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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-4306
DTSTART:20161128T170000Z
DURATION:PT1H0M0S
DTSTAMP:20260414T051537Z
LAST-MODIFIED:20161128T143832Z
LOCATION:5310 Chamberlin Hall
SUMMARY:High-fidelity entangling gate for double-quantum-dot spin qubi
 ts\, R. G. Herb Condensed Matter Seminar\, John Nichol\, University of
  Rochester
DESCRIPTION:Electron spins in semiconductors are promising qubits\, be
 cause their long coherence times enable nearly a billion coherent quan
 tum gate operations. However\, developing a scalable high-fidelity two
 -qubit gate remains challenging. We discuss a new entangling gate betw
 een two double-quantum-dot spin qubits in GaAs\, which uses a magnetic
  field gradient between the two dots in each qubit to suppress decoher
 ence due to charge noise. When the magnetic gradient dominates the vol
 tage-controlled exchange interaction between electrons\, qubit coheren
 ce times increase by an order of magnitude. Using randomized benchmark
 ing\, we measure single-qubit gate fidelities of approximately 99%\, a
 nd through self-consistent quantum measurement\, state\, and process t
 omography\, we measure an entangling gate fidelity of 90%. In the futu
 re\, operating double quantum dot spin qubits with large gradients in 
 nuclear-spin-free materials\, such as Si\, should enable a two-qubit g
 ate fidelity surpassing the threshold for fault tolerant quantum infor
 mation processing.
URL:https://www.physics.wisc.edu/events/?id=4306
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