Recent content by Coffee_

Is there a general way of knowing if an elementary boson for example is virtual or real? So for example, two leptons annihilate into an elementary boson. Then you can get real photons, W+-/Z° bosons depending on the leptons. However W+-/Z° and photons can also be virtual when acting as...

Let's say I have two particles A and B and I want to find the total charge parity of the system ##C_{AB}##. In what cases is it allowed to say ##C_{AB}=C_{A}.C_{B}##? I suspect that if A and B are their own antiparticles, then that is OK. Is this even the case when the system has a relative...

Let's say that we have some canonical ensemble where I know that the heat capacity is given by ##C_{V}=\alpha(N,V) T^{n}## Since ##C_{V}=T\frac{\partial S(T,V)}{\partial T}## I know that ##S(V,T)=\frac{1}{n} \alpha(N,V) T^{n} + f(N,V) ## Where the function ##f(N,V)## has to do with the fact...

Thanks for all the answers, what I meant was the following. To find the probability of a single particle having an energy ##E## which is mentioned in my original post one has to maximize the logarithm of the following expression under conservation of total energy and number of particles...

The probability of finding one single particle at energy ##\epsilon## in a system of such distinguishable particles at thermal equilibrium in the thermodynamic limit is given by the Boltzmann distribution that is: (up to a constant factor in front) ##e^{-\frac{\epsilon}{kT}}## To find this...

Oh I was thinking it was weird because I have never encountered such an extra constant term in the wavefunction so I was doubting my reasoning to arrive at the extra constant term. Based on your reactions I see that there is indeed nothing special about it, thanks.

When dealing with Dirichlet boundary conditions, that is asking for the wavefunction to be exactly zero at the boundaries, it can be clearly seen that (0,0,0) is not a physical situation as it is not normalizable. (Wavefunction becomes just 0 then) However when dealing with periodic boundary...

Fermi's golden rule contains a term that is the density of the final states ##\rho(E_{final})##. For my problem we have no time depending potentials so that's the same as ##\rho(E_{initial})##. If I understand the definition of ##\rho## correctly, it's the number of states in an interval...

It would be if you indeed correctly switch to ##C[F]## which they don't, they explicitly do minimize ##A[F]-µB[F]## but I think I understand it now. What they do is do not vary µ during the minimization such that ##µN## is just a constant which can be neglected. They will then find a solution...

No, this is a physics book on Bose Einstein condensates and N is the number of particles in the system. I am seriously confused now because now I've started looking more online for general explanations of this integral constraint minimization and some DO include the ''µN'' part and some don't...

Consider the following problem: ##A## is a functional (some integral operator to be more specific) of a (complex) function ##F##. We want to minimize ##A[F]## wrt. to a constraint ##B[F]=\int (|F|²)=N## If I read around online I find that in general such extremization problems are done by...

Hey DrDu. I don't mean to persist, but just a headsup to ask if you have seen my response? If you don't have time right now it's totally okay just making sure.

Great. This was exactly what I thought a few hours after posting it (the non-commuting part) but thanks for confirming. So the unitary transformation I wrote down is correct for rotating frames in general? This means both the lab frame and the rotating frame agree upon the values of the WF in a...

Hello, I have the following problem: A system in the lab frame is described by a time dependent rotating potential ##V(\vec{r},t)##. So ##H_{lab}=\frac{\boldsymbol{p}^{2}}{2m} + V(\vec{r},t)##. My book says that the Hamiltonian in the rotating frame is given by...

Wait something must be wrong here, consider eq(4) from the paper. Now set r=r' and integrate over the volume. The left term is 1 and the right term is a sum over ##n_l##. This doesn't result in the normalization condition they mention.