Publications (104)
Many-body Majorana braiding without an exponential Hilbert space
Eric Mascot, Themba Hodge, Dan Crawford +3
Qubits built out of Majorana zero modes (MZMs) constitute the primary path towards topologically protected quantum computing. Simulating the braiding process of multiple MZMs corre…
Effect of impurities and disorder on the braiding dynamics of Majorana zero modes
Cole Peeters, Themba Hodge, Eric Mascot +1
Impurities and random disorder are known to affect topological superconducting phases and their Majorana zero modes (MZMs). In particular, it is a common assumption that disorder n…
Spontaneous Parity Violation in a Quantum Spin Chain
Stephan Rachel, Dirk Schuricht, Burkhard Scharfenberger +2
We report on a spontaneous breakdown of parity in the ground state of a spin Hamiltonian involving nearest-neighbor interactions. This occurs for a one-dimensional model where spin…
Electronic structure, spin-orbit interaction and electron-phonon coupling of triangular adatom lattices on semiconductor substrates
Lucca Marchetti, Matthew Bunney, Domenico Di Sante +1
A one-third monolayer of the heavy metals Sn and Pb deposited on semiconductor substrates can lead to a surface reconstruction, constituting an exciting tr…
Correlated Topological Phases and Exotic Magnetism with Ultracold Fermions
Peter P. Orth, Daniel Cocks, Stephan Rachel +3
Motivated by the recent progress in engineering artificial non-Abelian gauge fields for ultracold fermions in optical lattices, we investigate the time-reversal-invariant Hofstadte…
Density wave instabilities and surface state evolution in interacting Weyl semimetals
Manuel Laubach, Christian Platt, Ronny Thomale +2
We investigate the interplay of many-body and band structure effects of interacting Weyl semimetals (WSM). Attractive and repulsive Hubbard interactions are studied within a model…
Spin-orbit coupled superconductivity: Rashba-Hubbard model on the square lattice
Sebastian Wolf, Stephan Rachel
The weak-coupling renormalization group method is an asymptotically exact method to find superconducting instabilities of a lattice model of correlated electrons. Here we extend it…
Theory of small charge solitons in one-dimensional arrays of Josephson junctions
Stephan Rachel, Alexander Shnirman
We identify and investigate the new parameter regime of small charge solitons in one-dimensional arrays of Josephson junctions. We obtain the dispersion relation of the soliton and…
Spin-resolved entanglement spectroscopy of critical spin chains and Luttinger liquids
Nicolas Laflorencie, Stephan Rachel
Quantum critical chains are well described and understood by virtue of conformal field theory. Still the meaning of the real space entanglement spectrum -- the eigenvalues of the r…
Entanglement Entropy of the Two-Dimensional Heisenberg Antiferromagnet
H. Francis Song, Nicolas Laflorencie, Stephan Rachel +1
We compute the von Neumann and generalized Rényi entanglement entropies in the ground-state of the spin-1/2 antiferromagnetic Heisenberg model on the square lattice using the modi…
Exact models for trimerization and tetramerization in spin chains
Stephan Rachel, Martin Greiter
We present exact models for an antiferromagnetic S=1 spin chain describing trimerization as well as for an antiferromagnetic S=3/2 spin chain describing tetramerization. These mode…
In-plane ferromagnetism-driven topological nodal-point superconductivity with tilted Weyl cones
Maciej Bazarnik, Levente Rózsa, Ioannis Ioannidis +11
The potential application of topological superconductivity in quantum transport and quantum information has fueled an intense investigation of hybrid materials with emergent electr…
Quantum disordered insulating phase in the frustrated cubic-lattice Hubbard model
Manuel Laubach, Darshan G. Joshi, Johannes Reuther +3
In the quest for quantum spin liquids in three spatial dimensions (3D), we study the half-filled Hubbard model on the simple cubic lattice with hopping processes up to third neighb…
Fluctuations and Entanglement spectrum in quantum Hall states
Alexandru Petrescu, H. Francis Song, Stephan Rachel +6
The measurement of quantum entanglement in many-body systems remains challenging. One experimentally relevant fact about quantum entanglement is that in systems whose degrees of fr…
