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Quantum anomaly and 2D-3D crossover in strongly interacting Fermi gases: We present an experimental investigation of collective oscillations in harmonically trapped Fermi gases through the crossover from two to three dimensions. Specifically, we measure the frequency of the radial monopole or breathing mode as a functi...
cond-mat_quant-gas
Notes on the Cluster Gutzwiller Method: Inhomogeneous Lattices, Excitations, and Cluster Time Evolution: Several perspectives of the cluster Gutzwiller method are briefly discussed. I show that the cluster mean-field method can be used for large inhomogeneous lattices, for computing local excitations, and for the tim...
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
Chiral condensates in a polariton hexagonal ring: We model generation of vortex modes in exciton-polariton condensates in semiconductor micropillars, arranged into a hexagonal ring molecule, in the presence of TE-TM splitting. This splitting lifts the degeneracy of azimuthally modulated vortex modes with opposite topol...
cond-mat_quant-gas
Hidden vortices in a Bose-Einstein condensate in a rotating double-well potential: We study vortex formation in a Bose-Einstein condensate in a rotating double-well potential. Besides the ordinary quantized vortices and elusive ghost vortices, "hidden" vortices are found distributing along the central barrier. These ...
cond-mat_quant-gas
Two types of dark solitons in a spin-orbit-coupled Fermi gas: Dark solitons in quantum fluids are well known nonlinear excitations that are usually characterized by a single length scale associated with the underlying background fluid. We show that in the presence of spin-orbit coupling and a linear Zeeman field, super...
cond-mat_quant-gas
Effects of thermal and quantum fluctuations on the phase diagram of a spin-1 87Rb Bose-Einstein condensate: We investigate effects of thermal and quantum fluctuations on the phase diagram of a spin-1 87Rb Bose-Einstein condensate (BEC) under a quadratic Zeeman effect. Due to the large ratio of spinindependent to spin...
cond-mat_quant-gas
Effective dipole-dipole interactions in multilayered dipolar Bose-Einstein condensates: We propose a two-dimensional model for a multilayer stack of dipolar Bose-Einstein condensates formed by a strong optical lattice. We derive effective intra- and interlayer dipole-dipole interaction potentials and provide simple a...
cond-mat_quant-gas
Particle and spin transports of spin-orbit coupled Fermi gas through a Quantum Point Contact: The particle and spin transport through a quantum point contact between two Fermi gases with Raman-induced spin-orbit coupling are investigated. We show that the particle and spin conductances both demonstrate the structure ...
cond-mat_quant-gas
Two-mode Dicke model from non-degenerate polarization modes: We realize a non-degenerate two-mode Dicke model with competing interactions in a Bose-Einstein condensate (BEC) coupled to two orthogonal polarization modes of a single optical cavity. The BEC is coupled to the cavity modes via the scalar and vectorial part ...
cond-mat_quant-gas
Gauge Violation Spectroscopy in Synthetic Gauge Theories: Recently synthetic gauge fields have been implemented on quantum simulators. Unlike the gauge fields in the real world, in synthetic gauge fields, the gauge charge can fluctuate and gauge invariance can be violated, which leading rich physics unexplored before. ...
cond-mat_quant-gas
From Nodal Ring Topological Superfluids to Spiral Majorana Modes in Cold Atomic Systems: In this work, we consider a 3D cubic optical lattice composed of coupled 1D wires with 1D spin-orbit coupling. When the s-wave pairing is induced through Feshbach resonance, the system becomes a topological superfluid with ring n...
cond-mat_quant-gas
Interacting quantum walk on a two-leg flux ladder: Emergence of re-entrant dynamics: We study the quench dynamics of interacting bosons on a two-leg flux ladder by implementing the continuous-time quantum walk and explore the combined effect of the magnetic field and onsite interaction in the presence of uniform flux...
cond-mat_quant-gas
Induced interaction and crystallization of self-localized impurity fields in a Bose-Einstein condensate: We model the behavior of N classical impurity fields immersed in a larger Bose-Einstein condensate by N+1 coupled nonlinear Schrodinger equations in 1, 2, and 3 space dimensions. We discuss the stability of the un...
cond-mat_quant-gas
Bose-Einstein condensation of light in a cavity: The paper considers Bose-Einstein condensation (BEC) of light in a cavity with medium. In the framework of two-level model we show the effect of gaseous medium on the critical temperature of light condensation in the system. Transition of the system to the state with rel...
