Publications associated with Superconducting Quantum Devices

Probing the Fluctuations of Optical Properties in Time-Resolved Spectroscopy.

Physical review letters 119 (2017) 187403-187403

F Randi, M Esposito, F Giusti, O Misochko, F Parmigiani, D Fausti, M Eckstein

We show that, in optical pump-probe experiments on bulk samples, the statistical distribution of the intensity of ultrashort light pulses after interaction with a nonequilibrium complex material can be used to measure the time-dependent noise of the current in the system. We illustrate the general arguments for a photoexcited Peierls material. The transient noise spectroscopy allows us to measure to what extent electronic degrees of freedom dynamically obey the fluctuation-dissipation theorem, and how well they thermalize during the coherent lattice vibrations. The proposed statistical measurement developed here provides a new general framework to retrieve dynamical information on the excited distributions in nonequilibrium experiments, which could be extended to other degrees of freedom of magnetic or vibrational origin.

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