APS Logo

Universal qubit control through FPGA-accelerated qubit classification, Hamiltonian estimation and real-time feedback [Part 2]

ORAL

Abstract

Gate-controlled spin qubits are a promising platform for implementing quantum processors [1,2] and now operate near the error-correctable threshold [3]. To correct errors, however, fast real-time feedback based on qubit measurements must be executed within the qubit coherence time. Moreover, continuous real-time feedback is also useful to tune and calibrate the qubit environment in order to maintain high fidelity gates and long coherence times.

Here, we use a singlet-triplet qubit implemented in a gallium arsenide double dot and FPGA-based single-shot readout classification on an OPX+ pulse processor (Quantum Machines [4]) to perform real-time Hamiltonian estimation [5]. The fluctuating Overhauser gradient within the double dot is estimated on-the-fly, based on single-shot classifications of separated singlet pairs, enabling coherent spin rotations of the electron pair. Together with exchange rotations, this method yields universal qubit control of a GaAs spin qubit without requiring a micromagnet or nuclear polarization protocols.



[1] A.M.J. Zwerver et al., Nat. Electron. 5, 184-190 (2022)

[2] S.G.J. Philips et al., Nature 609, 919-924 (2022)

[3] A. Noiri et al., Nature 601, 338–342 (2022)

[4] https://www.quantum-machines.co/opx+/

[5] M. Shulman et al., Nat. Comm., 5(1), 5156 (2014)

–

Presenters

  • Fabrizio Berritta

    Niels Bohr Institute, University of Copenhagen

Authors

  • Fabrizio Berritta

    Niels Bohr Institute, University of Copenhagen

  • Torbjørn R Rasmussen

    Niels Bohr Institute, University of Copenhagen

  • Joost van der Heijden

    Quantum Machines, QDevil

  • Federico Fedele

    Niels Bohr Institute, University of Copenhagen, University of Oxford, University Of Oxford

  • Jan A Krzywda

    Polish Academy of Sciences, Institute of Physics Polish Academy of Sciences

  • Saeed Fallahi

    Purdue University, Microsoft Quantum Purdue, Physics and Astronomy, Purdue University, Purdue University

  • Geoff C Gardner

    Purdue University, Materials Engineering, Purdue University, Department of Physics and Astronomy, Birck Nanotechnology Center, Purdue University

  • Michael J Manfra

    Purdue University, Microsoft Quantum Purdue, Purdue University, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA; Microsoft Quantum Lab, Purdue University, West Lafayette, IN, USA, Physics and Astronomy, Purdue University, Department of Physics and Astronomy, Birck Nanotechnology Center, School of Electrical and Computer Engineering and Microsoft Quantum Lab West Lafayette, Purdue University, Department of Physics and Astronomy and Nanotechnology Center Purdue University, Microsoft Quantum Lab West Lafayette, Department of Physics and Astronomy, Birck Nanotechnology Center, School of Materials Engineering and School of Electrical and Computer Engineering, Purdue University

  • Evert Van Nieuwenburg

    Niels Bohr Institute, University of Copenhagen

  • Jeroen Danon

    Norwegian Univ Tech (NTNU), Norwegian University of Science and Technology

  • Anasua Chatterjee

    Niels Bohr Institute, University of Copenhagen, Univ of Copenhagen

  • Ferdinand Kuemmeth

    Niels Bohr Institute, University of Copenhagen, Niels Bohr Institute, University of Copenhagen. Quantum Machines, QDevil, Niels Bohr Inst