Harmonic oscillator Definition and 743 Threads

  1. S

    Period of a simple harmonic oscillator

    Hi I'm having problems with solving this question: a 90.0 kg skydiver hanging from a parachute bounces up and down with a period of 1.50 seconds. What is the new period of oscillation when a second skydiver, whose mass is 60.0 kg, hangs from the legs first? the answer is 1.94 seconds...
  2. R

    Quantum mechanics: Quantum particle in a harmonic oscillator potential motion

    I'm sorry if the form of my post does not meet the general requirements(this is the first time i work with any kind of LaTeX) and I promise that my next posts will be more adequate. Right now I am in serious need of someone explaining me this problem, since on the 6th of June I'm supposed to...
  3. J

    Numerical 2D Harmonic Oscillator

    I'm solving the 2D harmonic oscillator, numerically. -\frac{1}{2}\left( u_{xx} + u_{yy}\right) + \frac{1}{2}(x^2+y^2)u = Eu The solutions my solver spits out for say, the |01> state, are linear combinations of the form |u\rangle = \alpha_1 |01\rangle + \alpha_2 |10\rangle which is...
  4. B

    Griffiths QM Ground State of Harmonic Oscillator

    Homework Statement Folks, I am looking at a past exam question regarding the Harmonic Oscillator. The question ask 'Justify that the ground state of a harmonic oscillator a_\psi_0=0 equation 2.58 on page 45 of griffiths. THis was not covered in my notes. Any ideas how to justify this...
  5. I

    Harmonic oscillator modeled with a contour integral

    Homework Statement Greetings, gents. I have a modelization problem you might be able to help me with... I have two oscillators, modeled as: osc_{1}=\cos{(a z)}osc_{2}=\cos{(\frac{b}{z})} and a resonance condition f(z) when these two oscillators are combined, modeled as...
  6. H

    Classical Lorentz harmonic oscillator model of photo-phonon inteaction

    Why the reciprocal of the damping rate in this model equal to the phonon lifetime? Can somebody give me a detailed exaplanation. Thanks.
  7. D

    Damped Harmonic Oscillator Using Greens Theorem

    Hi there, I just started an intermediate classical mechanics course at university and was smacked upside the head with this question that I don't know how to even start. Homework Statement We are to find the response function of a damped harmonic oscillator given a Forcing function. The...
  8. J

    Quantum Simple Harmonic Oscillator

    Homework Statement The period of a macroscopic pendulum made with a mass of 10 g suspended from a massless cord 50 cm long is 1.42 s. (a) Compute the ground state (zero-point) energy. (b) If the pendulum is set into motion so that the mass raises 0.1 mm above its equilibrium position, what will...
  9. A

    Finding Eigenstates of J_z and the Harmonic Oscillator Operators

    Homework Statement http://img191.imageshack.us/i/questionyw.png/ Homework Equations Given in problem The Attempt at a Solution a) I've been able to find expressions of operators x, p_x, y and p_y in terms of the creation/annihilation operators and hence been able to express the...
  10. F

    Changing potential in harmonic oscillator

    i have a quick question A particle in ground state of a S.H.O whose potential is given by V_1(X)=\frac{1}{2}mw^2_1x^2 suddenly changes to V_2(X)=\frac{1}{2}mw^2_2(x-x_o)^2 what is the wavefunction going to be like for the new potential? i'd think everything else stays the same in the...
  11. T

    Position expectation value in harmonic oscillator

    Hello, I want to find <xftf|x(t)|xiti> in harmonic oscillator. I tried to insert the complete set of energy eigenstates to the right and the left side of x(t), but it yields somewhat more complicated stuff. Thank you
  12. K

    Simple Damped Harmonic Oscillator with friction

    Homework Statement a block of mass m=.5kg is sliding on a horizontal table with coefficients of static and kinetic friction of .8 and .5 respectively. It is attached to a wall with a spring of unstretched length l=.13m and force constant 200 n/m. The block is released from rest at t=0 when...
  13. K

    Damped harmonic oscillator with a CONSTANT frictional force

    Homework Statement There is a block attached to the wall via a spring. The only damping force is friction, where there is kinetic and static. Homework Equations m(d^2x/dt^2)=-kx-? The Attempt at a Solution I can solve this, except usually the damping force is given as...
  14. B

