scholarly journals Integrating micromagnets and hybrid nanowires for topological quantum computing

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Malcolm Jardine ◽  
John Stenger ◽  
Yifan Jiang ◽  
Eline J. de Jong ◽  
Wenbo Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Computing ◽  
External Magnetic Field ◽  
Numerical Simulations ◽  
Hybrid Systems ◽  
Scaling Up ◽  
Magnet Design ◽  
Zero Modes ◽  
Magnetic Imaging ◽  
Topological Quantum

Majorana zero modes are expected to arise in semiconductor-superconductor hybrid systems, with potential topological quantum computing applications. One limitation of this approach is the need for a relatively high external magnetic field that should also change direction at the nanoscale. This proposal considers devices that incorporate micromagnets to address this challenge. We perform numerical simulations of stray magnetic fields from different micromagnet configurations, which are then used to solve for Majorana wavefunctions. Several devices are proposed, starting with the basic four-magnet design to align magnetic field with the nanowire and scaling up to nanowire T-junctions. The feasibility of the approach is assessed by performing magnetic imaging of prototype patterns.

scholarly journals Zero modes on cosmic strings in an external magnetic field

2006 ◽  
Vol 74 (2) ◽  
Author(s):  
Francesc Ferrer ◽  
Harsh Mathur ◽  
Tanmay Vachaspati ◽  
Glenn Starkman
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Cosmic Strings ◽  
Zero Modes

scholarly journals Observation of magnetic adatom-induced Majorana vortex and its fusion with field-induced Majorana vortex in an iron-based superconductor

2020 ◽  
Author(s):  
Peng Fan ◽  
Fazhi Yang ◽  
Guojian Qian ◽  
Hui Chen ◽  
Yu-Yang Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Bound States ◽  
Zero Mode ◽  
Fault Tolerant ◽  
Abrikosov Vortex ◽  
Zero Modes ◽  
Topological Quantum ◽  
Iron Based ◽  
Dual Origin ◽  
Single Material

Abstract Braiding Majorana zero modes is essential for fault-tolerant topological quantum computing. Iron-based superconductors with nontrivial band topology have recently emerged as a surprisingly promising platform for creating distinct Majorana zero modes in magnetic vortices in a single material and at relatively high temperatures. The magnetic field-induced Abrikosov vortex lattice makes it difficult to braid a set of Majorana zero modes or to study the fusion of a Majorana doublet due to overlapping wave functions. Here we report the observation of the proposed quantum anomalous vortex with integer quantized vortex core states and Majorana zero mode induced by magnetic Fe adatoms deposited on the surface and the realization of its fusion with a nearby field-induced Majorana vortex in iron-based superconductor FeTe0.55Se0.45. We also observe vortex-free Yu-Shiba-Rusinov bound states at the Fe adatoms with a weaker coupling to the substrate, and discover a reversible transition between Yu-Shiba-Rusinov states and Majorana zero mode by manipulating the exchange coupling strength. The dual origin of the Majorana zero modes, from magnetic adatoms and external magnetic field, provides a new single-material platform for studying their interactions and braiding in superconductors bearing topological band structures.

scholarly journals THE QUANTUM HALL EFFECT IN GRAPHENE

2012 ◽  
Vol 26 (13) ◽  
pp. 1250084 ◽  
Author(s):  
PAOLO CEA
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Numerical Simulations ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Landau Levels ◽  
Dynamical Generation ◽  
Dirac Sea

We investigate the quantum Hall effect in graphene. We argue that in graphene in presence of an external magnetic field there is dynamical generation of mass by a rearrangement of the Dirac sea. We show that the mechanism breaks the lattice valley degeneracy only for the n = 0 Landau levels and leads to the new observed ν = ±1 quantum Hall plateaus. We suggest that our result can be tested by means of numerical simulations of planar Quantum Electro Dynamics with dynamical fermions in an external magnetic fields on the lattice.