cond-mat_quant-gas
Thermalisation of Local Observables in Small Hubbard Lattices: We present a study of thermalisation of a small isolated Hubbard lattice cluster prepared in a pure state with a well-defined energy. We examine how a two-site subsystem of the lattice thermalises with the rest of the system as its environment. We explore n...
cond-mat_quant-gas
Critical velocity of a mobile impurity in one-dimensional quantum liquids: We study the notion of superfluid critical velocity in one spatial dimension. It is shown that for heavy impurities with mass $M$ exceeding a critical mass $M_\mathrm{c}$, the dispersion develops periodic metastable branches resulting in drama...
cond-mat_quant-gas
Polaronic atom-trimer continuity in three-component Fermi gases: Recently it has been proposed that three-component Fermi gases may exhibit a new type of crossover physics in which an unpaired Fermi sea of atoms smoothly evolves into that of trimers in addition to the ordinary BCS-BEC crossover of condensed pairs. Here...
cond-mat_quant-gas
Spin-Orbit Coupling and Spin Textures in Optical Superlattices: We proposed and demonstrated a new approach for realizing spin orbit coupling with ultracold atoms. We use orbital levels in a double well potential as pseudospin states. Two-photon Raman transitions between left and right wells induce spin-orbit coupling....
cond-mat_quant-gas
Dynamics of a quantum phase transition in the Bose-Hubbard model: Kibble-Zurek mechanism and beyond: In this paper, we study the dynamics of the Bose-Hubbard model by using time-dependent Gutzwiller methods. In particular, we vary the parameters in the Hamiltonian as a function of time, and investigate the temporal b...
cond-mat_quant-gas
Stability of supercurrents in a superfluid phase of spin-1 bosons in an optical lattice: We study collective modes and superfluidity of spin-1 bosons with antiferromagnetic interactions in an optical lattice based on the time-dependent Ginzburg-Landau (TDGL) equation derived from the spin-1 Bose-Hubbard model. Specif...
cond-mat_quant-gas
Fermionic Superradiance in a Transversely Pumped Optical Cavity: Following the experimental realization of Dicke superradiance in Bose gases coupled to cavity light fields, we investigate the behavior of ultra cold fermions in a transversely pumped cavity. We focus on the equilibrium phase diagram of spinless fermions ...
cond-mat_quant-gas
Self-consistent theory of Bose-Einstein condensate with impurity at finite temperature: We study the properties of Bose-Einstein condensate (BEC)-impurity mixtures at finite temperature employing the Balian-V\'en\'eroni (BV) variational principle. The method leads to a set of coupled nonlinear equations of motion for...
cond-mat_quant-gas
$N$-coherence vs. $t$-coherence: An alternative route to the Gross-Pitaevskii equation: We show how a candidate mean-field amplitude can be constructed from the exact wave function of an externally forced $N$-Boson system. The construction makes use of subsidiary $(N-1)$-particle states which are propagated in time i...
cond-mat_quant-gas
Relaxation and hysteresis near Shapiro resonances in a driven spinor condensate: We study the coherent and dissipative aspects of a driven spin-1 Bose-Einstein condensate (BEC) when the Zeeman energy is modulated around a static bias value. Resonances appear when the bias energy matches an integer number of modulatio...
cond-mat_quant-gas
Density correlations from analogue Hawking radiation in the presence of atom losses: The sonic analogue of Hawking radiation can now be experimentally recreated in Bose-Einstein Condensates that contain an acoustic black hole. In these experiments the signal strength and analogue Hawking temperature increase for dens...
cond-mat_quant-gas
Thermalization and localization of an oscillating Bose-Einstein condensate in a disordered trap: We numerically simulate an oscillating Bose-Einstein condensate in a disordered trap [Phys. Rev. A 82, 033603 (2010)] and the results are in good agreement with the experiment. It allows us to verify that total energy and...
cond-mat_quant-gas
Momentum distribution of a dilute unitary Bose gas with three-body losses: Using Boltzmann's equation, we study the effect of three-body losses on the momentum distribution of a homogeneous unitary Bose gas in the dilute limit where quantum correlations are negligible. We calculate the momentum distribution of the ga...
