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TT: Fachverband Tiefe Temperaturen

TT 79: Superconductivity: Superconducting Electronics - Circuit QED

TT 79.10: Talk

Thursday, March 15, 2018, 12:00–12:15, H 2053

New Spectroscopic Methods in Quantum Microwave Photonics: Accessing Correlated Noise, and Multiphoton Processes — •Tomás Ramos and Juan José García-Ripoll — Instituto de Física Fundamental IFF CSIC, Calle Serrano 113b, Madrid 28006, Spain

In this talk, we present new methods for characterizing correlated noise and multiphoton scattering processes in experiments with propagating photons in superconducting circuits.

First, we study how correlated dephasing noise is manifested in single-photon scattering experiments. We introduce a general noise model that describes correlated gaussian and non-gaussian noise, 1/f noise, white noise, telegraph noise, etc, and we study how the transmission lineshapes are modified on each case. Only for white noise, the dephasing can be characterized by a constant ’dephasing rate’, but a general dephasing response depends on the photon’s detuning. In addition, we demonstrate a general relation between these spectroscopic measurements and standard time-resolved Ramsey measurements, allowing one to infer the effect of correlated noise in one experiment from the knowledge of the other.

Second, we provide a spectroscopic protocol to characterize photon-photon interactions mediated by a qubit in a transmission line. The experimental method requires coherent state inputs and homodyne detection at the qubit’s output, and it can be generalized to determine the multiphoton scattering matrix of any quantum object [1].
T. Ramos, J.J. García-Ripoll, PRL 119, 153601 (2017).