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Non-Hermitian Stark Many-Body Localization: Utilizing exact diagonalization (ED) techniques, we investigate a one-dimensional, non-reciprocal, interacting hard-core boson model under a Stark potential with tail curvature. By employing the non-zero imaginary eigenenergies ratio, half-chain entanglement entropy, and eige...
cond-mat_quant-gas
Thermodynamics of Trapped Photon Gases at Dimensional Crossover from 2D to 1D: Photon Bose-Einstein condensates are characterised by a quite weak interaction, so they behave nearly as an ideal Bose gas. Moreover, since the current experiments are conducted in a microcavity, the longitudinal motion is frozen out and t...
cond-mat_quant-gas
Current-Phase Relation of a Bose-Einstein Condensate Flowing Through a Weak Link: We study the current-phase relation of a Bose-Einstein condensate flowing through a repulsive square barrier by solving analytically the one dimensional Gross-Pitaevskii equation. The barrier height and width fix the current-phase relat...
cond-mat_quant-gas
Birth of a quasi-stationary black hole in an outcoupled Bose-Einstein condensate: We study the evolution of an initially confined atom condensate which is progressively outcoupled by gradually lowering the confining barrier on one side. The goal is to identify protocols that best lead to a quasi-stationary sonic blac...
cond-mat_quant-gas
Energy spectrum of harmonically trapped two-component Fermi gases: Three- and Four-Particle Problem: Trapped two-component Fermi gases allow for the investigation of the so-called BCS-BEC crossover by tuning the interspecies atom-atom $s$-wave scattering length scattering $a^{(aa)}$ from attractive to repulsive, incl...
cond-mat_quant-gas
Strongly Interacting Atom Lasers in Three Dimensional Optical Lattices: We show that the dynamical melting of a Mott insulator in a three-dimensional lattice leads to condensation at nonzero momenta, a phenomenon that can be used to generate strongly interacting atom lasers in optical lattices. For infinite onsite repu...
cond-mat_quant-gas
Drag in Bose-Fermi Mixtures: We use kinetic theory to model the dynamics of a small Bose condensed cloud of heavy particles moving through a larger degenerate Fermi gas of light particles. Varying the Bose-Fermi interaction, we find a crossover between bulk and surface dominated regimes -- where scattering occurs throu...
cond-mat_quant-gas
Analysis and resolution of the ground-state degeneracy of the two-component Bose-Hubbard model: We study the degeneracy of the ground-state energy $E$ of the two-component Bose-Hubbard model and of the perturbative correction $E_1$. We show that the degeneracy properties of $E$ and $E_1$ are closely related to the co...
cond-mat_quant-gas
Conformal-invariance of 2D quantum turbulence in an exciton-polariton fluid of light: The similarities of quantum turbulence with classical hydrodynamics allow quantum fluids to provide essential models of their classical analogue, paving the way for fundamental advances in physics and technology. Recently, experimen...
cond-mat_quant-gas
Quantum phases from competing short- and long-range interactions in an optical lattice: Insights into complex phenomena in quantum matter can be gained from simulation experiments with ultracold atoms, especially in cases where theoretical characterization is challenging. However these experiments are mostly limited ...
cond-mat_quant-gas
The role of atomic interactions in cavity-induced continuous time crystals: We consider continuous time-crystalline phases in dissipative many-body systems of atoms in cavities, focusing on the role of short-range interatomic interactions. First, we show that the latter can alter the nature of the time crystal by cha...
cond-mat_quant-gas
Correlation properties of a one-dimensional repulsive Bose gas at finite temperature: We present a comprehensive study shedding light on how thermal fluctuations affect correlations in a Bose gas with contact repulsive interactions in one spatial dimension. The pair correlation function, the static structure factor, ...
cond-mat_quant-gas
Light-induced gauge fields for ultracold atoms: Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our univers...
