We show how Majorana end modes can be generated in a one-dimensional system by varying some of the parameters Hamiltonian periodically time. The specific model we consider is chain containing spinless electrons with nearest-neighbor hopping amplitude, $p$-wave superconducting term, and chemical potential; this equivalent to spin-$\frac{1}{2}$ anisotropic $XY$ couplings between nearest neighbors magnetic field applied $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{z}$ direction. that potential...

We present a comprehensive study of two the most experimentally relevant extensions Kitaev's spinless model 1D p-wave superconductor: those involving (i) longer range hopping and superconductivity (ii) inhomogeneous potentials. commence with pedagogical review and, as means characterizing topological phases exhibited by systems studied here, we introduce bulk invariants well derived from an explicit consideration boundary modes. In time-reversal invariant systems, find that leads to...

We study a periodically driven nanowire with Rashba-like conduction and valence bands in the presence of magnetic field. identify topological regimes which system hosts zero-energy Majorana fermions. further investigate effect strong electron-electron interactions that give rise to parafermion zero energy modes hosted at ends. The first setup we consider allows for phases by applying only static fields without need superconductivity. second involves both superconductivity time-dependent one...

We study the Majorana modes, both equilibrium and Floquet, which can appear at edges of Kitaev model on honeycomb lattice. first present analytical solutions known for edge modes zigzag armchair a semi-infinite chart parameter regimes in they appear. then examine how be generated if coupling bonds perpendicular to is varied periodically time as periodic $\delta$-function kicks. derive general condition appearance disappearance Floquet function drive frequency generic $d$-dimensional...

We consider a Floquet triple-layer setup composed of two-dimensional electron gas with spin-orbit interactions, proximity coupled to an s-wave superconductor and ferromagnet driven at resonance. The ferromagnetic layer generates time-oscillating Zeeman field which competes the induced superconducting gap leads topological phase transition. resulting states support second-order pair localized zero-energy Majorana corner states. Moreover, diagram comprises helical superconductor, hosting...

We analyze the effects of electron-electron interactions and disorder on a Rashba double-nanowire setup coupled to an s-wave superconductor, which has been recently proposed as versatile platform generate Kramers pairs Majorana bound states in absence magnetic fields. identify regime parameters for these are stable against interaction effects. use bosonization, perturbative renormalization group, replica techniques derive flow equations various model evaluate corresponding phase diagram with...

A hard proximity-induced superconducting gap has recently been observed in semiconductor nanowire systems at low magnetic fields. However, the topological regime high fields, a soft emerges and represents fundamental obstacle to topologically protected quantum information processing with Majorana bound states. Here we show that setup of double Rashba nanowires are coupled an $s$-wave superconductor subjected external field along wires, threshold can be significantly reduced by destructive...

We present a theory of charge density wave (CDW) states in Weyl semimetals and their interplay with the chiral anomaly. In particular, we demonstrate special nature shortest-period CDW state, which is obtained when separation between nodes equals exactly half primitive reciprocal lattice vector. Its topological properties are shown to be distinct from all other states. make connection this observation three-dimensional fractional quantum Hall was recently proposed exist magnetic semimetals.

We study the fractional boundary charges (FBCs) occurring in nanowires presence of periodically modulated chemical potentials and connect them to FBCs a two-dimensional electron gas perpendicular magnetic field integer quantum Hall effect (QHE) regime. First, we show that take values change linearly as function phase offset potential. This linear slope takes quantized determined by period modulation depends only on number filled bands. Next, establish mapping from one-dimensional system QHE...

We study the topological phase diagram of a setup composed two nanowires with strong Rashba spin-orbit interaction subjected to an external magnetic field and brought into proximity bulk $s$-wave superconductor in presence supercurrent flowing through it. The reduces critical values Zeeman energy crossed Andreev superconducting pairing required reach characterized by one Majorana bound state localized at each system end. demonstrate that, even regime being smaller than direct pairing,...

We develop a hydrodynamic field theory of the three-dimensional fractional quantum Hall effect, which was recently proposed to exist in magnetic Weyl semimetals, when nodes are gapped by strong repulsive interactions. This takes form BF theory, contains both one-form and two-form gauge fields, coupling quasiparticle loop excitations correspondingly. It may be regarded as generalization Chern-Simons two-dimensional liquids three dimensions.

