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Electrical control of a spin qubit in InSb nanowire quantum dots: Strongly suppressed spin relaxation in high magnetic field
摘要： In this paper we investigate the impact of gating potential and magnetic ?eld on phonon induced spin relaxation rate and the speed of the electrically driven single-qubit operations inside the InSb nanowire spin qubit. We show that a strong g factor and high magnetic ?eld strength lead to the prevailing in?uence of electron-phonon scattering due to deformation potential, considered irrelevant for materials with a weak g factor, like GaAs or Si/SiGe. In this regime we ?nd that spin relaxation between qubit states is signi?cantly suppressed due to the con?nement perpendicular to the nanowire axis. We also ?nd that maximization of the number of single-qubit operations that can be performed during the lifetime of the spin qubit requres single quantum dot gating potential.
关键词： spin qubit,spin relaxation,Rabi frequency,InSb nanowire,quantum dots
更新于2025-09-23 15:19:57
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Control of a spin qubit in a lateral GaAs quantum dot based on symmetry of gating potential
摘要： We study the influence of quantum dot symmetry on the Rabi frequency and phonon-induced spin relaxation rate in a single-electron GaAs spin qubit. We find that anisotropic dependence on the magnetic field direction is independent of the choice of the gating potential. Also, we discover that relative orientation of the quantum dot, with respect to the crystallographic frame, is relevant in systems with C1v, C2v, or Cn (n ≠ 4r) symmetry. To demonstrate the important impact of the gating potential shape on the spin qubit lifetime, we compare the effects of an infinite-wall equilateral triangle, square, and rectangular confinement with the known results for the harmonic potential. In the studied cases, enhanced spin qubit lifetime is revealed, reaching almost six orders of magnitude increase for the equilateral triangle gating.
关键词： spin qubit,GaAs,spin relaxation rate,Rabi frequency,quantum dot,gating potential
更新于2025-09-19 17:13:59
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Measurement of Spin Singlet-Triplet Qubit in Quantum Dots Using Superconducting Resonator <sup>*</sup>
摘要： The spin qubit in quantum dots is one of the leading platforms for quantum computation. A crucial requirement for scalable quantum information processing is the high efficient measurement. Here we analyze the measurement process of a quantum-dot spin qubit coupled to a superconducting transmission line resonator. Especially, the phase shift of the resonator is sensitive to the spin states and the gate operations. The response of the resonator can be used to measure the spin qubit efficiently, which can be extend to read out the multiple spin qubits in a scalable solid-state quantum processor.
关键词： quantum dots,quantum computation,superconducting resonator,spin qubit
更新于2025-09-19 17:13:59
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Electrically tunable effective g-factor of a single hole in a lateral GaAs/AlGaAs quantum dot
摘要： Electrical tunability of the g-factor of a confined spin is a long-time goal of the spin qubit field. Here we utilize the electric dipole spin resonance (EDSR) to demonstrate it in a gated GaAs double-dot device confining a hole. This tunability is a consequence of the strong spin-orbit interaction (SOI) in the GaAs valence band. The SOI enables a spin-flip interdot tunneling, which, in combination with the simple spin-conserving charge transport leads to the formation of tunable hybrid spin-orbit molecular states. EDSR is used to demonstrate that the gap separating the two lowest energy states changes its character from a charge-like to a spin-like excitation as a function of interdot detuning or magnetic field. In the spin-like regime, the gap can be characterized by the effective g-factor, which differs from the bulk value owing to spin-charge hybridization, and can be tuned smoothly and sensitively by gate voltages.
关键词： g-factor,spin qubit,electric dipole spin resonance,hole spin,quantum dot,GaAs,spin-orbit interaction
更新于2025-09-12 10:27:22