Floquet Majorana fermions in superconducting quantum dots

Benito, Mónica; Platero, Gloria

doi:10.1016/j.physe.2015.08.030

Cited by 7 publications

(5 citation statements)

References 61 publications

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“…* pasquale.marra@riken.jp Here we describe the simplest realization of such a 0D topological superconductor, i.e., a quantum dot [51][52][53][54] coupled with two superconducting leads in a magnetic Zeeman field, forming a superconductor-quantum dot-superconductor (SC-QD-SC) Josephson junction. Zero-energy modes and the corresponding CPR discontinuities and ground-state parity crossings [55][56][57][58][59][60][61] have been recognized as precursors of Majorana modes in the long-wire limit [27,50], and of Floquet Majorana modes realized in driven quantum dots [62,63]. We will analytically derive and discuss the spectrum and the Josephson current of the dot, which agrees with the universal prediction for zero-dimensional systems described in our previous work 50.…”

Section: Introductionsupporting

confidence: 77%

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

Marra

Braggio

Citro

2018

Beilstein J. Nanotechnol.

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The classification of topological states of matter in terms of unitary symmetries and dimensionality predicts the existence of nontrivial topological states even in zero-dimensional systems, i.e., systems with a discrete energy spectrum. Here, we show that a quantum dot coupled with two superconducting leads can realize a nontrivial zero-dimensional topological superconductor with broken time-reversal symmetry, which corresponds to the finite size limit of the one-dimensional topological superconductor. Topological phase transitions corresponds to a change of the fermion parity, and to the presence of zero-energy modes and discontinuities in the current–phase relation at zero temperature. These fermion parity transitions therefore can be revealed by the current discontinuities or by a measure of the critical current at low temperatures.

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Section: Introductionsupporting

confidence: 77%

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

Marra

Braggio

Citro

2018

Beilstein J. Nanotechnol.

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“…In addition, it could be used to study spin-polarised [41] or thermoelectric [42][43][44] transport properties of an engineered junction, starting from initial spin or temperature imbalances. Finally, since our method is suited to describe the interplay between driving and dissipation, it could be applied in the context of quantum heat engine or Floquet Majorana fermions [21,45,46].…”

Section: Resultsmentioning

confidence: 99%

Reservoir engineering of Cooper-pair-assisted transport with cold atoms

et al. 2019

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We show how Cooper-pair-assisted transport, which describes the stimulated transport of electrons in the presence of Cooper-pairs, can be engineered and controlled with cold atoms, in regimes that are difficult to access for condensed matter systems. Our model is a channel connecting two cold atomic gases, and the mechanism to generate such a transport relies on the coupling of the channel to a molecular BEC, with diatomic molecules of fermionic atoms. Our results are obtained using a Floquet-Redfield master equation that accounts for an exact treatment of the interaction between atoms in the channel. We explore, in particular, the impact of the coupling to the BEC and the interaction between atoms in the junction on its transport properties, revealing non-trivial dependence of the produced particle current. We also study the effects of finite temperatures of the reservoirs and the robustness of the current against additional dissipation acting on the junction. Our work is experimentally relevant and has potential applications to dissipation engineering of transport with cold atoms, studies of thermoelectric effects, quantum heat engines, or Floquet Majorana fermions.

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“…They could be generalized to multi-QD tunnelling junction, and to include the presence of measurement and feedback loop to control the transport dynamics of fermions in tunnelling junctions [67]. More possible outlooks include reservoir engineering of (Floquet)-Majorana fermions [13,68,69], or studies of the interplay between dissipation and driving in thermodynamics problems such as thermoelectric effects [70] or quantum heat engines [71] involving superconductors.…”

Section: (Panels A-d) We Show Thementioning

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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Floquet Majorana fermions in superconducting quantum dots

Cited by 7 publications

References 61 publications

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

Reservoir engineering of Cooper-pair-assisted transport with cold atoms

Controlling Quantum Transport via Dissipation Engineering

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