A5034573184- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Quantum many-body systems
- Topological Materials and Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Graphene research and applications
- Quantum Information and Cryptography
- Quantum Computing Algorithms and Architecture
- Semiconductor Quantum Structures and Devices
- Advanced Condensed Matter Physics
- Algebraic structures and combinatorial models
- Surface and Thin Film Phenomena
- Advanced MIMO Systems Optimization
- Advancements in Semiconductor Devices and Circuit Design
- Quantum, superfluid, helium dynamics
- Theoretical and Computational Physics
- Advanced Wireless Communication Techniques
- Strong Light-Matter Interactions
- Magnetic properties of thin films
- Noncommutative and Quantum Gravity Theories
- Quantum Mechanics and Applications
- Black Holes and Theoretical Physics
- Cooperative Communication and Network Coding
- Magnetic and transport properties of perovskites and related materials
- Molecular Junctions and Nanostructures
University of Oxford
2015-2025
Science Oxford
2024
ETH Zurich
2024
Otto-von-Guericke University Magdeburg
2022-2023
Centre for Policy Studies
2017-2019
KTH Royal Institute of Technology
2017
Stockholm University
2017
AlbaNova
2017
National University of Ireland, Maynooth
2014
Nokia (United States)
1988-2008
Topological quantum computation has emerged as one of the most exciting approaches to constructing a fault-tolerant computer. The proposal relies on existence topological states matter whose quasiparticle excitations are neither bosons nor fermions, but particles known non-Abelian anyons, meaning that they obey braiding statistics. Quantum information is stored in with multiple quasiparticles, which have degeneracy. unitary gate operations necessary for carried out by quasiparticles and then...
The use of multiple-antenna arrays in both transmission and reception promises huge increases the throughput wireless communication systems. It is therefore important to analyze capacities such systems realistic situations, which may include spatially correlated channels noise, as well interferers with known channel at receiver. Here, we present an approach that provides analytic expressions for statistics, i.e., moments distribution, mutual information arbitrary correlations, interferers,...
Squeezing out the oddness The material Sr 2 RuO 4 has long been thought to exhibit an exotic, odd-parity kind of superconductivity, not unlike superfluidity in 3 He. How would perturbing this material's electronic structure affect its superconductivity? Steppke et al. put under large uniaxial pressure and found that critical temperature more than doubled then fell as a function strain (see Perspective by Shen). maximum roughly coincided with point at which Fermi surface underwent topological...
The fractional quantum Hall effect, being one of the most studied phenomena in condensed matter physics during past thirty years, has generated many groundbreaking new ideas and concepts. Very early on it was realized that zoo emerging states would need to be understood a systematic manner. first attempts do this, by Haldane Halperin, set an agenda for further work which continued this day. Since time idea hierarchies quasiparticles condensing form been pillar our understanding physics. In...
Weyl semimetals exhibit exceptional quantum electronic transport due to the presence of topologically-protected band crossings called nodes. The nodes come in pairs with opposite chirality, but their number and location momentum space is otherwise material specific. Following initial discoveries there now a need for better realizations, ideally comprising single pair located at or very close Fermi level an energy window free from other overlapping bands. Here we propose layered intermetallic...
We investigate the full doping and strain-dependent phase diagram of normal state magic-angle twisted bilayer graphene (TBG). Using comprehensive Hartree-Fock calculations, we show that at temperatures where superconductivity is absent global structure can be understood based on competition coexistence between three types intertwined orders: a fully symmetric phase, spatially uniform flavor-symmetry-breaking states, an incommensurate Kekulé spiral (IKS) order. For small strain, IKS recently...
In this work we present a proposal for realising non-Abelian anyons on NISQ device. particular explore the feasibility of implementing quantum double model <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>D</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:msub><mml:mi>D</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:mo stretchy="false">)</mml:mo></mml:math>. We propose techniques to drastically simplify circuits manipulation and measurements anyons. Numerical simulations with...
Coherent wave propagation in disordered media gives rise to many fascinating phenomena as diverse universal conductance fluctuations mesoscopic metals and speckle patterns light scattering. Here, the theory of electromagnetic diffusive is combined with information show how interference affects transmission rate between antenna arrays. Nontrivial dependencies capacity on nature arrays are found, such dimensionality their direction respect local scattering medium. This approach provides a...
Fourth-generation (4G) systems are expected to support data rates of the order 100 Mb/s in outdoor environment and 1 Gb/s indoor/stationary environment. In such large payloads, radio physical layer must employ receiver algorithms that provide a significant increase spectrum efficiency (and, hence, capacity) over current wireless systems. Recently, an explosion multiple-input-multiple-output (MIMO) studies have appeared with many journals presenting special issues on this subject. This has...
In topological quantum computation, information is stored in states which are intrinsically protected from decoherence, and gates carried out by dragging particlelike excitations (quasiparticles) around one another two space dimensions. The resulting quasiparticle trajectories define world lines three-dimensional space-time, the corresponding depend only on topology of braids formed these lines. We show how to find that yield a universal set for qubits encoded using specific kind...
