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Measuring Electromagnetic and Gravitational Responses of Photonic Landau LevelsFeb 13 2018The topology of an object describes global properties that are insensitive to local perturbations. Classic examples include string knots and the genus (number of handles) of a surface: no manipulation of a closed string short of cutting it changes its ... More

Topological PhotonicsFeb 12 2018Topological photonics is a rapidly-emerging field of research in which geometrical and topological ideas are exploited to design and control the behavior of light. Drawing inspiration from the discovery of the quantum Hall effects and topological insulators ... More

Suppression and revival of long-range ferromagnetic order in the multiorbital Fermi-Hubbard modelFeb 08 2018By means of dynamical mean-field theory allowing for complete account of SU(2) rotational symmetry of interactions between spin-1/2 particles, we observe a strong effect of suppression of ferromagnetic order in the multiorbital Fermi-Hubbard model in ... More

A strongly interacting Sarma superfluid near orbital Feshbach resonancesFeb 08 2018We investigate the nature of superfluid pairing in a strongly interacting Fermi gas near orbital Feshbach resonances with spin-population imbalance in three dimensions, which can be well described by a two-band or two-channel model. We show that a Sarma ... More

Correlations of occupation numbers in the canonical ensemble and application to BEC in a 1D harmonic trapFeb 07 2018We study statistical properties of $N$ non-interacting identical bosons or fermions in the canonical ensemble. We derive several general representations for the $p$-point correlation function of occupation numbers $\overline{n_1\cdots n_p}$. We demonstrate ... More

Management of the Correlations of Ultracold Bosons in Triple WellsFeb 07 2018Ultracold interacting atoms are an excellent tool to study correlation functions of many-body systems that are generally eluding detection and manipulation. Herein, we investigate the ground state of bosons in a tilted triple-well potential and characterize ... More

Unitarity and Universality in non relativistic Conformal Field theoryFeb 06 2018We relate the notion of unitarity of a $SL(2,\mathbf{R})$ invariant field theory with that of a Schr\"odinger field theory using the fact that $SL(2,\mathbf{R})$ is a subgroup of Schr\"odinger group. Exploiting $SL(2,\mathbf{R})$ unitarity, we derive ... More

Tunable current circulation in triangular quantum-dot metastructuresFeb 06 2018Advances in fabrication and control of quantum dots allow the realization of metastructures that may exhibit novel electrical transport phenomena. Here, we investigate the electrical current passing through one such metastructure, a system composed of ... More

Exact local correlations and full counting statistics for arbitrary states of the one-dimensional interacting Bose gasFeb 06 2018We derive exact analytic expressions for the $n$-body local correlations in the one-dimensional Bose gas with contact repulsive interactions (Lieb-Liniger model) in the thermodynamic limit. Our results are valid for arbitrary states of the model, including ... More

Dimer-dimer zero crossing and dilute dimerized liquid in a one-dimensional mixtureFeb 06 2018We consider the system of dimers formed in a one-dimensional two-component mass-balanced Bose-Bose mixture with attractive inter- and repulsive intraspecies contact interactions. In the plane parameterized by the ratios of the coupling constants $g_{\uparrow\uparrow}/|g_{\uparrow\downarrow}|$ ... More

Observation of the topological Anderson insulator in disordered atomic wiresFeb 06 2018Topology and disorder have deep connections and a rich combined influence on quantum transport. In order to probe these connections, we synthesized one-dimensional chiral symmetric wires with controllable disorder via spectroscopic Hamiltonian engineering, ... More

Hyperspherical-LOCV Approximation to Resonant BECFeb 06 2018We study the ground state properties of a system of $N$ harmonically trapped bosons of mass $m$ interacting with two-body contact interactions, from small to large scattering lengths. This is accomplished in a hyperspherical coordinate system that is ... More