Su-Schrieffer-Heeger-Hubbard model at quarter filling: effects of magnetic field and non-local interactions
David Mikhail, Stephan Rachel
The interplay and competition of topology and electron-electron interactions have fascinated researchers since the discovery of topological insulators. The Su-Schrieffer-Heeger-Hub…
Origin of Topological Surface Superconductivity in FeSeTe
Eric Mascot, Sagen Cocklin, Martin Graham +3
The engineering of Majorana zero modes in topological superconductors, a new paradigm for the realization of topological quantum computing and topology-based devices, has been hamp…
Magnetic ordering phenomena of interacting quantum spin Hall models
Johannes Reuther, Ronny Thomale, Stephan Rachel
The two-dimensional Hubbard model defined for topological band structures exhibiting a quantum spin Hall effect poses fundamental challenges in terms of phenomenological characteri…
Topological Superconductivity in Skyrmion Lattices
Eric Mascot, Jasmin Bedow, Martin Graham +2
Atomic manipulation and interface engineering techniques have provided a novel approach to custom-designing topological superconductors and the ensuing Majorana zero modes, represe…
Competition of First-Order and Second-Order Topology on the Honeycomb Lattice
Matthew Bunney, Tomonari Mizoguchi, Yasuhiro Hatsugai +1
We investigate both first-order topology, as realized through Haldane's model, and second-order topology, implemented through an additional Kekulé-distortion, on the honeycomb lat…
Inelastic neutron scattering of the layered Kitaev ferromagnet LiCoSbO
Abdul Basit, Richard A. Mole, Alex J. Brown +3
Cobalt-based quantum magnets forming layered honeycomb arrangements have attracted much attention recently, as they are considered as a potential platform for materials with exotic…
Majorana braiding simulations with projective measurements
Philipp Frey, Themba Hodge, Eric Mascot +1
We summarize the key ingredients required for universal topological quantum computation using Majorana zero modes in networks of topological superconductor nanowires. Particular em…
Van-Hove tuning of Fermi surface instabilities through compensated metallicity
Hendrik Hohmann, Matteo Dürrnagel, Matthew Bunney +6
Van-Hove (vH) singularities in the vicinity of the Fermi level facilitate the emergence of electronically mediated Fermi surface instabilities. This is because they provide a momen…
Characterizing Dynamic Majorana Hybridization for Universal Quantum Computing
Themba Hodge, Eric Mascot, Dan Crawford +1
Qubits built out of Majorana zero modes (MZMs) have long been theorized as a potential pathway toward fault-tolerant topological quantum computation. Almost unavoidable in these pr…
Quantum Engineering of Majorana Fermions
Eric Mascot, Sagen Cocklin, Stephan Rachel +1
Chiral superconductors have the ability to host topologically protected Majorana zero modes which have been proposed as future qubits for topological quantum computing. The recentl…
Entanglement from Charge Statistics: Exact Relations for Many-Body Systems
H. Francis Song, Christian Flindt, Stephan Rachel +2
We present exact formulas for the entanglement and Rényi entropies generated at a quantum point contact (QPC) in terms of the statistics of charge fluctuations, which we illustrat…
Signatures of a gearwheel quantum spin liquid in a spin- pyrochlore molybdate Heisenberg antiferromagnet
Yasir Iqbal, Tobias Müller, Kira Riedl +6
We theoretically investigate the low-temperature phase of the recently synthesized LuMoON material, an extraordinarily rare realization of a three-dimension…
Detecting Quantum Critical Points using Bipartite Fluctuations
Stephan Rachel, Nicolas Laflorencie, H. Francis Song +1
We show that the concept of bipartite fluctuations F provides a very efficient tool to detect quantum phase transitions in strongly correlated systems. Using state of the art numer…
Altermagnet-Superconductor Heterostructure: a Scalable Platform for Braiding of Majorana Modes
Themba Hodge, Eric Mascot, Stephan Rachel
Topological quantum computation, featuring qubits built out of anyonic excitations known as Majorana zero modes (MZMs), have long presented an exciting pathway towards scalable qua…
Probing Hilbert space fragmentation and the block inverse participation ratio
Philipp Frey, David Mikhail, Stephan Rachel +1