    Harmonic oscillator verify both solutions to schrodinger equation

    Homework Statement a particle of mass m moving in one dimension has potential energy V(x)=0.5m [[omega(subscript0)]^2] x^2 verify that psi0 (proportional to) exp [(-m omega0 x^2)/2 h bar] and psi1 (proportional to) exp [(-m omega0 x^2)/2 h bar] are both solutions of the time...
  15. R

    Exploring the Physical Meaning of a Harmonic Oscillator Probability Density Plot

    Homework Statement I'm talking about the probability density plot of the harmonic oscillator. Is there some physical meaning to be extracted from this? Here's a link that contains the drawing of what I'm talking about http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/hosc5.html...
  16. C

    Finding a constant within a wavefuntion for a harmonic oscillator

    Homework Statement The question states for a harmonic oscillator the wavefunction is: \mu = C*x*exp(-\alphax2/2) it then wants you to find \alpha. using the standard hamiltonian: H = -\hbar/2m d2/dx2 + 1/2 mw2x2 I have differentiated \mu twice and put it into the TISE. for the left hand...
  17. C

    Doubling the frequency of a quantum harmonic oscillator

    Homework Statement A particle is in the ground state of a harmonic oscillator with classical frequency w. Suddenly the classical frequency doubles, w -> w' = 2w without initially changing the wavefunction. Instantaneously afterwards, what is the probability that a measurement of energy...
  18. M

    Why Must the State of a Quantum SHM Particle Be of This Form?

    Homework Statement We know that a particle in SHM is in a state such that measurements of the energy will yield either E_0 or E_1 (and nothing else), each with equal probability. Show that the state must be of the form \psi = \frac{1}{\sqrt2} \psi_0 + \frac{e^{i \phi}}{\sqrt2} \psi_1 where...
  19. P

    Proving solution for Schrodinger's Simple Harmonic Oscillator

    Homework Statement Hi guys. I've been working on this problem for a while, it's starting to frustrate me. "Show that the function of Ѱ=e^(-bx^2) with b=mw/2ħ is a solution and that the corresponding energy is ħw/2." Homework Equations Schrodinger Eqn...
  20. L

    Exploring the Probability of a Harmonic Oscillator in a Changed Spring Constant

    Homework Statement In the time interval (t + δt, t) the Hamiltonian H of some system varies in such a way that |H|ψi>| remains finite. Show that under these circumstances |ψi> is a continuous function of time. A harmonic oscillator with frequency ω is in its ground state when the stiffness of...
  21. P

    Simple relativistic harmonic oscillator

    In the attached file, I have formulated a simple one dimensional harmonic oscillator and solved the model numerically. Such a model might represent a simple reaction coordinate along which a liquid drop actinide nucleus might split after absorbing a neutron. Clearly the complete model involves...
  22. B

    Estimating the energy of the ground state of a harmonic oscillator from the

    uncertainty relation. I think I'm on the right track. Currently, I'm at, E = (1/2m)*<p^2> + (1/2)*k*<x^2> and when applying the uncertainty relation, deltax = <x^2>^(1/2) deltap = <p^2>^(1/2) How do I go about connecting everything from here? Thanks!
  23. Z

    Harmonic Oscillator Expectation Values

    Homework Statement A particle of mass m that is confined to a harmonic oscillator potential V(x) = \frac{1}{2} m \omega^2 x^2 is described by a wave packet having the probability density, |\Psi (x,t) |^2 = \left(\frac{m\omega}{\pi\hbar} \right )^{1/2}\textrm{exp}\left[-\frac{mw}{\hbar}(x -...
  24. K

    Ground state of harmonic oscillator

    Homework Statement Verify that the ground state (n=0) wavefunction is an eigenstate of the harmonic oscillator Hamiltonian. Using the explicit wavefunction of the ground state to calculate the average potential energy <0|\hat{v}|0> and average kinetic energy <0|\hat{T}| 0> Homework...
  25. A

    Minimum potential energy of a simple harmonic oscillator

    Homework Statement A simple harmonic oscillator of force constant 2*106 N/m and amplitude .01 m has total maechanical energy 160 J... Homework Equations The Attempt at a Solution Now this is not the question but what is the minimum potential energy...1/2kx^2 comes out to be...
  26. B