Effects of interaction imbalance in a strongly repulsive one-dimensional Bose gasFeb 06 2018We calculate the spatial distributions and the dynamics of a few-body two-component strongly interacting Bose gas confined to an effectively one-dimensional trapping potential. We describe the densities for each component in the trap for different interaction ... More

Probing the Interface of a Phase-Separated State in a Repulsive Bose-Fermi MixtureFeb 06 2018We probe the interface between a phase-separated Bose-Fermi mixture consisting of a small BEC of $^{41}$K residing in a large Fermi sea of $^6$Li. We quantify the residual spatial overlap between the two components by measuring three-body recombination ... More

Blow-up profile of rotating 2D focusing Bose gasesFeb 06 2018We consider the Gross-Pitaevskii equation describing an attractive Bose gas trapped to a quasi 2D layer by means of a purely harmonic potential, and which rotates at a fixed speed of rotation $\Omega$. First we study the behavior of the ground state when ... More

Integrable time-dependent Hamiltonians, solvable Landau-Zener models and Gaudin magnetsFeb 03 2018We solve the non-stationary Schrodinger equation for several time-dependent Hamiltonians, such as the BCS Hamiltonian with an interaction strength inversely proportional to time, periodically driven BCS and linearly driven inhomogeneous Dicke models as ... More

Trapping CollapseFeb 02 2018Weak potential wells (or traps) in one and two dimensions, and the potential wells slightly deeper than the critical ones in three dimensions, feature shallow bound states with localization length much larger than the well radii. We address a simple fundamental ... More

Spin-Imbalanced Pairing and Fermi Surface Deformation in Flat BandsFeb 01 2018We study the attractive Hubbard model with spin imbalance on two lattices featuring a flat band: the Lieb and kagome lattices. We present mean-field phase diagrams featuring exotic superfluid phases, similar to the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) ... More

Harmonically Trapped Four-Boson SystemFeb 01 2018Four identical spinless bosons with purely attractive two-body short-range interactions and repulsive three-body interactions under external spherically symmetric harmonic confinement are considered. The repulsive three-body potential prevents the formation ... More

SO(3) "Nuclear Physics" with ultracold GasesJan 31 2018An ab initio calculation of nuclear physics from Quantum Chromodynamics (QCD), the fundamental SU(3) gauge theory of the strong interaction, remains an outstanding challenge. Here, we discuss the emergence of key elements of nuclear physics using an SO(3) ... More

Two-dimensional vortex quantum dropletsJan 31 2018It was recently found that the Lee-Huang-Yang (LHY) correction to the mean-field Hamiltonian suppresses the collapse and creates stable localized modes (two-component "quantum droplets", QDs) in two and three dimensions. We construct two-dimensional\ ... More

Diversified vortex phase diagram for a rotating trapped two-band Fermi gas in the BCS-BEC crossoverJan 30 2018We report the equilibrium vortex phase diagram of a rotating two-band Fermi gas confined to a cylindrically symmetric parabolic trapping potential, using the recently developed finite-temperature effective field theory [Phys. Rev. A $\bf{94}$, 023620 ... More

Observation of interaction-induced gauge fields in a Bose-Einstein condensate based on micromotion control in a shaken two-dimensional latticeJan 30 2018We demonstrate an interaction-induced gauge field for Bose-Einstein condensates in a modulated two-dimensional optical lattice. The gauge field results from the synchronous coupling between the interactions and micromotion of the atoms. As a first step, ... More

Quantum metric contribution to the pair mass in spin-orbit coupled Fermi superfluidsJan 29 2018As a measure of the quantum distance between Bloch states in the Hilbert space, the quantum metric was introduced to solid-state physics through the real part of the so-called geometric Fubini-Study tensor, the imaginary part of which corresponds to the ... More

Polaron in a non-abelian Aubry-André-Harper model with \textit{p}-wave superfluidityJan 27 2018We theoretically investigate the behavior of a mobile impurity immersed in a one-dimensional quasi-periodic Fermi system with topological $p$-wave superfluidity. This polaron problem is solved by using a standard variational approach, the so-called Chevy ... More

