Guido Burkard

Sep 28, 2023 | link.aps.org | Florian Ginzel |Guido Burkard

We propose a paradigm of multiplexed dispersive qubit measurement performed while the qubits dephase. A Laplace transformation of the time-dependent cavity response allows to separate contributions from multiple qubits coupled to the same resonator mode, thus allowing for simultaneous single-shot readout. With realistic parameters for silicon spin qubits we find a competitive readout fidelity, while the measurement time compares favorably to conventional dispersive readout.

Sep 12, 2023 | link.aps.org | Stephen McMillan |Guido Burkard

A critical element towards the realization of scalable quantum processors is nonlocal coupling between nodes. Scaling connectivity beyond nearest-neighbor interactions requires the implementation of a mediating interaction often termed a quantum bus.

May 4, 2023 | link.aps.org | Philipp M Mutter |Guido Burkard

Abstract We develop a theory describing the transient transmission through noisy qubit-resonator systems with quadratic interactions as are found in superconducting and nanomechanical resonators coupled to solid-state qubits. After generalizing the quantum Langevin equations to arbitrary qubit-resonator couplings, we show that only the cases of linear and quadratic couplings allow for an analytical treatment within standard input-output theory.

Mar 13, 2023 | link.aps.org | Florian Ginzel |Guido Burkard

Abstract Both quantum transport measurements in the Pauli blockade regime and microwave cavity transmission measurements are important tools for spin-qubit readout and characterization. Based on a generalized input-output theory we derive a theoretical framework to investigate how a double quantum dot (DQD) in a transport setup interacts with a coupled microwave resonator while the current through the DQD is rectified by Pauli blockade.