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In this work we revisit collapse and revival oscillations in superfluids suddenly quenched by strong local interactions for the case of a one-dimensional Bose-Hubbard model. As the main result we identify the inherent nonequilibrium quantum many-body character of these oscillations by revealing that they are controlle... |
The effect of nearest-neighbor repulsion on the ground-state phase diagrams of three-body constrained attractive Bose lattice gases is explored numerically. When the repulsion is turned on, in addition to the uniform Mott insulating state and two superfluid phases (the atomic and the dimer superfluids), a dimer checke... |
We develop a theory of the phonon mediated Casimir interaction between two point-like impurities, which is based on the single impurity scattering T-matrix approach. Within this, we show that the Casimir interaction at $T = 0$ falls off as a power law with the distance between the impurities. |
It is shown for the Bose-Einstein condensate of cold atomic system that the new unperturbed Hamiltonian, which includes not only the first and second powers of the zero mode operators but also the higher ones, determines a unique and stationary vacuum at zero temperature. From the standpoint of quantum field theory, i... |
A time crystal is an exotic phase of matter where time-translational symmetry is broken; this phase differs from the spatial symmetry breaking induced in crystals in space. Lots of experiments report the transition from a thermal equilibrium phase to time crystal phase. |
We propose a phase-sensitive detection scheme to identify the unconventional $p_{x}\pm ip_{y}$ symmetry of the condensate wavefunctions of bosons, which have already been proposed and realized in high bands in optical lattices. Using the impulsive Raman operation combining with time-of-flight imaging, the off-diagonal... |
The condensation of the spinless ideal charged Bose gas in the presence of a magnetic field is revisited. The conventional approach is extended to include the macroscopic occupation of excited kinetic states lying in the lowest Landau level, which plays an essential role in the case of large magnetic fields. |
We investigate the ground-state phases of a mixture of spin-1 and spin-2 Bose-Einstein condensates at zero magnetic field. In addition to the intra-spin interactions, two spin-dependent interaction coefficients are introduced to describe the inter-spin interaction. |
Large three-body losses in a three-component Fermi gas confined in an optical lattice can prevent the occupation of a lattice site by three atoms. This effective constraint not only gives rise to a suppression of actual three-body loss, but stabilises BCS pairing phases by suppressing the formation of trions. |
We report on high-resolution optical spectroscopy of interacting bosonic $^{174}$Yb atoms in deep optical lattices with negligible tunneling. We prepare Mott insulator phases with singly- and doubly-occupied isolated sites and probe the atoms using an ultra-narrow "clock" transition. |
The prospect of using light to probe or manipulate quantum materials has become an active area of interest. Here, we investigate a quantum wire -- treated as a finite-sized one-dimensional electron gas -- that is coupled to a single photonic mode. |
We analytically study the atom-dimer scattering problem in the near-integrable limit when the oscillator length l_0 of the transverse confinement is smaller than the dimer size, ~l_0^2/|a|, where a<0 is the interatomic scattering length. The leading contributions to the atom-diatom reflection and break-up probabili... |
We study phase separation in a dilute two-component Fermi system with attractive interactions as a function of the coupling strength and the polarization or number density asymmetry between the two components. In weak and strong couplings with a finite number density asymmetry, phase separation is energetically more f... |
We report on pure-quantum-state polariton condensates in optical annular traps. The study of the underlying mechanism reveals that the polariton wavefunction always coalesces in a single pure-quantum-state that, counter-intuitively, is always the uppermost confined state with the highest overlap to the exciton reservo... |
In the last decade, quantum simulators, and in particular cold atoms in optical lattices, have emerged as a valuable tool to study strongly correlated quantum matter. These experiments are now reaching regimes that are numerically difficult or impossible to access. |
In this Letter we study the effect of Pauli blocking on the Efimov states in a quantum Fermi gas and illustrate that the universal Efimov potential is altered at large distances. We obtain the universal spectrum flow of Efimov trimers when the Fermi density is varied and further consider the effect of scattering of tr... |
