Saving Entanglement via a Nonuniform Sequence of $\pi$ Pulses

TL;DR

This paper demonstrates that applying Uhrig's sequence of nonuniform $c0$ pulses can significantly prolong quantum entanglement in bipartite and multiparticle states under dephasing, using exact quantum optical calculations.

Contribution

It shows the effectiveness of Uhrig's nonuniform pulse sequence in preserving quantum entanglement against dephasing noise.

Findings

Uhrig's pulse sequence delays entanglement death

Exact quantum optical results validate pulse effectiveness

Irregular pulse timing outperforms uniform sequences

Abstract

We examine the question of survival of quantum entanglement between the bipartite states and multiparticle states like GHZ states under the action of a dephasing bath by the application of sequence of $\pi$ pulses. We show the great advantage of the pulse sequence of Uhrig [ 2007 {\it Phys. Rev. Lett.} {\bf 98} 100504] applied at irregular intervals of time, in controlling quantum entanglement. In particular death of entanglement could be considerably delayed by pulses. We use quantum optical techniques to obtain exact results.