cond-mat_quant-gas
Phases of driven two-level systems with nonlocal dissipation: We study an array of two-level systems arranged on a lattice and illuminated by an external plane wave which drives a dipolar transition between the two energy levels. In this set up, the two-level systems are coupled by dipolar interactions and subject to n...
cond-mat_quant-gas
Physical Realization of von Neumann Lattices in Rotating Dipole-blockaded Bose Gases: A mathematical lattice, called the von Neumann lattice, is a subset of coherent states and exists periodically in the phase space. It is unlike solids or Abrikosov lattices that are observable in physical systems. Abrikosov lattices...
cond-mat_quant-gas
Realization of a distributed Bragg reflector for propagating guided matter waves: We report on the experimental realization of a Bragg reflector for guided matter waves. A Bose-Einstein condensate with controlled velocity distribution impinges onto an attractive optical lattice of finite length and directly probes it...
cond-mat_quant-gas
On quantum time crystals and interacting gauge theories in atomic Bose-Einstein condensates: We study the dynamics of a Bose-Einstein condensate trapped circumferentially on a ring, and which is governed by an interacting gauge theory. We show that the associated density-dependent gauge potential and concomitant curr...
cond-mat_quant-gas
Quantum Many-Body Scars in Optical Lattices: The concept of quantum many-body scars has recently been put forward as a route to describe weak ergodicity breaking and violation of the Eigenstate Thermalization Hypothesis. We propose a simple setup to generate quantum many-body scars in a doubly modulated Bose-Hubbard sy...
cond-mat_quant-gas
Fractional angular momentum in cold atom systems: The quantum statistics of bosons or fermions are manifest through even or odd relative angular momentum of a pair. We show theoretically that, under certain conditions, a pair of certain test particles immersed in a fractional quantum Hall state possesses, effectively, ...
cond-mat_quant-gas
Propagating wave-packets and quantised currents in coherently driven polariton superfluids: We study the properties of propagating polariton wave-packets and their connection to the stability of doubly charged vortices. Wave-packet propagation and related photoluminescence spectra exhibit a rich behaviour dependent o...
cond-mat_quant-gas
Thermodynamic signatures of the polaron-molecule transition in a Fermi gas: We consider the highly spin-imbalanced limit of a two-component Fermi gas, where there is a small density of $\downarrow$ impurities attractively interacting with a sea of $\uparrow$ fermions. In the single-impurity limit at zero temperature,...
cond-mat_quant-gas
Direct observation of coherent inter-orbital spin-exchange dynamics: We report on the first direct observation of fast spin-exchange coherent oscillations between different long-lived electronic orbitals of ultracold $^{173}$Yb fermions. We measure, in a model-independent way, the strength of the exchange interaction d...
cond-mat_quant-gas
Modulational Instabity of Spin-Orbit Coupled Bose-Einstein Condensates in Discrete Media: We address the impact of intra-site spin-orbit (SO) coupling and associated inter-component Rabi coupling on the modulational instability (MI) of plane-wave states in two-component discrete Bose-Einstein condensates (BECs). Cond...
cond-mat_quant-gas
In Situ Momentum Distribution Measurement of a Quantum Degenerate Fermi Gas using Raman Spectroscopy: The ability to directly measure the momentum distribution of quantum gases is both unique to these systems and pivotal in extracting many other important observables. Here we use Raman transitions to measure the mome...
cond-mat_quant-gas
The Peierls substitution in an engineered lattice potential: Artificial gauge fields open new possibilities to realize quantum many-body systems with ultracold atoms, by engineering Hamiltonians usually associated with electronic systems. In the presence of a periodic potential, artificial gauge fields may bring ultrac...
cond-mat_quant-gas
Anomalous Behavior of Spin Systems with Dipolar Interactions: We study the properties of spin systems realized by cold polar molecules interacting via dipole-dipole interactions in two dimensions. Using a spin wave theory, that allows for the full treatment of the characteristic long-distance tail of the dipolar intera...
cond-mat_quant-gas
Liquid crystal phases of two-dimensional dipolar gases and Berezinskii-Kosterlitz-Thouless melting: Liquid crystals are phases of matter intermediate between crystals and liquids. Whereas classical liquid crystals have been known for a long time and are used in electro-optical displays, much less is known about their...
