Controllable spin entanglement production in a quantum spin Hall ring

Ström, Anders; Johannesson, Henrik; Recher, Patrik

doi:10.1103/physrevb.91.245406

Cited by 21 publications

(27 citation statements)

References 64 publications

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“…The recent progress in pump-probe experiments and photo-current spectroscopy [32,33,[93][94][95][96], make the time-resolved detection of the photoexcited wave packets realistically accessible nowadays. These results seem promising in view of utilising two-dimensional TIs as possible alternative platform for an electron quantum optics [97][98][99][100], which is nowadays mostly implemented in quantum Hall systems [32,33] with the unavoidable limitation of the need for strong magnetic fields. Timereversal TIs, which are based on spin-orbit coupling, are immune to such drawback and offer the additional possibility of generating spin-polarised electron wave packets.…”

Section: Possible Setup Realisationsmentioning

confidence: 99%

Interplay between Rashba interaction and electromagnetic field in the edge states of a two-dimensional topological insulator

Dolcini

2017

Phys. Rev. B

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The effects of Rashba interaction and electromagnetic field on the edge states of a two-dimensional topological insulator are investigated in a non-perturbative way. We show that the electron dynamics is equivalent to a problem of massless Dirac fermions propagating with an inhomogeneous velocity, enhanced by the Rashba profile with respect to the bare Fermi value vF . Despite the inelastic and time-reversal breaking processes induced by the electromagnetic field, no backscattering occurs without interaction. The photoexcited electron densities are explicitly obtained in terms of the electric field and the Rashba interaction, and are shown to fulfil generalised chiral anomaly equations. The case of a Gaussian electromagnetic pulse is analysed in detail. When the photoexcitation occurs far from the Rashba region, the latter effectively acts as a "superluminal gate" boosting the photoexcited wavepacket outside the light-cone determined by vF . In contrast, for an electric pulse overlapping the Rashba region the emerging wavepackets are squeezed in a manner that depends on the overlap area. The electron-electron interaction effects are also discussed, for both intra-spin and inter-spin density-density coupling. The results suggest that Rashba interaction, often considered as an unwanted disorder effect, may be exploited to tailor the shape and the propagation time of photoexcited spin-polarised wave packets.

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Section: Possible Setup Realisationsmentioning

confidence: 99%

Interplay between Rashba interaction and electromagnetic field in the edge states of a two-dimensional topological insulator

Dolcini

2017

Phys. Rev. B

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“…Importantly, they are topologically protected from backscattering and characterized by the so called spin-momentum locking. These features allow for a richer phenomenology, in comparison with quantum Hall-based setups [46,47], and for the study of effects related to spin entanglement [48][49][50], relevant for quantum computation implementations. In this context, e-e interactions between counterpropagating edge channels can lead to remarkable effects, also in comparison with the case of interacting copropagating edge states of chiral conductors [30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Time-resolved energy dynamics after single electron injection into an interacting helical liquid

et al. 2016

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The possibility of injecting a single electron into ballistic conductors is at the basis of the new field of electron quantum optics. Here, we consider a single electron injection into the helical edge channels of a topological insulator. Their counterpropagating nature and the unavoidable presence of electron-electron interactions dramatically affect the time evolution of the single wave packet. Modeling the injection process from a mesoscopic capacitor in the presence of nonlocal tunneling, we focus on the time-resolved charge and energy packet dynamics. Both quantities split up into counterpropagating contributions whose profiles are strongly affected by the interaction strength. In addition, stronger signatures are found for the injected energy, which is also affected by the finite width of the tunneling region, in contrast to what happens for the charge. Indeed, the energy flow can be controlled by tuning the injection parameters, and we demonstrate that, in the presence of nonlocal tunneling, it is possible to achieve a situation in which charge and energy flow in opposite directions.

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“…with q α± defined in (14). This is precisely the particlehole pair contribution appearing for non-integer q α± .…”

Section: A Stationary Regimementioning

confidence: 97%

Probing interactions via nonequilibrium momentum distribution and noise in integer quantum Hall systems at ν=2

et al. 2018

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We consider the excitation of single-electron wave packets by means of a time dependent voltage applied to the ballistic edge channels of the integer quantum Hall effect at filling factor ν = 2. Due to electron-electron interactions, fractional excitations emerge along the edge. Their detailed structure is analyzed by evaluating the non-equilibrium momentum distributions associated with the different edge channels. We provide results for a generic time-dependent drive both in the stationary regime and for intermediate times, where the overlap between fractionalized wave packets carries relevant information on interaction strength. As a particular example we focus on a Lorentzian drive, which provides a clear signature of the minimal excitations known as Levitons. Here, we argue that inner-channel fractionalized excitations can be exploited to extract information about inter-channel interactions. We further confirm this idea by calculating the zero frequency noise due to the partitioning of these excitations at a quantum point contact and we propose a measurable quantity as a tool to directly probe electron-electron interactions and determine the so-called mixing angle of copropagating quantum Hall channels. arXiv:1806.03897v2 [cond-mat.mes-hall]

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Controllable spin entanglement production in a quantum spin Hall ring

Cited by 21 publications

References 64 publications

Interplay between Rashba interaction and electromagnetic field in the edge states of a two-dimensional topological insulator

Interplay between Rashba interaction and electromagnetic field in the edge states of a two-dimensional topological insulator

Time-resolved energy dynamics after single electron injection into an interacting helical liquid

Probing interactions via nonequilibrium momentum distribution and noise in integer quantum Hall systems at ν=2

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