Exact edge, bulk and bound states of finite topological systemsJan 26 2018Finite topologically non-trivial systems are often characterised by the presence of bound states at their physical edges. These topological edge modes can be distinguished from usual Shockley waves energetically, as their energies remain finite and in-gap. ... More

Entanglement sudden death and revival in quantum dark-soliton qubitsJan 26 2018We study the finite time entanglement dynamics between two dark soliton qubits due to quantum fluctuations in a quasi one dimensional Bose-Einstein condensates. Recently, dark solitons are proved to be an appealing platform for qubits due to their appreciably ... More

Ultrarobust calibration of an optical lattice depth based on a phase shiftJan 26 2018We report on a new method to calibrate the depth of an optical lattice. It consists in triggering the intrasite dipole mode of the cloud by a sudden phase shift. The corresponding oscillatory motion is directly related to the intraband frequencies on ... More

Self-bound droplets of light with orbital angular momentumJan 25 2018Systems with competing attractive and repulsive interactions have a tendency to condense into droplets. This is the case for water in a sink, liquid helium and dipolar atomic gases. Here, we consider a photon fluid which is formed in the transverse plane ... More

Spontaneous generation of entanglement in quantum dark-soliton qubitsJan 24 2018We show that entanglement between two solitary qubits in quasi one-dimensional Bose-Einstein condensates can be spontaneously generated due to quantum fluctuations. Recently, we have shown that dark solitons are an appealing platform for qubits due to ... More

From few to many body degrees of freedomJan 24 2018Here, I focus on the use of microscopic, few-body techniques that are relevant in the many-body problem. These methods can be divided into indirect and direct. In particular, indirect methods are concerned with the simplification of the many-body problem ... More

Stability of the 2+2 fermionic system with point interactionsJan 24 2018We give a lower bound on the ground state energy of a system of two fermions of one species interacting with two fermions of another species via point interactions. We show that there is a critical mass ratio m_c \approx 0.58 such that the system is stable, ... More

Negative absolute temperatures of vortices in a two-dimensional superfluidJan 22 2018We have observed negative absolute temperature configuration of vortices in a 2D superfluid atomic gas of Rb atoms confined in a circular-shaped, flat-bottom potential. We create the vortex configurations by sweeping a linear array of optical barriers ... More

Negative-Temperature Onsager Vortex Clusters in a Quantum FluidJan 22 2018Turbulence in classical fluids is a ubiquitous non-equilibrium phenomenon, yet a complete theoretical description for turbulent flow remains a challenging problem. A useful simplification for ideal two-dimensional (2D) fluids is to describe the turbulent ... More

Floquet Engineering in Quantum ChainsJan 21 2018We consider a one-dimensional interacting spinless fermion model, which displays the well-known Luttinger liquid (LL) to charge density wave (CDW) transition as a function of the ratio between the strength of the interaction, $U$, and the hopping, $J$. ... More

Quantum Landau damping in dipolar Bose-Einstein condensatesJan 18 2018We consider Landau damping of elementary excitations in Bose-Einstein condensates (BECs) with dipolar interactions. We discuss quantum and quasi-classical regimes of Landau damping. We use a generalized wave-kinetic description of BECs which, apart from ... More

Accurate Determination of the Dynamical Polarizability of DysprosiumJan 17 2018We report a measurement of the dynamical polarizability of dysprosium atoms in their electronic ground state at the optical wavelength of 1064 nm, which is of particular interest for laser trapping experiments. Our method is based on collective oscillations ... More

NOON state of Bose atoms in the double-well potential via an excited state quantum phase transitionJan 16 2018We suggest a simple scheme for creating a NOON state of repulsively interacting Bose atoms in the double-well potential. The protocol consists of two steps. First, by setting atom-atom interactions to zero, the system is driven to the upper excited state. ... More

