2017/01/31 by Chengxian Zhang, Robert E. Throckmorton, Xu-Chen Yang +3
Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Coherence (philosophical gambling strategy) #Coherence time #Coherent control #Computer science #Noise (video) #Physics #Quantum #Quantum and electron transport phenomena #Quantum decoherence #Quantum mechanics #Qubit #Semiconductor Quantum Structures and Devices #Singlet state #Spin (aerodynamics) #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.118.216802
published as Phys. Rev. Lett. 118, 216802 (2017) · 4+6 pages
openalex publication_date 2017/05/26 · arxiv created 2017/05/29 · arxiv updated 2017/05/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Decoherence due to charge noise is one of the central challenges in using spin qubits in semiconductor quantum dots as a platform for quantum information processing. Recently, it has been experimentally demonstrated in both Si and GaAs singlet-triplet qubits that the effects of charge noise can be suppressed if qubit operations are implemented using symmetric barrier control instead of the standard tilt control. Here, we investigate the key issue of whether the benefits of barrier control persist over the entire set of single-qubit gates by performing randomized benchmarking simulations. We find the surprising result that the improvement afforded by barrier control depends sensitively on the amount of spin noise: for the minimal nuclear spin noise levels present in Si, the coherence time improves by more than 2 orders of magnitude whereas in GaAs, by contrast the coherence time is essentially the same for barrier and tilt control. However, we establish that barrier control becomes beneficial if qubit operations are performed using a new family of composite pulses that reduce gate times by up to 90%. With these optimized pulses, barrier control is the best way to achieve high-fidelity quantum gates in singlet-triplet qubits.