cond-mat_quant-gas
Manipulating multimer propagation using lattice modulation: We propose a scheme for controlling the movement of dimers, trimers, and other multimers in optical lattices by modulating the lattice potential. In deep optical lattices the propagation of deeply bound atomic clusters is slowed down by the high energy cost of...
cond-mat_quant-gas
Light scattering in inhomogeneous Tomonaga-Luttinger liquids: We derive the dynamical structure factor for an inhomogeneous Tomonaga-Luttinger liquid as can be formed in a confined strongly interacting one-dimensional gas. In view of current experimental progress in the field, we provide a simple analytic expression fo...
cond-mat_quant-gas
Short note on the Rabi model: The spectral density of the Rabi model is calculated exactly within a continued fraction approach. It is shown that the method yields a convergent solution.
cond-mat_quant-gas
Prethermal Floquet Steady States and Instabilities in the Periodically Driven, Weakly Interacting Bose-Hubbard Model: We explore prethermal Floquet steady states and instabilities of the weakly interacting two-dimensional Bose-Hubbard model subject to periodic driving. We develop a description of the nonequilibrium d...
cond-mat_quant-gas
Experimental realization of a non-magnetic one-way spin switch: Controlling magnetism through non-magnetic means is highly desirable for future electronic devices, as such means typically have ultra-low power requirements and can provide coherent control. In recent years, great experimental progress has been made in th...
cond-mat_quant-gas
Asymptotic Bound-state Model for Feshbach Resonances: We present an Asymptotic Bound-state Model which can be used to accurately describe all Feshbach resonance positions and widths in a two-body system. With this model we determine the coupled bound states of a particular two-body system. The model is based on analyti...
cond-mat_quant-gas
Feedback-enhanced algorithm for aberration correction of holographic atom traps: We show that a phase-only spatial light modulator can be used to generate non-trivial light distributions suitable for trapping ultracold atoms, when the hologram calculation is included within a simple and robust feedback loop that corr...
cond-mat_quant-gas
Exotic photonic molecules via Lennard-Jones-like potentials: Ultracold systems offer an unprecedented level of control of interactions between atoms. An important challenge is to achieve a similar level of control of the interactions between photons. Towards this goal, we propose a realization of a novel Lennard-Jones-...
cond-mat_quant-gas
Time scale for adiabaticity breakdown in driven many-body systems and orthogonality catastrophe: The adiabatic theorem is a fundamental result established in the early days of quantum mechanics, which states that a system can be kept arbitrarily close to the instantaneous ground state of its Hamiltonian if the latter...
cond-mat_quant-gas
All-optical transport and compression of ytterbium atoms into the surface of a solid immersion lens: We present an all-optical method to load 174Yb atoms into a single layer of an optical trap near the surface of a solid immersion lens which improves the numerical aperture of a microscope system. Atoms are transporte...
cond-mat_quant-gas
Large-scale characterization of Cu2O monocrystals via Rydberg excitons: Rydberg states of excitons can reach microns in size and require extremely pure crystals. We introduce an experimental method for the rapid and spatially-resolved characterization of Rydberg excitons in copper oxide (Cu2O) with sub-micron resolutio...
cond-mat_quant-gas
Leggett collective excitations in a two-band Fermi superfluid at finite temperatures: The Leggett collective excitations for a two-band Fermi gas with s-wave pairing and Josephson interband coupling in the BCS-BEC crossover at finite temperatures are investigated within the Gaussian pair fluctuation approach. Eigenfr...
cond-mat_quant-gas
Quantum Charge Pumps with Topological Phases in Creutz Ladder: Quantum charge pumping phenomenon connects band topology through the dynamics of a one-dimensional quantum system. In terms of a microscopic model, the Su-Schrieffer-Heeger/Rice-Mele quantum pump continues to serve as a fruitful starting point for many cons...
cond-mat_quant-gas
Abnormal Superfluid Fraction of Harmonically Trapped Few-Fermion Systems: Superfluidity is a fascinating phenomenon that, at the macroscopic scale, leads to dissipationless flow and the emergence of vortices. While these macroscopic manifestations of superfluidity are well described by theories that have their origin i...
