# What is Time dependent: Definition and 130 Discussions

TIme-dependent neutronics and temperatures (TINTE) is a two-group diffusion code for the study of nuclear and thermal behavior of high temperature reactors. It was developed by Forschungszentrum Jülich in Germany, formally known as KFA (German: Kernforschungsanlage), to investigate HTGRs in 2D (r-Z) geometry.

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1. ### A Time dependent perturbation theory applied to energy levels

Hello! I am reading this paper and in deriving equations 6/7 and 11/12 they claim to use second oder time dependent perturbation theory (TDPT) in order to get the correction to the energy levels. Can someone point me towards some reading about that? In the QM textbooks I used, for TDPT they just...
2. ### Time dependent canonical transformation

THe question is pretty simple. I was doing an exercise, in which $$p = \lambda P, Q = \lambda q$$ is a canonical transformation. We can check it by $$\{Q,P \} = 1$$ But, if we add $$t' = \lambda ^2 t$$, the question says that the transformation is not canonical anymore. I am a little...
3. ### A Time dependent problem with a delta function

Hello, I try to solve a time dependent problem described by a Hamiltonian of the type $$\mathcal{H}(t) = H_0 + V \delta(t) .$$ I started by trying to solve the Schrödinger equation with ##H_0 = p^2 / 2m##, but I'm getting a bit stuck. I would like to know if you know of any books that deal...
4. ### I Time Dependent Sinusoidal Perturbation Energy Conservation

The transition probability -- the probability that a particle which started out in the state ##\psi_a## will be found, at time ##t##, in the state ##\psi_b## -- is $$P_{a \to b} = \frac{|V_{ab}|}{\hbar^2} \frac{sin^2[(\omega_0 - \omega)t/2]}{(\omega_0 - \omega^2}.$$ (Griffiths, Introduction...
5. ### I Wave function using the time dependent Schrodinger equation

Given a wavefunction ψ(x, 0) of a free particle at initial time t=0, I need to write the general expression of the function at time t. I used a Fourier transform of ψ(x, t) in terms of ψ(p, t), but, i don't understand how to use green's functions and the time dependent schrodinger equation to...
6. ### Time dependent perturbation theory (Berry phase)

If I plug the solution into the Schrodinger equation I get $$(i \hbar \partial_t - H)\ket{\psi} = 0$$ Since I know that the zeroth-order expansion is lambda is already a solution I think this is equal to $$(i \hbar \partial_t - H)e^{i\phi} e^{-i\gamma}\ket{\delta n} = 0$$ If now I carry on with...
7. ### I Energy shifts in time dependent perturbation theory

Hello! I saw in many papers people talking about the effects of a time dependent perturbation (usually an oscillating E or B field) on the energy levels of an atom or molecule (for now let's assume this is a 2 level system). Taking about energy makes sense when the hamiltonian is time...
8. ### Solving time dependent Hamiltonian

What I have tried is a completing square in the Hamiltonian so that $$\hat{H} = \frac{\hat{p}^2}{2} + \frac{(\hat{q}+\alpha(t))^2}{2} - \frac{(\alpha(t))^2}{2}$$ I treat ##t## is just a parameter and then I can construct the eigenfunctions and the energy eigenvalues by just referring to a...
9. ### Finding the potential energy of a time dependent force

U=-∫F*v*dt= -∫(m*g/3)*cos(ω*t) dt = -(m*g/3 )* (v/ω )* sin(ω*t) except that according to the official solution, I should be getting positive sign instead of negative. Am I doing something wrong?

46. ### QM: Work done due a time dependent perturbation

Homework Statement A quantum particle of mass ##m## is bound in the ground state of the one-dimensional parabolic potential well ##\frac{K_0x^2}{2}## until time ##t=0##. Between time moments of ##t=0## and ##t=T## the stiffness of the spring is ramped-up as ##K(t) = K_0...
47. ### Find the time dependent wave function

If you are given the state of a system at t=0 in vector form, how do you find the wave function for arbitrary t?
48. ### Dynamical Spacetime: Time or Space Dependent?

when do you call a spacetime dynamical...when metric is time dependent or it depends on space ??...
49. ### Calculating Electromotive Force in a Time-Dependent Magnetic Field

Homework Statement I have a problem with the next situation. I have a magnetic dipole moving at constant speed on the z axis. On the plane z=0 I have a circular wire with a resistance R and radius a. I have to calculate the electromotive force on the wire as a function of the speed of the...
50. ### Time dependent scattering theory - cross section

I am looking for a realistic explanation of the double-slit experiment in terms of wave packets (instead of stationary waves). First of all this results in using the scattering cross section, i.e. the probability current (not the density). Then, I guess, there is a kind of time average. So one...