Parametric longitudinal coupling between a high-impedance superconducting resonator and a semiconductor quantum dot singlet-triplet spin qubit

C G L Bøttcher; S P Harvey; S Fallahi; G C Gardner; M J Manfra; U Vool; S D Bartlett; A Yacoby

doi:10.1038/s41467-022-32236-w

Parametric longitudinal coupling between a high-impedance superconducting resonator and a semiconductor quantum dot singlet-triplet spin qubit

Nat Commun. 2022 Aug 15;13(1):4773. doi: 10.1038/s41467-022-32236-w.

Authors

C G L Bøttcher¹, S P Harvey^{2

3}, S Fallahi⁴, G C Gardner⁴, M J Manfra^{4

5

6

7}, U Vool^{2

8}, S D Bartlett⁹, A Yacoby²

Affiliations

¹ Department of Physics, Harvard University, Cambridge, MA, 02138, USA. cboettcher@g.harvard.edu.
² Department of Physics, Harvard University, Cambridge, MA, 02138, USA.
³ Stanford University, Stanford, CA, 94305, USA.
⁴ Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA.
⁵ School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA.
⁶ Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA.
⁷ School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA.
⁸ John Harvard Distinguished Science Fellowship, Harvard University, Cambridge, MA, 02138, USA.
⁹ Centre for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, NSW, 2006, Australia.

Abstract

Coupling qubits to a superconducting resonator provides a mechanism to enable long-distance entangling operations in a quantum computer based on spins in semiconducting materials. Here, we demonstrate a controllable spin-photon coupling based on a longitudinal interaction between a spin qubit and a resonator. We show that coupling a singlet-triplet qubit to a high-impedance superconducting resonator can produce the desired longitudinal coupling when the qubit is driven near the resonator's frequency. We measure the energy splitting of the qubit as a function of the drive amplitude and frequency of a microwave signal applied near the resonator antinode, revealing pronounced effects close to the resonator frequency due to longitudinal coupling. By tuning the amplitude of the drive, we reach a regime with longitudinal coupling exceeding 1 MHz. This mechanism for qubit-resonator coupling represents a stepping stone towards producing high-fidelity two-qubit gates mediated by a superconducting resonator.

Grants and funding

GBMF 9468/Gordon and Betty Moore Foundation (Gordon E. and Betty I. Moore Foundation)