Fast electron spin flips via strong subcycle electric excitation

Abstract

An important goal in quantum information processing is to reduce the duration of quantumlogical operations. Motivated by this, we provide a theoretical analysis of electrically induced fast dynamics of a single-electron spin-orbit qubit. We study the example of a one-dimensional quantum dot with Rashba spin-orbit interaction and harmonic driving, and focus on the case of strong driving, when the real-space oscillation amplitude of the driven electron is comparable to the width of its wave function. We provide simple approximate analytical relations between the qubit Larmor frequency, the shortest achievable qubit-flip time, and the driving amplitude required for the shortest achievable qubit flip. We find that these relations compare well with results obtained from numerical simulations of the qubit dynamics. Based on our results, we discuss practical guidelines to maximize speed and quality of electric single-qubit operations on spin-orbit qubits.PACS numbers:

Thermal effects on a nonadiabatic spin-flip protocol of spin-orbit qubits

“…Recent studies proposed nonadiabatic protocols, where spin-qubit manipulation is achieved by translating a spin-qubit in one dimension [22][23][24] in the presence of a time-dependent Rashba interaction [25][26][27]. References [22,23] give exact analytical solutions for the time-dependent Schrödinger equation of such a driven spin qubit, confined in a harmonic potential, and express the spin rotation in terms of the nonadiabatic non-Abelian Anandan phase [28].…”

“…(A3)Expressing x c (t ) and a c (t ) in terms of their Fourier componentsx c,n andâ c,n results in the form of Eq. (23),ae −iω 0 t + a † e iω 0 t + 2m * ω 0 n ∈ Z n = ±n dx c,n −ξ n +â read the jump operators of Eq (24)…”

Control of a spin qubit in a lateral GaAs quantum dot based on symmetry of gating potential

“…Our results indicate the enhanced lifetime of the spin qubit, reaching an almost six-orders-of-magnitude increase in the case of the equilateral triangle gating. In the end, we emphasize that in the regime of strong electric field, nonlinear effects [47][48][49] cannot be fully explained by the symmetry of the gating potential, thus placing the conclusions of our work in the weak driving regime solely.…”

Electric dipole spin resonance at shallow donors in quantum wires

“…no full spin flip is achieved. We attribute this effect to the presence of many states with different spin projections and with comparable weights, in the the total wavefunction (18). The coordinate mean value x(t) at a strong driving also demonstrates a complicated and irregularly oscillating behavior, with much greater amplitude than for weak driving, approaching or even exceeding the localization length l. This can be described as another evidence of significant contribution of continuum states in the driven dynamics even for moderate fields less then 3 V/cm.…”