Kick ass physics!

[CrONoS]

Originally posted by KrazyHorse
This is electroweak unification. The gauge couplings of blah blah blah are not directly observed. Instead we observe the mixed coupling constants blah blah blah blah ass blah blah. The mixing angle is blah blah bkah

This is actually how I understand that post....

[KrazyHorse]

You understand what's meant by "gauge coupling"?

If so, then it's not very difficult to explain the rest of it.

[KrazyHorse]

Originally posted by KrazyHorse
No. Photons are the massless degree of freedom of the BROKEN SU(2)(left) X U(1) (hypercharge).

To be clear here, you can make a theory where the photons are the gauge bosons of an unbroken U(1) (charge; not hypercharge). This is classic QED. However, the great development of HE theory of the last 50 years was electroweak unification along with the Higgs mechanism to break the resulting SU(2)XU(1) (thus giving the intermediate vector bosons W and Z mass while retaining a massless photon). The Higgs also provides fermions with mass.

[Krill]

I'm so glad I don't have tio understand the maths behind those statements...

[KrazyHorse]

What type of chemistry do you want to do?

[KrazyHorse]

My advisor is a group theory ninja.

I wish I could do **** like he can.

[Blaupanzer]

How would one test the correctness of the projections of the lattice QCD? How do we test the amount of mass in any given energy set. Obviously, we can theoretically do the opposite by blowing the mass up. But how do we process the energy into mass?

Separate question: If energy represents 95% of the "mass" in this object set, then could that be related meaningfully to the "missing" matter/energy called "dark matter" or "dark energy?" OR is that question totally irrelevant?

[KrazyHorse]

Obviously, we can theoretically do the opposite by blowing the mass up.

WTF does this mean?

[Krill]

[q=KH]What type of chemistry do you want to do?[/q]

I don't. I did everything last year (organic, inorganic, physical and computational chemistry), so a mix of heavy maths/physics and some handwaving, including lots of lab work, thermodynamics and kinetics for physical and lots of synthetic work in organic and inorganic. This year I dropped the physical chemistry because I suck at it and I've finished all of the computational chemistry, and I'm doing basically 95% organic/inorganic synthethis/handwaving and 5% physical, statistical thermodynamics (3 lectures so far) and transistion state theory (which I havent started yet). I'm writting my dissertation in the synthesis of pseudo-oligosaccharides, mainly focusing on carbocyclic pseudo-sugars that are used in drugs such as abacavir and acarbose

I plan on never doing any chemistry again beyond teaching A level. I don't have the dedication to be a post grad in organic, though if that changes after a few years out of academia, who knows. I suppose I could be persuaded to do a Ph.D in something interesting like protein synthesis or pseudo-carbohydrates which is interesting, but the institutions over here that are worth doing a Ph.D at are suprisingly fwe and far between.

[MrFun]

Re: Re: Kick ass physics!

Originally posted by KrazyHorse


I don't even know where to start on this article.

1) E = mc^2 (technically E = sqrt(m^2c^4 + p^2c^2)) has been proven time and time again. It is one of the best-tested hypotheses in all of science.

2) "The answer, according to the study published in the US journal Science on Thursday, comes from the energy from the movements and interactions of quarks and gluons.". Errrr. Yeah. I could have told you that. So could any undergraduate physics student.

3) "For those keen to know more: the computations involve "envisioning space and time as part of a four-dimensional crystal lattice, with discrete points spaced along columns and rows."". Okay, so somebody did a QCD lattice computation and got a reasonable estimate of the mass of nucleons. This is not particularly exciting.

Those damn scientists, claiming credit for something that's already been done.

[KrazyHorse]

Originally posted by Blaupanzer
Separate question: If energy represents 95% of the "mass" in this object set, then could that be related meaningfully to the "missing" matter/energy called "dark matter" or "dark energy?" OR is that question totally irrelevant?

There are two very different questions here:

1) The fact that there is so much mass stored in the interaction energy is due to the fact that the proton is tightly bound. The interaction between quarks in a nucleon is enormously strong. The interaction BETWEEN nucleons etc in space is tiny compared to this. The residual strong force and electroweak forces do not bind things together strongly enough to lead to the kind of energy density you need. The interaction energy between nucleons etc is very low compared to their rest mass, so you can basically just add up the rest masses to get the total mass. So dark matter is not simply the energy of interaction of visible particles.

2) A qualitative argument can be made that dark energy is the vacuum energy of the universe. Now, in a certain sense this is related to the energy stored as binding energy in a proton. However, it is due to the vacuum talking to itself, not quarks talking to each other. If it was from particles talking to each other it would exhibit some positive pressure, while we need dark energy to have strongly negative pressure (to accelerate the Universe). Also, the estimate for vacuum energy you get from a naive calculation is way, way off of what the observed dark energy density is (vacuum energy estimate is ~120 orders of magnitude too high). This is known as the cosmological constant problem.

[KrazyHorse]

Originally posted by Krill
[q=KH]What type of chemistry do you want to do?[/q]

I don't. I did everything last year (organic, inorganic, physical and computational chemistry), so a mix of heavy maths/physics and some handwaving, including lots of lab work, thermodynamics and kinetics for physical and lots of synthetic work in organic and inorganic. This year I dropped the physical chemistry because I suck at it and I've finished all of the computational chemistry, and I'm doing basically 95% organic/inorganic synthethis/handwaving and 5% physical, statistical thermodynamics (3 lectures so far) and transistion state theory (which I havent started yet). I'm writting my dissertation in the synthesis of pseudo-oligosaccharides, mainly focusing on carbocyclic pseudo-sugars that are used in drugs such as abacavir and acarbose

I plan on never doing any chemistry again beyond teaching A level. I don't have the dedication to be a post grad in organic, though if that changes after a few years out of academia, who knows. I suppose I could be persuaded to do a Ph.D in something interesting like protein synthesis or pseudo-carbohydrates which is interesting, but the institutions over here that are worth doing a Ph.D at are suprisingly fwe and far between.

The reason I asked was that if you were doing any type of crystalline chemistry you would have to fall in love with group theory (technically discrete groups, whereas the important ideas in HE physics are continuous groups).

[KrazyHorse]

Re: Re: Re: Kick ass physics!

Originally posted by MrFun


Those damn scientists, claiming credit for something that's already been done.

I don't know if this is due to some ******* physicist trying to make his work sound hugely more important than it is or just a stupid reporter misrepresenting what the physicist told him, but to somebody who actually knows something about this, that piece is so bad as to border on outright lying.

[Krill]

Yah, done group theory before (discrete groups, anyway), we have to understand in to explain molecular orbital theory. I's not that difficult, just not interesting.

[Blaupanzer]

Originally posted by KrazyHorse

Obviously, we can theoretically do the opposite by blowing the mass up.

WTF does this mean?

KH, We can theoretically test the amount of energy in a unit of mass using a nuclear explosion to convert the mass to energy. Thus we can test the great equation: E = MC^2. However, can we somehow convert the energy to mass to test the opposite process: how much mass is represented by a given unit of energy? This was a curiousity question as was the dark matter/energy question. I know you keep up on these thins so I thought I would ask while you were looking.