We consider a family of quantum many-body Hamiltonians that show exact Hilbert space fragmentation in certain limits. The question arises whether fragmentation has implications for…
Topological superconductivity on the honeycomb lattice: Effect of normal state topology
Sebastian Wolf, Tyler Gardener, Karyn Le Hur +1
The search for topological superconductors is one of the most pressing and challenging questions in condensed matter and material research. Despite some early suggestions that dopi…
Interplay of magnetic textures with spin-orbit coupled substrates
Zachary Llewellyn, Eric Mascot, Oleg A. Tretiakov +1
Magnetic textures such as skyrmions in thin films grown on substrates possess significant technological potential. Inhomogeneous magnetic structures can be described as homogeneous…
Inelastic electron backscattering in a generic helical edge channel
Thomas L. Schmidt, Stephan Rachel, Felix von Oppen +1
We evaluate the low-temperature conductance of a weakly interacting one-dimensional helical liquid without axial spin symmetry. The lack of that symmetry allows for inelastic backs…
Landau levels of Majorana fermions in a spin liquid
Stephan Rachel, Lars Fritz, Matthias Vojta
Majorana fermions were originally proposed as elementary particles acting as their own antiparticles. In recent years, it has become clear that Majorana fermions can instead be rea…
General Relation between Entanglement and Fluctuations in One Dimension
H. Francis Song, Stephan Rachel, Karyn Le Hur
In one dimension very general results from conformal field theory and exact calculations for certain quantum spin systems have established universal scaling properties of the entan…
Realization of a discrete time crystal on 57 qubits of a quantum computer
Philipp Frey, Stephan Rachel
Novel dynamical phases that violate ergodicity have been a subject of extensive research in recent years. A periodically driven system is naively expected to lose all memory of its…
Implementation of Topological Quantum Gates in Magnet-Superconductor Hybrid Structures
Jasmin Bedow, Eric Mascot, Themba Hodge +2
The creation of topological quantum gates using Majorana zero modes -- an outstanding problem in the field of topological quantum computing -- relies on our ability to control the…
Laser modulation of superconductivity in a cryogenic widefield nitrogen-vacancy microscope
Scott E. Lillie, David A. Broadway, Nikolai Dontschuk +6
Microscopic imaging based on nitrogen-vacancy (NV) centres in diamond, a tool increasingly used for room-temperature studies of condensed matter systems, has recently been extended…
Interacting topological insulators: a review
Stephan Rachel
The discovery of the quantum spin Hall effect and topological insulators more than a decade ago has revolutionized modern condensed matter physics. Today, the field of topological…
A family of spin-S chain representations of SU(2)_k Wess-Zumino-Witten models
Ronny Thomale, Stephan Rachel, Peter Schmitteckert +1
We investigate a family of spin-S chain Hamiltonians recently introduced by one of us. For S=1/2, it corresponds to the Haldane-Shastry model. For general spin S, we find indicatio…
Increased localization of Majorana modes in antiferromagnetic chains on superconductors
Daniel Crawford, Eric Mascot, Makoto Shimizu +4
Magnet-superconductor hybrid (MSH) systems are a key platform for custom-designed topological superconductors. Ideally, the ends of a one-dimensional MSH structure will host Majora…
Stability of Disordered Topological Superconducting Phases in Magnet--Superconductor Hybrid Systems
Eric Mascot, Chaitra Agrahar, Stephan Rachel +1
Magnet-superconductor hybrid heterostructures constitute a promising candidate system for the quantum engineering of chiral topological superconductivity. Here, we investigate the…
Rashba spin orbit coupling in the Kane-Mele-Hubbard model
Manuel Laubach, Johannes Reuther, Ronny Thomale +1
Spin-orbit (SO) coupling is the crucial parameter to drive topological insulating phases in electronic band models. In particular, the generic emergence of SO coupling involves the…
Pressure-tuned magnetic interactions in honeycomb Kitaev materials
Ravi Yadav, Stephan Rachel, Liviu Hozoi +2
A range of honeycomb-lattice compounds has been proposed and investigated in the search for a topological Kitaev spin liquid. However, sizable Heisenberg interactions and additiona…
