Publications (144)
Superconducting proximity effect and order parameter fluctuations in disordered and quasiperiodic systems
Gautam Rai, Stephan Haas, Anuradha Jagannathan
We study the superconducting proximity effect in inhomogeneous systems in which a disordered or quasicrystalline normal-state wire is connected to a BCS superconductor. We self-con…
Healing of Defects in Random Antiferromagnetic Spin Chains
Romain Vasseur, Arash Roshani, Stephan Haas +1
We study the effects of a weakened link in random antiferromagnetic spin chains. We show that healing occurs, and that homogeneity is restored at low energy, in a way that is quali…
Control of Plasmons in Doped Topological Insulators via Basis Atoms
Zhihao Jiang, Henning Schlömer, Stephan Haas
Collective excitations in topologically non-trivial systems have attracted considerable attention in recent years. Here we study plasmons in the Su-Schrieffer-Heeger model whose lo…
Plasmonic Waveguides from Coulomb-Engineered Two-Dimensional Metals
Zhihao Jiang, Stephan Haas, Malte Rösner
Coulomb interactions play an essential role in atomically-thin materials. On one hand, they are strong and long-ranged in layered systems due to the lack of environmental screening…
Collision Dynamics of Bose-Einstein Condensates
Aaron Wirthwein, Stephan Haas, Sheng-wey Chiow
We study the collision dynamics of two Bose-Einstein condensates with their dynamical wave functions modeled by a set of coupled, time-dependent Gross-Pitaevskii equations. Beginni…
Quasiparticle spectrum of the hybrid s+g-wave superconductors YNi_2B_2C and LuNi_2B_2C
Kazumi Maki, Hyekyung Won, Stephan Haas
Recent experiments on single crystals of YNiBC have revealed the presence of point nodes in the superconducting energy gap Delta(k} at k = (1,0,0), (0,1,0), (-1,0,0), and (…
Induced superconducting pair correlations in a quasicrystal coupled to a BCS superconductor
Gautam Rai, Stephan Haas, Anuradha Jagannathan
In this report, we describe the proximity effect which arises when a quasicrystal is placed in contact with a superconductor. We consider the simplest known model of a quasicrystal…
Vortex stability in interacting Bose-Einstein condensates
Ajay Srinivasan, Aaron Wirthwein, Stephan Haas
We study the stability of vortices in a binary system of Bose-Einstein condensates, with their wave functions modeled by a set of coupled, time-dependent Gross-Pitaevskii equations…
Quantum Antiferromagnetism in Quasicrystals
Stefan Wessel, Anuradha Jagannathan, Stephan Haas
The antiferromagnetic Heisenberg model is studied on a two-dimensional bipartite quasiperiodic lattice. The distribution of local staggered magnetic moments is determined on finite…
Superconductivity in the Fibonacci Chain
Ying Wang, Gautam Rai, Chris Matsumura +2
Superconductivity was recently reported in several quasicrystalline systems. These are materials which are structurally ordered, but since they are not translationally invariant, t…
Dynamics of Majorana Fermions on a Quantum Computer
Yuxiao Hang, Rosa Di Felice, Aiichiro Nakano +1
The study of quasiparticle dynamics is central to understanding non-equilibrium phenomena in quantum many-body systems. Direct simulation of such dynamics on quantum hardware has b…
Theory of c-axis Josephson tunneling in d-wave superconductors
Kazumi Maki, Stephan Haas
The temperature and angular dependence of the c-axis Josephson current and the superfluid density in layered d-wave superconductors are studied within the framework of an extended…
Adaptive quantum design of atomic clusters
Jason Thalken, Yu Chen, A. F. J. Levi +1
Adaptive quantum design identifies the best broken-symmetry configurations of atoms and molecules that enable a desired target function response. In this work, numerical optimizati…
Quantum Phase Transitions in Coupled Dimer Compounds
Omid Nohadani, Stefan Wessel, Stephan Haas
We study the critical properties in cubic systems of antiferromagnetically coupled spin dimers near magnetic-field induced quantum phase transitions. The quantum critical points in…
Adaptive Design of Excitonic Absorption in Broken-Symmetry Quantum Wells
Jason Thalken, Weifei Li, Stephan Haas +1
