Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 29: Poster Session: Quantum Information Systems, Quantum Coherence (jointly with SAMOP)

TT 29.11: Poster

Dienstag, 15. März 2011, 18:00–21:00, P1

Non-Equilibrium Transport Properties of a Tunnel Junction Coupled to an Harmonic Oscillator in the Non-Markovian Regime — •Stefan Walter and Björn Trauzettel — Institute for Theoretical Physics and Astrophysics, University of Würzburg, D-97074 Würzburg, Germany

We are interested in the true quantum behavior of the coupled system of a quantum harmonic oscillator and a tunnel junction beyond Born and Markov approximation. The non-equilibrium transport properties of the tunnel junction (I-V characteristics and finite frequency noise) are perturbatively calculated in the tunneling Hamiltonian using the Keldysh formalism. We find that the transport properties of the tunnel junction significantly depend on the properties of the oscillator.

For a non-stationary oscillator, we find a complex noise (in second order in the tunnel amplitudes) which complements the proposal for a momentum detector in Ref. [1].

We further investigate the noise signatures of the oscillator to fourth order in the tunneling similar to Ref. [2]. As in Ref. [1] we additionally include an arbitrary relative phase between the tunnel amplitudes, allowing for the detection of the oscillator’s momentum. The non-equilibrium treatment permits us to extend previous results to the non-Markovian regime.

[1] C. B. Doiron, B. Trauzettel, and C. Bruder., Phys. Rev. Lett. 100, 027202 (2008)

[2] J. Wabnig, J. Rammer, and A. L. Shelankov, Phys. Rev. B 75, 205319 (2007)