One-Dimensional Quantum Systems - From Few to Many ParticlesJan 15 2018In this thesis, I go through the well-known solutions to the one and two-particle systems trapped in a quantum harmonic oscillator and then continue to the three, four and many-body quantum systems. This is done by developing new analytical models and ... More

Long-lived quantum vortex knotsJan 15 2018Dynamics of simplest quantum vortex knots of torus type in a superfluid at zero temperature has been simulated within a regularized Biot-Savart law (the torus radii $R_0$ and $r_0$ for initial vortex configuration were large in comparison with a vortex ... More

Negative-mass effects in spin-orbit coupled Bose-Einstein condensatesJan 15 2018Negative effective masses can be realised by engineering the dispersion relation in a variety of quantum systems. A recent experiment with spin-orbit coupled Bose-Einstein condensates has shown that a negative effective mass can halt the free expansion ... More

Global fluctuations for 1D log-gas dynamics. (2) Covariance kernel and supportJan 09 2018We consider the hydrodynamic limit in the macroscopic regime of the coupled system of stochastic differential equations, $ d\lambda_t^i=\frac{1}{\sqrt{N}} dW_t^i - V'(\lambda_t^i) dt+ \frac{\beta}{2N} \sum_{j\not=i} \frac{dt}{\lambda^i_t-\lambda^j_t}, ... More

Wigner function of noninteracting trapped fermionsJan 08 2018We study analytically the Wigner function $W_N({\bf x},{\bf p})$ of $N$ noninteracting fermions trapped in a smooth confining potential $V({\bf x})$ in $d$ dimensions. At zero temperature, $W_N({\bf x},{\bf p})$ is constant over a finite support in the ... More

Density functional theory versus quantum Monte Carlo simulations of Fermi gases in the optical-lattice arenaJan 06 2018We benchmark the ground state energies and the density profiles of atomic repulsive Fermi gases in optical lattices computed via Density Functional Theory (DFT) against the results of diffusion Monte Carlo (DMC) simulations. The main focus is on a half-filled ... More

Exploring the Kondo model in and out of equilibrium with alkaline-earth atomsJan 03 2018We propose a scheme to realize the Kondo model with tunable anisotropy using alkaline-earth atoms in an optical lattice. The new feature of our setup is Floquet engineering of interactions using time-dependent Zeeman shifts, that can be realized either ... More

Unitary $n$-designs via random quenches in atomic Hubbard and Spin models: Application to the measurement of Rényi entropiesJan 03 2018Feb 05 2018We present a general framework for the generation of random unitaries based on random quenches in atomic Hubbard and spin models, forming approximate unitary $n$-designs, and their application to the measurement of R\'enyi entropies. We generalize our ... More

Dark-dark-soliton dynamics in two density-coupled Bose-Einstein condensatesDec 31 2017We study the 1D dynamics of dark-dark solitons in the miscible regime of two density-coupled Bose-Einstein condensates having repulsive interparticle interactions within each condensate ($g>0$). By using an adiabatic perturbation theory in the parameter ... More

Ground-state energy of one-dimensional free Fermi gases in the thermodynamic limitDec 30 2017We study the ground-state energy of one-dimensional, non-interacting fermions subject to an external potential in the thermodynamic limit. To this end, we fix some (Fermi) energy $\nu>0$, confine fermions with total energy below $\nu$ inside the interval ... More

Chiral Topological Phases in Optical Lattices: Beyond Synthetic FieldsDec 29 2017Synthetic fields applied to atomic and molecular gases can be used to study topological phases that transcend conventional Bose and Fermi-liquid paradigms. Raman laser beams in particular are currently under scrutiny as a route to create synthetic fields ... More

Experimental Realization of a Relativistic Harmonic OscillatorDec 27 2017We report the experimental study of a harmonic oscillator in the relativistic regime. The oscillator is composed of Bose-condensed lithium atoms in the third band of an optical lattice, which have an energy-momentum relation nearly identical to that of ... More