Adaptive quantum design is used to identify broken-symmetry quantum well potential profiles with optical response properties superior to previous ad-hoc solutions. This technique p…
Disorder-enhanced phase coherence in trapped bosons on optical lattices
Pinaki Sengupta, Aditya Raghavan, Stephan Haas
The consequences of disorder on interacting bosons trapped in optical lattices are investigated by quantum Monte Carlo simulations. At small to moderate strengths of potential diso…
Fractal dimension and threshold properties in a spatially correlated percolation model
Hongting Yang, Wen Zhang, Noah Bray-Ali +1
We consider the effects of spatial correlations in a two-dimensional site percolation model. By generalizing the Newman-Ziff Monte Carlo algorithm to include spatial correlations,…
Entanglement and factorized ground states in two-dimensional quantum antiferromagnets
Tommaso Roscilde, Paola Verrucchi, Andrea Fubini +2
Making use of exact results and quantum Monte Carlo data for the entanglement of formation, we show that the ground state of anisotropic two-dimensional S=1/2 antiferromagnets in a…
Spectral Functions of One-dimensional Models of Correlated Electrons
Julien Favand, Stephan Haas, Karlo Penc +2
Using the Ogata-Shiba wave function, the spectral functions of the one-dimensional infinite U Hubbard model are calculated for various concentrations. It is shown that the ``shadow…
Real-space BCS-BEC crossover in FeSe monolayer
Haicheng Lin, Wantong Huang, Gautam Rai +7
The quantum many body states in the BCS-BEC crossover regime are of long-lasting interest. Here we report direct spectroscopic evidence of BCS-BEC crossover in real-space in a FeSe…
Spectral Analysis of Correlated One-Dimensional Systems with Impurities
Stephan Haas
An averaging procedure is proposed to account for spectral features of correlated one-dimensional systems in the presence of non-magnetic impurities. The dynamical spin structure f…
Temperature dependence of impurity bound states in d-wave superconductors
Stephan Haas, Kazumi Maki
We study the evolution with temperature of quasiparticle bound states around non-magnetic impurities in d-wave superconductors. The associated local density of states has a fourfol…
Optimal control of electromagnetic field using metallic nanoclusters
Ilya Grigorenko, Stephan Haas, Alexander Balatsky +1
The dielectric properties of metallic nanoclusters in the presence of an applied electromagnetic field are investigated using non-local linear response theory. In the quantum limit…
Bose-Glass Phases in Disordered Quantum Magnets
Omid Nohadani, Stefan Wessel, Stephan Haas
In disordered spin systems with antiferromagnetic Heisenberg exchange, transitions into and out of a magnetic-field-induced ordered phase pass through a unique regime. Using quantu…
Electron-phonon bound states and impurity band formation in quantum wells
Bruna P. W. de Oliveira, Stephan Haas
A generalized propagation matrix method is used to study how scattering off local Einstein phonons affects resonant electron transmission through quantum wells. In particular, the…
Aperiodic nano-photonic design
Ioan L. Gheorma, Stephan Haas, A. F. J. Levi
The photon scattering properties of aperiodic nano-scale dielectric structures can be tailored to closely match a desired response by using adaptive algorithms for device design. W…
Bose glass and Mott glass of quasiparticles in a doped quantum magnet
Rong Yu, Liang Yin, Neil S. Sullivan +12
The low-temperature states of bosonic fluids exhibit fundamental quantum effects at the macroscopic scale: the best-known examples are Bose-Einstein condensation (BEC) and superflu…
Using the J1-J2 Quantum Spin Chain as an Adiabatic Quantum Data Bus
Nicholas Chancellor, Stephan Haas
This paper investigates numerically a phenomenon which can be used to transport a single q-bit down a J1-J2 Heisenberg spin chain using a quantum adiabatic process. The motivation…
Hole Doping Evolution of the Quasiparticle Band in Models of Strongly Correlated Electrons for the High-T_c Cuprates
Daniel Duffy, Alexander Nazarenko, Stephan Haas +3
Quantum Monte Carlo (QMC) and Maximum Entropy (ME) techniques are used to study the spectral function of the one band Hubbard model in strong coupling including a n…
