234 citations · 1.6k across the 46 of their papers we have counts for
47 papers
Time-Optimal Transport of a Harmonic Oscillator: Analytic Solution
Gerhard C. Hegerfeldt
Motivated by the experimental transport of a trap with a quantum mechanical system modeled as a harmonic oscillator (h.o.) the corresponding classical problem is investigated. Prot…
On the ocean beach -- why elliptic pebbles do not become spherical
Klaus Winzer, Gerhard C. Hegerfeldt
Among pebbles strewn across a sandy ocean beach one can find relatively many with a nearly perfect elliptical (ellipsoidal) shape, and one wonders how this shape was attained and w…
High-Speed Driving of a Two-Level System
Gerhard C. Hegerfeldt
A remarkably simple result is found for the optimal protocol of drivings for a general two-level Hamiltonian which transports a given initial state to a given final state in minima…
Driving at the quantum speed limit: Optimal control of a two-level system
Gerhard C. Hegerfeldt
A remarkably simple result is derived for the minimal time required to drive a general initial state to a final target state by a Landau-Zener type Hamiltonian or, eq…
Discriminating between the von Neumann and Lüders reduction rule
G. C. Hegerfeldt, R. Sala Mayato
Given an ensemble of systems in an unknown state, as well as an observable and a physical apparatus which performs a measurement of on the ensemble, whose detaile…
Symmetries and time operators
G. C. Hegerfeldt, J. G. Muga
All covariant time operators with normalized probability distribution are derived. Symmetry criteria are invoked to arrive at a unique expression for a given Hamiltonian. As an app…