Optimizing stochastic trajectories in exact quantum-jump approaches of interacting systems

Journal Article · Fri Jul 15 04:00:00 EDT 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.72.013805· OSTI ID:20718416

Lacroix, Denis ^[1]

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1. Laboratoire de Physique Corpusculaire, ENSICAEN and Universite de Caen, IN2P3-CNRS, Blvd du Marechal Juin 14050 Caen (France)

The quantum-jump approach, where pairs of state vectors follow the stochastic Schroedinger equation (SSE) in order to treat the exact quantum dynamics of two interacting systems, is described. In this work the nonuniqueness of such stochastic Schroedinger equations is investigated to propose strategies to optimize the stochastic paths and reduce statistical fluctuations. In the proposed method, called the 'adaptative noise method', a specific SSE is obtained for which the noise depends explicitly on both the initial state and on the properties of the interaction Hamiltonian. It is also shown that this method can be further improved by introduction of a mean-field dynamics. The different optimization procedures are illustrated quantitatively in the case of interacting spins. A significant reduction of the statistical fluctuations is obtained. Consequently a much smaller number of trajectories is needed to accurately reproduce the exact dynamics as compared to the SSE without optimization.

• OSTI ID: 20718416
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 1 Vol. 72; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
FLUCTUATIONS
HAMILTONIANS
MEAN-FIELD THEORY
NOISE
OPTIMIZATION
QUANTUM MECHANICS
SCHROEDINGER EQUATION
SPIN
STOCHASTIC PROCESSES
VECTORS