Hofstadter Butterflies in Topological Insulators
Larry Li, Marcin Abram, Abhinav Prem +1
In this chapter, we investigate the energy spectra as well as the bulk and surface states in a two-dimensional system composed of a coupled stack of one-dimensional dimerized chain…
Phase Diagram and Thermodynamic Properties of the Square Lattice of Antiferromagnetic Spin-1/2 Triangles in La_4Cu_3MoO_12
Stefan Wessel, Stephan Haas
The magnetic phase diagram and the thermodynamic properties of a square lattice containing antiferromagnetically coupled spin-1/2 triangles are studied. A Heisenberg Hamiltonian wi…
Propagation of Disturbances in Degenerate Quantum Systems
Nicholas Chancellor, Stephan Haas
Disturbances in gapless quantum many-body models are known to travel an unlimited distance throughout the system. Here, we explore this phenomenon in finite clusters with degenerat…
Entanglement Entropy in the Two-Dimensional Random Transverse Field Ising Model
Rong Yu, Hubert Saleur, Stephan Haas
The scaling behavior of the entanglement entropy in the two-dimensional random transverse field Ising model is studied numerically through the strong disordered renormalization gro…
Low-Energy Properties of Antiferromagnetic Spin-1/2 Heisenberg Ladders with an Odd Number of Legs
Beat Frischmuth, Stephan Haas, German Sierra +1
An effective low-energy description for multi-leg spin-1/2 Heisenberg ladders with an odd number of legs is proposed. Using a newly developed Monte Carlo loop algorithm and exact d…
SNS Junctions along the BCS-BEC Crossover
Gautam Rai, Arman Babakhani, Ying Wang +2
We present a theory of SNS junctions, a normal metal sandwiched between two superconductors, along the crossover from the BCS to the BEC regime. We calculate the Josephson current…
Statistical properties of random matrix product states
Silvano Garnerone, Thiago R. de Oliveira, Stephan Haas +1
We study the set of random matrix product states (RMPS) introduced in arXiv:0908.3877 as a tool to explore foundational aspects of quantum statistical mechanics. In the present wor…
Impurity Bound States and Symmetry of the Superconducting Order Parameter in Sr_2RuO_4
Kazumi Maki, Stephan Haas
Recent experiments on Sr_2RuO_4 have indicated the presence of linear nodes in the superconducting order parameter. Among the possible spin triplet states, 2D p-wave superconductiv…
Quantum percolation in two-dimensional antiferromagnets
Rong Yu, Tommaso Roscilde, Stephan Haas
The interplay of geometric randomness and strong quantum fluctuations is an exciting topic in quantum many-body physics, leading to the emergence of novel quantum phases in strongl…
The disordered-free-moment phase: a low-field disordered state in spin-gap antiferromagnets with site dilution
Rong Yu, Tommaso Roscilde, Stephan Haas
Site dilution of spin-gapped antiferromagnets leads to localized free moments, which can order antiferromagnetically in two and higher dimensions. Here we show how a weak magnetic…
Detection of Topology via Entanglement Oscillations
Chunyu Tan, Hubert Saleur, Stephan Haas
We introduce a characterization of topological order based on bulk oscillations of the entanglement entropy and the definition of an `entanglement gap', showing that it is generall…
Quantum Hall States in Graphene from Strain-Induced Nonuniform Magnetic Fields
Yichen Chang, Tameem Albash, Stephan Haas
We examine strain-induced quantized Landau levels in graphene. Specifically, arc-bend strains are found to cause nonuniform pseudomagnetic fields. Using an effective Dirac model wh…
Fast realization of a spatially correlated percolation model
Hongting Yang, Stephan Haas
We propose two schemes to achieve fast realizations of spatially correlated percolation models. The schemes are shown to be efficient in complementary regimes of correlation phase…
Excitation Spectra and Thermodynamic Response of Segmented Heisenberg Spin Chains
Stefan Wessel, Stephan Haas
The spectral and thermodynamic response of segmented quantum spin chains is analyzed using a combination of numerical techniques and finite-size scaling arguments. Various distribu…
