KIT - Campus South - Wolfgang-Gaede-Str.1
Seminar Room 12.01, Bldg. 30.23 (Physikhochhaus)

28.05.2009

Dr. Neil Oxtoby
Liverpool University, U.K.

15:45

Abstract: Can correlation measurements in a probe system encode information about the environment structure in open quantum systems?
Motivated by efforts in solid-state quantum computation, in a recent paper (http://arxiv.org/abs/0901.4470) we considered a pair of non-interacting qubits as a controllable probe of a non-equilibrium environment of defects/impurities.  The impurities are themselves quantum-coherent two-level systems (TLSs) subject to damping by independent bosonic baths (phonons, for example).  Hence the nomenclature `composite spin-boson environment'.
During this talk, I will present results from the aforementioned paper.  I'll focus on discussing how correlation measurements in the probe system could be exploited to efficiently discriminate between different experimental preparation techniques, with particular emphasis on the quantum correlations (entanglement) that build up in the probe as a result of an indirect, TLS-mediated interaction between the probe qubits.
I'll also discuss the harmful effects that a spin-boson environment has on bipartite qubit state entanglement and entangling gate performance.