Bound states in the continuum in a two-dimensional PT-symmetric systemDec 23 2017We address a two-dimensional parity-time (PT)-symmetric structure built as a chain of waveguides, where all waveguides except for the central one are conservative, while the central one is divided into two halves with gain and losses. We show that such ... More

Droplet crystal ground states of a dipolar Bose gasDec 22 2017We show that the ground state of a dipolar Bose gas in a cylindrically symmetric harmonic trap has a rich phase diagram, including droplet crystal states in which a set of droplets arrange into a lattice pattern that breaks the rotational symmetry. An ... More

Postquench prethermalization in a disordered quantum fluid of lightDec 22 2017We study the coherence of a disordered and interacting quantum light field after propagation along a nonlinear optical fiber. Disorder is generated by a cross-phase modulation with a randomized auxiliary classical light field, while interactions are induced ... More

Polarization of a Bose-Einstein Condensate of Photons in a Dye-Filled MicrocavityDec 22 2017We measure the polarization of a photon gas in a dye-filled microcavity. The polarization is obtained by a single-shot measurement of the Stokes parameters. We find that the polarization of both the thermal cloud and the Bose-Einstein condensate of photons ... More

Dynamical Equilibration Across a Quenched Phase Transition in a Trapped Quantum GasDec 21 2017The formation of an equilibrium quantum state from an uncorrelated thermal one through the dynamical crossing of a phase transition is a central question of non-equilibrium many-body physics. During such crossing, the system breaks its symmetry by establishing ... More

The Effective Interaction Strength in a Bose-Einstein Condensate of Photons in a Dye-Filled MicrocavityDec 21 2017Dec 29 2017We experimentally study Bose-Einstein condensation of photons (phBEC) in a dye-filled microcavity. Through multiple absorption and emission cycles the photons inside the microcavity thermalize to the rovibronic temperature of the dye solution. Raising ... More

Density Distribution of a Bose-Einstein Condensate of Photons in a Dye-Filled MicrocavityDec 21 2017The achievement of Bose-Einstein condensation of photons (phBEC) in a dye-filled microcavity has led to a renewed interest in the density distribution of the ideal Bose gas in a two-dimensional harmonic oscillator. We present measurements of the radial ... More

Echo-Ramsey Interferometry with Motional Quantum StatesDec 20 2017Ramsey interferometers (RIs) using internal electronic or nuclear states find wide applications in science and engineering. We develop a matter wave Ramsey interferometer for motional quantum states exploiting the S- and D-bands of an optical lattice ... More

Kardar-Parisi-Zhang universality in the phase distributions of one-dimensional exciton-polaritonsDec 11 2017Exciton-polaritons under driven-dissipative conditions exhibit a condensation transition which belongs to a different universality class than equilibrium Bose-Einstein condensates. By numerically solving the generalized Gross-Pitaevskii equation with ... More

Effective self-similar expansion for the Gross-Pitaevskii equationDec 01 2017We consider an effective scaling approach for the free expansion of a one-dimensional quantum wave packet, consisting in a self-similar evolution to be satisfied on average, i.e. by integrating over the coordinates. A direct comparison with the solution ... More

Driven-dissipative Bose-Einstein condensation of just a few photonsNov 29 2017Coherence and correlations are defining features of quantum condensates. These condensates are inherently multimode phenomena and in the macroscopic limit it becomes extremely difficult to resolve populations of individual modes and correlations among ... More

Signatures of the Many-body Localized Regime in Two DimensionsNov 07 2017Lessons from Anderson localization highlight the importance of dimensionality of real space for localization due to disorder. More recently, studies of many-body localization have focussed on the phenomena in one dimension using techniques of exact diagonalization ... More

Resonant persistent currents for ultracold bosons on a lattice ringOct 24 2017Dec 21 2017We consider a one-dimensional bosonic gas on a ring lattice, in the presence of a localized barrier, and under the effect of an artificial gauge field. By means of exact diagonalization we study the persistent currents at varying interactions and barrier ... More

