Recent content by asheg

Thanks DrDu. Do you have a reference so I can take a look into the details? Also do you have idea about the other questions?

In some quantum textbooks [1], the tunneling transmission formula depends only on the density of states of 2 regions (DOS) involved in tunneling. (T(E)=C×DOS1(E)×DOS2(E), where C is constant). However, in Landauer transmission formula (without tunneling) the transmission depends on both DOS and...

Is there any simple justification about graphene having no band gap? How bout its linear E-K? Why bilayer graphene has a quadratic E-K and electric field can open a band gap there? I do not completely understand the broken symmetry argument? Also Why MoS2 which has similar structure, do not...

Thanks for your reply. I think if the incompressible be what you say (changes propagates instantly all over space) then the velocity distribution would be: V(R,t) = t^2/R^2 t is time R is Radius from center Because the radius of ball at time t would be t and the velocity of fluid there...

Hi every one, consider ideal fluid claiming the space all over, and a ball in it which is becoming larger and larger with radius of zero at the begin. Is such a situation possible? Doesn't it in contradiction with ideality (in-compressibility of the fluid). If it's not so, Do places far away...

Yes, I think you're right (just change energy -> free energy).

Are they green's functions and if it's so how they have been calculated?

As I know photons only can have circular polarization (left rotating or right rotating) and linear polarization are superposition of being in these state. i.e. when |Photon> = .5 |LHR> + .5|RHR > it behaves like linearly polarized. That's why when a molecule emits photon, the electron (which...

Yes I saw that figure and it made me unsure about what "Configuration coordinate diagram" means? E-Q (page 35) or E-x (page 37)?

The entropy also can be considered in energy like in Gibbs free energy: G = H - TS (Equ_1) Where H is enthalpy and T is Temp and S is entropy. As far as I know every system in the world behaves so that its G becomes minimum. When temp is very low the second term in equ 1 would be low and we...

Excuse me if I was wrong but I think q usually stands for momentum or wave vector. i.e. see following link (page 35/57)...

1- Set ky=0 kz=0 plot the function (Constant+Cos(kx.b)) 2- mx = Constant*1/(d^2E/dkx^2)

For a moment forget the uncertainty principle, my discussion doesn't depend on it. In a single atom the wave function of electron is confined to a region near it so the wavelength of electron is short hence its momentum is high. when you have a metal, there exists many states which their...

you can look it from this point of view that metals are favorable state (in respect to energy) because the electron wave function can expand all over the metal and momentum is inverse of wavelength so momentum decreases and as a result the energy decreases. The same thing is true for crystal...

When you have a periodic structure you will have clean energy bands but when there be defects you will have some energy states in middle of these band. As far as I know, we always plot E-K (or name it E-Q) where k(/q) is wave vector. Since defect is localized in space it would spread in...