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TT: Tiefe Temperaturen
TT 29: Transport: Quantum Coherence and Quantum Information Systems - Part 1
TT 29.3: Talk
Thursday, March 30, 2006, 10:15–10:30, HSZ 304
Excitation and Entanglement Transfer and Quantum Critical Points — •Michael J. Hartmann1,2, Moritz E. Reuter1,2, and Martin B. Plenio1,2 — 1Institute for Mathematical Sciences, Imperial College London, SW7 2PE, UK. — 2QOLS, The Blackett Laboratory, Imperial College London, SW7 2BW, UK.
We consider analytically and numerically quantum many body systems as quantum channels in the vicinity of their quantum critical point. In our setup two ancillas are weakly coupled to the quantum many body system at different sites and we study the propagation of an excitation and quantum information from one ancilla to the other. We observe two different scenarios: A slow but perfect transfer if the gap between the ground state and the first excited state of the system is large and a fast but un-complete transfer otherwise. We provide a simplified physical model explaining our findings and suggest ways in which they may be employed to detect quantum critical points experimentally.