Time-dependent invariants for dirac equation and Newton–Wigner position operator
Vladimir I. Man’ko, R. Vilela Mendes
For Dirac equation, operator-invariants containing explicit time-dependence in parallel to known time-dependent invariants of nonrelativistic Schrödinger equation are introduced and discussed. As an example, a free Dirac particle is considered and new invariants are constructed for it. The integral of motion, which is initial Newton-Wigner position operator, is obtained explicitly for a free Dirac particle. For such particle with kick modeled by delta-function of time, the time-depending integral, which has physical meaning of initial momentum, is found.
arXiv:quant-ph/9702035•Physica Scripta•Nov 1, 1997•5 citations