We propose a novel way of modulating exceptional topology by implementing Floquet engineering in non-Hermitian (NH) systems. introduce topological insulator which results from shining circularly polarized light on three-dimensional NH i.e. generalization insulator. The light-matter interaction facilitates the quantum phases matter to exhibit phenomenon, where point gap bulk hosts surface states. These doubly degenerate states, are localized at opposite surfaces, fill complex eigenspectrum...

We study Majorana modes and transport in one-dimensional systems with a p-wave superconductor (SC) normal metal leads. For system an SC lying between two leads, it is known that there mode at the junction each lead. If pairing Δ changes sign or if strong impurity present some point inside SC, additional appear near point. effect of all these on sub-gap conductance leads SC. derive analytical expression as function length L for energy shifts junctions due to hybridization them; oscillate...

Higher-order topology in non-Hermitian (NH) systems has recently become one of the most promising and rapidly developing fields condensed matter physics. Many distinct phases that were not present Hermitian equivalents are shown these systems. In this work, we examine how higher-order Weyl semimetals impacted by NH perturbation. We identify a new type topological semimetal, i.e., semimetal (NHHOWS) with surface diabolic points. demonstrate such an NHHOWS, exceptional points inside bulk can...

Recently it has been shown that the fidelity of ground state a quantum many-body system can be used to detect its critical points (QCPs). If $g$ denotes parameter in Hamiltonian with respect which is computed, we find for one-dimensional models large but finite size, susceptibility ${\ensuremath{\chi}}_{F}$ QCP provided correlation length exponent satisfies $\ensuremath{\nu}<2$. We then show locate even if $\ensuremath{\nu}\ensuremath{\ge}2$ introduce boundary conditions labeled by twist...

A conceptual difficulty in formulating the density-functional theory of fractional quantum Hall effect is that while standard approach Kohn-Sham orbitals are either fully occupied or unoccupied, physics calls for fractionally orbitals. This has necessitated averaging over an ensemble Slater determinants to obtain meaningful results. We develop alternative which we express and minimize grand canonical potential terms composite fermion variables. provides a natural resolution...

We study the quenching dynamics of a many-body system in one dimension described by Hamiltonian that has spatial periodicity. Specifically, we consider spin-$\frac{1}{2}$ chain with equal $xx$ and $yy$ couplings subject to periodically varying magnetic field $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{z}$ direction or, equivalently, tight-binding model spinless fermions periodic local chemical potential, having period $2q$, where $q$ is positive integer. For linear quench strength (or...

The authors compute the spin current flowing between a local spin- polarized probe and double-nanowire system in Keldysh formalism, to identify possible mechanisms observe bulk signatures of phase transitions transport experiments. They find that contains information about sign flip polarization can be used determine topological transition point

We analyze, analytically and numerically, a periodically driven Rashba nanowire proximity coupled to an $s$-wave superconductor using bosonization renormalization group analysis in the regime of strong electron-electron interactions. Due repulsive interactions, superconducting gap is suppressed, whereas Floquet Zeeman enhanced, resulting higher effective value $g$-factor compared non-interacting case. The flow equations for different coupling constants, velocities, Luttinger-liquid...

We study Majorana modes and transport in one-dimensional systems with a $p$-wave superconductor (SC) normal metal leads. For system SC lying between two leads, it is known that there mode at the junction each lead. If pairing $\Delta$ changes sign or if strong impurity present some point inside SC, additional appear near point. effect of all these on sub-gap conductance leads SC. derive an analytical expression as function length $L$ for energy shifts junctions due to hybridization them;...

Higher-order topology in non-Hermitian (NH) systems has recently become one of the most promising and rapidly developing fields condensed matter physics. Many distinct phases that were not present Hermitian equivalents are shown these systems. In this work, we examine how higher-order Weyl semimetals impacted by NH perturbation. We identify a new type topological semimetal, i.e., semimetal (NHHOWS) with surface diabolic points. demonstrate such an NHHOWS, exceptional points inside bulk can...