    Verifying Bohr's Hypothesis for 3-D Harmonic Oscillator

    1. Homework Statement Show that bohr's hypothesis (that a particle's angular momentum must be an integer multiple of h/2pi) when applied to the three dimensional harmonic oscillator, predicts energy levels E=lh/pi w with l = 1,2,3. Is there an experiment that would falsify this prediction...
  27. R

    Simple harmonic oscillator - scaled variables

    The TISE can be written as -\frac{\hbar^{2}}{2m}\frac{d^{2}u}{dx^{2}} + \frac{1}{2}m\omega_{0}^{2}x^{2}u = Eu Now my lecture notes say that it is convenient to define scaled variables y = \sqrt{\frac{m\omega_{0}}{\hbar} x} and \alpha = \frac{2E}{\hbar\omega_{0}} Hence \frac{d}{dx} =...
  28. T

    Is the normal mode frequency of harmonic oscillator related to temperature?

    It is well known that for an isolated system, the normal mode frequency of a N-body harmonic oscillator satisfies Det(T-\omega^{2}V)=0. How about a non-isolated, fixed temperature system? In solid state physics I have learned that in crystal the frequency does not change, but the amplitude of...
  29. A

    A harmonic oscillator problem

    Homework Statement A particle in the ground state of the harmonic oscillator with classical frequency \omega, when the spring const quadruples (so \omega^{'}=2\omega) without initially changing the wave function. What is the probability that a measurement of the energy would still return the...
  30. J

    Harmonic oscillator - rotating molecule?

    I have a planar molecule with a torsional oscillation mode where it twists around a C-C bond by an angle \theta from some equilibrium position. The restoring force is a function of theta, and the potential energy involved is given by V(\theta) = V_0(1-cos(2\theta)) I need to "use a Taylor...
  31. D

    Anisotropic harmonic oscillator

    Homework Statement The particle with the mass m is in 2D potential: V(r)=\frac{m}{2}(\omega_x^2x^2+\omega_y^2y^2),\quad \omega_x=2\omega_y, and is described with wave package for which the following is valid: \langle x\rangle (0)=x_0,\ \langle y\rangle (0)=0,\ \langle p_x\rangle (0)=0\...
  32. B

    Harmonic Oscillator grandfather clock

    Homework Statement The pendulum of a grandfather clock has a period of 1s and makes excursions of 3cm either side of dead centre. Given that the bob weighs 0.2kg, around what value of n would you expect its non negligible quantum amplitudes to cluster? Homework Equations [/B] The...
  33. T

    Step operators for harmonic oscillator

    Hi! Info: This is a rather elementary question about the creation a(+) and annihilation (a-) operators for the 1D H.O. The problem is to calculate the energy shift for a given state if the weak perturbation is proportional to x⁴. Using first order perturbation theory for the...
  34. K

    Solve Harmonic Oscillator w/ Impulsive Force: M & Time

    So here is the problem. A mass hanging from a spring is modeled by the operator L(y)=2y"+y'/10+2y (y=0 corresponds to hanging equilibrium). Assume mass starts with y(0)=1 and y'(0)=1. Assume an upward impulsive force of mag M is applied at the first possible time which results in complete end...
  35. T

    Harmonic oscillator and fourier series

    Hello, Attached are two problems I can not solve, thanks for the help. The Attempt at a Solution For the first question, I understand that I need insert A1coswt+A2sinwt into the homogenous equation , but don't know what's then .. But I'm pretty much lost on both of em :(
  36. R

    Harmonic Oscillator Negative Energy(Quantum)

    Homework Statement Ok so the question is, is the state u(x) = Bxe^[(x^2)/2] an energy eigenstate of the system with V(x) = 1/2*K*X^2 and what is the probability per unit length of this state.Homework Equations The Attempt at a Solution So the way i did this was, to find if the state is an...
  37. P

    Harmonic Oscillator - Quantum mechanics

    A particle of mass m moves along the x-direction such that V(x)=½Kx^2. Is the state u(¥)=B¥exp(+¥2/2), where ¥ is Hx (H = constant), an energy eigenstate of the system?. What is probability per unit length for measuring the particle at position x=0 at t=t0>0?
  38. P

    Coherent states of a Quantum Harmonic Oscillator

    Homework Statement Given that a^+|n\rangle=\sqrt{n+1}|n+1\rangle a|n\rangle=\sqrt{n}|n-1\rangle and that the other eigenstates |n> are given by |n\rangle=\frac{(a^+)^n}{\sqrt{n!}}|0\rangle where |0> is the lowest eigenstate. Define for each complex number z the coherent state...
  39. J

    Can a Damped Anti-Spring System Explode Under Certain Conditions?

