Recent content by atat1tata

Thanks, but my question is if such a basis can be constructed by Slater determinants of single-particle spin-orbitals

We have a system of 2 particles, let's say with following hamiltonian: $$\hat{H} = -\frac{\hbar^2\hat{\nabla}_1^2}{2m} -\frac{\hbar^2\hat{\nabla}_2^2}{2m} $$ The eigenstates are often represented as (spatial wavefunction)*(spin wavefunction), where the spin wavefunction is a singlet or a...

Thanks! So: ##\exp (tAXA^{-1}) = 1 + tAXA^{-1} + \frac{t^2}{2}AX^2A^{-1} + ... = A(\exp{tX})A^{-1} \in G## Why I was stuck, I don't understand... Thank you for the hint!

Homework Statement My textbooks takes for granted that, given a Lie group ##g## and its algebra ##\mathfrak{g}##, we have that ##AXA^{-1} \in \mathfrak{g}##. Homework Equations For ##Y## to be in ##\mathfrak{g}## means that ##e^{tY} \in G## for each ##t \in \mathbf{R}## The Attempt at a...

Actually both, since I don't quite grasp the meaning of "locked degrees of freedom" and its representation in the state space

But can there be a way to derive this from an equation, if not in QM, at least in QFT?

Sure, but, I am afraid I don't understand what is the probability of exchanging the particles. What does it mean? If it is dependent on the distance, why can a whole gas of atoms be considered a BEC, with no regard (or maybe there is?) to the total volume of the gas? Moreover, what does it mean...

I have seen only two arguments for the fact that composite particles, like protons, nuclei, or even Helium-4 atoms, are identical and can be considered bosons or fermions according to their total spin. The first, in Feyman's lectures [third volume, 4-2]. It is said that if the composite...

Sure, it happens a lot of time with me. However, it is not the same for most of my friends, so maybe we have a worse time following a lecture than them. And I must say that there are some lecturers that are worth their time.

In my (Italian) university it is called "Fisica della materia" (I just don't know if I am allowed to translate it as "condensed matter physics", maybe I should say "physics of materials"). My theoretical courses were Condensed Matter, Statistical Mechanics, Physics of Materials, Semiconductor...

Of the water in the bucket (or of the gas inside the vessel, although this can be easily negligible). I'm saying that the pressure inside a "thermodynamic system" is actually non-uniform, but calculations are done as if it were.

Because in all the textbooks that I know of, they speak of "the pressure of a gas", or the "pressure of a bucket of water", and they do not consider \rho g h

In almost every textbook I have seen, pressure is said to be one of the most important state variables of a thermodynamical system. But if the system is three-dimensional and on planet Earth, it is not constant! This problem, however, is neglected in every reference I consulted. It seems to...

Having completed my undergraduate degree in Physics, I was pressed to take a Ms immediately after. Despite my aspirations, since it was not a good time for me and it was difficult for me to study, I decided to take an address, "physics of matter", that is less prestigious than "theoretical...

Possibly I should get an expression of \vec v_{CM} with its components in the inertial frame of reference basis that should be a sum of the relative velocity of the center of mass from the pivot and the velocity of the pivot