Quantum detectors for the third cumulant of current fluctuations

Abstract

We consider the measurement of the third cumulant of current fluctuations arising from a point contact, employing the transitions that they cause in a quantum detector connected to the contact. We detail two generic detectors: a quantum two-level system and a harmonic oscillator. In these systems, for an arbitrary relation between the voltage driving the point contact and the energy scales of the detectors, the results can be expressed in terms of an effective detector temperature T_eff. The third cumulant can be found from the dependence of T_eff on the sign of the driving voltage. We find that proper ordering of the fluctuation operators is relevant in the analysis of the transition rates. This is reflected in the effective Fano factor for the third cumulant measured in such setups: it depends on the ratio of the voltage and an energy scale describing the circuit where the fluctuations are produced.

12+ pages, 8 figures

References in corpus (6)

• Spectroscopy on two coupled flux qubits
• Counting statistics and super-Poissonian noise in a quantum dot
• Temperature dependent third cumulant of tunneling noise
• Frequency-dependent current correlation functions from scattering theory
• Qubits as devices to detect the third moment of current fluctuations
• Circuit theory for noise in incoherent normal-superconducting dot structures

Cited by in corpus (6)

• DMRG-study of current and activity fluctuations near non-equilibrium phase transitions
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• Quasiprobabilistic Interpretation of Weak measurements in Mesoscopic Junctions
• Josephson junctions as detectors for non-Gaussian noise
• Coherent interaction-free detection of noise
• Absence of skewness in the voltage fluctuations of a tunnel junction in the quantum regime