cond-mat_quant-gas
BCS-BEC crossover in a quasi-two-dimensional Fermi gas: We consider a two-component gas of fermionic atoms confined to a quasi-two-dimensional (quasi-2D) geometry by a harmonic trapping potential in the transverse direction. We construct a mean field theory of the BCS-BEC crossover at zero temperature that allows us to...
cond-mat_quant-gas
On Berezinskii-Kosterlitz-Thouless Phase Transition in Quasi-One Dimensional Bose-Einstein Condensate: We show that quasi-one dimensional Bose-Einstein condensate under suitable conditions can exhibit a Berezinskii-Kosterlitz-Thouless phase transition. The role played by quantized vortices in two dimensional case, is...
cond-mat_quant-gas
Bose-Einstein condensates in an eightfold symmetric optical lattice: We investigate the properties of Bose-Einstein condensates (BECs) in a two-dimensional quasi-periodic optical lattice (OL) with eightfold rotational symmetry by numerically solving the Gross-Pitaevskii equation. In a stationary external harmonic trapp...
cond-mat_quant-gas
Floquet operator engineering for quantum state stroboscopic stabilization: Optimal control is a valuable tool for quantum simulation, allowing for the optimized preparation, manipulation, and measurement of quantum states. Through the optimization of a time-dependent control parameter, target states can be prepared t...
cond-mat_quant-gas
Tailoring quantum gases by Floquet engineering: Floquet engineering is the concept of tailoring a system by a periodic drive. It has been very successful in opening new classes of Hamiltonians to the study with ultracold atoms in optical lattices, such as artificial gauge fields, topological band structures and density...
cond-mat_quant-gas
Interaction-Enhanced Group Velocity of Bosons in the Flat Band of an Optical Kagome Lattice: Geometric frustration of particle motion in a kagome lattice causes the single-particle band structure to have a flat s-orbital band. We probe this band structure by exciting a Bose-Einstein condensate into excited Bloch stat...
cond-mat_quant-gas
Charge Gaps at Fractional Fillings in Boson Hubbard Ladders: The Bose-Hubbard Hamiltonian describes the competition between superfluidity and Mott insulating behavior at zero temperature and commensurate filling as the strength of the on-site repulsion is varied. Gapped insulating phases also occur at non-integer densi...
cond-mat_quant-gas
Quantum annealing for the number partitioning problem using a tunable spin glass of ions: Exploiting quantum properties to outperform classical ways of information-processing is an outstanding goal of modern physics. A promising route is quantum simulation, which aims at implementing relevant and computationally hard...
cond-mat_quant-gas
Mean-field phase diagram of the 1-D Bose gas in a disorder potential: We study the quantum phase transition of the 1D weakly interacting Bose gas in the presence of disorder. We characterize the phase transition as a function of disorder and interaction strengths, by inspecting the long-range behavior of the one-body d...
cond-mat_quant-gas
Phase diagrams and multistep condensations of spin-1 bosonic gases in optical lattices: Motivated by recent experimental processes, we systemically investigate strongly correlated spin-1 ultracold bosons trapped in a three-dimensional optical lattice in the presence of an external magnetic field. Based on a recently ...
cond-mat_quant-gas
Time crystals: analysis of experimental conditions: Time crystals are quantum many-body systems which are able to self-organize their motion in a periodic way in time. Discrete time crystals have been experimentally demonstrated in spin systems. However, the first idea of spontaneous breaking of discrete time translati...
cond-mat_quant-gas
Resonant light enhances phase coherence in a cavity QED simulator of fermionic superfluidity: Cavity QED experiments are natural hosts for non-equilibrium phases of matter supported by photon-mediated interactions. In this work, we consider a cavity QED simulation of the BCS model of superfluidity, by studying regime...
cond-mat_quant-gas
Bogoliubov-Cherenkov Radiation in an Atom Laser: We develop a simple yet powerful technique to study Bogoliubov-Cherenkov radiation by producing a pulsed atom laser from a strongly confined Bose-Einstein condensate. Such radiation results when the atom laser pulse falls past a Bose-Einstein condensate at high-hypersoni...