We consider a bilayer of dipolar bosons in which the polarization of dipoles are perpendicular to the planes. Using accurate static structure factor $S(q)$ data from hypernetted-chain calculation for single layer dipolar bosons we construct effective screened interactions for intralayer particles. |
Many-body physics describes phenomena which cannot be understood looking at a systems' constituents alone. Striking manifestations are broken symmetry, phase transitions, and collective excitations. |
We demonstrate how different types of $SU(3)$ Heisenberg models can be implemented with the use of the $p$ orbitals of three dimensional optical lattices. By considering a Mott insulator with unit filling, the dynamics is well described by an effective model derived from the perturbative treatment of the tunneling ele... |
We study the thermal activation of spin fluctuations in dynamically-stable spinor Bose-Einstein condensates. We analyze the specific cases of a non-dipolar spin-1 condensate in m = 0, where thermal activation results from spin-changing collisions, and of a Chromium condensate in the maximally stretched state m = -3, w... |
The suppression of antiferromagnetic ordering in geometrically frustrated Hubbard models leads to a variety of exotic quantum phases including quantum spin liquids and chiral states. Here, we focus on the Hubbard model on one of the simplest frustrated lattice geometries, a triangular lattice. |
Density-wave patterns in (quasi-) discrete media with local interactions are known to be unstable. We demonstrate that \emph{stable} double- and triple- period patterns (DPPs and TPPs), with respect to the period of the underlying lattice, exist in media with nonlocal nonlinearity. |
A comprehensive search for "broad" Feshbach resonances (FRs) in all possible combinations of stable alkali-metal atoms is carried out, using a multi-channel quantum-defect theory assisted by the analytic wave functions for a long-range van-der-Waals potential. A number of new "broad" $s$-, $p$- and $d$... |
Very different strongly interacting quantum systems such as Fermi gases, quark-gluon plasmas formed in high energy ion collisions and black holes studied theoretically in string theory are known to exhibit quantitatively similar damping of hydrodynamic modes. It is not known if such similarities extend beyond the hydr... |
We consider the low-energy particle-particle scattering properties in a periodic simple cubic crystal. In particular, we investigate the relation between the two-body scattering length and the energy shift experienced by the lowest-lying unbound state when this is placed in a periodic finite box. |
We study the nonequilibrium properties of the one dimensional Lieb Liniger model in the finite repulsion regime. Introducing a new version of the Yudson representation applicable to finite size systems and appropriately taking the infinite volume limit we are able to study equilibration of the Lieb Liniger gas in the ... |
We propose a general scheme for inducing resonant exchange between spins or pseudo-spins of unmatched levels via periodic driving. The basic idea is illustrated for a system of two heteronuclear atoms, for which analytical results are provided for the effective spin exchange (SE) interaction strength. |
We characterize a system of tilted dipoles in a quasi two-dimensional (flattened) geometry and in the thermodynamic limit. We consider a finite trapping in the z-axis achievable in current experiments. |
We study the low-energy excitations of a bosonic lattice gas with cavity-mediated interactions. By performing two successive Hubbard-Stratonovich transformations, we derive an effective field theory to study the strongly-coupling regime. |
A central requirement for the faithful implementation of large-scale lattice gauge theories (LGTs) on quantum simulators is the protection of the underlying gauge symmetry. Recent advancements in the experimental realizations of large-scale LGTs have been impressive, albeit mostly restricted to Abelian gauge groups. |
We report on the preparation of a pure ultracold sample of bosonic DyK Feshbach molecules, which are composed of the fermionic isotopes 161Dy and 40K. Employing a magnetic sweep across a resonance located near 7.3 G, we produce up to 5000 molecules at a temperature of about 50 nK. |
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 dynamics of condensates and quantized vortices.... |
We compute the energy per particle of normal liquid ${}^3$He in the temperature range $0.15-2$ K using Path Integral Monte Carlo simulations, leveraging a recently proposed method to overcome the sign problem -- a long-standing challenge in many-body fermionic simulations. This approach is based on introducing a param... |
The present short note is simply intended to communicate that I have analytically diagonalized the Bogoliubov truncated Hamiltonian $H_c$~\cite{Bogo1,Bogo2}, in an interacting bosonic gas. This is the natural prosecution of my work~\cite{MS}, now denoted as (I), where the diagonalization was performed only in the subs... |
