Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 6: Superconductivity: Tunnelling & Josephson Junctions
TT 6.9: Talk
Monday, March 11, 2013, 11:45–12:00, H18
Quantum critical temperature of a modulated oscillator — Lingzhem Guo1,2, Vittorio Peano3, •Michael Marthaler1, Gerd Schön1, and Mark Dykman3 — 1Institut für Theoretische Festkörperphysik — 2Department of Physics, Beijing Normal University, Beijing 100875, China — 3Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
We show that the rate of switching between the vibrational states of a modulated nonlinear oscillator is characterized by a quantum critical temperature Tc∝ℏ2. The rate is independent of T for T<Tc. Above Tc there emerges a quantum crossover region where the slope of the logarithm of the distribution over the oscillator states displays a kink and the change of the switching rate with T is independent of the modulation. The results demonstrate the limitations of the conventional instanton theory of switching in systems lacking detailed balance.