cond-mat_quant-gas
Spinor Condensates on a Cylindrical Surface in Synthetic Gauge Fields: We point out that by modifying the setup of a recent experiment that generates a Dirac string, one can create a quasi 2D spinor Bose condensate on a cylindrical surface with a synthetic magnetic field pointing radially outward from the cylindrical s...
cond-mat_quant-gas
Effect of an Impurity on Grey Soliton Dynamics in Cigar-Shaped Bose-Einstein Condensate: In a cigar shaped Bose-Einstein condensate, explicit solutions of the coupled mean-field equations, describing defect-grey soliton dynamics are obtained, demonstrating the coexistence of grey soliton and a localized defect. Unlik...
cond-mat_quant-gas
Realizing the entanglement Hamiltonian of a topological quantum Hall system: Topological quantum many-body systems, such as Hall insulators, are characterized by a hidden order encoded in the entanglement between their constituents. Entanglement entropy, an experimentally accessible single number that globally quanti...
cond-mat_quant-gas
Interacting Fermionic Atoms in Optical Lattices Diffuse Symmetrically Upwards and Downwards in a Gravitational Potential: We consider a cloud of fermionic atoms in an optical lattice described by a Hubbard model with an additional linear potential. While homogeneous interacting systems mainly show damped Bloch oscill...
cond-mat_quant-gas
Stable dilute supersolid of two-dimensional dipolar bosons: We consider two-dimensional bosonic dipoles oriented perpendicularly to the plane. On top of the usual two-body contact and long-range dipolar interactions we add a contact three-body repulsion as expected, in particular, for dipoles in the bilayer geometry wi...
cond-mat_quant-gas
Quantized conductance through a spin-selective atomic point contact: We implement a microscopic spin filter for cold fermionic atoms in a quantum point contact (QPC) and create fully spin-polarized currents while retaining conductance quantization. Key to our scheme is a near-resonant optical tweezer inducing a large e...
cond-mat_quant-gas
Self-Assembled Chains and Solids of Dipolar Atoms in a Multilayer: We predict that ultracold bosonic dipolar gases, confined within a multilayer geometry, may undergo self-assembling processes, leading to the formation of chain gases and solids. These dipolar chains, with dipoles aligned across different layers, emerge...
cond-mat_quant-gas
Matter wave switching in Bose-Einstein condensates via intensity redistribution soliton interactions: Using time dependent nonlinear (s-wave scattering length) coupling between the components of a weakly interacting two component Bose-Einstein condensate (BEC), we show the possibility of matter wave switching (fracti...
cond-mat_quant-gas
Preparing and probing Chern bands with cold atoms: The present Chapter discusses methods by which topological Bloch bands can be prepared in cold-atom setups. Focusing on the case of Chern bands for two-dimensional systems, we describe how topological properties can be triggered by driving atomic gases, either by dress...
cond-mat_quant-gas
Level statistics of the one-dimensional ionic Hubbard model: In this work we analyze the spectral level statistics of the one-dimensional ionic Hubbard model, the Hubbard model with an alternating on-site potential. In particular, we focus on the statistics of the gap ratios between consecutive energy levels. This quan...
cond-mat_quant-gas
Bound Bogoliubov quasiparticles in photon superfluids: Bogoliubov's description of Bose gases relies on the linear dynamics of noninteracting quasiparticles on top of a homogeneous condensate. Here, we theoretically explore the weakly-nonlinear regime of a one-dimensional photon superfluid in which phonon-like elementa...
cond-mat_quant-gas
Spin Orbit Coupling in Periodically Driven Optical Lattices: We propose a method for the emulation of artificial spin orbit coupling in a system of ultracold, neutral atoms trapped in a tight-binding lattice. This scheme does not involve near-resonant laser fields, avoiding the heating processes connected to the sponta...
