Andreev molecules in semiconductor nanowire double quantum dots

Su, Zhaoen; Tacla, Alexandre B.; Hocevar, Moïra; Car, Diana; Plissard, Sébastien; Bakkers, Epam Erik; Daley, Andrew J.; Pekker, David; Frolov, Sergey

doi:10.1038/s41467-017-00665-7

Cited by 81 publications

(82 citation statements)

References 31 publications

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“…The simplest case where Majorana manipulation is possible is in a double quantum dot (DQD). Tunneling Majorana modes in these basic structures have inspired theoretical studies [26][27][28][29] and experimental setups confirming the observations of Andreev molecules 30 . However, despite the fact that DQDs offer several possibilities for manipulation of MZMs, there is still no complete analysis of the possible transitions of these Majorana signatures between the QDs even in a simple model.…”

Section: Introductionsupporting

confidence: 53%

Manipulating Majorana zero modes in double quantum dots

Silva

2019

Phys. Rev. B

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Majorana zero modes (MZMs) emerging at the edges of topological superconducting wires have been proposed as the building blocks of novel, fault-tolerant quantum computation protocols. Coherent detection and manipulation of such states in scalable devices are, therefore, essential in these applications. Recent detection proposals include semiconductor quantum dots (QDs) coupled to the end of these wires, as changes in the QD electronic spectral density due to the MZM coupling could be detected in transport experiments. Here, we propose that multi-QD systems can also be used to manipulate MZMs through precise control over the QDs' parameters. The simplest case where Majorana manipulation is possible is in a double quantum dot (DQD) geometry. By using exact analytical methods and numerical renormalization-group calculations, we show that the QDs' spectral functions can be used to characterize the presence or not of MZMs "leaking" into the DQD. More importantly, we find that these signatures respond to changes in the DQD parameters such as gate-voltages and couplings in a consistent fashion. Additionally, we show that different MZM-DQD coupling geometries ("symmetric" , "in-series" and "T-shaped" junctions) offer distinct ways in which MZMs can be switched from dot to dot. These results highlight the interesting possibilities that DQDs offer for all-electrical MZM control in scalable devices. arXiv:1905.09140v1 [cond-mat.mes-hall]

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Section: Introductionsupporting

confidence: 53%

Manipulating Majorana zero modes in double quantum dots

Silva

2019

Phys. Rev. B

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“…Our four-terminal model allows us by essence to consider independent electron and Cooper-pair tunnelling. We note however that independent tunnelling can also be the result of modelling superconducting leads with two components, as done in [39]. We consider the system-bath (S-B) decomposition H S (t) ≡ H eff QD (t) and H B ≡ H lead , assuming the electron tunnelling amplitude κ to be the smallest frequency scale.…”

Section: Derivation Of the Master Equationmentioning

confidence: 99%

Controlling Quantum Transport via Dissipation Engineering

et al. 2019

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Inspired by the microscopic control over dissipative processes in quantum optics and cold atoms, we develop an open-system framework to study dissipative control of transport in strongly interacting fermionic systems, relevant for both solid state and cold atom experiments. We show how subgap currents exhibiting Multiple Andreev Reflections -the stimulated transport of electrons in the presence of Cooper-pairs -can be controlled via engineering of superconducting leads or superfluid atomic gases. Our approach incorporates dissipation within the channel, which is naturally occurring and can be engineered in cold gas experiments. This opens opportunities for engineering many phenomena with transport in strongly interacting systems. As examples, we consider particle loss and dephasing, and note different behaviour for currents with different microscopic origin. We also show how to induce nonreciprocal electron and Cooper-pair currents.Introduction. Understanding and controlling the outof-equilibrium dynamics of strongly interacting manybody systems constitutes one of the key forefronts in quantum physics across a variety of subfields in experiment and theory. In this context, opportunities to achieve their control via dissipation mechanisms have arisen [1,2], as is applied for few-body systems in quantum optics [3,4]. This is especially true in cold-atom platforms, where large separations between frequency scales allows well-controlled theoretical models and implementations of dissipative processes, as realized for laser cooling and trapping [5]. The longer timescales of cold atom experiments also allow dynamics to be tracked and potentially controlled time-dependently [6,7]. Outof-equilibrium transport dynamics remain a ubiquitous paradigm in the solid state [8], and recent developments in cold atom systems have also made it possible to engineer quantised transport of atoms between reservoirs, as well as quantum point contacts and waveguides [9][10][11][12]. Here we explore the emerging new opportunity of using dissipation engineering to achieve control of quantum transport properties, that are relevant for both coldatom and solid-state platforms.

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“…[23][24][25] Another way to simulate the Kitaev chain is with chains of semiconductor-superconductor quantum dots. [26][27][28][29][30] For an infinite chain of quantum dots, the MZMs are sepa-rated in a continuous range of control parameters. However, for a chain of a finite number of dots, as in Fig.…”

Section: Introductionmentioning

confidence: 99%

Weyl points in systems of multiple semiconductor-superconductor quantum dots

Stenger

Pekker

2019

Phys. Rev. B

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As an analogy to the Weyl point in k-space, we search for energy levels which close at a single point as a function of a three dimensional parameter space. Such points are topologically protected in the sense that any perturbation which acts on the two level subsystem can be corrected by tuning the control parameters. We find that parameter controlled Weyl points are ubiquitous in semiconductorsuperconductor quantum dots and that they are deeply related to Majorana zero modes. In this paper, we present several semiconductor-superconductor quantum dot devices which host parameter controlled Weyl points. Further, we show how these points can be observed experimentally via conductance measurements. arXiv:1904.09158v2 [cond-mat.mes-hall]

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Andreev molecules in semiconductor nanowire double quantum dots

Cited by 81 publications

References 31 publications

Manipulating Majorana zero modes in double quantum dots

Manipulating Majorana zero modes in double quantum dots

Controlling Quantum Transport via Dissipation Engineering

Weyl points in systems of multiple semiconductor-superconductor quantum dots

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