Long-range entanglement for spin qubits via quantum Hall edge modes

Elman, Samuel J.; Bartlett, Stephen D.; Doherty, Andrew C.

doi:10.1103/physrevb.96.115407

Cited by 23 publications

(30 citation statements)

References 66 publications

(118 reference statements)

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“…The characteristic impedance of these devices was estimated to be proportional to the resisitance quantum, and so orders of magnitude higher than the typical value ∼ 50Ω of microwave circuits [16]. There has been a growing interest in high impedance transmission lines in the quantum information community [17][18][19][20][21] and different implementations have been proposed [22][23][24][25][26][27][28][29][30]. In fact, the excitations in devices with a large characteristic impedance have a high electric field: this property can enhance the electrostatic coupling between the photon and the qubit.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, the excitations in devices with a large characteristic impedance have a high electric field: this property can enhance the electrostatic coupling between the photon and the qubit. This enhancement is particularly arXiv:1901.01455v1 [cond-mat.mes-hall] 5 Jan 2019 attractive for semiconductor based quantum computing, where the charge dipole of the qubits can be low, and it can be exploited for the challenging task of reaching the strong coupling regime, where the photon-qubit interaction strength is higher than the losses in the system [17][18][19][20][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

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Transmission lines and resonators based on quantum Hall plasmonics: Electromagnetic field, attenuation, and coupling to qubits

Bosco

DiVincenzo

2019

Phys. Rev. B

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Quantum Hall edge states have some characteristic features that can prove useful to measure and control solid state qubits. For example, their high voltage to current ratio and their dissipationless nature can be exploited to manufacture low-loss microwave transmission lines and resonators with a characteristic impedance of the order of the quantum of resistance h/e 2 ∼ 25kΩ. The high value of the impedance guarantees that the voltage per photon is high and for this reason high impedance resonators can be exploited to obtain larger values of coupling to systems with a small charge dipole, e.g. spin qubits. In this paper, we provide a microscopic analysis of the physics of quantum Hall effect devices capacitively coupled to external electrodes. The electrical current in these devices is carried by edge magnetoplasmonic excitations and by using a semiclassical model, valid for a wide range of quantum Hall materials, we discuss the spatial profile of the electromagnetic field in a variety of situations of interest. Also, we perform a numerical analysis to estimate the lifetime of these excitations and, from the numerics, we extrapolate a simple fitting formula which quantifies the Q factor in quantum Hall resonators. We then explore the possibility of reaching the strong photonqubit coupling regime, where the strength of the interaction is higher than the losses in the system. We compute the Coulomb coupling strength between the edge magnetoplasmons and singlet-triplet qubits, and we obtain values of the coupling parameter of the order 100MHz; comparing these values to the estimated attenuation in the resonator, we find that for realistic qubit designs the coupling can indeed be strong. * bosco@physik.rwth-aachen.de † d.divincenzo@fz-juelich.de A. Far-field analysis 1. EMPs in the half-plane

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transmission lines and resonators based on quantum Hall plasmonics: Electromagnetic field, attenuation, and coupling to qubits

Bosco

DiVincenzo

2019

Phys. Rev. B

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“…We expect that the same kind of analysis can be readily applied to the triple QD spin-qubit strongly coupled to a resonator [29]. The performance of other two-qubit gates [54][55][56] and other qubit-resonator coupling schemes, such as longitudinal coupling [51,57,58], will be the subject of future studies.…”

Section: Discussionmentioning

confidence: 97%

Optimized cavity-mediated dispersive two-qubit gates between spin qubits

2019

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The recent realization of a coherent interface between a single electron in a silicon quantum dot and a single photon trapped in a superconducting cavity opens the way for implementing photonmediated two-qubit entangling gates. In order to couple a spin to the cavity electric field some type of spin-charge hybridization is needed, which impacts spin control and coherence. In this work we propose a cavity-mediated two-qubit gate and calculate cavity-mediated entangling gate fidelities in the dispersive regime, accounting for errors due to the spin-charge hybridization, as well as photonand phonon-induced decays. By optimizing the degree of spin-charge hybridization, we show that two-qubit gates mediated by cavity photons are capable of reaching fidelities exceeding 90% in present-day device architectures. High iSWAP gate fidelities are achievable even in the presence of charge noise at the level of 2 µeV.

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“…Coherent control via a mesoscopic system is an emerging tool in quantum information processing [1][2][3][4][5][6][7][8]. Using a mesoscopic system to indirectly measure a joint property of two noninteracting qubits through a coarse-grained collective measurement has recently been introduced as a new approach for entangling uncoupled qubits [9].…”

Section: Introductionmentioning

confidence: 99%

“…(3). There should exist as least one measurement operator, M β , that overlaps with the states ψ L over, this measurement operator ideally must preserve the amplitude and the phase of the spectral expansion of the states ψ L .…”

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confidence: 99%

Mesoscopic spin systems as quantum entanglers

Mirkamali

Cory²

2020

Phys. Rev. A

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We quantify the resources required for entangling two uncoupled spin qubits through an intermediate mesoscopic spin system (MSS) by indirect joint measurement. Indirect joint measurement benefits from coherent magnification of the target qubits' state in the collective magnetization of the MSS; such that a low-resolution collective measurement on the MSS suffices to prepare post-selected entanglement on the target qubits. A MSS consisting of two non-interacting halves, each coupled to one of the target qubits is identified as a geometry that allows implementing the magnification process with experimentally available control tools. It is proved that the requirements on the amplified state of the target qubits and the MSS perfectly map to the specifications of micro-macro entanglement between each target qubit and its nearby half of the MSS. In the light of this equivalence, the effects of experimental imperfections are explored; in particular, bipartite entanglement between the target qubits is shown to be robust to imperfect preparation of the MSS. Our study provides a new approach for using an intermediate spin system for connecting separated qubits. It also opens a new path in exploring entanglement between microscopic and mesoscopic spin systems.PACS numbers:

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Long-range entanglement for spin qubits via quantum Hall edge modes

Cited by 23 publications

References 66 publications

Transmission lines and resonators based on quantum Hall plasmonics: Electromagnetic field, attenuation, and coupling to qubits

Transmission lines and resonators based on quantum Hall plasmonics: Electromagnetic field, attenuation, and coupling to qubits

Optimized cavity-mediated dispersive two-qubit gates between spin qubits

Mesoscopic spin systems as quantum entanglers

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