cond-mat_quant-gas
Persistent Currents in Ferromagnetic Condensates: Persistent currents in Bose condensates with a scalar order parameter are stabilized by the topology of the order parameter manifold. In condensates with multicomponent order parameters it is topologically possible for supercurrents to `unwind' without leaving the manif...
cond-mat_quant-gas
Higgs-like Excitations of Cold Atom System with Spin-orbit Coupling: The Higgs-like excitations, which distinguish from the Higgs amplitude mode in many-body system, are single-particle excitations in system with non-Abelian gauge potential. We investigate the Higgs-like excitations of cold atom system in artificial no...
cond-mat_quant-gas
Collective many-body bounce in the breathing-mode oscillations of a Tonks-Girardeau gas: We analyse the breathing-mode oscillations of a harmonically quenched Tonks-Giradeau (TG) gas using an exact finite-temperature dynamical theory. We predict a striking collective manifestation of impenetrability---a collective ma...
cond-mat_quant-gas
Self-consistent Keldysh approach to quenches in weakly interacting Bose-Hubbard model: We present a non-equilibrium Green's functional approach to study the dynamics following a quench in weakly interacting Bose Hubbard model (BHM). The technique is based on the self-consistent solution of a set of equations which re...
cond-mat_quant-gas
Generation of spin currents by a temperature gradient in a two-terminal device: Theoretical and experimental studies of the interaction between spins and temperature are vital for the development of spin caloritronics, as they dictate the design of future devices. In this work, we propose a two-terminal cold-atom sim...
cond-mat_quant-gas
Quantum phases of atomic Fermi gases with anisotropic spin-orbit coupling: We consider a general anisotropic spin-orbit coupling (SOC) and analyze the phase diagrams of both balanced and imbalanced Fermi gases for the entire BCS--Bose-Einstein condensate (BEC) evolution. In the first part, we use the self-consistent ...
cond-mat_quant-gas
Structure of Spin Correlations in High Temperature SU($N$) Quantum Magnets: Quantum magnets with a large SU($N$) symmetry are a promising playground for the discovery of new forms of exotic quantum matter. Motivated by recent experimental efforts to study SU($N$) quantum magnetism in samples of ultracold fermionic al...
cond-mat_quant-gas
Large-$N$ expansion for condensation and stability of Bose-Bose mixtures at finite temperatures: The two-component mixture of Bose particles with short-range pairwise interaction at finite temperatures in three dimensions is considered. Particularly we examine, by means of the large-$N$ expansion technique, the stabi...
cond-mat_quant-gas
Forming doublons by a quantum quench: Repulsive interactions between particles on a lattice may lead to bound states, so called doublons. Such states may be created by dynamically tuning the interaction strength, e.g. using a Feshbach resonance, from attraction to repulsion. We study the doublon production efficiency a...
cond-mat_quant-gas
Simulation of the many-body dynamical quantum Hall effect in an optical lattice: We propose an experimental scheme to simulate the many-body dynamical quantum Hall effect with ultra-cold bosonic atoms in a one-dimensional optical lattice. We first show that the required model Hamiltonian of a spin-1/2 Heisenberg chai...
cond-mat_quant-gas
BCS-BEC crossover and quantum phase transition in an ultracold Fermi gas under spin-orbit coupling: In this work, we study the BCS-BEC crossover and quantum phase transition in a Fermi gas under Rashba spin-orbit coupling close to a Feshbach resonance. By adopting a two-channel model, we take into account of the clos...
cond-mat_quant-gas
Current production in ring condensates with a weak link: We consider attractive and repulsive condensates in a ring trap stirred by a weak link, and analyze the spectrum of solitonic trains dragged by the link, by means of analytical expressions for the wave functions, energies and currents. The precise evolution of cu...
cond-mat_quant-gas
Hydrodynamic description of Hard-core Bosons on a Galileo ramp: We study the quantum evolution of a cloud of hard-core bosons loaded on a one-dimensional optical lattice after its sudden release from a harmonic trap. Just after the trap has been removed, a linear ramp potential is applied, mimicking the so called Galil...