Perspectives on Nodal Superconductors
Kazumi Maki, Stephan Haas, David Parker +1
In the last few years the gap symmetries of many new superconductors,including SrRuO, CeCoIn, -(ET)Cu(NCS), YNiBC and PrOsSb, h…
Subarea law of entanglement in nodal fermionic systems
Letian Ding, Noah Bray-Ali, Rong Yu +1
We investigate the subarea law scaling properties of the block entropy in bipartite fermionic systems which do not have a finite Fermi surface. It is found that in gapped regimes t…
Small quench dynamics as a probe for trapped ultracold atoms
Sunil Yeshwanth, Marcos Rigol, Stephan Haas +1
Finite systems of bosons and/or fermions described by the Hubbard model can be realized using ultracold atoms confined in optical lattices. The ground states of these systems often…
Formation of collective excitations in quasi-one dimensional metallic nanostructures: size and density dependance
Amy Cassidy, Ilya Grigorenko, Stephan Haas
We investigate theoretically the formation of collective excitations in atomic scale quasi-one dimensional metallic nanostructures. The response of the system is calculated within…
Quantum phase transition in spin systems studied through entanglement estimators
Andrea Fubini, Stephan Haas, Tommaso Roscilde +2
Entanglement represents a pure quantum effect involving two or more particles. Spin systems are good candidates for studying this effect and its relation with other collective phen…
Anisotropic superconductivity in PrOs4Sb12
David Parker, Kazumi Maki, Stephan Haas
Recently the superconducting gap functions of the skutterudite PrOsSb have been proposed [K. Maki et al, Europhys. Lett. {\bf 68}, 720 (2004)]. The superconductivity is…
Coherent control of non-Markovian photon-resonator dynamics
Anthony F. J. Levi, Lorenzo Campos Venuti, Tameem Albash +1
We study the unitary time evolution of photons interacting with a dielectric resonator using coherent control pulses. We show that non-Markovianity of transient photon dynamics in…
Two-dimensional percolation with multiple seeds
Hongting Yang, Stephan Haas
We study non-uniform percolation in a two-dimensional cluster growth model with multiple seeds. With increasing concentration of seeds, the percolation threshold is found to increa…
Crossover physics in the non-equilibrium dynamics of quenched quantum impurity systems
Romain Vasseur, Kien Trinh, Stephan Haas +1
A general framework is proposed to tackle analytically local quantum quenches in integrable impurity systems, combining a mapping onto a boundary problem with the form factor appro…
Entanglement Properties of Disordered Quantum Spin Chains with Long-Range Antiferromagnetic Interactions
Youcef Mohdeb, Javad Vahedi, N. Moure +5
We examine the concurrence and entanglement entropy in quantum spin chains with random long-range couplings, spatially decaying with a power-law exponent . Using the strong dis…
Bose-Einstein condensation vs. localization of bosonic quasiparticles in disordered weakly-coupled dimer antiferromagnets
Tommaso Roscilde, Stephan Haas
We investigate the field-induced insulator-to-superfluid transition of bosonic quasiparticles in weakly-coupled dimer antiferromagnets. In presence of realistic disorder du…
Generalization of the Luttinger Theorem for Fermionic Ladder Systems
Patrick Gagliardini, Stephan Haas, T. M. Rice
We apply a generalized version of the Lieb-Schultz-Mattis Theorem to fermionic ladder systems to show the existence of a low-lying excited state (except for some special fillings).…
From the Hubbard to the SO(5) Ladder: A Numerical Study
Daniel Duffy, Stephan Haas, Eugene Kim
The Hubbard Hamiltonian on a two-leg ladder is studied numerically using quantum Monte Carlo and Exact Diagonalization techniques. A rung interaction, , is turned on such that t…
Plasmonic Excitations in Tight-Binding Nanostructures
Rodrigo A. Muniz, Stephan Haas, A. F. J. Levi +1
We explore the collective electromagnetic response in atomic clusters of various sizes and geometries. Our aim is to understand, and hence to control, their dielectric response, ba…
Topological Phase Diagram of Generalized SSH Models with Interactions
Yuxiao Hang, Stephan Haas