In the present paper, the Bose-Hubbard model (BHM) with the nearest-neighbor (NN) repulsions is studied from the view point of possible bosonic analogs of the fractional quantum Hall (FQH) state in the vicinity of the Mott insulator (MI). First, by means of the Gutzwiller approximation, we obtain the phase diagram of ... |
We report the thermodynamic properties of an ideal boson gas confined in an infinite periodic array of channels modeled by two, mutually perpendicular, Kronig-Penney delta-potentials. The particle's motion is hindered in the x-y directions, allowing tunneling of particles through the walls, while no confinement al... |
We investigate the many-body states of exciton-polaritons that can be observed by pump-probe spectroscopy. Here, a weak-probe `spin-down' polariton is introduced into a coherent state of `spin-up' polaritons created by a strong pump. |
We study spontaneous-symmetry-breaking circularly-asymmetric phase separation of vortex lattices in a rapidly rotating harmonically-trapped quasi-two-dimensional (quasi-2D) binary Bose-Einstein condensate (BEC) with repulsive inter- and intra-species interactions. The phase separated vortex lattices of the components ... |
A weakly interacting, spin-orbit coupled, ultracold, dilute Bose gas on a two-dimensional square lattice with an external Zeeman field is studied. We explore the plane and stripe wave phases of the system involving nonzero condensate momenta, which occur when the Zeeman field is below a critical value. |
We investigate the dynamical spreading of spatial correlations after a quantum quench starting from a magnetically disordered state in the transverse-field Ising model at one (1D) and two spatial dimensions (2D). We analyze specifically the longitudinal and transverse spin-spin correlation functions at equal time with... |
We lay out an experiment to realize time-reversal invariant topological insulators in alkali atomic gases. We introduce an original method to synthesize a gauge field in the near-field of an atom-chip, which effectively mimics the effects of spin-orbit coupling and produces quantum spin-Hall states. |
Quantum criticality near a tricritical point (TCP) is studied in the two-component Bose-Hubbard model on square lattices. The existence of quantum TCP on a boundary of superfluid-insulator transition is confirmed by quantum Monte Carlo simulations. |
Quantum fluctuations can stabilize Bose-Einstein condensates (BEC) against the mean-field collapse. Stabilization of the condensate has been observed in quantum degenerate Bose-Bose mixtures and dipolar BECs. |
We show that a vector matter-wave soliton in Bose-Einstein condensate loaded into an optical lattice can escape from a trap formed by a parabolic potential, resembling a Hawking emission. The particle-antiparticle pair is emulated by a low-amplitude bright-bright soliton in two-component Bose-Einstein condensate with ... |
Although crystallization is a ubiquitous phenomenon in nature, crystal formation and melting still remain fascinating processes with several open questions yet to be addressed. In this work, we study the emergent crystallization of a laser-driven dipolar Bose-Einstein condensate due to the interplay between long-range... |
We derive a closed form expression for the quantum corrections to the kinetic energy density (KED) in the Thomas-Fermi (TF) limit of a linear potential model system in three dimensions (the Airy gas). The universality of the expression is tested numerically in a number of three dimensional model systems: |
This manuscript studies harmonically trapped ideal Bose and Fermi gas systems and their thermodynamics in the framework of the Extended Uncertainty Principle (EUP). In particular, we demonstrated how the ground and thermal particle ratios, condensate temperature, internal energy, specific heat, and equation of state f... |
We study theoretically the deformation of the Fermi surface (FS) of a three-dimensional gas of Rydberg-dressed $^6$Li atoms. The laser dressing to high-lying Rydberg $D$ states results in angle-dependent soft-core-shaped interactions whose anisotropy is described by multiple spherical harmonics. |
Transmission of high power laser beams through partially absorbing materials modifies the light propagation via a thermally-induced effect known as thermal lensing. This may cause changes in the beam waist position and degrade the beam quality. |
Phase transitions to absorbing states are among the simplest examples of critical phenomena out of equilibrium. The characteristic feature of these models is the presence of a fluctuationless configuration which the dynamics cannot leave, which has proved a rather stringent requirement in experiments. |