cond-mat_quant-gas
Partial Fermionization---Spectral Universality in 1D Repulsive Bose Gases: Due to the vast growth of the many-body level density with excitation energy, its smoothed form is of central relevance for spectral and thermodynamic properties of interacting quantum systems. We compute the cumulative of this level density f...
cond-mat_quant-gas
Self-similar non-equilibrium dynamics of a many-body system with power-law interactions: The influence of power-law interactions on the dynamics of many-body systems far from equilibrium is much less explored than their effect on static and thermodynamic properties. To gain insight into this problem we introduce and ...
cond-mat_quant-gas
Proposal to directly observe the Kondo effect through enhanced photo-induced scattering of cold fermionic and bosonic atoms: We propose an experimental protocol to directly observe the Kondo effect by scattering ultracold atoms with spin-dependent interactions. We propose using an optical Feshbach resonance to engine...
cond-mat_quant-gas
Thermodynamics of Attractive and Repulsive Fermi Gases in Two Dimensions: We study the attractive and repulsive two-component Fermi gas with spin imbalance in two dimensions. Using a generalized $T$-matrix approximation, we examine the thermodynamic properties of both attractive and repulsive contact interacting Fermi ...
cond-mat_quant-gas
Numerical Studies of Quantum Turbulence: We review numerical studies of quantum turbulence. Quantum turbulence is currently one of the most important problems in low temperature physics and is actively studied for superfluid helium and atomic Bose--Einstein condensates. A key aspect of quantum turbulence is the dynamic...
cond-mat_quant-gas
Deformation Dependence of Breathing Oscillations in Bose - Fermi Mixtures at Zero Temperature: We study the breathing oscillations in bose-fermi mixtures in the axially-symmetric deformed trap of prolate, spherical and oblate shapes, and clarify the deformation dependence of the frequencies and the characteristics of...
cond-mat_quant-gas
Emergent spacetimes from Hermitian and non-Hermitian quantum dynamics: We show that quantum dynamics of any systems with $SU(1,1)$ symmetry give rise to emergent Anti-de Sitter spacetimes in 2+1 dimensions (AdS$_{2+1}$). Using the continuous circuit depth, a quantum evolution is mapped to a trajectory in AdS$_{2+1}$. W...
cond-mat_quant-gas
Hard-core bosons in flat band systems above the critical density: We investigate the behaviour of hard-core bosons in one- and two-dimensional flat band systems, the chequerboard and the kagom\'e lattice and one-dimensional analogues thereof. The one dimensional systems have an exact local reflection symmetry which all...
cond-mat_quant-gas
Observation of $1/k^4$-tails after expansion of Bose-Einstein Condensates with impurities: We measure the momentum density in a Bose-Einstein condensate (BEC) with dilute spin impurities after an expansion in the presence of interactions. We observe tails decaying as $1/k^4$ at large momentum $k$ in the condensate an...
cond-mat_quant-gas
Interactions and scattering of quantum vortices in a polariton fluid: Quantum vortices, the quantized version of classical vortices, play a prominent role in superfluid and superconductor phase transitions. However, their exploration at a particle level in open quantum systems has gained considerable attention only rec...
cond-mat_quant-gas
Strong Boundary and Trap Potential Effects on Emergent Physics in Ultra-Cold Fermionic Gases: The field of quantum simulations in ultra-cold atomic gases has been remarkably successful. In principle it allows for an exact treatment of a variety of highly relevant lattice models and their emergent phases of matter. Bu...
cond-mat_quant-gas
Fermionization of two-component few-fermion systems in a one-dimensional harmonic trap: The nature of strongly interacting Fermi gases and magnetism is one of the most important and studied topics in condensed-matter physics. Still, there are many open questions. A central issue is under what circumstances strong sho...
