arXiv:1101.3248 · Physical Review Letters

Noise and Controllability: Suppression of Controllability in Large Quantum Systems

Michael Khasin, Ronnie Kosloff

Published Mar 22, 2011• 13 citations

Abstract

A closed quantum system is defined as completely controllable if an arbitrary unitary transformation can be executed using the available controls. In practice, control fields are a source of unavoidable noise. Can one design control fields such that the effect of noise is negligible on the timescale of the transformation? Complete controllability in practice requires that the effect of noise can be suppressed for an arbitrary transformation. The present study considers a paradigm of control, where the Lie-algebraic structure of the control Hamiltonian is fixed, while the size of the system increases, determined by the dimension of the Hilbert space representation of the algebra. We show that for large quantum systems, generic noise in the controls dominates for a typical class of target transformation; i.e., complete controllability is destroyed by the noise.

DOI: 10.1103/physrevlett.106.123002

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