cond-mat_quant-gas
Twin matter waves for interferometry beyond the classical limit: Interferometers with atomic ensembles constitute an integral part of modern precision metrology. However, these interferometers are fundamentally restricted by the shot noise limit, which can only be overcome by creating quantum entanglement among the ato...
cond-mat_quant-gas
Non-thermal fixed points of universal sine-Gordon coarsening dynamics: We examine coarsening of field-excitation patterns of the sine-Gordon (SG) model, in two and three spatial dimensions, identifying it as universal dynamics near non-thermal fixed points. The SG model is relevant in many different contexts, from soli...
cond-mat_quant-gas
Lifetime of Single-Particle Excitations in a Dilute Bose-Einstein Condensate at Zero Temperature: We study the lifetime of single-particle excitations in a dilute homogeneous Bose-Einstein condensate at zero temperature based on a self-consistent perturbation expansion of satisfying Goldstone's theorem and conservati...
cond-mat_quant-gas
Symmetric and asymmetric solitons trapped in H-shaped potentials: We report results of numerical and analytical studies of the spontaneous symmetry breaking in solitons, both two- and one-dimensional, which are trapped in H-shaped potential profiles, built of two parallel potential troughs linked by a narrow rung in th...
cond-mat_quant-gas
Mobile Impurity in a Two-Leg Bosonic Ladder: We study the dynamics of a mobile impurity in a two-leg bosonic ladder. The impurity moves both along and across the legs and interacts with a bath of interacting bosonic particles present in the ladder. We use both analytical (Tomonaga-Luttinger liquid - TLL) and numerical ...
cond-mat_quant-gas
Spin modulation instabilities and phase separation dynamics in trapped two-component Bose condensates: In the study of trapped two-component Bose gases, a widely used dynamical protocol is to start from the ground state of a one-component condensate and then switch half the atoms into another hyperfine state. The sli...
cond-mat_quant-gas
Universal subdiffusion in strongly tilted many-body systems: The quantum dynamics away from equilibrium is of fundamental interest for interacting many-body systems. In this letter, we study tilted many-body systems using the effective Hamiltonian derived from the microscopic description. We first give general argument...
cond-mat_quant-gas
Classical fields and quantum measurement for Bose-Einstein condensate: We analyze a process of splitting of the Bose-Einstein condensate and the mutual coherence of two separated atomic clouds. Within the classical fields approximation we show that coherence between clouds is degraded if atoms interact and if we accoun...
cond-mat_quant-gas
Acoustic Superradiance from a Bose-Einstein Condensate Vortex with a Self-Consistent Background Density Profile: The axisymmetric acoustic perturbations in the velocity potential of a Bose-Einstein condensate in the presence of a single vortex behave like minimally coupled massless scalar fields propagating in a curv...
cond-mat_quant-gas
Photon Bose-Condensate as a Tunable Terahertz Laser Source without Inversion: We develop a theoretical model for a tunable coherent terahertz radiation source based on the long-lived Bose condensate of photons. In the device we propose, the original photon pumping is performed incoherently by a blackbody radiation em...
cond-mat_quant-gas
The improved Gaussian approximation Calculation of Bogoliubov Mode in One Dimensional Bosonic Gas: In this paper, we study the homogeneous one-dimensional bosonic gas interacting via a repulsive contact potential by using the improved Gaussian approximation. We obtain the gapless excitation spectrum of Bogoliubov mod...
cond-mat_quant-gas
Full and fractional defects across the Berezinskii-Kosterlitz-Thouless transition in a driven-dissipative spinor quantum fluid: We investigate the properties of a two-dimensional \emph{spinor} microcavity polariton system driven by a linearly polarised continuous pump. In particular, we establish the role of the elem...
cond-mat_quant-gas
Parametric instability of oscillations of a vortex ring in a $z$-periodic Bose-Einstein condensate and the recurrence to starting state: The dynamics of deformations of a quantum vortex ring in a Bose-Einstein condensate with periodic equilibrium density $\rho(z)= 1-\epsilon\cos z$ has been considered within the loca...
cond-mat_quant-gas
Propagation of phase-imprinted solitons from superfluid core to Mott-insulator shell and superfluid shell: We study phase-imprinted solitons of ultracold bosons in an optical lattice with a harmonic trap, which shows the superfluid (SF) and Mott-insulator (MI) shell structures. The earlier study [Konstantin V. Krutit...
