Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 71: Quantum Information Systems (joint session HL/TT)
TT 71.2: Vortrag
Mittwoch, 14. März 2018, 15:15–15:30, EW 203
Synchronized high-fidelity quantum gates in Si/SiGe double quantum dots — •Maximilian Russ1, D. M. Zajac2, A. J. Sigillito2, F. Borjans2, J. M. Taylor3, J. R. Petta2, and Guido Burkard1 — 1Department of Physics, University of Konstanz, D-78457 Konstanz, Germany — 2Department of Physics, Princeton University, Princeton, NJ 08544, USA — 3JQI and QuICS, NIST and University of Maryland, College Park, MD 20742, USA
Motivated by recent experiments [1], we theoretically describe a high-fidelity controlled-NOT (CNOT) gate using the exchange interaction between the spins in neighboring quantum dots subject to a magnetic field gradient from a micromagnet. We use a combination of analytical calculations and numerical simulations to provide the optimal pulse sequences and parameter settings for the gate operation [2]. We present a synchronization method which avoids detrimental spin flips when the state of the control qubit is | 0⟩, and provide details about phase mismatches accumulated during the two-qubit gate. By synchronizing the resonant and off-resonant transitions and compensating these phase mismatches by phase control the overall gate fidelity can be increased significantly. Numerical simulations demonstrate a high tolerance towards charge noise coupled to the two spins due to a partial intrinsic refocussing mechanism.
[1] D. M. Zajac, A. J. Sigillito, M. Russ, F. Borjans, J. M. Taylor, G. Burkard, and J. R. Petta, arXiv:1708.03530 (2017)
[2] M. Russ, D. M. Zajac, A. J. Sigillito, F. Borjans, J. M. Taylor, J. R. Petta, and G. Burkard, arXiv:1711.00754 (2017)