In multicomponent superfluids and superconductors, co- and counter-flows of components have in general different properties. It was discussed in 1975 by Andreev and Bashkin, in the context of He$^3$/He$^4$ superfluid mixtures, that inter-particle interactions produce a dissipationless drag. |
We studied the scattering problem of two distinguishable atoms with unequal mass, where one atom (atom $\alpha$) is trapped in a quasi-one-dimensional (quasi-1D) tube and the other one (atom $\beta$) is localized by a 3D harmonic trap. We show that in such a system if atom $\alpha$ is much heavier than $\beta$, confin... |
We present a unified description of different types of matter-wave solitons that can emerge in quasi one-dimensional spin-orbit coupled (SOC) Bose-Einstein condensates (BECs). This description relies on the reduction of the original two-component Gross-Pitaevskii SOC-BEC model to a single nonlinear Schrödinger equatio... |
A light impurity in a Fermi sea undergoes a transition from a polaron to a molecule for increasing interaction. We develop a new method to compute the spectral functions of the polaron and molecule in a unified framework based on the functional renormalization group with full self-energy feedback. |
We study an optical cavity coupled to a lattice of Rydberg atoms, which can be represented by a generalized Dicke model. We show that the competition between the atomic interaction and atom-light coupling induces a rich phase diagram. |
We reply to Jacek Dziarmaga, Piotr Deuar, and Krzysztof Sacha's comment, <a href="https://arxiv.org/abs/1001.1045" data-arxiv-id="1001.1045" class="link-https">arXiv:1001.1045</a>, supporting the authors' simulations but differentiating between near-mean-field and strongly quantum regimes. We clarify that we h... |
We theoretically study a weakly interacting gas of spin-1 atoms with Bose-Einstein condensate in external magnetic field within the Bogoliubov approach. To this end, in contrast to previous studies, we employ the general Hamiltonian, which includes both spin and quadrupole exchange interactions as well as the coupling... |
We investigate the dynamics of two bosons trapped in an infinite one-dimensional optical lattice potential within the framework of the Bose-Hubbard model and derive an exact expression for the wavefunction at finite time. As initial condition we chose localized atoms that are separated by a distance of $d$ lattice sit... |
In a shaken Bose-Einstein condensate, confined in a vibrating trap, there can appear different nonlinear coherent modes. Here we concentrate on two types of such coherent modes, vortex ring solitons and vortex rings. |
The superfluid, pair condensed spin-1/2 Fermi gases are supposed to exhibit at nonzero wave vector a still unobserved collective excitation mode in their pair-breaking continuum. Using BCS theory at zero temperature and in the long wavelength limit, we predict that this mode is quantitatively observable (in frequency,... |
We address stationary patterns in exciton-polariton condensates supported by a narrow external pump beam, and we discover that even in the absence of trapping potentials, such condensates may support stable localized stationary dissipative solutions (quasi-compactons), whose field decays faster than exponentially or ev... |
We describe the emergence of color superfluidity in ultra-cold fermions induced by color-orbit and color-flip fields that transform a conventional singlet-pairing s-wave system into an unconventional non-s-wave superfluid with quintuplet pairing. We show that the tuning of interactions, color-orbit and color-flip fiel... |
We study continuous interaction of a trapped two-component Bose-Einstein condensate with light fields in a $\Lambda$-type configuration. Using light beams with orbital angular momentum, we theoretically show how to create a stable, pinned vortex configuration, where the rotating component is confined to the region sur... |
The role of disorder on physical systems has been widely studied in the macroscopic and microscopic world. While static disorder is well understood in many cases, the impact of time-dependent disorder on quantum gases is still poorly investigated. |
Ultracold atoms in optical lattices form a clean quantum simulator platform which can be utilized to examine topological phenomena and test exotic topological materials. Here we propose an experimental scheme to measure the Chern numbers of two-dimensional multiband topological insulators with bosonic atoms. |
We study laterally trapped dipolar exciton ensembles in coupled GaAs quantum wells at high magnetic fields in the Faraday configuration. In photoluminescence experiments, we identify three magnetic field regimes. |
Fermi gases with short-range interactions are ubiquitous in ultracold atomic systems. In the absence of spin-flipping processes the number of atoms in each spin species is conserved separately, and we discuss the associated Ward identities. |
