Berlin 2012 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

TT: Fachverband Tiefe Temperaturen

TT 20: Transport: Quantum Coherence and Quantum Information Systems 3 (jointly with MA and HL)

TT 20.7: Talk

Tuesday, March 27, 2012, 11:45–12:00, BH 243

Emission spectrum of a driven nonlinear resonator — •Stephan André^1,2, Lingzhen Guo^1,3, Michael Marthaler^1,2, and Gerd Schön^1,2 — ¹Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany — ²DFG Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany — ³Department of Physics, Beijing Normal University, Beijing 100875, China

Motivated by recent “circuit QED” experiments [1,2] we investigate the properties of coherently driven nonlinear resonators. By using Josephson junctions in superconducting circuits, strong nonlinearities can be engineered, which lead to the appearance of pronounced quantum effects with a low number of photons in the resonator.

Based on a master equation approach we determine the emission spectrum and observe for typical circuit QED parameters, in addition to the primary side-peaks, second-order peaks which are not predicted by a linearized theory. These peaks result from transitions between next-to-nearest levels in the rotating frame and from fluctuations of the oscillation amplitude. We show that an effective Planck constant provides a measure for the importance of the quantum effects.
I. Siddiqi et al., Phys. Rev. B 73, 054510 (2006).
F.R. Ong et al., Phys. Rev. Lett. 106, 167002 (2011).