Exact simulation of multi-qubit dynamics with only three qubits

Centre for Quantum Computation and Physics Department, Clarendon Laboratory Oxford University - Parks Road, OX1 3PU, UK

Received: 15 January 2006
Accepted: 20 February 2006

Abstract

We present equivalence relations which simplify the dynamics of an important class of interacting multi-qubit systems. We show that a wide class of qubit systems, with one or M excitations, can be reduced to an equivalent qubit system with , for any M. The equivalent system faithfully reproduces the overall dynamics of the original one including the entanglement properties. In addition to its direct application to qubit-cavity systems, the formalism offers insight into a variety of situations ranging from decoherence due to a spin-bath with its own internal entanglement, through to energy transfer processes in organic systems such as biological photosynthetic units.