4. (20 points). 5-function perturbation. Consider a particle in a one-dimensional infinite square well with boundaries...
4. (20 points). δ. unction perturbation. Consider a particle in a one-dimensional infinite square well with boundaries at -a and-a. We introduce the following 6-function perturbation at x=0: a. Compute the first-order corrections to the energies of the particle induced by the ν' perturbation b. Recall that you solved this problem exactly in problem set 4 (Griffiths 2.43). Compare your perturbation theory result to the exact solution.
4. 3D Infinite Square Well Perturbation (20 pts) Consider the three-dimensional infinite cubic well: otherwise The stationary states are where n, ny, and n, are integers. The corresponding allowed energies are Now let us introduce the perturbation otherwise a) Find the first-order correction to the ground state energy b) Find the first-order correction to the first excited state 4. 3D Infinite Square Well Perturbation (20 pts) Consider the three-dimensional infinite cubic well: otherwise The stationary states are where n, ny,...
Consider a one-dimensional (1D) harmonic oscillator problem, where the perturbation V causes a modification of the oscillator frequency: 2 K22 H = H. +V, (1) 2 K2 V = - K +K > 0. Of course, this problem (1), (2) is trivially solved exactly yielding the oscillator solutions with a new frequency. Show that corrections to the nth energy level as calculated within the perturbation theory indeed reproduce the exact result, restricting yourselves to terms up to the second order...
Calculate the Fermi energy for electrons in a 4-dimensional infinite square well. (See Griffiths Quantum Mechanics 2nd edition, problem 5.34 for reference. NOTE: The problem in Griffiths is for a 2-dimensional infinite square-well, NOT a 4-dimensional infinite square well.)
1) Consider a particle with mass m confined to a one-dimensional infinite square well of length L. a) Using the time-independent Schrödinger equation, write down the wavefunction for the particle inside the well. b) Using the values of the wavefunction at the boundaries of the well, find the allowed values of the wavevector k. c) What are the allowed energy states En for the particle in this well? d) Normalize the wavefunction
Please answer all parts: Consider a particle in a one-dimensional box, where the potential the potential V(x) = 0 for 0 < x <a and V(x) = 20 outside the box. On the system acts a perturbation Ĥ' of the form: 2a ad αδα 3 Approximation: Although the Hilbert space for this problem has infinite dimensions, you are allowed (and advised) to limit your calculations to a subspace of the lowest six states (n = 6), for the questions of...
Q1) Consider 2.dimensional infinite "well" with the potential otherwise The stationary states are ny = (a) sin ( x) sin (y,) The corresponding energies are n) , 123 Note that the ground state, ?11 is nondegenerate with the energy E00)-E1)-' r' Now introduce the perturbation, given by the shaded region in the figure ma AH,-{Vo, if 0<x otherwise y<a/2 (a) What is the energy of the 1.st excited state of the unperturbed system? What is its degree of degeneracy,v? (b)...
4) (2096) For an electron in a one-dimensional infinite square well of width L, find (a) (5%) < x >, (b) (5%) < x2 >, and (c) (5%) Δ). (d) (5%) What is the probability of finding the electron between x = 0.2 L and x = 0.4 L if the electron is in n=5 state
Problem 3: Time-Independent Perturbation Theory Consider the particle in a 1D box of size L, as in Fig. 3. A perturbation of the form. V,δ ((x-2)2-a2) with a < L is applied to the unperturbed Hamiltonian of the 1D particle in a box (solutions on the equation sheet). Here V is a constant with units of energy. Remember the following propertics of the Dirac delta function m,f(x)6(x-a)dx f(a) 6(az) が(z) = = ds( dz E, or Ψ(x)-En 10 0.0 0.2...
4. (30 points) Harmonic oscillator with perturbation Recall the Hamiltonian of an harmonic oscillator in 1D: p21 ÃO = + mwf?, where m is the mass of the particle and w is the angular frequency. Now, let us perturb the oscillator with a quadratic potential. The perturbation is given by Î' = zgmw?h?, where g is a dimensionless constant and g <1. (a) Write down the eigen-energies of the unperturbed Hamiltonian. (b) In Lecture 3, we introduced the lowering (or...