Anisotropic polarizability of erbium atomsOct 19 2017Oct 20 2017We report on the determination of the dynamical polarizability of ultracold erbium atoms in the ground and in one excited state at three different wavelengths, which are particularly relevant for optical trapping. Our study combines experimental measurements ... More

Optimal Matterwave GravimetryOct 17 2017We calculate quantum and classical Fisher informations for gravity sensors based on matterwave interference, and find that current Mach-Zehnder interferometry is not optimally extracting the full metrological potential of these sensors. We show that by ... More

Observation of Feshbach resonances between alkali and closed-shell atomsOct 09 2017Magnetic Feshbach resonances are an invaluable tool for controlling ultracold atoms and molecules. They can be used to tune atomic interactions and have been used extensively to explore few- and many-body phenomena. They can also be used for magnetoassociation, ... More

Photons and polaritons in a time-reversal-broken non-planar resonatorAug 31 2017Dec 01 2017From generation of backscatter-free transmission lines, to optical isolators, to chiral Hamiltonian dynamics, breaking time-reversal symmetry is a key tool for development of next-generation photonic devices and materials. Of particular importance is ... More

Chimera patterns in conservative systems and ultracold atoms with mediated nonlocal hoppingAug 15 2017Chimera patterns, characterized by coexisting regions of phase coherence and incoherence, have so far been studied in non-conservative systems with dissipation. Here, we show that the formation of chimera patterns can also be observed in conservative ... More

Localized magnetic moments with tunable spin exchange in a gas of ultracold fermionsAug 12 2017We report on the experimental realization of a state-dependent lattice for a two-orbital fermionic quantum gas with strong interorbital spin exchange. In our state-dependent lattice, the ground and metastable excited electronic states of $^{173}$Yb take ... More

Entanglement between two spatially separated atomic modesAug 08 2017Modern quantum technologies in the fields of quantum computing, quantum simulation and quantum metrology require the creation and control of large ensembles of entangled particles. In ultracold ensembles of neutral atoms, highly entangled states containing ... More

Endoscopic imaging of quantum gases through a fiber bundleAug 07 2017We use a coherent fiber bundle to demonstrate the endoscopic absorption imaging of quantum gases. We show that the fiber bundle introduces spurious noise in the picture mainly due to the strong core-to-core coupling. By direct comparison with free-space ... More

Quarter-Flux Hofstadter Lattice in Qubit-Compatible Microwave Cavity ArrayAug 04 2017Nov 14 2017Topological- and strongly-correlated- materials are exciting frontiers in condensed matter physics, married prominently in studies of the fractional quantum hall effect [1]. There is an active effort to develop synthetic materials where the microscopic ... More

AC Stark Effect in Ultracold Polar RbCs MoleculesAug 02 2017We investigate the effect of far-off-resonant trapping light on ultracold bosonic RbCs molecules. We use kHz-precision microwave spectroscopy to measure the differential AC Stark shifts between the ground and first excited rotational levels of the molecule ... More

Observation of Bose-enhanced photoassociation productsAug 01 2017We produce ${^{84}\mathrm{Sr}_2}$ molecules using Bose-enhanced Raman photoassociation. We apply the stimulated Raman adiabatic passage (STIRAP) technique on a Bose-Einstein condensate (BEC) to produce more than $8 \times 10^3$ ultracold molecules. This ... More

Spectroscopic determination of magnetic-field-dependent interactions in an ultracold Yb(3P2)-Li mixtureAug 01 2017Sep 19 2017We present experimental results on the inelastic and elastic interspecies interactions between ytterbium (Yb) in the metastable ${}^3\mathrm{P}_2$ state loaded into a deep optical lattice and spin polarized lithium (Li) in its ground state. Focusing on ... More

Multi-second magnetic coherence in a single domain spinor Bose-Einstein condensateJul 30 2017We describe a compact, robust and versatile system for studying magnetic dynamics in a spinor Bose-Einstein condensate. Condensates of 87 Rb are produced by all-optical evaporation in a 1560 nm optical dipole trap, using a non-standard loading sequence ... More