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
Statics and dynamics of atomic dark-bright solitons in the presence of delta-like impurities: Adopting a mean-field description for a two-component atomic Bose-Einstein condensate, we study the stat- ics and dynamics of dark-bright solitons in the presence of localized impurities. We use adiabatic perturbation theory...
cond-mat_quant-gas
Parametric Excitation of a 1D Gas in Integrable and Nonintegrable Cases: We study the response of a highly excited 1D gas with pointlike interactions to a periodic modulation of the coupling constant. We calculate the corresponding dynamic structure factors and show that their low-frequency behavior differs dramaticall...
cond-mat_quant-gas
Dimensional crossover in non-relativistic effective field theory: Isotropic scattering in various spatial dimensions is considered for arbitrary finite-range potentials using non-relativistic effective field theory. With periodic boundary conditions, compactifications from a box to a plane and to a wire, and from a pla...
cond-mat_quant-gas
On the hydrodynamic canonical formalism of the Gross-Pitaevskii field: We derive a canonical formalism for the hydrodynamic representation of the Gross-Pitaevskii field (nonlinear Schr\"odinger field), where the density and the phase of the condensate form a canonical pair of conjugate field variables. To do so, we tre...
cond-mat_quant-gas
Skyrmion crystals in the pseudo-spin-1/2 Bose-Einstein condensates: Exact two-dimensional solutions are constructed for the pseudo-spin-1/2 Bose-Einstein condensates which are described by the coupled nonlinear Gross-Pitaevskii equations where the intraspecies and interspecies coupling constants are assumed to be equal...
cond-mat_quant-gas
Phonon-mediated Casimir interaction between finite mass impurities: The Casimir effect, a two-body interaction via vacuum fluctuations, is a fundamental property of quantum systems. In solid state physics it emerges as a long-range interaction between two impurity atoms via virtual phonons. In the classical limit for t...
cond-mat_quant-gas
Theory of a resonantly interacting impurity in a Bose-Einstein condensate: We investigate a Bose-Einstein condensate in strong interaction with a single impurity particle. While this situation has received considerable interest in recent years, the regime of strong coupling remained inaccessible to most approaches du...
cond-mat_quant-gas
Active Learning Algorithm for Computational Physics: In large-scale computation of physics problems, one often encounters the problem of determining a multi-dimensional function, which can be time-consuming when computing each point in this multi-dimensional space is already time-demanding. In the work, we propose that...
cond-mat_quant-gas
Complex scaling flows in the quench dynamics of interacting particles: Many-body systems driven out of equilibrium can exhibit scaling flows of the quantum state. For a sudden quench to resonant interactions between particles we construct a new class of analytical scaling solutions for the time evolved wave function wi...
cond-mat_quant-gas
Mott Insulators of Ultracold Fermionic Alkaline Earth Atoms: Underconstrained Magnetism and Chiral Spin Liquid: We study Mott insulators of fermionic alkaline earth atoms, described by Heisenberg spin models with enhanced SU(N) symmetry. In dramatic contrast to SU(2) magnetism, more than two spins are required to for...
cond-mat_quant-gas
Simultaneous Readout of Noncommuting Collective Spin Observables beyond the Standard Quantum Limit: We augment the information extractable from a single absorption image of a spinor Bose-Einstein condensate by coupling to initially empty auxiliary hyperfine states. Performing unitary transformations in both, the orig...
cond-mat_quant-gas
On quantum melting of superfluid vortex crystals: from Lifshitz scalar to dual gravity: Despite a long history of studies of vortex crystals in rotating superfluids, their melting due to quantum fluctuations is poorly understood. Here we develop a fracton-elasticity duality to investigate a two-dimensional vortex lat...
cond-mat_quant-gas
Spatial Patterns of Rydberg Excitations from Logarithmic Pair Interactions: The collective excitations in ensembles of dissipative, laser driven ultracold atoms exhibit crystal-like patterns, a many-body effect of the Rydberg blockade mechanism. These crystalline structure are revealed in experiment from a post-selec...
cond-mat_quant-gas
Bose Einstein condensation and superfluidity in an open system: theory: We propose a new theoretical formalism which describes the Bose Einstein condensation of weakly interacting bosons with finite life time interacting with a thermal bath. We show that if a quasi-thermal distribution function of particles is achieved...