We study a two-component quasi-two-dimensional Fermi gas with imbalanced spin populations. We probe the gas at different interaction strengths and polarizations by measuring the density of each spin component in the trap and the pair momentum distribution after time of flight. |
In this paper we present Open Multi-Processing (OpenMP) Fortran 90/95 versions of previously published numerical programs for solving the dipolar Gross-Pitaevskii (GP) equation including the contact interaction in one, two and three spatial dimensions. The atoms are considered to be polarized along the z axis and we c... |
We study a pair of anharmonic microwave cavities that is connected by an optical fiber. The photonic spectral density characterizes the evolution of the coupled cavities after the system has been prepared in a Fock or N00N state. |
We study the effect of the induced interaction on the superfluidtransition temperature of a spin-polarized Fermi gas. In the BCS limit, the polarization is very small in the superfluid state, and the effect of the induced interaction is almost the same as in the spin-balanced case. |
The Einstein-de Haas effect is a phenomenon in which angular momentum is transferred from microscopic spins to mechanical rotation of a rigid body. Here, we report the first observation of the Einstein-de Haas effect in a spinor-dipolar Bose-Einstein condensate where quantized vortices emerge in depolarized spinor com... |
We study the ground-state physics of a single-component Haldane model on a hexagonal two-leg ladder geometry with a particular focus on strongly interacting bosonic particles. We concentrate our analysis on the regime of less than one particle per unit-cell. |
We develop a quantum dynamical field theory for studying phase transitions in driven open systems coupled to Markovian noise, where non-linear noise effects and fluctuations beyond semiclassical approximations influence the critical behaviour. We systematically compare the diagrammatics, the properties of the renormal... |
We study the Faraday patterns generated by spin-orbit-coupling induced parametric resonance in a spinor Bose-Einstein condensate with repulsive interaction. The collective elementary excitations of the Bose-Einstein condensate, including density waves and spin waves, are coupled as the result of the Raman-induced spin... |
Quantum simulation is at the heart of the ongoing "second" quantum revolution, with various synthetic quantum matter platforms realizing evermore exotic condensed matter and particle physics phenomena at high levels of precision and control. The implementation of gauge theories on modern quantum simulators is ... |
We study the Mott phase of three-component bosons, with one particle per site, in an optical lattice by mapping it onto an SU(3) spin model. In the simplest case of full SU(3) symmetry, one obtains a ferromagnetic Heisenberg model. |
The Dicke model describes the coherent interaction of a laser-driven ensemble of two level atoms with a quantized light field. It is realized within cavity QED experiments, which in addition to the coherent Dicke dynamics feature dissipation due to e.g. atomic spontaneous emission and cavity photon loss. |
We investigate the sensitivity of an ion sensor in determining the temperature of an atomic Fermi gas. Our study extends to charged impurities the proposal by M. T. Mitchison et al. |
Meaningful topological invariants for mixed quantum states are challenging to identify as there is no unique way to define them, and most choices do not directly relate to physical observables. Here, we propose a simple pragmatic approach to construct topological invariants of mixed states while preserving a connectio... |
Several new features arise in the ground-state phase diagram of a spin-1 condensate trapped in an optical trap when the magnetic dipole interaction between the atoms is taken into account along with confinement and spin precession. The boundaries between the regions of ferromagnetic and polar phases move as the dipole... |
The cluster Gutzwiller method is widely used to study the strongly correlated bosonic systems, owing to its ability to provide a more precise description of quantum fluctuations. However, its utility is limited by the exponential increase in computational complexity as the cluster size grows. |
We investigate an imbalanced mixture composed of two-color fermions and scalar bosons in the hard-core limit, considering repulsive and attractive interspecies and intraspecies interactions. The interplay between commensurability, repulsive interactions and imbalance generates three insulating phases: a mixed Mott sta... |
By selectively probing the center of a trapped gas, we measure the local, or homogeneous, contact of a unitary Fermi gas as a function of temperature. Tan's contact, C, is proportional to the derivative of the energy with respect to the interaction strength, and is thus an essential thermodynamic quantity for a ga... |
