Physlib.QuantumMechanics.RectangularBarrier.Basic
The rectangular potential barrier
i. Overview
The rectangular potential barrier in one dimension provides the simplest example of quantum tunnelling. A particle of mass `m` is subject to a piece-wise constant potential which is `V₀` on a closed interval and zero elsewhere.
ii. Key results
iii. Table of contents
- A. Basic properties - B. Potential function - C. Hilbert space - D. Operators - D.1. Kinetic - D.2. Potential - D.3. Hamiltonian - E. As a quantum system
iv. References
A. Basic properties
B. Potential function
C. Hilbert space
D. Operators
D.1. Kinetic
D.2. Potential
D.3. Hamiltonian
E. As a quantum system
13 declarations
The mass of the particle is positive ()
For a rectangular potential barrier system , the mass of the particle is strictly positive, satisfying .
The mass is non-negative ()
In the context of a rectangular potential barrier system, let be the mass of the particle. This theorem states that the mass is non-negative, satisfying .
The mass is non-zero ()
For a particle of mass in a rectangular potential barrier system, the mass is non-zero, denoted as .
Potential function for a rectangular barrier
For a one-dimensional rectangular potential barrier , the potential function maps a position to the barrier height if lies within the closed interval (defined by the lower bound and upper bound ), and to otherwise. Mathematically, it is defined as .
The potential function for a rectangular barrier equals
For a one-dimensional rectangular potential barrier with barrier height , lower bound , and upper bound , the potential function is defined by the indicator function of the closed interval . Specifically, for a position , if and otherwise. Mathematically, this is expressed as: where denotes the indicator function on the interval .
The potential function is a.e. strongly measurable
For a quantum mechanical rectangular barrier, the potential function , which is defined as on the closed interval and zero elsewhere, is almost everywhere (a.e.) strongly measurable.
Hilbert space for the 1D rectangular barrier
The Hilbert space for a one-dimensional rectangular potential barrier is defined as the space of square-integrable functions mapping from the 1-dimensional real space to the complex numbers .
Kinetic energy operator for the rectangular barrier
For a one-dimensional rectangular potential barrier with particle mass , the kinetic energy operator is the partial linear map on the Hilbert space defined as , where is the momentum-squared operator. In terms of the wavefunction in the domain, this operator acts as .
Potential operator for the rectangular barrier
For a one-dimensional rectangular potential barrier , the potential operator is the partially defined linear operator on the Hilbert space defined by multiplication by the potential function . For a wave function in its domain, the operator maps to the product , where is the real-valued potential function of the barrier (mapped to the complex numbers).
The potential operator is self-adjoint
In the quantum mechanical model of a one-dimensional rectangular potential barrier, the potential operator acting on the system's Hilbert space is self-adjoint.
Hamiltonian for the rectangular potential barrier
In the quantum mechanical model of a one-dimensional rectangular potential barrier, the Hamiltonian operator is defined as the sum of the kinetic energy operator and the potential energy operator , acting on the Hilbert space .
The Hamiltonian for the rectangular barrier is essentially self-adjoint
The Hamiltonian operator associated with a one-dimensional rectangular potential barrier is essentially self-adjoint.
Quantum system of the rectangular potential barrier
The definition characterizes the one-dimensional quantum mechanical system of a particle of mass subject to a rectangular potential barrier of height . This system is defined by the Hilbert space and its associated self-adjoint Hamiltonian operator , where is the kinetic energy operator and is the potential energy operator corresponding to a potential that is on a closed interval and zero elsewhere.
