Photon-mediated electron transport in hybrid circuit-QED

Abstract

-We investigate photon-mediated transport processes in a hybrid circuit-QED structure consisting of two double quantum dots coupled to a common microwave cavity. Under suitable resonance conditions, electron transport in one double quantum dot is facilitated by the transport in the other dot via photon-mediated processes through the cavity. We calculate the average current in the quantum dots, the mean cavity photon occupation, and the current cross-correlations with both a full numerical simulation and a recursive perturbation scheme that allows us to include the influence of the cavity order-by-order in the couplings between the cavity and the quantum dot systems. We can then clearly identify the photon-mediated transport processes.Introduction. -Hybrid structures that combine electronic and photonic degrees of freedom in on-chip circuit-QED architectures are currently undergoing a rapid development [1]. A series of recent experiments [2,3] have shown that controllable coupling between electronic transport in quantum dot structures and a single mode of the electromagnetic field in a microwave cavity is now achievable. Several experiments have realized both a single quantum dot and two tunnel-coupled quantum dots interacting with a microwave resonator [2]. Very recently two quantum dots were successfully coupled to distant parts of a common cavity resonator, and photon-mediated interaction between the spatially separated quantum dot circuits was reported [3].These experimental advances are now fueling an increasing theoretical interest in understanding and predicting the physics of hybrid circuit-QED structures [1,4]. A number of proposals [5] have already considered the coupling of electronic spins in quantum dots to microwave resonators. In parallel, other works [6] have focused on the influence of cavity resonators on the transport properties of nearby quantum dot systems. A very recent work [7] expands theoretically on the experimental setup from Ref.[3] by considering two separated double quantum dots (DQDs) connected to the same cavity mode. With the DQDs weakly coupled to electronic leads at finite voltages, this system displays intriguing Tavis-Cummings physics, non-local charge transport and electronic entan-

Tunable photonic cavity coupled to a voltage-biased double quantum dot system: Diagrammatic nonequilibrium Green's function approach

“…On a more general front, we plan to extend the present formalism to spin systems coupled to light degrees of freedom [63,64], further driven out of equilibrium by a source-drain voltage realized in experiments on hybrid quantum systems [28,65,66]. …”

Non-equilibrium correlations and entanglement in a semiconductor hybrid circuit-QED system

“…In this large-voltage regime, the results are essentially independent on the electronic reservoir temperature and are valid at arbitrary couplings to the reservoirs. This large-voltage regime is also analysed in [26], where some overlapping results about photon-mediated transport and finite shot noise cross-correlations have been reported.…”

“…In these hybrid structures, the semiconducting QDs are typically coupled to normal electronic reservoirs such that electronic transport may be used to characterize/modify the properties of the circuit-QED system. Although this possibility had remained largely unexplored, except for some works analysing the transport-induced lasing states in the resonator [20][21][22][23][24], these kind of setups are now attracting growing theoretical attention [25,26].…”

Single-electron double quantum dot dipole-coupled to a single photonic mode

“…Recent theoretical work on coupling semiconductor quantum dots with superconducting transmission line resonators [1][2][3][4][5][6][7][8] has promised novel research avenues towards a well-controlled coherent interface between electronic quantum dot excitations and quantized microwave frequency fields. On the experimental side, pioneering experiments [9][10][11][12][13][14][15] have demonstrated electrical dipole coupling between electrons confined into quantum dots and the microwave photons stored into a resonator by measuring dispersive and dissipative effects in the resonant transmission of photons through the resonator.…”