Triplet Superconductivity from Nonlocal Coulomb Repulsion in an Atomic Sn Layer Deposited onto a Si(111) Substrate
Sebastian Wolf, Domenico Di Sante, Tilman Schwemmer +2
Atomic layers deposited on semiconductor substrates introduce a platform for the realization of the extended electronic Hubbard model, where the consideration of electronic repulsi…
Topological superconductivity induced by a triple-Q magnetic structure
Jasmin Bedow, Eric Mascot, Thore Posske +4
We demonstrate that the recently discovered triple-Q (3Q) magnetic structure, when embedded in a magnet-superconductor hybrid (MSH) system, gives rise to the emergence of topologic…
Giant magnetoresistance and perfect spin filter in silicene, germanene, and stanene
Stephan Rachel, Motohiko Ezawa
Silicene, germanene and stanene are two-dimensional topological insulators exhibiting helical edge states. We investigate global and local manipulations at the edges by exposing th…
Magnet-superconductor hybrid quantum systems: a materials platform for topological superconductivity
Roberto Lo Conte, Jens Wiebe, Stephan Rachel +2
Magnet-superconductor hybrid (MSH) systems have recently emerged as one of the most significant developments in condensed matter physics. This has generated, in the last decade, a…
Charge solitons and their dynamical mass in 1-D arrays of Josephson junctions
Jens Homfeld, Ivan Protopopov, Stephan Rachel +1
We investigate the charge transport in one-dimensional arrays of Josephson junctions. In the interesting regime of "small charge solitons" (polarons), the charge dynamics is strong…
Valence bond solid states with symplectic symmetry
Dirk Schuricht, Stephan Rachel
We introduce a one-dimensional valence bond solid (VBS) state with symplectic symmetry SP(n) and construct the corresponding parent Hamiltonian. We argue that there is a gap in the…
Majorana modes with side features in magnet-superconductor hybrid systems
Daniel Crawford, Eric Mascot, Makoto Shimizu +6
Magnet-superconductor hybrid (MSH) systems represent promising platforms to host Majorana zero modes (MZMs), the elemental building blocks for fault-tolerant quantum computers. The…
Rashba spin-orbit coupling in the square lattice Hubbard model: A truncated-unity functional renormalization group study
Jacob Beyer, Jonas B. Profe, Lennart Klebl +5
The Rashba-Hubbard model on the square lattice is the paradigmatic case for studying the effect of spin-orbit coupling, which breaks spin and inversion symmetry, in a correlated el…
Time-Reversal-Invariant Hofstadter-Hubbard Model with Ultracold Fermions
Daniel Cocks, Peter P. Orth, Stephan Rachel +3
We consider the time-reversal-invariant Hofstadter-Hubbard model which can be realized in cold atom experiments. In these experiments, an additional staggered potential and an arti…
Correlation-driven charge order in a frustrated two-dimensional atom lattice
Florian Adler, Stephan Rachel, Manuel Laubach +4
We thoroughly examine the ground state of the triangular lattice of Pb on Si(111) using scanning tunneling microscopy. We detect charge-order, accompanied by a subtle structural re…
Quantized charge transport in chiral Majorana edge modes
Stephan Rachel, Eric Mascot, Sagen Cocklin +2
Majorana fermions can be realized as quasiparticles in topological superconductors, with potential applications in topological quantum computing. Recently, lattices of magnetic ada…
Quantum and Classical Phases of the Pyrochlore Heisenberg Model with Competing Interactions
Yasir Iqbal, Tobias Müller, Pratyay Ghosh +5
We investigate the quantum Heisenberg model on the pyrochlore lattice for a generic spin in the presence of nearest-neighbor and second-nearest-neighbor exchang…
Exact Excited States of Non-Integrable Models
Sanjay Moudgalya, Stephan Rachel, B. Andrei Bernevig +1
We discuss a method of numerically identifying exact energy eigenstates for a finite system, whose form can then be obtained analytically. We demonstrate our method by identifying…
From high- to low-: Multi-orbital effects in transition metal oxides
Michael Klett, Tilman Schwemmer, Sebastian Wolf +8
Despite the structural resemblance of certain cuprate and nickelate parent compounds there is a striking spread of among such transition metal oxide superconductors. We adopt…