We investigate interacting Su-Schrieffer-Heeger (SSH) chains with two- and three-site unit cells using density matrix renormalization group (DMRG) simulations. By selecting appropr…
Emulating Quantum Dynamics with Neural Networks via Knowledge Distillation
Yu Yao, Chao Cao, Stephan Haas +3
High-fidelity quantum dynamics emulators can be used to predict the time evolution of complex physical systems. Here, we introduce an efficient training framework for constructing…
Correlations in Quantum Spin Ladders with Site and Bond Dilution
Kien Trinh, Stephan Haas, Rong Yu +1
We investigate the effects of quenched disorder, in the form of site and bond dilution, on the physics of the antiferromagnetic Heisenberg model on even-leg ladders. Site d…
Control of Plasmons in Topological Insulators via Local Perturbations
Yuling Guan, Zhihao Jiang, Stephan Haas
We use a fully quantum mechanical approach to demonstrate control of plasmonic excitations in prototype models of topological insulators by molecule-scale perturbations. Strongly l…
Fidelity and superconductivity in two-dimensional t-J models
Marcos Rigol, B. Sriram Shastry, Stephan Haas
We compute the ground-state fidelity and various correlations to gauge the competition between different orders in two-dimensional t-J-type models. Using exact numerical diagonaliz…
Bulk topological signatures of a quasicrystal
Gautam Rai, Henning Schlömer, Chris Matsumura +2
We show how measuring real space properties such as the charge density in a quasiperiodic system can be used to gain insight into their topological properties. In particular, for t…
Threshold Response to Stochasticity in Morphogenesis
George Courcoubetis, Sammi Ali, Sergey V Nuzhdin +2
During development of biological organisms, multiple complex structures are formed. In many instances, these structures need to exhibit a high degree of order to be functional, alt…
Visualization of nano-plasmons in graphene
Hari Dahal, Rodrigo A. Muniz, Stephan Haas +2
We study localized plasmons at the nanoscale (nano-plasmons) in graphene. The collective excitations of induced charge density modulations in graphene are drastically changed in th…
Magnetic and Metallic State at Intermediate Hubbard U Coupling in Multiorbital Models for Undoped Fe Pnictides
Rong Yu, Kien T. Trinh, Adriana Moreo +4
Multi-orbital Hubbard model Hamiltonians for the undoped parent compounds of the Fe-pnictide superconductors are here investigated using mean-field techniques. For a realistic four…
Localized Plasmons in Topological Insulators
Zhihao Jiang, Malte Rösner, Roelof E. Groenewald +1
We investigate in a fully quantum-mechanical manner how the many-body excitation spectrum of topological insulators is affected by the presence of long-range Coulomb interactions.…
Entanglement Entropy Growth in Disordered Spin Chains with Tunable Range Interactions
Youcef Mohdeb, Javad Vahedi, Ravindra N. Bhatt +2
The non-equilibrium dynamics of disordered many-body quantum systems after a global quantum quench unveils important insights about the competition between interactions and disorde…
Defect Induced Resonances and Magnetic Patterns in Graphene
Yi Chen Chang, Stephan Haas
We investigate the effects of point and line defects in monolayer graphene within the framework of the Hubbard model, using a self-consistent mean field theory. These defects are f…
Quantification and Control of non-Markovian Evolution in Finite Quantum Systems via Feedback
Nicholas Chancellor, Christoph Petri, Lorenzo Campos Venuti +2
We consider the unitary time evolution of continuous quantum mechanical systems confined to a cavity in contact with a finite bath of variable size. Measures for Markovianity for s…
Excitonic Instabilities and Insulating States in Bilayer Graphene
Kok Wee Song, Yung-Ching Liang, Stephan Haas
The competing ground states of bilayer graphene are studied by applying renormalization group techniques to a bilayer honeycomb lattice with nearest neighbor hopping. In the absenc…
Effects of Strong Correlations and Disorder in d-Wave Superconductors
Marcos Rigol, B. Sriram Shastry, Stephan Haas
