Hamburg 2009 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 5: Quanteninformation: Konzepte I
Q 5.3: Talk
Monday, March 2, 2009, 11:15–11:30, VMP 6 HS-D
Manipulating entanglement sudden death of two-qubit X-states in zero- and finite-temperature reservoirs — •Mazhar Ali1, Gernot Alber1, and Ravi Rau2 — 1Institut für Angewandte Physik, Technische Universität Darmstadt, D-64289, Germany — 2Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
The finite-time end of quantum entanglement or entanglement sudden death (ESD) has been investigated both theoretically and experimentally. In many situations however it is of interest to stabilize quantum states against ESD. Recently, we have shown that, it is possible to hasten, delay or even avert ESD in zero-temperature reservoirs [1]. Generalizing these first results it is demonstrated that ESD of two qubits interacting with statistically uncorrelated thermal reservoirs can also be controlled by application of simple local unitary transformations. In particular, for initially prepared X-states of two qubits a simple (necessary and sufficient) criterion for ESD can be derived with the help of the Peres-Horodecki criterion. Based on this criterion it is possible to prove that, in contrast to the zero-temperature case, at finite temperatures of at least one of the reservoirs all initially prepared two-qubit X-states exhibit ESD. General conditions are derived under which ESD can be hastened, delayed, or averted [2].
[1] A. R. P. Rau, M. Ali, and G. Alber, Eur. Phys. Lett. 82, 40002 (2008).
[2] M. Ali, G. Alber, and A. R. P. Rau, arXiv: quant-ph/0810.2936 (To appear in J. Phys. B)