Fractionalized Superconductivity Mediated by Majorana Fermions in the Kitaev-Kondo Lattice
Matthew Bunney, Urban F. P. Seifert, Stephan Rachel +1
Superconductivity usually emerges from a metallic normal state which follows the Fermi-liquid paradigm. If, in contrast, the normal state is a fractionalized non-Fermi liquid, then…
Incommensurate magnetic order: A fingerprint for electronic correlations in hole-doped cuprates
Michael Klett, Jacob Beyer, David Riegler +4
Intertwined charge and magnetic fluctuations in high- copper oxide superconductors (cuprates) are hypothesized to be a consequence of their correlated electronic nature…
Spiral order in the honeycomb iridate Li2IrO3
Johannes Reuther, Ronny Thomale, Stephan Rachel
The honeycomb iridates A2IrO3 (A=Na, Li) constitute promising candidate materials to realize the Heisenberg-Kitaev model (HKM) in nature, hosting unconventional magnetic as well as…
Impurity bound states as detectors of topological band structures revisited
Seydou-Samba Diop, Lars Fritz, Matthias Vojta +1
Band structures of topological insulators are characterized by non-local topological invariants. Consequently, proposals for the experimental detection using local probes are rare.…
Chern number landscape of spin-orbit coupled chiral superconductors
Matthew Bunney, Jacob Beyer, Ronny Thomale +2
Chiral superconductors are one of the predominant quantum electronic states of matter where topology, symmetry, and Fermiology intertwine. This is pushed to a new limit by further…
Three-band Hubbard model for NaIrO: Topological insulator, zigzag antiferromagnet, and Kitaev-Heisenberg material
Manuel Laubach, Johannes Reuther, Ronny Thomale +1
NaIrO was one of the first materials proposed to feature the Kane-Mele type topological insulator phase. Contemporaneously it was claimed that the very same material is in…
High-Temperature Majorana Fermions in Magnet-Superconductor Hybrid Systems
Daniel Crawford, Eric Mascot, Dirk K. Morr +1
Magnet-superconductor hybrid (MSH) structures represent one of the most promising platforms to realize, control and manipulate Majorana modes using scanning tunneling methods. By d…
Unconventional superconductivity in the extended Hubbard model: Weak-coupling renormalization group
Sebastian Wolf, Thomas L. Schmidt, Stephan Rachel
We employ the weak-coupling renormalization group approach to study unconventional superconducting phases emerging in the extended, repulsive Hubbard model on paradigmatic two-dime…
Quantum phase transitions of topological insulators without gap closing
Stephan Rachel
We consider two-dimensional Chern insulators and time-reversal invariant topological insulators and discuss the effect of perturbations breaking either particle-number conservation…
Quantum spin models of commensurate -wave magnets
GiBaik Sim, Stephan Rachel
The -wave magnet has emerged as a new type of magnetism exhibiting odd-parity, time-reversal-symmetric spin splitting in momentum space, and has attracted considerable interest…
Spin 3/2 dimer model
Stephan Rachel
We present a parent Hamiltonian for weakly dimerized valence bond solid states for arbitrary half-integral S. While the model reduces for S=1/2 to the Majumdar-Ghosh Hamiltonian we…
Direct observation of dynamical quasi-condensation on a quantum computer
Philipp Frey, Stephan Rachel
Hard-core bosons (HCB) in one dimension are predicted to show surprisingly interesting dynamics after a quantum quench. Far from equilibrium, quasi-condensation at finite momenta h…
Critical theory of the topological quantum phase transition in a spin-2 chain
Hong-Chen Jiang, Stephan Rachel, Zheng-Yu Weng +2
We systematically study the phase diagram of S=2 spin chain, by means of density-matrix renormalization group and exact diagonalization methods and confirm the presence of a dimer…
Dominant Kitaev interactions in the honeycomb materials NaCoSbO and NaCoTeO
Alaric L. Sanders, Richard A. Mole, Jiatu Liu +4
Cobaltates with 3 based layered honeycomb structure were recently proposed as Kitaev magnets and putative candidates to host the long-sought Kitaev spin liquid. Here we present…
Magnon Landau levels and emergent supersymmetry in strained antiferromagnets
Mary Madelynn Nayga, Stephan Rachel, Matthias Vojta
Inhomogeneous strain applied to lattice systems can induce artificial gauge fields for particles moving on this lattice. Here we demonstrate how to engineer a novel state of matter…