We use exact diagonalization techniques to study the interplay between strong correlations, superconductivity, and disorder in a model system. We study an extension of the t-J mode…
Quantum disorder and Griffiths singularities in bond-diluted two-dimensional Heisenberg antiferromagnets
Rong Yu, Tommaso Roscilde, Stephan Haas
We investigate quantum phase transitions in the spin-1/2 Heisenberg antiferromagnet on square lattices with inhomogeneous bond dilution. It is shown that quantum fluctuations can b…
Chiral d-wave superconductivity in the heavy-fermion compound CeIrIn_5
Kazumi Maki, Aditya Raghavan, Stephan Haas
Recent thermal conductivity measurements in the heavy-fermion compound CeIrIn_5 indicate that its superconducting order parameter is very different from CeCoIn_5. Here we show that…
Plasmons in Two-Dimensional Topological Insulators
Henning Schlömer, Zhihao Jiang, Stephan Haas
We analyze collective excitations in models of two-dimensional topological insulators using the random phase approximation. In a two-dimensional extension of the Su-Schrieffer-Heeg…
Shadow Bands in the Cuprates
Stephan Haas, Adriana Moreo, Elbio Dagotto
A consequence of strong antiferromagnetic correlations in models of high-Tc cuprates is the appearance in photoemission (PES) calculations of considerable more weight above the Fer…
Quantum glass phases in the disordered Bose-Hubbard model
Pinaki Sengupta, Stephan Haas
The phase diagram of the Bose-Hubbard model in the presence of off-diagonal disorder is determined using Quantum Monte Carlo simulations. A sequence of quantum glass phases interve…
Anisotropic s-wave superconductivity in MgB_2
Stephan Haas, Kazumi Maki
It has recently been observed that MgB_2 is a superconductor with a high transition temperature. Here we propose a model of anisotropic s-wave superconductivity which consistently…
Quasi-Particle Bound States around Impurities in d-wave Superconductors
Stephan Haas, Kazumi Maki
Zn and Ni impurities in the hole-doped high-temperature superconductors are known to have strong effects on thermodynamic and transport properties. A recent scanning tunneling micr…
Dynamics of Symmetry-Protected Topological Matter on a Quantum Computer
Miguel Mercado, Kyle Chen, Parth Darekar +3
Control of topological edge modes is desirable for encoding quantum information resiliently against external noise. Their implementation on quantum hardware, however, remains a lon…
Adaptation and Performance of the Cartesian Coordinates Fast Multipole Method for Nanomagnetic Simulations
Wen Zhang, Stephan Haas
An implementation of the fast multiple method (FMM) is performed for magnetic systems with long-ranged dipolar interactions. Expansion in spherical harmonics of the original FMM is…
Parity effects and universal terms of O(1) in the entanglement near a boundary
Henning Schlömer, Chunyu Tan, Stephan Haas +1
In the presence of boundaries, the entanglement entropy in lattice models is known to exhibit oscillations with the (parity of the) length of the subsystem, which however decay to…
Anatomy of Gossamer Superconductivity
Stephan Haas, Kazumi Maki, Thomas Dahm +1
There are many systems in which two order parameters compete with each other. Of particular interest are systems in which these order parameters are both unconventional. In this co…
Universal phase diagram of disordered bosons from a doped quantum magnet
Rong Yu, Stephan Haas, Tommaso Roscilde
A quantum particle cannot in general diffuse through a disordered medium because of its wavelike nature, but interacting particles can escape localization by collectively percolati…
Fidelity in topological quantum phases of matter
Silvano Garnerone, Damian Abasto, Stephan Haas +1
Quantum phase transitions that take place between two distinct topological phases remain an unexplored area for the applicability of the fidelity approach. Here, we apply this meth…
Scalable universal holonomic quantum computation realized with an adiabatic quantum data bus and potential implementation using superconducting flux qubits
Nicholas Chancellor, Stephan Haas
In this paper we examine the use of an adiabatic quantum data transfer protocol to build a universal quantum computer. Single qubit gates are realized by using a bus protocol to tr…
