Emission and Absorption Quantum Noise Measurement with an On-Chip Resonant Circuit

Abstract

Using a quantum detector, a superconductor-insulator-superconductor junction, we probe separately the emission and absorption noise in the quantum regime of a superconducting resonant circuit at equilibrium. At low temperature the resonant circuit exhibits only absorption noise related to zero point fluctuations, whereas at higher temperature emission noise is also present. By coupling a Josephson junction, biased above the superconducting gap, to the same resonant circuit, we directly measure the noise power of quasiparticles tunneling through the junction at two resonance frequencies. It exhibits a strong frequency dependence, consistent with theoretical predictions.

Microwave quantum optics and electron transport through a metallic dot strongly coupled to a transmission line cavity

“…Refs. 24-26. Lately also systems with mesoscopic or nanoscale conductors, such as Josephson junctions, [27][28][29] superconducting single electrons transistors 18,28,30 and quantum dots, [31][32][33][34] inserted into microwave cavities have been investigated. In particular, the spectral properties of microwaves emitted from a Josephson junction in the dynamical Coulomb blockade regime were investigated in Ref.…”

“…This will introduce new physical effects, beyond what was investigated in earlier works where electronic transport through conductors in the presence of a thermalized electromagnetic environment was at the focus. [27][28][29][36][37][38][39][40][41] The ultrastrong coupling regime in transport corresponds to a coupling strength between the transport electrons and cavity photons of the order of the fre-quency of the fundamental mode of the cavity. In this regime electrons entering the conductor strongly modify the photon states of the cavity and microwave polarons are formed.…”

Emission of Nonclassical Radiation by Inelastic Cooper Pair Tunneling

“…In such a junction, at bias voltage less than the gap voltage 2∆/e, no quasiparticle excitation can be created in the superconducting electrodes. Thus, a DC current can only flow through the junction when the electrostatic energy 2eV associated to transfer of the charge of a Cooper pair through the circuit is absorbed by modes of the surrounding circuit [12][13][14][15][16][17].In order to obtain a situation in which the quantum nature of the emitted radiation can be probed quantitatively, we place such a dc-biased Josephson junction in an engineered environment made of two series resonators with different frequencies ν a , ν b , as shown in Fig. 1a.…”

Charge transport through ultrasmall single and double Josephson junctions coupled to resonant modes of the electromagnetic environment

“…Although the effect of the resonant EE is well understood and received sufficient experimental support [8,9] and theoretical explanations [10] in the case of a single Josephson junction (JJ), clear experimental data for transport properties is still lacking in the case of a superconducting SET (SSET). The SSET coupled to a lossy transmission line was studied experimentally in Ref.…”

“…For example, high-impedance environment can be created by placing miniature thin-film resistors in the dc leads in the vicinity of the tunnel junction [6,7]. It is also possible to construct an environment with distinct, well-characterized resonance modes [8,9].…”