Quantum driving of a two level system: quantum speed limit and superadiabatic protocols – an experimental investigation
Authors: Malossi N., Bason M.G., Viteau M., Arimondo E., Ciampini D., Mannella R., Morsch O.
Autors Affiliation: Università di Pisa Dipartimento di Fisica ‘E. Fermi’, Lgo Pontecorvo 3, I-56127 Pisa, Italy; INO-CNR, Dipartimento di Fisica ‘E. Fermi’, Lgo Pontecorvo 3, I-56127 Pisa, Italy; CNISM UdR Pisa, Dipartimento di Fisica ‘E. Fermi’, Lgo Pontecorvo 3, I-56127 Pisa, Italy
Abstract: A fundamental requirement in quantum information processing and in many other areas of science is the capability of precisely controlling a quantum system by preparing a quantum state with the highest fidelity and/or in the fastest possible way. Here we present an experimental investigation of a two level system, characterized by a time-dependent Landau-Zener Hamiltonian, aiming to test general and optimal high-fidelity control protocols. The experiment is based on a Bose-Einstein condensate (BEC) loaded into an optical lattice, then accelerated, which provides a high degree of control over the experimental parameters. We implement generalized Landau-Zener sweeps, comparing them with the well-known linear Landau-Zener sweep. We drive the system from an initial state to a final state with fidelity close to unity in the shortest possible time (quantum brachistochrone), thus reaching the ultimate speed limit imposed by quantum mechanics. On the opposite extreme of the quantum control spectrum, the aim is not to minimize the total transition time but to maximize the adiabaticity during the time-evolution, the system being constrained to the adiabatic ground state at any time. We implement such transitionless superadiabatic protocols by an appropriate transformation of the Hamiltonian parameters. This transformation is general and independent of the physical system.
Journal/Review: JOURNAL OF PHYSICS. CONFERENCE SERIES
Volume: 442 Pages from: 012062 to: 012062
KeyWords: Bose-Einstein condensate; Optical lattice; Adiabatic evolution; Fidelity; DOI: 10.1088/1742-6596/442/1/012062Citations: 4data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2020-01-12References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here