21 citations · 46 across the 6 of their papers we have counts for
6 papers
Evolution and invariants of free-particle moments
Mark Andrews
Moments are expectation values of products of powers of position and momentum, taken over quantum states (or averages over a set of classical particles). For free particles, the ev…
Evolution of piecewise polynomial wave functions
Mark Andrews
For a non-relativistic particle, we consider the evolution of wave functions that consist of polynomial segments, usually joined smoothly together. These spline wave functions are…
The evolution of oscillator wave functions
Mark Andrews
We consider some of the methods that can be used to reveal the general features of how wave functions evolve with time in the harmonic oscillator. We first review the periodicity p…
The effect of linear terms in a quadratic Hamiltonian
Mark Andrews
For a non-relativistic particle subject to a Hamiltonian that is quadratic in position and momentum, with coefficients that may vary with time, it is shown that the effect of the l…
The evolution of free wave packets
Mark Andrews
We discuss four general features of force-free evolution: (1) The spatial spread of any packet changes with time in a very simple way. (2) Over sufficiently short periods of time (…
Bounds to unitary evolution
Mark Andrews
Upper and lower bounds are established for the survival probability of a quantum state, in terms of the energy moments . Introducing a cut-of…