Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 57: Transport: Fluctuations and Noise (jointly with CPP, DY)

TT 57.3: Talk

Wednesday, March 18, 2015, 12:00–12:15, H 3005

Waiting-time distribution of light from superconducting resonators coupled to voltage-biased Josephson junctions — •Simon Dambach, Björn Kubala, Vera Gramich, and Joachim Ankerhold — Institute for Complex Quantum Systems, Ulm University, Ulm, Germany

The interplay of the tunneling transfer of charges and the emission and absorption of light can be investigated in a set-up, where a voltage-biased Josephson junction is placed in series to a microwave cavity. In such devices measurements of the emitted microwave radiation can yield information about the Cooper pair current and its fluctuations and vice versa.

Due to the inherent nonlinearity of the Josephson junction tunneling Cooper-pairs can create a variety of non-classical states of light already at weak driving. Depending on experimental parameters and tuning, the device can be described by effective Hamiltonians, indicating specific photon creation mechanisms which lead to strongly bunched or anti-bunched light emission [1].

We will use the waiting-time distribution [2] of emitted photons to highlight how charge quantization of the Cooper pair current drives a crossover from a coherent light source to a single-photon source. Analytical results for the weak driving regime, based on a quantum regression approach, are complemented by numerical results for the full nonlinear quantum case.

[1] B. Kubala, V. Gramich, and J. Ankerhold, arXiv:1404.6259.

[2] T. Brandes, Ann. Phys. (Berlin) 17, 477 (2008).