Abstract

, We investigate tripartite entanglement in an open quantum system, specifically three qubits, all of which are damped, and one of which is driven. We address a systematic approach in calculating the entanglement of various bipartite splits using concurrence as a measure of entanglement Our calculations are based on a direct detection scheme (quantum jump method - with and without knowledge of which qubit jumps) that is a particular unravelling of the density matrix. Our results are unravelling dependent, but apply to applications of entanglement based on direct detection. We also calculate the ’Three-way tangle’ or ’Residual Entanglement’ for this system. We present calculations for a variety of driving and damping rates, and examine what decay rate is adequate for the system to be reduced to two qubits with a readout port. We also consider how knowledge (or not) of which qubit decays affects the entanglement.

© 2012 Optical Society of America