Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 36: TR: Poster Session

TT 36.25: Poster

Donnerstag, 25. März 2010, 14:00–18:00, Poster A

Dissipative dynamics of a qubit coupled to a nonlinear undriven or driven oscillator — •Carmen Vierheilig, Johannes Hausinger, and Milena Grifoni — Universität Regensburg, 93040 Regensburg, Germany

Coupling a qubit to a nonlinear readout device, for example a DC-SQUID in the nonlinear regime or a Josephson junction bifurcation amplifier, lead to advantages in several measurement schemes and to new physical observations. In this poster we consider the case of a qubit coupled to a nonlinear, driven or undriven, oscillator. The oscillator is in turn coupled to a thermal bath, which thus indirectly induces dissipation and dephasing in the qubit’s dynamics.

In the undriven situation focus is on the regime where the frequency of the linear oscillator nearly equals the qubit’s energy splitting. This yields a multiplicity of quasi-degenerate states of the coupled qubit-nonlinear oscillator system, reflected in a complex dynamics of the qubit towards equilibrium [1].

When an additional ac-field is included, resonant transitions between the multiplets can be induced.

[1] C. Vierheilig, J. Hausinger, and M. Grifoni, Phys. Rev. A 80, 052331 (2009)