Stochastic Dynamics of Magnetic Nanoparticles at Finite Temperatures

2010 ◽  
Vol 168-169 ◽  
pp. 105-108
Author(s):  
V.V. Zverev ◽  
G.A. Usachev
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
External Magnetic Field ◽  
Numerical Simulations ◽  
Magnetic Particles ◽  
Stochastic Dynamics ◽  
Thermal Fluctuations ◽  
Spatial Complexity ◽  
Temporal And Spatial

We consider unstable motion in small magnetic particles, driven by an external magnetic field and influenced by thermal fluctuations. Our studies demonstrate both temporal and spatial complexity of the dynamics in this system. The results are obtained using numerical simulations of the Landau-Lifshitz-Gilbert equations.

scholarly journals Observation of magnetic adatom-induced Majorana vortex and its hybridization with field-induced Majorana vortex in an iron-based superconductor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peng Fan ◽  
Fazhi Yang ◽  
Guojian Qian ◽  
Hui Chen ◽  
Yu-Yang Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Bound States ◽  
Zero Mode ◽  
Fault Tolerant ◽  
Abrikosov Vortex ◽  
Zero Modes ◽  
Topological Quantum ◽  
Iron Based ◽  
Dual Origin ◽  
Single Material

AbstractBraiding Majorana zero modes is essential for fault-tolerant topological quantum computing. Iron-based superconductors with nontrivial band topology have recently emerged as a surprisingly promising platform for creating distinct Majorana zero modes in magnetic vortices in a single material and at relatively high temperatures. The magnetic field-induced Abrikosov vortex lattice makes it difficult to braid a set of Majorana zero modes or to study the coupling of a Majorana doublet due to overlapping wave functions. Here we report the observation of the proposed quantum anomalous vortex with integer quantized vortex core states and the Majorana zero mode induced by magnetic Fe adatoms deposited on the surface. We observe its hybridization with a nearby field-induced Majorana vortex in iron-based superconductor FeTe0.55Se0.45. We also observe vortex-free Yu-Shiba-Rusinov bound states at the Fe adatoms with a weaker coupling to the substrate, and discover a reversible transition between Yu-Shiba-Rusinov states and Majorana zero mode by manipulating the exchange coupling strength. The dual origin of the Majorana zero modes, from magnetic adatoms and external magnetic field, provides a new single-material platform for studying their interactions and braiding in superconductors bearing topological band structures.

scholarly journals Quantum confinement of the Dirac surface states in topological-insulator nanowires

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Felix Münning ◽  
Oliver Breunig ◽  
Henry F. Legg ◽  
Stefan Roitsch ◽  
Dingxun Fan ◽  
...  
Keyword(s):  
Quantum Computing ◽  
Quantum Confinement ◽  
Dirac Point ◽  
Direct Evidence ◽  
Chemical Potential ◽  
Three Dimensional ◽  
Surface States ◽  
Mesoscopic Physics ◽  
Zero Modes ◽  
Topological Quantum

AbstractThe non-trivial topology of three-dimensional topological insulators dictates the appearance of gapless Dirac surface states. Intriguingly, when made into a nanowire, quantum confinement leads to a peculiar gapped Dirac sub-band structure. This gap is useful for, e.g., future Majorana qubits based on TIs. Furthermore, these sub-bands can be manipulated by a magnetic flux and are an ideal platform for generating stable Majorana zero modes, playing a key role in topological quantum computing. However, direct evidence for the Dirac sub-bands in TI nanowires has not been reported so far. Here, using devices fabricated from thin bulk-insulating (Bi1−xSbx)2Te3 nanowires we show that non-equidistant resistance peaks, observed upon gate-tuning the chemical potential across the Dirac point, are the unique signatures of the quantized sub-bands. These TI nanowires open the way to address the topological mesoscopic physics, and eventually the Majorana physics when proximitized by an s-wave superconductor.

Numerical Simulations of Fluid Flow During Electromagnetic Stirring of Metals

2001 ◽  
Author(s):  
Sorin G. Teodorescu ◽  
Mihai Dupac ◽  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Fluid Flow ◽  
External Magnetic Field ◽  
Numerical Simulations ◽  
Electric Conductivity ◽  
Electromagnetic Stirring ◽  
Metal Sample ◽  
Rotating Liquid ◽  
Better Than

Abstract In this paper we propose a new relationship between the opposing mechanical torque and the electric conductivity of a rotating liquid specimen in a permanent external magnetic field of constant induction. It is shown that the proposed relationship describes the experimental data for a rotating specimen better than Braunbeck formula derived under the assumption that a magnetic field rotates around a stationary metal sample.

scholarly journals Manipulating Majorana zero modes on atomic rings with an external magnetic field

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Jian Li ◽  
Titus Neupert ◽  
B. Andrei Bernevig ◽  
Ali Yazdani
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Zero Modes
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