We study a class of three-dimensional (3D) exactly solvable models topological matter first put forward by Walker and Wang [Front. Phys. 7(2) 150 (2012)]. While these are not interacting fermions, they may well capture the behavior some strongly correlated systems. In this work, we give full pedagogical treatment special simple case models, which call 3D semion model: calculate its ground-state degeneracies for variety boundary conditions, classify low-lying excitations. point defects in...
Recent progress in nanoscale quantum optics and superconducting qubits has made the creation of strongly correlated, even topologically ordered, states photons a real possibility. Many these are gapped exhibit anyon excitations, which could be used for robust form information processing. However, while numerous qubit array proposals exist to engineer Hamiltonian systems, question how stabilize many-body ground state photonic simulators against photon losses remains largely unanswered. We...
We study the superconductivity pairing symmetry in ${\mathrm{Sr}}_{2}$${\mathrm{RuO}}_{4}$ limit of small interaction by extending a renormalization group calculation developed Raghu et al. [Phys. Rev. B 81, 224505 (2010)] to include spin-orbit coupling and multiband effects. show these effects be crucial discriminate between possible order parameters. In contrast previous results without necessity fine-tuning, we obtain pseudospin-triplet gaps same magnitude on two-dimensional...
We study magic angle graphene in the presence of both strain and particle-hole symmetry breaking due to non-local inter-layer tunneling. perform a self-consistent Hartree-Fock that incorporates these effects alongside realistic interaction substrate potentials, explore comprehensive set competing orders including those break translational at arbitrary wavevectors. find all non-zero integer fillings very small strains, comparable measured scanning tunneling experiments, stabilize...
We consider a narrowband point-to-point communication system with n/sub T/ transmitters and R/ receivers. assume the receiver has perfect knowledge of channel, while transmitter no channel knowledge. case where receiving antenna array uncorrelated elements, elements transmitting are arbitrarily correlated. Focusing on T/=2, we derive simple analytic expressions for ergodic average cumulative distribution function mutual information arbitrary input (transmission) signal covariance. then...
In finite magnetic field H, the excitation spectrum of low energy quasiparticles in a 2 dimensional d-wave superconductor exhibits scaling with respect to $H^{1/2}$. This property can be used calculate relations for various physical quantities at temperature T. As examples, we make predictions behavior specific heat, quasiparticle susceptibility, optical conductivity tensor, and thermal tensor. These are compatible existing experimental data. Most notably, Hall coefficient $κ_{xy}$ measured...
We report on new experiments and theory that unambiguously resolve the recent puzzling observation of large diameter exciton emission halos around a laser excitation spot in two dimensional systems. find novel separation plasmas opposite charge with from sharp circular boundary between these regions. This allows for cooling initially hot optically generated carriers as they dwell reservoirs very long times.
We show that dipolar interactions have dramatic effects on the ground states of rotating atomic Bose gases in weak-interaction limit. With increasing interaction (relative to net contact interaction), mean field, or high filling factor, state undergoes a series transitions between vortex lattices different symmetries: triangular, square, ``stripe,'' and ``bubble'' phases. also study quantum fluids at low factors. incompressible Laughlin factor $\ensuremath{\nu}=1/2$ is replaced by...
We construct a wave function, generalizing the well-known Moore-Read Pfaffian, that describes spinless electrons at filling fraction $\ensuremath{\nu}=2∕5$ (or bosons $\ensuremath{\nu}=2∕3$) as ground state of very simple three body potential. find, analogous to when quasiholes are added there is degeneracy which can be identified zero modes quasiholes. The having semionic statistics. write this function correlator Virasoro minimal model conformal field theory $\mathcal{M}(5,3)$. Since...
We perform numerical studies to determine if the fractional quantum Hall state observed at filling nu=5/2 is Moore-Read wavefunction or its particle hole conjugate, so-called AntiPfaffian. Using a truncated Hilbert space approach we find that for realistic interactions, including Landau-level mixing, ground remains fully polarized and AntiPfaffian strongly favored.
We describe a family of phase transitions connecting phases differing non-trivial topological order by explicitly constructing Hamiltonians the Levin-Wen[PRB 71, 045110] type which can be tuned between two solvable points, each realizes different topologically ordered phase. show that low-energy degrees freedom near transition mapped onto those Potts model, and we discuss stability resulting diagram to small perturbations about model. further explain how excitations in condensed are formed...
We show from a weak-coupling microscopic calculation that the most favored chiral superconducting order parameter in Sr2RuO4 has Chern number of |C|=7. The two dominant components this are given by sin(3k(x))+isin(3k(y)) and sin(k(x))cos(k(y))+isin(k(y))cos(k(x)) lie same irreducible representation E(u) tetragonal point group as usually assumed gap function, sin(k(x))+isin(k(y)). While latter function leads to C=1, former lead C=-7, which is also allowed for an E_{u} since symmetry only...
We study the effects of Landau level mixing in limit weak electron interaction. use a numerical method to obtain two- and three-body corrections quantum Hall pseudopotentials, which are exact lowest order parameter. Our results general agreement with certain analytic (some derived here; some by other authors) thermodynamic limit. find that convergence this can be slow. This suggests errors could occur if one tries pseudopotentials for work on finite systems.