Charged-particle coupling and quantum gauge phase
A nonrelativistic spinless particle of signed charge q in electromagnetic potentials has H=(−iħ∇−qA)²/(2m)+qφ and kinetic momentum Π=p−qA.
Key knowledge
A nonrelativistic spinless particle of signed charge q in electromagnetic potentials has H=(−iħ∇−qA)²/(2m)+qφ and kinetic momentum Π=p−qA. The gauge transformation A′=A+∇χ, φ′=φ−∂_tχ, ψ′=exp(iqχ/ħ)ψ preserves the Schrödinger equation and electromagnetic observables.
Values and equations
H=(−iħ∇−qA)²/(2m)+qφ; Π=p−qA; ψ′=e^(iqχ/ħ)ψ
- H,qφ
- Hamiltonian and scalar potential energy J
- m
- Mass kg
- q
- Signed charge C
- A
- Magnetic vector potential T m
- φ
- Electric scalar potential V
- χ
- Gauge function V s
- p,Π
- Canonical/kinetic momentum kg m s⁻¹
- ħ
- Reduced Planck constant J s
- t
- Time s
- ψ
- Position-state wavefunction
Conditions and scope
- External classical potentials, m>0, adequate regularity and boundary/domain conditions; square the full operator without discarding noncommuting derivatives of A.
- Canonical p is gauge dependent; kinetic momentum and field observables are the physical invariant quantities. Electron spin, relativistic corrections and dynamical quantum electromagnetic fields are separate models.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Richard Fitzpatrick / University of Texas at Austin2 sources
Evidence and review
Quantum Mechanics (2016): Charged particle motion: Equations 3.71–3.77: signed-charge SI Hamiltonian, fields and kinetic momentum. Quantum Mechanics (2016): Gauge transformations: Equations 3.90–3.95 and 3.102: potential/state transformation and kinetic-momentum invariance. The source's gauge f is replaced by χ=−f.
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Entry details
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