We propose a realistic scheme to detect the 4D quantum Hall effect using ultracold atoms. Based on contemporary technology, motion along a synthetic fourth dimension can be accomplished through controlled transitions between internal states of atoms arranged in a 3D optical lattice. |
The study of unconventional phases and elucidation of correspondences between topological invariants and their intriguing properties are pivotal in topological physics. Here, we investigate a complex exceptional ring (CER), composed of a third-order exceptional ring and multiple Weyl exceptional rings, and establish a... |
We propose a method to suppress the chemical reactions between ultracold bosonic ground-state $^{23}$Na$^{87}$Rb molecules based on optical shielding. By applying a laser with a frequency blue-detuned from the transition between the lowest rovibrational level of the electronic ground state $X^1\Sigma^+ (v_X=0, j_X=0)$... |
We study systematically the period-doubled Bloch states for a weakly interacting Bose-Einstein condensate in a one-dimensional optical lattice. This kind of state is of form $\psi_k=e^{ikx}\phi_k(x)$, where $\phi_k(x)$ is of period twice the optical lattice constant. |
Vortex lattices in rapidly rotating Bose-Einstein condensates lead to a periodic modulation of the superfluid density with a triangular symmetry. Here we show that this symmetry can be combined with an external perturbation in order to create super-lattice structures with two or more periodicities. |
We investigate the effect of losses on an interacting quantum gas. We show that, for gases in dimension higher than one, assuming together a vanishing correlation time of the reservoir where dissipation occurs, and contact interactions leads to a divergence of the energy increase rate. |
The collision of molecules at ultracold temperatures is of great importance for understanding the chemical interactions at the quantum regime. While much theoretical work has been devoted to this, experimental data are only available sparsely mainly due to the difficulty in producing ground-state molecules at ultracol... |
We systematically studied the two-body loss in a two-component Fermi gas of $^6$Li atoms near a p-wave Feshbach resonance. The two-body loss rate constants were measured for various temperatures and magnetic fields using atoms trapped in three-dimensional and quasi-two-dimensional traps. |
Density correlations unambiguously reveal the quantum nature of matter. Here, we study correlations between measurements of density in cold-atom clouds at different times at one position, and also at two separated positions. |
We consider impurity atoms embedded in a two-component Bose-Einstein condensate in a quasi-one dimensional regime. We study the effects of repulsive coupling between the impurities and Bose species on the equilibrium of the system for both miscible and immiscible mixtures by numerically solving the underlying coupled ... |
Quantum Monte Carlo simulations of a two-component Bose mixture of trapped dipolar atoms of identical masses and dipole moments, provide numerical evidence of de-mixing at low finite temperatures. De-mixing occurs as a consequence of quantum statistics, which results in an effective attraction between like bosons. |
Rapid advancements in the experimental capabilities with ultracold alkaline-earth-like atoms (AEAs) bring to a surprisingly near term the prospect of performing quantum simulations of spin models and lattice field theories exhibiting SU($N$) symmetry. Motivated in particular by recent experiments preparing high densit... |
We analyze the eigenstates of a two-dimensional lattice with additional harmonic confinement in the presence of an artificial magnetic field. While the softness of the confinement makes a distinction between bulk and edge states difficult, the interplay of harmonic potential and lattice leads to a different classifica... |
In recent literature on trapped ultracold atomic gases, calculations for 2D-systems are often done within the Dynamical Mean Field Theory (DMFT) approximation. In this paper, we compare DMFT to a fully two-dimensional, self-consistent second order perturbation theory for weak interactions in a repulsive Fermi-Hubbard ... |
We consider an analogue de Sitter cosmos in an expanding quasi-two-dimensional Bose-Einstein condensate with dominant dipole-dipole interactions between the atoms or molecules in the ultracold gas. It is demonstrated that a hallmark signature of inflationary cosmology, the scale invariance of the power spectrum of inf... |
We consider the phase transition dynamics of a trapped Bose-Einstein condensate subject to Raman-type spin-orbit coupling (SOC). By tuning the coupling strength the condensate is taken through a second order phase transition into an immiscible phase. |
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