cond-mat_quant-gas
Energy spectra and fluxes of turbulent rotating Bose-Einstein condensates in two dimensions: We investigate the scaling of the energy cascade in a harmonically trapped, turbulent, rotating Bose-Einstein condensate (BEC) in two dimensions. We achieve turbulence by injecting a localized perturbation into the condensate...
cond-mat_quant-gas
Tools for designing atom interferometers in a microgravity environment: We present a variational model suitable for rapid preliminary design of atom interferometers in a microgravity environment. The model approximates the solution of the 3D rotating--frame Gross--Pitaevskii equation (GPE) as the sum of Nc Gaussian clo...
cond-mat_quant-gas
Motion of a Solitonic Vortex in the BEC-BCS Crossover: We observe a long-lived solitary wave in a superfluid Fermi gas of $^6$Li atoms after phase-imprinting. Tomographic imaging reveals the excitation to be a solitonic vortex, oriented transverse to the long axis of the cigar-shaped atom cloud. The precessional motion...
cond-mat_quant-gas
Phase space theory of Bose-Einstein condensates and time-dependent modes: A phase space theory approach for treating dynamical behaviour of Bose-Einstein condensates applicable to situations such as interferometry with BEC in time-dependent double well potentials is presented. Time-dependent mode functions are used, ch...
cond-mat_quant-gas
Quantum Fluctuations of Vortex Lattices in Ultracold Gases: We discuss the effects of quantum fluctuations on the properties of vortex lattices in rapidly rotating ultracold atomic gases. We develop a variational method that goes beyond the Bogoliubov theory by including the effects of interactions between the quasipar...
cond-mat_quant-gas
Observation of Stückelberg oscillations in accelerated optical lattices: We report the experimental observation of St\"{u}ckelberg oscillations of matter waves in optical lattices. Extending previous work on Landau-Zener tunneling of Bose-Einstein condensates in optical lattices, we study the effects of the accumulat...
cond-mat_quant-gas
Observing Properties of an Interacting Homogeneous Bose--Einstein Condensate: Heisenberg-Limited Momentum Spread, Interaction Energy and Free-Expansion Dynamics: We study the properties of an atomic Bose--Einstein condensate produced in an optical-box potential, using high-resolution Bragg spectroscopy. For a range...
cond-mat_quant-gas
Intersubband Polaritons in the Electrical Dipole Gauge: We provide a theoretical description for the coupling between the intersubband excitations of a bi-dimensional electron gas with the electromagnetic field. This description, based on the electrical dipole gauge, applies to an arbitrary quantum heterostructure embe...
cond-mat_quant-gas
The Anyon Hubbard Model in One-Dimensional Optical Lattices: Raman-assisted hopping may be used to realize the anyon Hubbard model in one-dimensional optical lattices. We propose a feasible scenario that significantly improves the proposal of [T. Keilmann et al., Nature Commun. 2, 361 (2011)], allowing as well for an e...
cond-mat_quant-gas
Instabilities of vortex-ring-bright soliton in trapped binary 3D Bose-Einstein condensates: Instabilities of vortex-ring-bright coherent structures in harmonically trapped two-component three-dimensional Bose-Einstein condensates are studied numerically within the coupled Gross-Pitaevskii equations and interpreted an...
cond-mat_quant-gas
Coherent molecule formation in anharmonic potentials near confinement-induced resonances: We perform a theoretical and experimental study of a system of two ultracold atoms with tunable interaction in an elongated trapping potential. We show that the coupling of center-of-mass and relative motion due to an anharmonic...
cond-mat_quant-gas
Periodic waves in two-component Bose-Einstein condensates with repulsive interactions between atoms: We consider periodic waves in miscible two-component Bose-Einstein condensates with repulsive nonlinear interactions constants. Exact one-phase solution is found for the case when all these constants are equal to each...
cond-mat_quant-gas
The Efimov effect for heteronuclear three-body systems at positive scattering length and finite temperature: We study the recombination process of three atoms scattering into an atom and diatomic molecule in heteronuclear mixtures of ultracold atomic gases with large and positive interspecies scattering length at fin...
