Electric-field control and noise protection of the flopping-mode spin qubit

Benito, Mónica; Croot, Xanthe; Adelsberger, Christoph; Putz, Stefan; Mi, Xiao; Petta, J. R.; Burkard, Guido

doi:10.1103/physrevb.100.125430

Cited by 53 publications

(40 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Motivated by recent experimental work on capacitive coupling between QD qubits [13,16,17,31,32] and in QD arrays with different spatial configurations [33][34][35][36][37], we consider here the capacitive coupling between flopping-mode spin qubits [38][39][40][41] and investigate the realization of two-qubit gates. As shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Programable two-qubit gates in capacitively coupled flopping-mode spin qubits

2020

Self Cite

View full text Add to dashboard Cite

Recent achievements in the field of gate-defined semiconductor quantum dots reinforce the concept of a spinbased quantum computer consisting of nodes of locally connected qubits which communicate with each other via superconducting circuit resonator photons. In this paper, we theoretically demonstrate a versatile set of quantum gates between adjacent spin qubits defined in semiconductor quantum dots situated within the same node of such a spin-based quantum computer. The electric dipole acquired by the spin of an electron that moves across a double quantum dot potential in a magnetic field gradient has enabled strong coupling to resonator photons and low-power spin control. Here we show that this flopping-mode spin qubit also provides the tunability to program multiple two-qubit gates. Since the capacitive coupling between these qubits brings about additional dephasing, we calculate the estimated infidelity of different two-qubit gates in the most immediate possible experimental realizations.

show abstract

Section: Introductionmentioning

confidence: 99%

Programable two-qubit gates in capacitively coupled flopping-mode spin qubits

2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…We define 2b i (i = x, y, z) as the difference in total magnetic field between the left and right dots in the i direction. Without loss of generality, we take b y = 0 in the remainder of the Letter [37]. The total magnetic field components at the left and right dots can be written as B tot…”

mentioning

confidence: 99%

“…is the homogeneous magnetic field in the z(x) direction. For our micromagnet design, we expect B x ≈ 0, but note that in the case where B x = 0, the geometric coordinate system can always be rotated to satisfy B x = 0 [37]. The Zeeman energy is given by…”

mentioning

confidence: 99%

“…From theory [37], the drive power required to drive Rabi oscillations at frequency f Rabi is given by…”

mentioning

confidence: 99%

“…In the absence of a longitudinal (b z ) gradient the sweet spot occurs at = 0. Theory predicts that a b z gradient may shift the sweet spot to finite detuning, or if the gradient field is large enough, destroy it entirely [37]. We search for evidence of a sweet spot by examining the quality factor of π-rotations Q ≡ 2T Rabi 2 f Rabi as a function of detuning [1].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Flopping-mode electric dipole spin resonance

Croot

Putz

et al. 2020

Phys. Rev. Research

Self Cite

View full text Add to dashboard Cite

Traditional approaches to controlling single spins in quantum dots require the generation of large electromagnetic fields to drive many Rabi oscillations within the spin coherence time. We demonstrate "flopping-mode" electric dipole spin resonance, where an electron is electrically driven in a Si/SiGe double quantum dot in the presence of a large magnetic field gradient. At zero detuning, charge delocalization across the double quantum dot enhances coupling to the drive field and enables low power electric dipole spin resonance. Through dispersive measurements of the single electron spin state, we demonstrate a nearly three order of magnitude improvement in driving efficiency using flopping-mode resonance, which should facilitate low power spin control in quantum dot arrays.Recent advances in silicon spin qubits have bolstered their standing as a platform for scalable quantum information processing. As single-qubit gate fidelities exceed 99.9% [1], two-qubit gate fidelities improve [2][3][4][5][6], and the field accelerates towards large multi-qubit arrays [7,8], developing the tools necessary for efficient and scalable spin control is critical [9]. While it is possible to implement single electron spin resonance in quantum dots (QDs) using ac magnetic fields [10], the requisite high drive powers and associated heat loads are technically challenging and place limitations on attainable Rabi frequencies [11]. As spin systems are scaled beyond a few qubits, methods of spin control which minimize dissipation and reduce qubit crosstalk will be important for low temperature quantum information processing [12].Electric dipole spin resonance (EDSR) is an alternative to conventional electron spin resonance. In EDSR, static gradient magnetic fields and oscillating electric fields are used to drive spin rotations [13]. The origin of the effective magnetic field gradient varies across implementations: intrinsic spin-orbit coupling [14][15][16], hyperfine coupling [17], and g-factor modulation [18] have been used to couple electric fields to spin states. The inhomogeneous magnetic field generated by a micromagnet [19,20] has been used to create a synthetic spin-orbit field for EDSR, enabling high fidelity control [1]. Conveniently, this magnetic field gradient gives rise to a spatially varying Zeeman splitting, enabling spins in neighboring QDs to be selectively addressed [11,19,[21][22][23][24][25].In this Letter, we demonstrate a novel mechanism for driving low-power, coherent spin rotations, which we call "flopping-mode EDSR". In conventional EDSR, the electric drive field couples to a charge trapped in a single quantum dot, leading to a relatively small electronic displacement [16]. We instead drive single spin rotations in a DQD close to zero detuning, = 0, where the electric field can force the electron to flop back and forth between the left and right dots, thereby sampling a larger variation in transverse magnetic field. We call this configuration the "flopping-mode".Neglecting spin, the Hamiltonian describing a singl...

show abstract

Dephasing of Exchange‐Coupled Spins in Quantum Dots for Quantum Computing

Huang

2021

Adv Quantum Tech

View full text Add to dashboard Cite

A spin qubit in semiconductor quantum dots holds promise for quantum information processing for scalability and long coherence time. An important semiconductor qubit system is a double quantum dot trapping two electrons or holes, whose spin states encode either a singlet–triplet qubit or two single‐spin qubits coupled by exchange interaction. In this article, progress on the spin dephasing of two exchange‐coupled spins in a double quantum dot is reported. First, the schemes of two‐qubit gates and qubit encodings in gate‐defined quantum dots or donor atoms based on the exchange interaction are discussed. Then, the progress on spin dephasing of a singlet–triplet qubit or a two‐qubit gate is reported. The methods of suppressing spin dephasing are further discussed. The understanding of the spin dephasing may provide insights into the realization of high‐fidelity quantum gates for spin‐based quantum computing.

show abstract

Electric-field control and noise protection of the flopping-mode spin qubit

Cited by 53 publications

References 67 publications

Programable two-qubit gates in capacitively coupled flopping-mode spin qubits

Programable two-qubit gates in capacitively coupled flopping-mode spin qubits

Flopping-mode electric dipole spin resonance

Dephasing of Exchange‐Coupled Spins in Quantum Dots for Quantum Computing

Contact Info

Product

Resources

About