Sublattice modulated superconductivity in the Kagome Hubbard model
Tilman Schwemmer, Hendrik Hohmann, Matteo Dürrnagel +8
We identify a superconducting order featuring spatial pair modulations on the kagome lattice subject to onsite Hubbard U and nearest neighbor V interactions. Within our functional…
Transport through a quantum spin Hall antidot as a spectroscopic probe of spin textures
Alexia Rod, Giacomo Dolcetto, Stephan Rachel +1
We investigate electron transport through an antidot embedded in a narrow strip of two-dimensional topological insulator. We focus on the most generic and experimentally relevant c…
Entanglement analysis of isotropic spin-1 chains
Ronny Thomale, Stephan Rachel, B. Andrei Bernevig +1
We investigate entanglement spectra of the SO(3) bilinear-biquadratic spin-1 chain, a model with phases exhibiting spontaneous symmetry breaking (both translation and spin rotation…
Dimensional Tuning of Majorana Fermions and the Real Space Counting of the Chern Number
Eric Mascot, Sagen Cocklin, Stephan Rachel +1
We demonstrate that it is possible to use atomic manipulation techniques to adiabatically tune between one-dimensional and two-dimensional topological superconductors in magnet--su…
Atomic-Scale Interface Engineering of Majorana Edge Modes in a 2D Magnet-Superconductor Hybrid System
Alexandra Palacio-Morales, Eric Mascot, Sagen Cocklin +4
Topological superconductors are predicted to harbor exotic boundary states - Majorana zero-energy modes - whose non-Abelian braiding statistics present a new paradigm for the reali…
Negative Hybridization: a Potential Cure for Braiding with Imperfect Majorana Modes
Cole Peeters, Themba Hodge, Stephan Rachel
Majorana zero modes, the elementary building blocks for the quantum bits of topological quantum computers, are known to suffer from hybridization as their wavefunctions begin to ov…
Majorana Landau Level Raman Spectroscopy
Brent Perreault, Stephan Rachel, F. J. Burnell +1
The unambiguous experimental detection of quantum spin liquids and, in particular, of the long-sought Kitaev quantum spin liquid (KQSL) with its Majorana fermion excitations remain…
Strain-induced Landau Levels in arbitrary dimensions with an exact spectrum
Stephan Rachel, Ilja Goethel, Daniel P. Arovas +1
Certain non-uniform strain applied to graphene flakes has been shown to induce pseudo-Landau levels in the single-particle spectrum, which can be rationalized in terms of a pseudo-…
Fusion Dynamics of Majorana Zero Modes
Themba Hodge, Tuan Kieu, Jasmin Bedow +3
Braiding and fusion of Majorana zero modes are key elements of any future topological Majorana-based quantum computer. Here, we investigate the fusion dynamics of Majorana zero mod…
Projective Measurements: Topological Quantum Computing with an Arbitrary Number of Qubits
Themba Hodge, Philipp Frey, Stephan Rachel
Topological quantum computing promises intrinsic fault tolerance by encoding quantum information in non-Abelian anyons, where quantum gates are implemented via braiding. While brai…
Phase Diagram and Quantum Order by Disorder in the Kitaev - Honeycomb Magnet
Ioannis Rousochatzakis, Johannes Reuther, Ronny Thomale +2
We show that the topological Kitaev spin liquid on the honeycomb lattice is extremely fragile against the second-neighbor Kitaev coupling , which has recently been shown to be…
Quantum paramagnet in a flux triangular lattice Hubbard model
Stephan Rachel, Manuel Laubach, Johannes Reuther +1
We propose the flux triangular lattice Hubbard model (-THM) as a prototypical setup to stabilize magnetically disordered quantum states of matter in the presence of charge…
Evidence of topological Shiba bands in artificial spin chains on superconductors
Lucas Schneider, Philip Beck, Thore Posske +5
A major challenge in developing topological superconductors for implementing topological quantum computing is their characterization and control. It has been proposed that a p-wave…
Robustness of Majorana modes to potential disorder in Fe chains on a superconducting Rashba alloy
Harim Jang, Daniel Crawford, Khai Ton That +6
Majorana modes offer great potential for fault-tolerant quantum computation due to their topological protection. However, for superconductor-semiconductor nanowire hybrids, intrins…