cond-mat_quant-gas
Momentum-space Harper-Hofstadter model: We show how the weakly trapped Harper-Hofstadter model can be mapped onto a Harper-Hofstadter model in momentum space. In this momentum-space model, the band dispersion plays the role of the periodic potential, the Berry curvature plays the role of an effective magnetic field, th...
cond-mat_quant-gas
Collective excitation frequencies and stationary states of trapped dipolar Bose-Einstein condensates in the Thomas-Fermi regime: We present a general method for obtaining the exact static solutions and collective excitation frequencies of a trapped Bose-Einstein condensate (BEC) with dipolar atomic interactions in th...
cond-mat_quant-gas
Two-dimensional dipolar Bose-Einstein condensate bright and vortex solitons on one-dimensional optical lattice: By solving the three-dimensional Gross-Pitaevskii equation we generate two-dimensional axially-symmetric and anisotropic dipolar Bose-Einstein condensate bright solitons, for repulsive atomic interaction, s...
cond-mat_quant-gas
Properties of the signal mode in the polariton OPO regime: Theoretical analyses of the polariton optical parametric oscillator (OPO) regime often rely on a mean field approach based on the complex Gross-Pitaevskii equations in a three-mode approximation, where only three momentum states, the signal, pump and idler, are...
cond-mat_quant-gas
Four fermions in a one-dimensional harmonic trap: Accuracy of a variational-ansatz approach: Detailed analysis of the system of four interacting ultra-cold fermions confined in a one-dimensional harmonic trap is performed. The analysis is done in the framework of a simple variational ansatz for the many-body ground s...
cond-mat_quant-gas
Quantum phases of a spin-1 ultracold Bose gas with three body interactions: We study the effects of both a repulsive and an attractive three body interaction potential on a spin-1 ultracold Bose gas using mean field approach (MFA). For an antiferromagnetic (AF) inter- action, we have found the existence of the odd-ev...
cond-mat_quant-gas
Negative differential conductivity and quantum statistical effects in a three-site Bose-Hubbard model: The use of an electron beam to remove ultracold atoms from selected sites in an optical lattice has opened up new opportunities to study transport in quantum systems [R. Labouvie {\it et al.\ }, Phys.\ Rev.\ Lett.\ ...
cond-mat_quant-gas
Mesoscopics of half-quantum vortex pair deconfinement in a trapped spin-one condensate: Motivated by a recent experiment in an antiferromagnetic spin-1 Bose-Einstein condensate of ${}^{23} \textrm{Na}$ atoms, we study the energetical stability of a singly quantum vortex injected into the center of a quasi-two-dimensi...
cond-mat_quant-gas
Dark soliton oscillations in Bose-Einstein condensates with multi-body interactions: We consider the dynamics of dark matter solitons moving through non-uniform cigar-shaped Bose-Einstein condensates described by the mean field Gross-Pitaevskii equation with generalized nonlinearities, in the case when the condition ...
cond-mat_quant-gas
Quantum Kinetic Theory of Collisionless Superfluid Internal Convection: Superfluids can transport heat via simultaneous opposite flows of their spatially interpenetrating condensate and thermal components. While this internal convection is usually described within Landau's phenomenological two fluid hydrodynamics, we a...
cond-mat_quant-gas
Hanbury-Brown and Twiss bunching of phonons and of the quantum depletion in a strongly-interacting Bose gas: We report the realisation of a Hanbury-Brown and Twiss (HBT)-like experiment with a gas of strongly interacting bosons at low temperatures. The regime of large interactions and low temperatures is reached in a...
cond-mat_quant-gas
Theory of the Rotating Polaron: Spectrum and Self-Localization: We study a quantum impurity possessing both translational and internal rotational degrees of freedom interacting with a bosonic bath. Such a system corresponds to a `rotating polaron', which can be used to model, e.g., a rotating molecule immersed in an ul...
