A5034451186- Topological Materials and Phenomena
- Quantum and electron transport phenomena
- Graphene research and applications
- Physics of Superconductivity and Magnetism
- Quantum many-body systems
- Advanced Condensed Matter Physics
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Mechanics and Non-Hermitian Physics
- Quantum, superfluid, helium dynamics
- Electronic and Structural Properties of Oxides
- 2D Materials and Applications
- Chaos control and synchronization
- Semiconductor Quantum Structures and Devices
- Nonlinear Dynamics and Pattern Formation
- Quantum optics and atomic interactions
- Photonic Crystals and Applications
- Cellular Automata and Applications
- Spectral Theory in Mathematical Physics
- Photonic and Optical Devices
- Iron-based superconductors research
- Intermetallics and Advanced Alloy Properties
- Crystallography and Radiation Phenomena
- Rare-earth and actinide compounds
- Atomic and Subatomic Physics Research
- Advanced Antenna and Metasurface Technologies
Microsoft (United States)
2017-2024
University of California, Santa Barbara
2019-2024
Quantum (Australia)
2020-2021
University of British Columbia
2015-2017
Leiden University
2011-2015
Riga Technical University
2011-2015
Landau Institute for Theoretical Physics
2010
Moscow Institute of Physics and Technology
2010
We show that weak antilocalization by disorder competes with resonant Andreev reflection from a Majorana zero mode to produce zero-voltage conductance peak of order e2/h in superconducting nanowire. The phase conjugation needed for quantum interference survive average is provided particle–hole symmetry—in the absence time-reversal symmetry and without requiring topologically nontrivial phase. identify methods distinguishing resonance effect.
Dirac and Weyl semimetals form an ideal platform for testing ideas developed in high energy physics to describe massless relativistic particles. One such quintessentially field-theoretic idea of chiral anomaly already resulted the prediction subsequent observation pronounced negative magnetoresistance these novel materials parallel electric magnetic fields. Here we predict that occurs - has experimentally observable consequences when real electromagnetic fields E B are replaced by...
By tuning the angle between graphene layers to specific "magic angles" lowest energy bands of twisted bilayer (TBLG) can be made flat. The flat nature favors formation collective ground states and, in particular, TBLG has been shown support superconductivity. When participating superconductivity are well-isolated, superfluid weight scales inversely with effective mass such bands. For flat-band systems one would therefore conclude that even if superconducting pairing is present most...
Quantum computation by non-Abelian Majorana zero modes (MZMs) offers an approach to achieve fault tolerance encoding quantum information in the non-local charge parity states of semiconductor nanowire networks topological superconductor regime. Thus far, experimental studies MZMs chiefly relied on single electron tunneling measurements which leads decoherence stored MZM. As a next step towards computation, conserving experiments based Josephson effect are required, can also help exclude...
Topological phases of matter can enable highly stable qubits with small footprints, fast gate times, and digital control. These hardware-protected must be fabricated a material combination in which topological phase reliably induced. The challenge: disorder destroy the obscure its detection. This paper reports on devices low enough to pass gap protocol, thereby demonstrating gapped superconductivity paving way for new qubit.
The helical edge state of a quantum spin-Hall insulator can carry supercurrent in equilibrium between two superconducting electrodes (separation $L$, coherence length $\ensuremath{\xi}$). We calculate the maximum (critical) current ${I}_{c}$ that flow without dissipation along single edge, going beyond short-junction restriction $L\ensuremath{\ll}\ensuremath{\xi}$ earlier work, and find dependence on fermion parity ground when $L$ becomes larger than $\ensuremath{\xi}$. Fermion-parity...
Recent years saw the complete classification of topological band structures, revealing an abundance crystalline insulators. Here we theoretically demonstrate existence materials beyond this framework, protected by quasicrystalline symmetries. We construct a higher-order phase point group symmetry that is impossible in any system. Our tight-binding model describes superconductor on Ammann-Beenker tiling which hosts localized Majorana zero modes at corners octagonal sample. The are...
System of Majorana zero modes with random infinite range interactions -- the Sachdev-Ye-Kitaev (SYK) model is thought to exhibit an intriguing relation horizons extremal black holes in two-dimensional anti-de Sitter (AdS$_2$) space. This connection provides a rare example holographic duality between solvable quantum-mechanical and dilaton gravity. Here we propose physical realization SYK solid state system. The proposed setup employs Fu-Kane superconductor realized at interface three...
Electrons in clean macroscopic samples of graphene exhibit an astonishing variety quantum phases when strong perpendicular magnetic field is applied. These include integer and fractional Hall states as well symmetry broken ferromagnetism. Here we show that mesoscopic flakes the regime disorder can another remarkable phase described by holographic duality to extremal black hole two-dimensional anti–de Sitter space. This matter be characterized a maximally chaotic non-Fermi liquid since it...