Cluster-glass phase in pyrochlore XY antiferromagnets with quenched disorder
Eric C. Andrade, José A. Hoyos, Stephan Rachel +1
We study the impact of quenched disorder (random exchange couplings or site dilution) on easy-plane pyrochlore antiferromagnets. In the clean system, order-by-disorder selects a ma…
Functional renormalization group for three-dimensional quantum magnetism
Yasir Iqbal, Ronny Thomale, Francesco Parisen Toldin +2
We formulate a pseudofermion functional renormalization group (PFFRG) scheme to address frustrated quantum magnetism in three dimensions. In a scenario where many numerical approac…
Topological Insulators and Mott Physics from the Hubbard Interaction
Stephan Rachel, Karyn Le Hur
We investigate the Hubbard model on the honeycomb lattice with intrinsic spin orbit interactions as a paradigm for two-dimensional topological band insulators in the presence of in…
Exact results for SU(3) spin chains: trimer states, valence bond solids, and their parent Hamiltonians
Martin Greiter, Stephan Rachel, Dirk Schuricht
We introduce several exact models for SU(3) spin chains: (1) a translationally invariant parent Hamiltonian involving four-site interactions for the trimer chain, with a three-fold…
Chiral topological superconductivity in hole-doped Sn/Si(111)
Matthew Bunney, Lucca Marchetti, Domenico Di Sante +2
A third monolayer of tin atoms on the semiconductor substrate Si(111) has been shown to become superconducting upon six to ten percent hole doping. Experiments have reported promis…
Majorana quasiparticles in atomic spin chains on superconductors
Stephan Rachel, Roland Wiesendanger
For the past decade, Majorana quasiparticles have become one of the hot topics in condensed matter research. Besides the fundamental interest in the realization of particles being…
Bipartite Fluctuations as a Probe of Many-Body Entanglement
H. Francis Song, Stephan Rachel, Christian Flindt +3
We investigate in detail the behavior of the bipartite fluctuations of particle number and spin in many-body quantum systems, focusing on systems where such U…
Quasiparticle excitations in a one-dimensional interacting topological insulator: Application for dopant-based quantum simulation
David Mikhail, Benoit Voisin, Dominique Didier St Medar +3
We study the effects of electron-electron interactions on the charge excitation spectrum of the spinful Su-Schrieffer-Heeger (SSH) model, a prototype of a 1D bulk obstructed topolo…
Tunneling spectra simulation of interacting Majorana wires
Ronny Thomale, Stephan Rachel, Peter Schmitteckert
Recent tunneling experiments on InSb hybrid superconductor-semiconductor devices have provided hope for a stabilization of Majorana edge modes in a spin-orbit quantum wire subject…
Dimensional crossover and cold-atom realization of topological Mott insulators
Mathias S. Scheurer, Stephan Rachel, Peter P. Orth
We propose a cold-atom setup which allows for a dimensional crossover from a two-dimensional quantum spin Hall insulating phase to a three-dimensional strong topological insulator…
Detrimental effects of disorder in two-dimensional time-reversal invariant topological superconductors
Mahdi Mashkoori, Fariborz Parhizgar, Stephan Rachel +1
The robustness against local perturbations, as long as the symmetry of the system is preserved, is a distinctive feature of topological quantum states. Magnetic impurities and defe…
Relevance of on-site and intersite Coulomb interactions in the Kitaev-Heisenberg magnet NaCoSbO
Pritam Bhattacharyya, Abdul Basit, Thorben Petersen +3
The detection of considerable spin frustration in honeycomb cobalt oxide compounds indicates the presence of sizable Kitaev interactions in these systems, enlarging the pool of Kit…
Preparation and readout of Majorana qubits in magnet-superconductor hybrid systems
Dan Crawford, Roland Wiesendanger, Stephan Rachel
Initializing the ground state of a quantum bit (qubit) based on Majorana zero modes is one of the most pressing issues for future topological quantum computers. We explore a protoc…
Quantum Spin Hall Insulators with Interactions and Lattice Anisotropy
Wei Wu, Stephan Rachel, Wu-Ming Liu +1
We investigate the interplay between spin-orbit coupling and electron-electron interactions on the honeycomb lattice combining the cellular dynamical mean-field theory and its real…