Recent content by babylonia

Thanks for you reply. I have no difficulty working out this particular integral, since I actually picked an easy form just to present my question about those limits. My problem is to know the full expression of those limits. Thanks any way.

Hi, Thanks for your reply, but I'm not sure you are replying to my post? What you mentioned does not seem to be the thing I was asking? I'm more interested to know the limits of integral variables in CM frame instead of working out this particular integral. Could you tell more details even if...

Hi, I am having some difficulty doing the integral ∫d^{3}v1d^{3}v2 | \overline{v1}-\overline{v2}|, where u1\leq|v1|,|v2|\lequ2, and \overline{v1} means vectors. It seems better to evaluate it in the center of mass frame, by substitution \overline{v1}+\overline{v2}=\overline{V}, and...

Hi, Thanks a lot for your reply. I think for Fock state the Wick theorem leads to \langle a^+_k a^+_l a_m a_n\rangle = \langle a^+_k a_m\rangle\langle a^+_l a_n\rangle \delta_{k,m}\delta_{l,n}+\langle a^+_k a_n\rangle\langle a^+_l a_m\rangle\delta_{k,n}\delta_{l,m}, because particle number...

Hi all, I read on some paper that for a system of Fock state |...nk...>, and with the field operator expanded as \Psi(r)=\sumak \phik(r), the second order density correlation function can be expressed as G(2)=<\Psi+(r)\Psi+(r')\Psi(r')\Psi(r)>=<n(r)><n(r')>+|<\Psi(r)+\Psi(r')>|2-\sum^{N}_{k}...

Hi all, I am trying to find numerically the eigenvalues of a nonlinear schroedinger equation in a similar way as the Self Consistent Field method for Hatree-Fock problems. Does anybody know in the SCF calculation how to improve the convergency? Is there any trick other than simply inserting...

Hi Kanato, Thanks for reply. Still I'm not clear with which basis it is appropriate to calculate the E(k) spectrum in disordered potential, since there may be a trucation problem in numerical implementation. Is there any special technique? Best regards

Hi everyone, I'm having some problems with this topic. how to numerically calculate the energy spectrum for a certain Hamiltonian? eg., in a periodic potential or disordered potential: \widehat{H}=-\frac{\partial^{2}}{\partial x^{2}}+cos(x)+V(x) Thanks for your time and attention.