Weak topological phases are usually described in terms of protection by the lattice translation symmetry. Their characterization explicitly relies on periodicity since weak invariants expressed momentum-space torus. We prove compatibility superconductors with aperiodic systems, such as quasicrystals. go beyond usual descriptions and introduce a novel, real-space formulation invariant, based Clifford pseudospectrum. A nontrivial value this index implies bulk phase, which is robust against...
We study the phase diagram of inverted InAs/GaSb bilayer quantum wells. For a small tunneling amplitude between layers, we find that system is prone to formation an s-wave exciton condensate phase, where spin structure order parameter uniquely determined by spin-orbit coupling arising from bulk inversion asymmetry. The topologically trivial and does not support edge transport. On contrary, for large amplitude, obtain nontrivial Hall insulator with p-wave parameter, which enhances...
We derive a generic phenomenological model of Majorana Josephson junction that accounts for avoided crossing Andreev states, and investigate its dynamics at constant bias voltage to reveal an unexpected pattern any-$\ensuremath{\pi}$ effect in the limit slow decoherence: sharp peaks noise not related any definite fraction frequency.
Interesting phases of quantum matter often arise when the constituent particles---electrons in solids---interact strongly. Such strongly interacting systems are, however, quite rare and occur only extreme environments low spatial dimension, temperatures or intense magnetic fields. Here we introduce a system which fundamental electrons interact weakly but energy effective theory is described by Majorana fermions. The consists an Abrikosov vortex lattice surface strong topological insulator...
We show how a quantum dot with ballistic single-channel point contact to superconductor can be created by means of gate electrode at the edge spin Hall insulator (such as an InAs/GaSb well). A weak perpendicular magnetic field traps Majorana zero-mode, so that it observed in gate-voltage-averaged differential conductance <dI/dV> 4e^2/h zero-bias peak above (2/3{\pi}^2 - 4)e^2/h background. The one-dimensional does not permit braiding pairs fermions, but this obstacle overcome coupling...
When magnetic field $B$ is applied to a metal, nearly all observable quantities exhibit oscillations periodic in $1/B$. Such quantum reflect the fundamental reorganization of electron states into Landau levels as canonical response metal field. We predict here that, remarkably, recently discovered Dirac and Weyl semimetals can occur complete absence These zero-field are driven by elastic strain which, space low-energy fermions, acts chiral gauge potential. propose an experimental setup which...
Qubits based on Majorana zero modes are a promising path towards topological quantum computing. Such qubits, though, susceptible to quasiparticle poisoning which does not have be small by argument. We study the main sources of relevant for realistic devices -- non-equilibrium above-gap quasiparticles and equilibrium localized subgap states. Depending parameters system architecture qubit either these can dominate decoherence. However, we find in contrast naive estimates that moderately...
We study black and white hole analogues in Weyl semimetals with inhomogenous nodal tilts. how the presence of a microscopic lattice, giving rise to low-energy fermion doubler states at large momenta that are not present for elementary particles, affects analogy between Hamiltonians general relativity. Using tight-binding lattice model, we find give Hawking fragmentation attenuation wavepackets by analogue event horizon. These phenomena depend on an temperature, can be measured metamaterials...
Flat-band systems are a promising platform for realizing exotic collective ground states with spontaneously broken symmetry because the electron-electron interactions dominate over kinetic energy. A state of particular interest is chased after exciton condensate (EC). However, in flat band other can compete an EC phase, and conventional treatment effect thermal quantum fluctuations predicts phase should be unstable. Here, using double twisted bilayer graphene (TBLG) heterostructures as...
Junctions created by coupling two superconductors via a semiconductor nanowire in the presence of high magnetic fields are basis for potential detection, fusion, and braiding Majorana bound states. We study $\mathrm{NbTiN}/\mathrm{InSb}$ $\text{nanowire}/\mathrm{NbTiN}$ Josephson junctions find that dependence critical current on field exhibits gate-tunable nodes. This is contrast with well-known Fraunhofer effect, under which nodes form regular pattern period fixed junction area. Based...
Motivated by the recent advances in studying Majorana states nanowires under conditions of superconducting proximity effect, we address correspondence between common topological transition an infinite system and a another type that manifests itself positions poles scattering matrices. We establish universal dependence pole vicinity on parameter controlling transition, discuss manifestations transitions differential conductance.
Time-reversal symmetry suppresses electron backscattering in a quantum-spin-Hall edge, yielding quantized conductance at zero temperature. Understanding the dominant corrections finite-temperature experiments remains an unsettled issue. We study novel mechanism for suppression: caused by incoherent electromagnetic noise. Specifically, we show that electric potential fluctuating randomly time can backscatter electrons inelastically without constraints faced electron-electron interactions....
Electrons with large kinetic energy have a superconducting instability for infinitesimal attractive interactions. Quenching the and creating flat band renders an repulsive interaction relevant perturbation. Thus, flat-band systems are ideal platform to study competition of superconductivity magnetism their possible coexistence. Recent advances in field twisted bilayer graphene highlight this context two-dimensional materials. Two dimensions, however, put severe restrictions on stability...