cond-mat_quant-gas
Signatures of the single particle mobility edge in the ground state properties of Tonks-Girardeau and non-interacting Fermi gases in a bichromatic potential: We explore the ground state properties of cold atomic gases, loaded into a bichromatic lattice, focusing on the cases of non-interacting fermions and hard-cor...
cond-mat_quant-gas
Imaging of quantum Hall states in ultracold atomic gases: We examine off-resonant light scattering from ultracold atoms in the quantum Hall regime. When the light scattering is spin dependent, we show that images formed in the far field can be used to distinguish states of the system. The spatial dependence of the far-...
cond-mat_quant-gas
Persistent currents with non-quantized angular momentum: We analyze the generation of persistent currents in Bose-Einstein condensates of ultracold gases confined in a ring. This phenomenon has been recently investigated in an experiment [Nature \textbf{506}, 200 (2014)], where hysteresis loops have been observed in th...
cond-mat_quant-gas
Mechanism of Tunneling in Interacting Open Ultracold Few-Boson Systems: We investigate the mechanism in the tunneling dynamics of open ultracold few-boson systems by numerically solving the time-dependent few-boson Schr\"{o}dinger equation exactly. By starting from a weakly repulsive, initially coherent two-boson syste...
cond-mat_quant-gas
Interaction-induced instability and chaos in the photoassociative stimulated Raman adiabatic passage from atomic to molecular Bose-Einstein condensates: We study the effect of interactions on the conversion of atomic -to molecular Bose-Einstein condensates via stimulated Raman adiabatic passage. Both energetic inst...
cond-mat_quant-gas
Multi-Stability in Cavity QED with Spin-Orbit Coupled Bose-Einstein Condensate: We investigate the occurrence of steady-state multi-stability in a cavity system containing spin-orbit coupled Bose-Einstein condensate and driven by a strong pump laser. The applied magnetic field splits the Bose-Einstein condensate into...
cond-mat_quant-gas
Superfluid properties of bright solitons in a ring: We theoretically investigate superfluid properties of a one-dimensional annular superfluid with a boost. We derive the formula of the superfluid fraction in the one-dimensional superfluid, which was originally derived by Leggett in the context of supersolid. We see th...
cond-mat_quant-gas
Phase-separated vortex-lattice in a rotating binary Bose-Einstein condensate: We study circularly-symmetric phase separation of vortex lattices in a rapidly rotating harmonically-trapped quasi--two-dimensional binary Bose-Einstein condensate (BEC) by introducing a weak quartic trap in one of the components. The incre...
cond-mat_quant-gas
Spin squeezing in dipolar spinor condensates: We study the effect of dipolar interactions on the level of squeezing in spin-1 Bose-Einstein condensates by using the single mode approximation. We limit our consideration to the $\mathfrak{su}(2)$ Lie subalgebra spanned by spin operators. The biaxial nature of dipolar int...
cond-mat_quant-gas
Universal quantum dynamics of Bose polarons: Predicting the emergent properties of impurities immersed in a quantum bath is a fundamental challenge that can defy quasiparticle treatments. Here, we measure the spectral properties and real-time dynamics of mobile impurities injected into a homogeneous Bose--Einstein cond...
cond-mat_quant-gas
Quantum phase transitions in the dimerized extended Bose-Hubbard model: We present an unbiased numerical density-matrix renormalization group study of the one-dimensional Bose-Hubbard model supplemented by nearest-neighbor Coulomb interaction and bond dimerization. It places the emphasis on the determination of the gro...
cond-mat_quant-gas
Three-level Haldane-like model on dice optical lattice: We consider ultracold atoms in a two-dimensional optical lattice of the dice geometry in a tight-binding regime. The atoms experience a laser-assisted tunneling between the nearest neighbour sites of the dice lattice accompanied by the momentum recoil. This allows...
cond-mat_quant-gas