Field Tuning the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>g</mml:mi></mml:math>Factor in InAs Nanowire Double Quantum Dots

Circuit quantum electrodynamics allows spatially separated superconducting qubits to interact via a "quantum bus", enabling two-qubit entanglement and the implementation of simple quantum algorithms. We combine the circuit quantum electrodynamics architecture with spin qubits by coupling an InAs nanowire double quantum dot to a superconducting cavity. We drive single spin rotations using electric dipole spin resonance and demonstrate that photons trapped in the cavity are sensitive to single spin dynamics. The hybrid quantum system allows measurements of the spin lifetime and the observation of coherent spin rotations. Our results demonstrate that a spin-cavity coupling strength of 1 MHz is feasible.

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“…3(b)]. Hyperfine fields rapidly mix spin states when E Z =gµ B B < B N , where B N ∼ 2 mT is the hyperfine field [12].…”

mentioning

confidence: 99%

Circuit quantum electrodynamics with a spin qubit

Petersson

McFaul

Schroer

et al. 2012

Nature

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458

589

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“…Subharmonic spin resonances have recently been observed [3][4][5][6][7] in electrically driven quantum dots (QDs) [8][9][10][11][12]. In these systems, electrical driving might be favorable over magnetic excitation, as the former allows for selective addressing of spin-based quantum bits in a multi-quantum-dot register.…”

Section: Introductionmentioning

confidence: 99%

Maximal Rabi frequency of an electrically driven spin in a disordered magnetic field

Széchenyi

Pályi

2014

Phys. Rev. B

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We present a theoretical study of the spin dynamics of a single electron confined in a quantum dot. Spin dynamics is induced by the interplay of electrical driving and the presence of a spatially disordered magnetic field, the latter being transverse to a homogeneous magnetic field. We focus on the case of strong driving, i.e., when the oscillation amplitude A of the electron's wave packet is comparable to the quantum dot length L. We show that electrically driven spin resonance can be induced in this system by subharmonic driving, i.e., if the excitation frequency is an integer fraction ( 1 2 , 1 3 , etc.) of the Larmor frequency. At strong driving we find that (i) the Rabi frequencies at the subharmonic resonances are comparable to the Rabi frequency at the fundamental resonance, and (ii) at each subharmonic resonance, the Rabi frequency can be maximized by setting the drive strength to an optimal, finite value. In the context of practical quantum information processing, these findings highlight the availability of subharmonic resonances for qubit control with effectivity close to that of the fundamental resonance, and the possibility that increasing the drive strength might lead to a decreasing qubit-flip speed. Our simple model is applied to describe electrical control of a spin-valley qubit in a weakly disordered carbon nanotube.

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“…the spin separation is a typical result. We find that the spin configuration in the second excited state is then either ↑↓ or ↓↑, depending on the specific HF field distribution, the sign of the spin was hence neglected, instead, the values were taken as negative (orange) for the cases where the second state participating in the spin separation is the ground singlet S. In nanowire double quantum dots a substantial variation of the g factors in both the dots has been found [28][29][30] . The variation should fix the orientation of the spins in the Hamiltonian eigenstates in the absence of the exchange interaction.…”

Section: A Two-electron Eigenstatesmentioning

confidence: 99%

“…In the weak interdot tunneling regime the S and T 0 states are nearly degenerate and can be mixed by either the spatial variation of the effective Landé g factor [28][29][30] , the spin-orbit coupling 27 , or the HF field 3 . For the maximal mixing case one obtains the spin separation over the dots…”

Section: A Two-electron Eigenstatesmentioning

confidence: 99%

Spin separation and exchange for quantum dots in the Overhauser field

Leśnicki

Szafran

2017

Phys. Rev. B

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We describe the spin and charge dynamics of the system of two electrons confined within a double quantum dot defined in a quantum wire. The spin dynamics is driven by the electron motion in presence of the spin-orbit interaction and the randomly varying local Overhauser field due to the nuclear spins. The Schroedinger equation is solved with the time-dependent configuration interaction method that allows for an exact description of the system dynamics. The procedures of the spin separation, exchange and read-out by the spin to charge conversion all induced by the detuning variation are simulated. The rates of the potential variation that are necessary for the spin separation and spin to charge conversion in the context of the Landau-Zener transitions are determined. The average over random configurations of the hyperfine field produce spin exchange results which qualitatively agree with the experimental data.

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Field Tuning thegFactor in InAs Nanowire Double Quantum Dots

Cited by 152 publications

References 29 publications

Circuit quantum electrodynamics with a spin qubit

Circuit quantum electrodynamics with a spin qubit

Maximal Rabi frequency of an electrically driven spin in a disordered magnetic field

Spin separation and exchange for quantum dots in the Overhauser field

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