cond-mat_quant-gas
The multiconfigurational time-dependent Hartree method for bosons with internal degrees of freedom: Theory and composite fragmentation of multi-component Bose-Einstein condensates: In this paper the multiconfigurational time-dependent Hartree for bosons method (MCTDHB) is derived for the case of $N$ identical boson...
cond-mat_quant-gas
Density wave instability in a 2D dipolar Fermi gas: We consider a uniform dipolar Fermi gas in two-dimensions (2D) where the dipole moments of fermions are aligned by an orientable external field. We obtain the ground state of the gas in Hartree-Fock approximation and investigate RPA stability against density fluctuati...
cond-mat_quant-gas
Mobile impurity probing a two-dimensional superfluid phase transition: The use of atomically sized quantum systems as highly sensitive measuring devices represents an exciting and quickly growing research field. Here, we explore the properties of a quasiparticle formed by a mobile impurity interacting with a two-dimens...
cond-mat_quant-gas
Effect of Rare Fluctuations on the Thermalization of Isolated Quantum Systems: We consider the question of thermalization for isolated quantum systems after a sudden parameter change, a so-called quantum quench. In part icular we investigate the pre-requisites for thermalization focusing on the statistical properties...
cond-mat_quant-gas
Fractional topological states of dipolar fermions in one-dimensional optical superlattices: We study the properties of dipolar fermions trapped in one-dimensional bichromatic optical lattices and show the existence of fractional topological states in the presence of strong dipole-dipole interactions. We find some int...
cond-mat_quant-gas
Precise measurements on a quantum phase transition in antiferromagnetic spinor Bose-Einstein condensates: We investigate, both experimentally and theoretically, the quench dynamics of antiferromagnetic spinor Bose-Einstein condensates in the vicinity of a zero temperature quantum phase transition at zero quadratic Ze...
cond-mat_quant-gas
Unstable Avoided Crossing in Coupled Spinor Condensates: We consider the dynamics of a Bose-Einstein condensate with two internal states, coupled through a coherent drive. We focus on a specific quench protocol, in which the sign of the coupling field is suddenly changed. At a mean-field level, the system is transferre...
cond-mat_quant-gas
Comment on: `Single-shot simulations of dynamic quantum many-body systems' [arXiv:1501.03224]: In their recent paper [Nature Physics 15, 451 (2006)], Sakmann and Kasevich study the formation of fringe patterns in ultra-cold Bose gases and claim: `Here, we show how single shots can be simulated from numerical solution...
cond-mat_quant-gas
Tuning an effective spin chain of three strongly interacting one-dimensional fermions with the transversal confinement: Strongly interacting one-dimensional fermions form an effective spin chain in the absence of an external lattice potential. We show that the exchange coefficients of such a chain may be locally tune...
cond-mat_quant-gas
Dynamics of a Polariton Condensate in an Organic Semiconducting Microcavity: Recent experiments on thin-film microcavities give evidence of Bose condensation of exciton-polariton states. Inspired by these observations, we consider the possibility that such exotic "half-light/half matter" states could be observed in t...
cond-mat_quant-gas
Real-Time Dynamics of an Impurity in an Ideal Bose Gas in a Trap: We investigate the behavior of a harmonically trapped system consisting of an impurity in a dilute ideal Bose gas after the boson-impurity interaction is suddenly switched on. As theoretical framework, we use a field theory approach in the space-time dom...
cond-mat_quant-gas
Unitary dynamics of strongly-interacting Bose gases with time-dependent variational Monte Carlo in continuous space: We introduce time-dependent variational Monte Carlo for continuous-space Bose gases. Our approach is based on the systematic expansion of the many-body wave-function in terms of multi-body correlations...
cond-mat_quant-gas
Controlling Correlated Tunneling and Superexchange Interactions with AC-Driven Optical Lattices: The dynamical control of tunneling processes of single particles plays a major role in science ranging from Shapiro steps in Josephson junctions to the control of chemical reactions via light in molecules. Here we show ho...
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
Dissipative Transport of Trapped Bose-Einstein Condensates through Disorder: After almost half a century since the work of Anderson [Phys. Rev. {\bf 109}, 1492 (1958)], at present there is no well established theoretical framework for understanding the dynamics of interacting particles in the presence of disorder. He...
cond-mat_quant-gas