculate what happens to the SiO2, but assume that its solubility is similar to the MgO component. So that would mean that the SiO2 also goes into solution in the Jovian core.

Also of interest (at least to me) but not addressed in this paper is what happens to the nickel-iron component of the core. Perhaps they figure Jovians don't have enough to worry about, since they form so far from the center of the protoplanetary disk?

It's consistent with DAMA and Cogent in the sense that it's ruled out by those experiments at only a few sigma. It's "near" Cogent in the sense that 8 is "near" 25, and it's "near" DAMA in the sense that 35 is "near" 10; that is, it's not near at all. It's ruled out by Xenon by many orders of magnitude. My favorite theoretical model to explain these results is IDM (Italian Dark Matter), which consists of dark matter that only exists in Italy. Presumably similar particles are responsible for whatever makes Guinness taste better in Ireland.

Probably nobody is reading this several days later, but I just remembered Abstract Algebra. Maybe it's not as crucial as some of the others, but you need to be able to understand the relation between SO(3,1) and so(3,1), at least. Also what those are in the first place...

Linear Algebra, Differential Equations, Advanced Calculus, Partial Differential Equations, Electromagnetism, Waves, Introduction to Astronomy, Special Relativity, Differential Geometry

The phase diagram of carbon at extreme temperature and pressure is pretty much unknown. We don't even have any really good studies of liquid carbon. So it's entirely possible the core of such a white dwarf would be made of some other phase of carbon. See, for example, this figure of the carbon phase diagram from density functional theory, showing that over a terapascal, diamond is unstable. Stuff is not the same at the core of a star (even a small one) as in your backyard.

It's not that you're wrong, you're just using different metrics. In physics (and astronomy, I think), the authors are usually listed in decreasing order of work done, starting with the person who did the most. The people at the end of the list have done so little work, why are they even on the paper? Because, as you say, they are listed in increasing order of importance (read: amount of grant money received). If you have enough people, sometimes they just throw them all into alphabetical order and pretend that everybody reading the CVs of the people who actually did the work will somehow know that they did.

This guide may also be helpful: PHD's Guide to the Author List