Strongly correlated one-dimensional Bose-Fermi quantum mixtures: symmetry and correlationsJul 28 2017We consider multi-component quantum mixtures (bosonic, fermionic, or mixed) with strongly repulsive contact interactions in a one-dimensional harmonic trap. In the limit of infinitely strong repulsion and zero temperature, using the class-sum method, ... More

A steady-state magneto-optical trap with 100 fold improved phase-space densityJul 17 2017Sep 28 2017We demonstrate a continuously loaded $^{88}\mathrm{Sr}$ magneto-optical trap (MOT) with a steady-state phase-space density of $1.3(2) \times 10^{-3}$. This is two orders of magnitude higher than reported in previous steady-state experiments. Our approach ... More

Probing many-body dynamics on a 51-atom quantum simulatorJul 13 2017Nov 30 2017Controllable, coherent many-body systems can provide insights into the fundamental properties of quantum matter, enable the realization of new quantum phases and could ultimately lead to computational systems that outperform existing computers based on ... More

Detecting topological transitions in two dimensions by Hamiltonian evolutionJul 06 2017Oct 29 2017We show that the evolution of two-component particles governed by a two-dimensional spin-orbit lattice Hamiltonian can reveal transitions between topological phases. A kink in the mean width of the particle distribution signals the closing of the band ... More

Occupation-constrained interband dynamics of a non-hermitian two-band Bose-Hubbard HamiltonianJun 29 2017The interband dynamics of a two-band Bose-Hubbard model is studied with strongly correlated bosons forming single-site double occupancies referred to as doublons. Our model for resonant doublon interband coupling exhibits interesting dynamical features ... More

Phonon mediated conversion of exciton-polaritons Rabi oscillation into THz radiationJun 12 2017Semiconductor microcavities in the strong-coupling regime exhibit an energy scale in the THz frequency range, which is fixed by the Rabi splitting between the upper and lower exciton-polariton states. While this range can be tuned by several orders of ... More

Multicomponent exciton gas in cuprous oxide: cooling behaviour and the role of Auger decayMay 24 2017In this paper we present a hydrodynamic model to describe the dynamics of para- and orthoexcitons in cuprous oxide at ultralow temperatures inside a stress induced potential trap. We take into account the finite lifetime of the excitons, the excitation ... More

A Strongly Interacting Polaritonic Quantum DotMay 21 2017Polaritons are an emerging platform for exploration of synthetic materials [1] and quantum information processing [2] that draw properties from two disparate particles: a photon and an atom. Cavity polaritons are particularly promising, as they are long-lived ... More

Observation of the Roton Mode in a Dipolar Quantum GasMay 19 2017The concept of a roton, a special kind of elementary excitation, forming a minimum of energy at finite momentum, has been essential to understand the properties of superfluid $^4$He. In quantum liquids, rotons arise from strong interparticle interactions, ... More

Spin dependent inelastic collisions between metastable state two-electron atoms and ground state alkali-atomsMay 19 2017Nov 02 2017Experimentally the spin dependence of inelastic collisions between ytterbium (Yb) in the metastable 3P0 state and lithium (Li) in the Li ground state manifold is investigated at low magnetic fields. Using selective excitation all magnetic sublevels mJ ... More

Universality and tails of long range interactions in one dimensionMay 11 2017Long-range interactions and, in particular, two-body potentials with power-law long-distance tails are ubiquitous in nature. For two bosons or fermions in one spatial dimension, the latter case being formally equivalent to three-dimensional $s$-wave scattering, ... More

The onset of nanoscale dissipation in superfluid He-4 at zero temperature: the role of vortex shedding and cavitationMay 09 2017Two-dimensional flow past an infinitely long cylinder of nanoscopic radius in superfluid He-4 at zero temperature is studied by time-dependent density functional theory. The calculations reveal two distinct critical phenomena for the onset of dissipation: ... More

