Potential barrier Definition and 83 Threads

In quantum mechanics, the rectangular (or, at times, square) potential barrier is a standard one-dimensional problem that demonstrates the phenomena of wave-mechanical tunneling (also called "quantum tunneling") and wave-mechanical reflection. The problem consists of solving the one-dimensional time-independent Schrödinger equation for a particle encountering a rectangular potential energy barrier. It is usually assumed, as here, that a free particle impinges on the barrier from the left.
Although classically a particle behaving as a point mass would be reflected if its energy is less than




V

0




{\displaystyle V_{0}}
, a particle actually behaving as a matter wave has a non-zero probability of penetrating the barrier and continuing its travel as a wave on the other side. In classical wave-physics, this effect is known as evanescent wave coupling. The likelihood that the particle will pass through the barrier is given by the transmission coefficient, whereas the likelihood that it is reflected is given by the reflection coefficient. Schrödinger's wave-equation allows these coefficients to be calculated.

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  1. Rhdjfgjgj

    Potential barrier problem in mechanics

    Here our sir said if I would apply energy conservation b/w initial point and B , we would get it wrong. But If I apply between initial point and D , we would get it right. He didn't tell why. Could anyone just explain why. One reason I thought was that since the question asked for minimum...
  2. ValeForce46

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  3. M

    I Potential step and tunneling effect

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  4. Leonardo Muzzi

    I Can an electron quantum tunnel inside the potential barrier?

    When I see explanations for quantum tunneling, the discussion is around the probability of an electron manifesting itself before the potential barrier, and after the potential barrier. However, looking at the curves draw, there is a non-zero probability (the evanescent part of the wave) inside...
  5. T

    Quantum tunneling: T(E) graph for a potential barrier diagram

    This is the V(x) diagrams and what I am thinking (really not sure though) is that for the first one you the energy has to reach V2 before it can start transmitting and the graph can take off from T=0, since there is an increase in energy potential that is V2. And as the energy increases, the...
  6. Haynes Kwon

    I Probability flux inside the finite potential barrier

    In Bransden textbook, it is stated that the probability current density is constant since we are dealing with 1-d stationary states. It gives probability flux outside the finite potential barrier which I verified to be constant with respect to x, but it doesn't provide the probability current...
  7. J

    Finding the expected value of position in a Potential Well

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  8. Clara Chung

    I Question about the solution of TISE (finite potential barrier)

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  9. M

    Stuck on Quantum Mechanics Potential Steps Problem?

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  10. B

    I Tunneling through a finite potential barrier

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  11. E

    Probability of penetrating a potential barrier

    Homework Statement The probability for a particle of energy E<<V0 to penetrate a potential barrier of height V0 and width d is approximately \frac{16E}{V_0}exp\left[\frac{-2d\sqrt{2m(V_0-E)}}{\hbar}\right]. An electron moves between two potential barriers of height V0 and 2v0 that are of widths...
  12. D

    I Does a Delta Potential Barrier Allow for Bound Solutions?

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  13. S

    Infinite Square Well, Potential Barrier and Tunneling

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  14. S

    Centrifugal term in mechanical energy in gravitation

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  15. I

    Potential barrier, reflection coefficient

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  16. Chip

    Penetrating the Rectangular Potential Barrier, E < V0

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  17. Chip

    Penetrating the Rectangular Potential Barrier, E < V0

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  18. H

    100% transmission through a potential barrier

    A particle of energy ##E## is incident upon a potential barrier of potential ##V_0## and of thickness ##a##. Given that ##E>V_0##, the transmission coefficient is given by If destructive interference occurs when the path difference between the two reflected waves (at points ##x=0##...
  19. I

    What does the potential barrier energy measure?

    The energy of an incident charged particle refers to its kinetic energy. What does the potential barrier energy refer to qualitatively? EDIT: Is it just in reference to the "potential barrier" in the classical sense? where if the particle has less than the energy V, then it doesn't go through...
  20. Summer95

    Algebra in potential barrier problem

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  21. D

    Particle waves through a potential barrier

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  22. Joy Prakash Das

    Wave function for a potential barrier

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  23. B

    Transmission Coefficient for Quantum Barrier

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  24. X

    What is potential barrier against the photon penetration

    It is known that the penetration depth of photon into a material depends on the energy of the photon, density and atomic number of the material; because the photon energy is normally smaller than the potential against the penetration of photon, which is the potential barrier, so the incident...
  25. G

    Rectangular Potential Barrier Boundary Conditions with E=V

    Homework Statement I am trying to calculate the transmission and reflection coefficients for rectangular finite potential barrier between (-a, a) for a particle of mass m with energy equal to the height of the barrier (E = V0 > 0). Homework Equations...
  26. K

    Quantum physics potential barrier R and T

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  27. kq6up

    Delta Function Potential Barrier

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  28. J

    Potential Barrier for different types of junctions

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  29. L

    Potential barrier. Schroedinger equation.

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  30. R

    Help with Potential Barrier question

    I have always understood (As well as I can) potential barrier questions, but this one has stumped me, and I was hoping someone could point out where my thinking has gone wrong. The wave function of an electron of mass m incident to the step from x = -∞ with energy E < V is = eikx + ρe-ikx for...
  31. M

    Solving Schrod. Eqn. for Potential Barrier with E > V

    I have a question that's driving me insane and I'm sure there's a simple answer that I'm missing for some reason, but I'm not getting my a-ha moment. Consider 2 cases from intro QM: Infinite square well Potential barrier with E > V0 For the infinite square well, the Schrodinger eqn...
  32. H

    Number of standing waves in a potential barrier

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  33. H

    Possible Rectangular Potential Barrier Transmission Problem

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  34. Z

    Eigenfunction & Potential Barrier

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  35. A

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  36. dexterdev

    Conceptual difference between potential barrier & potential difference

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  37. J

    Potential Barrier help starting problem

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  38. Y

    Who does or sees an experiment on rectangluar potential barrier?

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  39. R

    Potential Barrier (quantum mechanics)

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  40. J

    Description of a wave packet incident on a square potential barrier

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  41. A

    Calculation of ion flux across potential barrier

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  42. fluidistic

    Potential barrier in QM problem with coefficient of transmission

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  43. fluidistic

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  44. G

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  45. M

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  46. O

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  47. X

    Infinite potential barrier question.

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  48. P

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  49. R

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  50. Z

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