Predictions for Neutron Scattering and Photoemission Experiments on CuGeO_3
Stephan Haas, Elbio Dagotto
Applying numerical techniques to a model recently proposed for the one dimensional spin-Peierls compound CuGeO_3, we calculate dynamical properties that can be directly compared wi…
Magnetic Bose glass phases of coupled antiferromagnetic dimers with site dilution
Rong Yu, Omid Nohadani, Stephan Haas +1
We numerically investigate the phase diagram of two-dimensional site-diluted coupled dimer systems in an external magnetic field. We show that this phase diagram is characterized b…
Possible Nematic Order Driven by Magnetic Fluctuations in Iron Pnictides
Kok Wee Song, Yung-Ching Liang, Hokiat Lim +1
In this paper, instabilities of the isotropic metallic phase in iron pnictides are investigated. The relevant quartic fermionic interaction terms in the model are identified using…
Mott glass in site-diluted S=1 antiferromagnets with single-ion anisotropy
Tommaso Roscilde, Stephan Haas
The interplay between site dilution and quantum fluctuations in S=1 Heisenberg antiferromagnets on the square lattice is investigated using quantum Monte Carlo simulations. Quantum…
On the Liaison Between Superconductivity and Phase Separation
Stephan Haas, Elbio Dagotto, Alexander Nazarenko +1
Models of strongly correlated electrons that tend to phase separate are studied including a long-range 1/r repulsive interaction. It is observed that charge-density-wave states bec…
Scaling of the fidelity susceptibility in a disordered quantum spin chain
N. Tobias Jacobson, Silvano Garnerone, Stephan Haas +1
The phase diagram of a quantum XY spin chain with Gaussian-distributed random anisotropies and transverse fields is investigated, with focus on the fidelity susceptibility, a recen…
Fidelity approach to the disordered quantum XY model
Silvano Garnerone, N. Tobias Jacobson, Stephan Haas +1
We study the random XY spin chain in a transverse field by analyzing the susceptibility of the ground state fidelity, numerically evaluated through a standard mapping of the model…
Probing Majorana Modes via Local Spin Dynamics
Johannes Bjerlin, Anders S. Sørensen, Stephan Haas
We investigate Majorana modes in a quantum spin chain with bond-dependent exchange interactions by studying its dynamics. Specifically, we consider two-time correlations for the Ki…
Influence of Hole Doping on Antiferromagnetic Real-Space Approaches for the High-Tc Cuprates
Alexander Nazarenko, Stephan Haas, Jose Riera +2
Recently proposed scenarios for the cuprates make extensive use of a ``flat'' quasiparticle (q.p.) dispersion and short-range hole-hole interactions in real-space, both caused by a…
Topological Protection of Coherence in a Dissipative Environment
Lorenzo Campos Venuti, Zhengzhi Ma, Hubert Saleur +1
One dimensional topological insulators are characterized by edge states with exponentially small energies. According to one generalization of topological phases to non-Hermitian sy…
Lightly Doped t-J Three-Leg Ladders - an Analog for the Underdoped Cuprates
T. M. Rice, Stephan Haas, Manfred Sigrist +1
The three-leg ladder has one odd-parity and two even-parity channels. At low doping these behave quite differently. Numerical calculations for a t-J model show that the initial pha…
Entanglement and its evolution after a quench in the presence of an energy current
Anirban Das, Silvano Garnerone, Stephan Haas
We study the Ising spin chain with a Dzyaloshinskii-Moriya interaction focusing on the static and dynamic properties of the entanglement entropy, following a quantum quench. We sho…
Entanglement in quantum critical spin systems
Tommaso Roscilde, Paola Verrucchi, Andrea Fubini +2
We study the field dependence of the entanglement of formation in anisotropic S=1/2 antiferromagnetic chains and two-leg ladders displaying a T=0 field-driven quantum phase transit…
The Proximity Effect in a Superconductor-Quasicrystal Hybrid Ring
Gautam Rai, Stephan Haas, Anuradha Jagannathan
We compute the real-space profile of the superconducting order parameter (OP) in a hybrid ring that consists of a 1D superconductor connected to a Fibonacci chain using a self-cons…