Journal article
Beating the Thermal Limit of Qubit Initialization with a Bayesian Maxwell's Demon
MAI Johnson, MT Mądzik, FE Hudson, KM Itoh, AM Jakob, DN Jamieson, A Dzurak, A Morello
Physical Review X | AMER PHYSICAL SOC | Published : 2022
Abstract
Fault-tolerant quantum computing requires initializing the quantum register in a well-defined fiducial state. In solid-state systems, this is typically achieved through thermalization to a cold reservoir, such that the initialization fidelity is fundamentally limited by temperature. Here, we present a method of preparing a fiducial quantum state with a confidence beyond the thermal limit. It is based on real-time monitoring of the qubit through a negative-result measurement - the equivalent of a "Maxwell's demon"that triggers the experiment only upon the appearance of a qubit in the lowest-energy state. We experimentally apply it to initialize an electron spin qubit in silicon, achieving a g..
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Grants
Awarded by Army Research Office
Funding Acknowledgements
We thank N. Ares and S. Asaad for discussions. The research was supported by the Australian Research Council (Grant No. CE170100012) , the U.S. Army Research Office (Contract No. W911NF-17-1-0200) , and the Australian Department of Industry, Innovation and Science (Grant No. AUSMURI000002) . M. A. I. J. acknowledges the support of an Australian Government Research Training Program Scholarship. We acknowledge support from the Australian National Fabrication Facility (ANFF) . All statements of fact, opinion, or conclusions contained hereinare those of the authors and should not be construed asrepresenting the official views or policies of the U.S.Government