/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q. 13P A particle in the harmonic oscil... [FREE SOLUTION] | 91影视

91影视

A particle in the harmonic oscillator potential starts out in the state(x,0)=A[30(x)+41(x)]

a) Find A.

b) Construct (x,t)and|(x,t)2|

c) Find xand p. Don't get too excited if they oscillate at the classical frequency; what would it have been had I specified 2(x), instead of 1(x)?Check that Ehrenfest's theorem holds for this wave function.

d) If you measured the energy of this particle, what values might you get, and with what probabilities?

Short Answer

Expert verified

Answer

(a) The value ofA=15

(b) The value of |(x,t)|is1530(x)e-t/2+41(x)e-t/2and the value of localid="1657965309411" |(x,t)|2is125902+1612+2401cos(t)

(c) The value of localid="1660906192703" x=24252mcos(t)and localid="1660906161075" p=-2425m2sin(t).and Ehrenfest's theorem holds for this wave function.

(d) The value can be got localid="1660906185824" E0-12with probability

c02=925, or localid="1660906200623" E1=32with probabilityc12=1625

Step by step solution

01

- The given expression

The starting state of the particle in the harmonic oscillator potential is, (x,0)=A3w0(x)+4w1(x)......................(1)

02

- Define harmonic oscillator

A system is said to be a harmonic oscillator if it experiences a restoring force F proportionate to the displacement x, where k is a positive constant, when it is moved from its equilibrium position.

03

- The value of A

(a)

The value of Awill be :

1-(x.0)2dx

=|A|2902+120*1+121*0+1612dx

=A2(9+0+0+16)=25A2

A=15

Thus, the value of A=15

04

- The value of Ψ(x,t) and Ψ(x,t)2

(b)

The value are in below

|(x,t)|=1530(x)e-E0t/+41(x)e-iEtt/U

For given equation,

Using the equation 2, 3 and 4 , then the above equation is expressed as,

|(x,t)|=1530(x)e-it/2+41(x)e-3i蝇t/2

Here,

0(x)=mWk14em2x2.......................(2)

1(x)=A1mW142mxe-m02x2 ...........................(3)

En=n+12 ........................(4)

E0=2

E1=32

And the value of

|(x,t)|2=125902+1201eit/2e-3it/2+1201e-it/2e3it/2+1612

|(x,t)|2=125902+1612+2401cos(t)

The value of |(x,t)|is 1530(x)e-i蝇t/2+41(x)e-ii蝇t/2]and the value of |(x,t)|2islocalid="1657966352148" 125902+1612+2401cos(t)

05

- Finding x and P

(c)

The value of xwill be

x=1259x02dx+16x1d12x+24cos(t)x01dx

But x02dx=x12dx=0while

localid="1660906338752" x01dx=m2mxemx2xemx2dx=2m2212m3=2m

so,

localid="1660906349104" x=24252mcos(t);and

p=mddtx

localid="1660906367748" =-2425m2sin(t).

(With 1and 2in place of 1the frequency would be localid="1660906408776" E2-E0=252-1=2)

Ehrenfest's theorem says dpdt=-Vx. Here

localid="1660906425192" dpdt=-2425m2cost

V=12m2x2

Differentiate with respect to x.

Vx-m2x

So,

-Vx=-m2x

localid="1660906435100" =-m224252mcos(t)

localid="1660906449990" =-2425m2cos(t)

So, Ehrenfest's theorem holds.

06

- The value of the energy of this particle and probability

(d)

The value can be got E0-12, with probability ,or c02=925, or localid="1660906537134" E1=32, with probability c12=1625.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Consider the double delta-function potentialV(x)=-[x+a+x-a]Whereand are positive constants

(a) Sketch this potential.

(b) How many bound states does it possess? Find the allowed energies, for=/maand for=2/4ma, and sketch the wave functions.

A particle of mass m is in the ground state of the infinite square well (Evaluation 2.19). Suddenly the well expands to twice its original size 鈥 the right wall moving from a to 2a 鈥 leaving the wave function (momentarily) undisturbed. The energy of the particle is now measured.

  1. What is the most probable result? What is the probability of getting that result?
  2. What is the next most probable result, and what is its probability?
  3. What is the expectation value of the energy? (Hint: if you find yourself confronted with an infinite series, try another method)

A particle of mass m and kinetic energy E > 0 approaches an abrupt potential drop V0 (Figure 2.19).

(a)What is the probability that it will 鈥渞eflect鈥 back, if E = V0/3? Hint: This is just like problem 2.34, except that the step now goes down, instead of up.

(b) I drew the figure so as to make you think of a car approaching a cliff, but obviously the probability of 鈥渂ouncing back鈥 from the edge of a cliff is far smaller than what you got in (a)鈥攗nless you鈥檙e Bugs Bunny. Explain why this potential does not correctly represent a cliff. Hint: In Figure 2.20 the potential energy of the car drops discontinuously to 鈭扸0, as it passes x = 0; would this be true for a falling car?

(c) When a free neutron enters a nucleus, it experiences a sudden drop in potential energy, from V = 0 outside to around 鈭12 MeV (million electron volts) inside. Suppose a neutron, emitted with kinetic energy 4 MeV by a fission event, strikes such a nucleus. What is the probability it will be absorbed, thereby initiating another fission? Hint: You calculated the probability of reflection in part (a); use T = 1 鈭 R to get the probability of transmission through the surface.

Show that E must be exceed the minimum value of V(x) ,for every normalizable solution to the time independent Schrodinger equation what is classical analog to this statement?

d2dx2=2mh2[V(x)E];

IfE<Vmin then and its second derivative always have the same sign. Is it normalized?

A particle in the infinite square well has as its initial wave function an even mixture of the first two stationary states:

(x,0)=A[1(x)+2(x)]

You can look up the series

116+136+156+=6960

and

114+134+154+=496

in math tables. under "Sums of Reciprocal Powers" or "Riemann Zeta Function."

(a) Normalize (x,0) . (That is, find A. This is very easy, if you exploit the orthonormality of 1and 2 Recall that, having normalized at , t=0 , you can rest assured that is stays normalized鈥攊f you doubt this, check it explicitly after doing part(b).

(b) Find (x,t)and |(x,t)|2Express the latter as a sinusoidal function of time. To simplify the result, let 22ma2

c)Compute x . Notice that it oscillates in time. What is the angular frequency of the oscillation? What is the amplitude of the oscillation?(If your amplitude is greater than a2 , go directly to jail.

(d) Compute p

(e) If you measured the energy of this particle, what values might you get, and what is the probability of getting each of them? Find the expectation value ofH.How does it compare with E1 and E2

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.