Coherent control in a decoherence-free subspace of a collective multi-level system

Abstract

Decoherence-free subspaces (DFS) in systems of dipole-dipole interacting multi-level atoms are investigated theoretically. It is shown that the collective state space of two dipole-dipole interacting four-level atoms contains a four-dimensional DFS. We describe a method that allows to populate the antisymmetric states of the DFS by means of a laser field, without the need of a field gradient between the two atoms. We identify these antisymmetric states as long-lived entangled states. Further, we show that any single-qubit operation between two states of the DFS can be induced by means of a microwave field. Typical operation times of these qubit rotations can be significantly shorter than for a nuclear spin system.

15 pages, 11 figures

References in corpus (3)

• A Magnetic Resonance Realization of Decoherence-Free Quantum Computation
• Theory of Initialization-Free Decoherence-Free Subspaces and Subsystems
• Experimental Fault-Tolerant Quantum Cryptography in a Decoherence-Free Subspace

Cited by in corpus (5)

• Incoherent Control of Locally Controllable Quantum Systems
• Super- and subradiant emission of two-level systems in the near-Dicke limit
• Multi-particle decoherence free subspaces in extended systems
• Dipole-dipole interaction between orthogonal dipole moments in time-dependent geometries
• Breakdown of the few-level approximation in collective systems