Time-Domain Spectroscopy of Mesoscopic Conductors Using Voltage Pulses

The development of single-electron sources are paving the way for a novel type of experiments in which individual electrons are emitted into a quantum-coherent circuit. However, to facilitate further progress towards fully coherent on-chip experiments with electrons, a detailed understanding of the quantum circuits is needed. We propose to perform time-domain spectroscopy of mesoscopic conductors by applying Lorentzian-shaped voltage pulses to an input contact. We show how characteristic timescales of a quantum-coherent conductor can be extracted from the distribution of waiting times between charge pulses propagating through the circuit. To illustrate our idea, we employ Floquet scattering theory to evaluate the electron waiting times for an electronic Fabry-Pérot cavity and a Mach-Zehnder interferometer. Our spectroscopic method benefits from the particle-like behavior of the charge pulses, while still being sensitive to their quantum statistics. This unique combination makes our scheme promising for the characterization of quantum-coherent circuits.

P. Burset, J. Kotilahti, M. Moskalets, C. Flindt, arXiv:1808.10204.