Quantum state transfer in a XX chain with impurities

ANALIA ZWICK, OMAR OSENDA

JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL

IOP PUBLISHING LTD

Año: 2011 vol. 44 p. 105302 - 105302

1751-8113

One spin excitation states are involved in the transmission of quantum states andentanglement through a quantum spin chain, the localization properties of thesestates are crucial to achieve the transfer of information from one extreme of thechain to the other. We investigate the bipartite entanglement and localizationof the one excitation states in a quantum XX chain with one impurity. Thebipartite entanglement is obtained using the concurrence and the localizationis analyzed using the inverse participation ratio (IPR). Changing the strengthof the exchange coupling of the impurity allows us to control the number oflocalized or extended states. The analysis of the IPR allows us to identifyscenarios where the transmission of quantum states or entanglement can beachieved with a high degree of fidelity. In particular, we identify a regimewhere the transmission of quantum states between the extremes of the chain isexecuted in a short transmission time ∼ N/2, where N is the number of spinsin the chain, and with a large fidelity.