Decondensation in non-equilibrium photonic condensates: when less is moreMay 05 2017Aug 17 2017We investigate the steady state of a system of photons in a pumped dye-filled microcavity. By varying pump and thermalization the system can be tuned between Bose-Einstein condensation, multimode condensation, and lasing. We present a rich non-equilibrium ... More

A connection between non-local one-body and local three-body correlations of the Lieb-Liniger modelMay 05 2017Jul 20 2017We derive a connection between the fourth coefficient of the short-distance Taylor expansion of the one-body correlation function, and the local three-body correlation function of the Lieb-Liniger model of $\delta$-interacting spinless bosons in one dimension. ... More

Thermalization of isolated Bose-Einstein condensates by dynamical heat bath generationMay 04 2017Dec 16 2017If and how an isolated quantum system thermalizes despite its unitary time evolution is a long-standing, open problem of many-body physics. The eigenstate thermalization hypothesis (ETH) postulates that thermalization happens at the level of individual ... More

Efficient production of long-lived ultracold Sr$_2$ moleculesMay 03 2017Jul 22 2017We associate Sr atom pairs on sites of a Mott insulator optically and coherently into weakly-bound ground-state molecules, achieving an efficiency above 80\%. This efficiency is 2.5 times higher than in our previous work [S. Stellmer, B. Pasquiou, R. ... More

Strongly repulsive anyons in one dimensionApr 24 2017Jun 26 2017To explore the static properties of the one-dimensional anyon-Hubbard model for a mean density of one particle per site, we apply perturbation theory with respect to the ratio between kinetic energy and interaction energy in the Mott insulating phase. ... More

Interspecies thermalization in an ultracold mixture of Cs and Yb in an optical trapApr 11 2017Jul 16 2017We present measurements of interspecies thermalization between ultracold samples of $^{133}$Cs and either $^{174}$Yb or $^{170}$Yb. The two species are trapped in a far-off-resonance optical dipole trap and $^{133}$Cs is sympathetically cooled by Yb. ... More

Dissipation in mesoscale superfluidsApr 06 2017We investigate the maximum speed at which a driven superfluid can flow through a narrow constriction with a size on the order of the healing length. Considering dissipation via the thermal nucleation of quantized vortices, we calculate the critical velocity ... More

Multi-mode Bose-Hubbard model for quantum dipolar gases in confined geometriesApr 04 2017We theoretically consider ultracold polar molecules in a wave guide. The particles are bosons, they experience a periodic potential due to an optical lattice oriented along the wave guide and are polarised by an electric field orthogonal to the guide ... More

Tunable third-harmonic generation from polaritons in the ultrastrong coupling regimeMar 24 2017Strong inter-particle interactions between polaritons have traditionally stemmed from their exciton component. In this work, we impart a strong photonic nonlinearity to a polaritonic mode by embedding a nonlinear polymethine dye within a high-Q all-metal ... More

Ultracold atoms in quasi-1D traps: a step beyond the Lieb-Liniger modelMar 24 2017Ultracold atoms placed in a tight cigar-shaped trap are usually described in terms of the Lieb-Liniger model. We study the extensions of this model which arise when van der Waals interaction between atoms is taken into account. We find that the corrections ... More

Photo-association of trilobite Rydberg molecules via resonant spin-orbit couplingMar 03 2017May 04 2017We report on a novel method for photo-association of strongly polar trilobite Rydberg molecules. This exotic ultralong-range dimer, consisting of a ground-state atom bound to the Rydberg electron via electron-neutral scattering, inherits its polar character ... More

Quantum Noise in Bright Soliton Matterwave InterferometryMar 01 2017Nov 17 2017There has been considerable recent interest in matterwave interferometry with bright solitons in quantum gases with attractive interactions, for applications such as rotation sensing. We model the quantum dynamics of these systems and find that the attractive ... More