Quantum Scattering: Finding E0 & Estimating Fraction of Particles Transmitted

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SUMMARY

The discussion centers on quantum scattering, specifically the conditions for transmission resonance in a square potential energy well and barrier. The lowest energy E0 for 100% transmission is established as E0 = V0/2, where V0 is the height of the barrier. The participants explore the implications of this energy condition for different particle energies, including E1 and the fraction of particles transmitted through the barrier when V0 = 1.0ħ²/mL². The analysis involves solving the Schrödinger equation across three distinct zones of the potential energy landscape.

PREREQUISITES
  • Understanding of quantum mechanics principles, particularly wave functions and potential wells
  • Familiarity with the Schrödinger equation and its applications in quantum scattering
  • Knowledge of energy levels and transmission resonance in quantum systems
  • Basic concepts of tunneling phenomena in quantum mechanics
NEXT STEPS
  • Study the derivation of transmission coefficients in quantum mechanics
  • Learn about the implications of potential barriers and wells in quantum scattering
  • Explore the mathematical solutions to the Schrödinger equation for different potential shapes
  • Investigate tunneling probabilities and their dependence on barrier height and width
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Students and researchers in quantum mechanics, particularly those focusing on quantum scattering phenomena, potential energy barriers, and tunneling effects in particle physics.

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Homework Statement



A beam of particles, each of mass m and energy E0,is incident on a square potential energy well of width L and depth V0,where 0 <V0 < h(bar)^2\pi^2/2mL^2 . Outside the region of the well, the potential energy is equal to zero. Suppose that E0 is the lowest energy at which a transmission resonance occurs, with 100% of the beam being transmitted and none reflected.

(a)
A second beam of particles, each of mass m and energy E1 is incident
on a square potential energy barrier of width L and height V0. Outside the
region of the barrier, the potential energy is equal to zero. What is the
lowest value of E1 at which a transmission resonance occurs in this
situation, with 100% of the beam being transmitted and none reflected?
Express your answer in terms of E0 and V0.
(b)
A third beam of particles, each of mass m and energy V0/2is
incident on a square potential energy barrier of width L and height V0.
Outside the region of the barrier, the potential energy is equal to zero.
Estimate the fraction of particles that tunnels through the barrier if
V0 =1.0h(bar)^2/mL^2 .
(c)
Suppose that the barrier in part (b) extends from x =0 to x = L and the incident beam travels in the positive x-direction. For x< 0 the energy eigenfunction describing the beam is Aexp(ikx) + Bexp(−ikx), while for x>L it is Fexp(ikx),where k is the wave number and A, B and F are constants. For the conditions described in part (b), what is the value of the ratio |F|/|B|?


Homework Equations





The Attempt at a Solution



Can someone give me help with starting this please?

Is the lowest energy E0 = V0/2 ?

if so how is this derived?
 
Last edited:
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first you need to sketch the problem, so you can understand it well [I've done it for you:smile:], apparently you have three zones as shown bellow

in a general matter, you have to solve the Schrödinger equation in the x direction, you should have 3 equations for this system [one for each zone], you also need to consider the primary conditions to solve it.

hint: with the beam being 100% transmitted, what do you think the energy of the particles in this system should be, E>Vo or E<Vo?
 

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