/pg/ Physics General #1

[Anonymous No.11541288]

ITT: everything physics.

REMEMBER: INSTEAD OF CREATING A NEW THREAD JUST FOR YOUR QUESTION - ASK IT HERE. Single question threads drown in like a day anyway.


I'll start.

I just began going through my undergrad nuclear physics course.
Am I right in understanding that:

> nuclei to the right of the maximum (pic related) have lower B/A because at that point Coulomb potential is very high so nucleus can be split into various combinations of ("strongest") nuclei with a limited loss of nuclear force potential since it's limited range, but with a big loss of net Coulomb potential, which makes it energetically economical
> nuclei to the left of the maximum have lower B/A since for nucleons closer to the surface there are less other nucleons to strongly interact with due to higher curvature?
> nuclei with minimal A numbers have lowest B/A due to some quantum stuff (what is it?)

> nuclear force between same nucleons is bigger than between different ones

> there are separate shells of stability for neutrons and protons in the nucleus?

[Anonymous No.11541517]

This is supposed to be Coloumb energy of interaction between potential V_c and Z protons in a nucleus modeled as a uniform ball. rho is e/V.

I don't get what e is doing in the denominator.
AFAIU Z*(4pi*r^2dr)*rho is gonna give total charge of Z protons when integrated - not really but it's basically an integral of q*V which should give E. But why is there an e in the denominator?

[Anonymous No.11541524]

>>11541517

[Anonymous No.11542698]

>/pg/ is physics /sqt/ now
Whatever, bumping.

[Anonymous No.11543690]

>>11541288
If nuclear states are defined by parity, energy and spin then how are atomic states defined? Energy, specific spin structure of electrons (cause Pauli's principle) and that's it? I just don't really remember talks about parity in atomic physics.

[Anonymous No.11543737]

>>11541288
Whats the most interesting schizo/retarded take you have evee heard thats physics related?

[Anonymous No.11543760]

>>11543737
For me, it's ether theory by some Russian mechanical engineer. It got some traction.

[Anonymous No.11543834]

>>11542698
Yes, disappointing.
Allow me to be the first to post something of actual interest.
https://arxiv.org/abs/1012.2635
>We outline a proof of a remarkable conjecture of Labastida-Mariño-Ooguri-Vafa about certain new algebraic structures of quantum link invariants and the integrality of infinite family of new topological invariants. Our method is based on the cut-and-join analysis and a special rational ring characterizing the structure of the Chern-Simons partition function.
The LMOV conjecture in essence states that, in the large-[math]N[/math] limit, [math]U_q(\mathfrak{sl}_2)[/math]-coloured Turaev-Viro TQFT encodes the same physics as topological strings. The latter theory is a CFT with geometric datum, hence this means that we can in a sense "assemble" topological invariants (e.g. Maslov, rational linking form) into geometric invariants (e.g. Gromov-Witten, quantum traces) through this duality by algebraically (e.g. Khovanov homology) organizing the data on either side.

[Anonymous No.11544215]

>>11543834
Do you even have a job? For knowing things you seem to know I don't think you can get paid any more than 5k per month.

[Anonymous No.11544735]

>>11543737
Really anything from uneducated morons who read two lines of pop sci.

[Anonymous No.11544752]

>>11541288
>Binding_energy_curve_-_co(...).png
Does this imply that lithium-6 can be used both for fusion and fission?

[Anonymous No.11546760]

>>11542698
But mg covers noob level questions as well.

[Anonymous No.11547075]

>>11543690
You're right, I would also include angular momentum in the common descriptors for atomic states. Parity is more often of interest in nuclear states since you have to consider weak interactions to convert your neutrons or protons and to emit or absorb your beta particles. The weak nuclear interaction is inherently coupled to chirality and handedness so parity begins to play a role here

[Anonymous No.11547289]

>>11541288
> > nuclear force between same nucleons is bigger than between different ones
It's exactly the same, which is the meaning of charge independence property. However, because of exclusion principle there are more states in odd-odd systems than in odd-even and even less in even-even.

[Anonymous No.11547316]

HYPSM or Oxbridge for grad school? mostly interested in optical/laser/quantum related physics but wont be applying for another two years so might change my mind later