    Imagine a fictitious universe where springs want to stretch: the spring force is proportional to, and in the same direction as, displacement from equilibrium. We'll call these anti-springs. (a) Set up a differential equation modeling the motion of a damped anti-spring if the mass is m = 1 kg...
  40. J

    Quantum Mechanics Treatment of Harmonic Oscillator

    Homework Statement Given the Hamiltonian for the harmonic oscillator H=\frac{p^2}{2m}+\frac{1}{2}m\omega^2 x^2 , and [x,p]=i\hbar . Define the operators a=\frac{ip+m\omega x}{\sqrt{2m\hbar \omega}} and a^+=\frac{-ip+m\omega x}{\sqrt{2m\hbar \omega}} (1) show that [a,a^+]=1 and that...
  41. A

    Is the harmonic oscillator Hamiltonian an unbounded operator?

    My answer would be "yes," and here's my argument: If we let H = -\frac{\hbar^2}{2m} \frac{\partial^2}{\partial x^2} + \frac 12 m \omega^2 x^2, it is a Hermitian operator with familiar normalized eigenfunctions \phi_n(x) (these are products of Hermite polynomials and gaussians) and associated...
  42. A

    Harmonic oscillator momentum distribution

    Hi, I don't understand why the momentum probability distribution of the quantum mechanical oscillator has the same shape as the position probability distribution (with peaks at the extremes), I mean, I understand the mathematics but I don't understand the concept. This is my reasoning (which...
  43. N

    Computing harmonic oscillator propagator via path integral

    Homework Statement Show that G(q_2,q_1;t)=\mathcal{N}\frac{e^{iS_{lc}}}{\sqrt{\det A}} where \mathcal{N} is a normalization factor independent of q1, q2, t, and w. Using the known case of w=0, write a formula for G such that there is no unknown normalization factor. Homework Equations I...
  44. B

    Probability of a particle in a simple harmonic oscillator -

    Homework Statement What is the probability that a particle in the ground state of a simple harmonic oscillator 1-D potential will be found outside the region accessible classically Homework Equations ∫(between 1 and infinity) e^(-y^2 ) dy=0.08π^(1/2) I feel like it's quite a...
  45. L

    Problem with evolution operator and harmonic oscillator

    Homework Statement Show that U*(pi/(2*omega)) |x> is an eigenvecor of p and specify its eigenvalue. Similarly, establish that U*(pi/(2*omega)) |p> is an eigenvector of x. Homework Equations U*(t) = exp((i/h_bar)H*t) The Attempt at a Solution I've tried using closure with P...
  46. K

    Simple Harmonic Oscillator Problem with Slight Variation

    Homework Statement A particle is moving in a simple harmonic oscillator potential V(x)=1/2*K*x^2 for x\geq0, but with an infinite potential barrier at x=0 (the paddle ball potential). Calculate the allowed wave functions and corresponding energies.Homework Equations I am thinking that the...
  47. N

    Coefficients Cn for a Harmonic Oscillator in an Electric field

    Homework Statement Harmonic oscillator is in the first excited state |1> when a constant electric field E is switched on. Find the time evolution of the wave functionHomework Equations Schrodinger equation H\Psi = E_n\Psi H = \frac{P^2}{2m} + \frac{m\omega^2x^2}{2}-qEx The Attempt at a...
  48. M

    Under what conditions is a pendulum a Simple Harmonic Oscillator, why?

    For part of my lab write up on pendulum motion, my professor wanted us to find out why a pendulum was not a simple harmonic oscillator, and under what conditions it was. He also wanted to show this mathematically. So far what I have is that if there is no damping(friction?) and if the the...
  49. J

    Mircocanonical Damped Harmonic Oscillator

    I am supposed to find the number of mircostates for the following Hamiltonian \ \begin{equation} \Sigma {(q_n+mwp_n)^2}<2mE \end{equation} So I am attempting to take the integral as follows \ \int e^{(q_n+mwp_n)^2} d^{3n}q d^{3n} p [tex\] I found a solution that tells me \...
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