Recent content by Yoni V

Which books/resources would you recommend to study superfluidity for a 3rd year undergrad seminar? It needs to focus on phenomenology rather than technical details. Assume some QM background, but before a first course on condensed matter. Thanks!

Is there a good description or formula regarding how the sound pressure from a constant source depends upon ambient pressure? That is, if I were to conduct an experiment where I put a source and a microphone in a container, and then change the pressure in that container with a pump, assuming...

Homework Statement Let ##\left|\psi\right\rangle## be a non-degenerate stationary state, i.e. an eigenstate of the Hamiltonian. Suppose the system exhibits symmetry for time inversion, but not necessarily for rotations. Show that the expectation value for the angular momentum operator is zero...

Thanks for your replies! I managed both (a) and (b) and understood its underlying principles. I'm now left with (c). We were suggested to define ##\phi = |\psi_0|## where ##\psi_0## is the wave function of the ground state, and then express ##\phi## in terms of the Hamiltonian eigenvectors and...

Homework Statement Assume a particle with a wave function ##\psi(x)## such that ##-\infty < x < \infty##, that move under some potential ##V(x)##. Show that: a) two wave functions with same energies can only differ by a complex phase; b) if the potential is real, then you can choose the wave...

Homework Statement An infinite plane in z=0 is held in potential 0, except a square sheet -2a<x,y<2a which is held in potential V. Above it in z=d there is a grounded plane. Find: a) the potential in 0<z<d? b) the total induced charge on the z=0 plane. Homework Equations Green's function for a...

Ok, got it, it indeed doesn't matter- we can decompose the expression for the y component and take the real part. One last thing, I didn't understand your discussion of the dot products. Is there anything wrong with how I calculated the coefficients?

Ok, we can solve for them by $$ \begin{pmatrix}1\\ 0 \end{pmatrix}=\frac{c_{l}}{\sqrt{2}}\begin{pmatrix}1\\ i \end{pmatrix}+\frac{c_{r}}{\sqrt{2}}\begin{pmatrix}1\\ -i \end{pmatrix}\Rightarrow c_{l}=c_{r}=\frac{1}{\sqrt{2}}$$ and now $$ \mathbf{E} =...

Yes, the vectors are ##\frac{1}{\sqrt 2}(1,-i), \frac{1}{\sqrt 2}(1,i)## for circularly polarized light, and (a,b) for some linear polarization. But I'm not sure how the initial linear input should be written. I thought that if ## E_0 = E_{x0} \hat x ## then $$\frac{1}{\sqrt 2}E_{x0}...

Homework Statement Linearly polarized light in the x direction with wave number ##k_0## travels in the z direction. It enters a medium such that a RHCP component of the wave and a LHCP component each accumulate a phase of ##n_Rk_0z## and ##n_Lk_0z## respectively, where z is the distance...

Ok, I think I got it while writing this reply. What I started typing is: It's part of the constant of integration ##s_0'##, or if we neglect a constant that has nothing to do with the temp. and volume, it is exactly ##s_0'##. This I understand, but even writing it explicitly, I'm not sure on how...

Hmm... from Maxwell's relations $$(\frac{\partial S}{\partial V})_T = (\frac{\partial P}{\partial T})_V$$ which equals ##\frac{P_1}{T_1}## from the given equation of state, and then $$s = \frac{P_1}{T_1}V + s_0'$$ The heat cap. is given by ##C_P = T(\frac{\partial s}{\partial T})_P##. I could...

Homework Statement Given the equation of state ##V(P,T)=V_1\cdot exp(\frac{T}{T_1}-\frac{P}{P_1})## where ##V_1\;,T_1\;,P_1## are constants: a. derive an equivalent equation ##P(V,T)##; b. given ##C_V=DT^3## where D is a const, calculate the entropy of the system ##s(V,T)## up to a const; c...

Ok, I finally made it, thank you all for you help and patience!

So maybe I didn't understand it after all, as I'm not familiar with circulation loops. From what I've learned, I can notate the currents on a circuit like in the following figure (and I could also add bigger loop eqs., but they cancel out eventually)