Self-bound quantum droplets are a newly discovered phase in the context of ultracold atoms. In this Letter, we report their experimental realization following original proposal by Petrov [Phys. Rev. Lett. 115, 155302 (2015)PRLTAO0031-900710.1103/PhysRevLett.115.155302], using an attractive bosonic mixture. system, spherical form due to balance competing and repulsive forces, provided mean-field energy close collapse threshold first-order correction fluctuations. Thanks optical levitating...

We report on the study of binary collisions between quantum droplets formed by an attractive mixture ultracold atoms. distinguish two main outcomes collision, i.e., merging and separation, depending velocity colliding pair. The critical ${v}_{c}$ that discriminates cases displays a different dependence atom number $N$ for small large droplets. By comparing our experimental results with numerical simulations, we show nonmonotonic behavior ${v}_{c}(N)$ is due to crossover from compressible...

We want to characterize the dynamical state of galaxy clusters detected with Sunyaev–Zeldovich (SZ) effect by Planck and compare them selected in X-rays survey. analysed a representative subsample SZ catalogue, containing 132 highest signal noise ratio their using as an indicator projected offset between peak X-ray emission position Brightest cluster galaxy. distribution this for SZ-selected sample three X-ray-selected samples (HIFLUGCS, MACS REXCESS). The distributions are significantly...

We explore the interplay between tunneling and interatomic interactions in dynamics of a bosonic Josephson junction. tune scattering length an atomic $^{39}$K Bose-Einstein condensate confined double-well trap to investigate regimes inaccessible other superconducting or superfluid systems. In limit small-amplitude oscillations, we study transition from Rabi plasma oscillations by crossing over attractive repulsive interactions. observe critical slowing down oscillation frequency increasing...

We experimentally study resonant light scattering by a one-dimensional randomly filled chain of cold two-level atoms. By local measurement the scattered along chain, we observe constructive interferences in light-induced dipole-dipole interactions between They lead to shift collective resonance despite average interatomic distance being larger than wavelength light. This result demonstrates that strong effects can be enhanced structuring geometrical arrangement ensemble. also explore high...

We report the experimental observation of a superradiant emission emanating from an elongated dense ensemble laser cooled two-level atoms, with radial extent smaller than transition wavelength. In presence strong driving laser, we observe that system is along its symmmetry axis. This occurs even though orthogonal to superradiance direction. modifies spontaneous emission, and, resultantly, Rabi oscillations. also investigate Dicke in almost fully inverted as function atom number. The results...

We report experimental measurements of the second-order coherence function ${g}^{(2)}(\ensuremath{\tau})$ light emitted by a laser-driven dense ensemble $^{87}\mathrm{Rb}$ atoms. observe clear departure from Siegert relation valid for Gaussian chaotic light. Measuring intensity and first-order coherence, we conclude that violation is not due to emergence coherent field. This indicates obeys non-Gaussian statistics, stemming correlations in atomic medium. More specifically, steady state this...

The driven Dicke model, wherein an ensemble of atoms is by external field and undergoes collective spontaneous emission due to coupling a leaky cavity mode, paradigmatic example system exhibiting driven-dissipative phase transition as function driving strength. Recently, similar phenomenon was experimentally observed, not in setting, but rather free-space atomic ensemble. reason why behavior should emerge free space obvious, the interacts with continuum optical modes, which encodes...

We report the observation of subradiance in dense ensembles cold Rb87 atoms operating near Dicke's regime a large number volume with dimensions smaller than transition wavelength. validate that atom is only cooperativity parameter governing subradiance. probe dynamics many-body and support picture multiply excited subradiant states are built as superposition singly decay independently. Moreover, we implement an experimental procedure to release excitation stored long-lived modes pulse light....

We report the experimental realization of a new kind optical lattice for ultracold atoms where arbitrarily large separation between sites can be achieved without renouncing to stability ordinary lattices. Two collinear lasers, with slightly different commensurate wavelengths and retroreflected on mirror, generate superlattice potential periodic ``beat-note'' profile regions amplitude modulation provide effective minima atoms. To prove analogy standard spacing we study Bloch oscillations Bose...

We report a time-resolved study of collective emission in dense ensembles two-level atoms. compare, on the same sample, buildup superradiance and subradiance from ensemble when driven by strong laser. This allows us to measure dynamics population superradiant subradiant states as function time. In particular, we demonstrate time through dynamics. illustrates many-body density matrix atoms departing ideal conditions Dicke superradiance, which symmetry forbids states.

Ultra-cold atomic systems are among the most promising platforms that have potential to shed light on complex behavior of many-body quantum systems. One prominent example is case a dense ensemble illuminated by strong coherent drive while interacting via dipole-dipole interactions. Despite being subjected intense investigations, this system retains many open questions. A recent experiment carried out in pencil-shaped geometry reported measurements seemed consistent with emergence collective...

We report the efficient and fast ($\sim 2\mathrm{Hz}$) preparation of randomly loaded 1D chains individual $^{87}$Rb atoms dense atomic clouds trapped in optical tweezers using a new experimental platform. This platform is designed for study both structured disordered systems free space. It composed two high-resolution perpendicular to each other, enhancing observation manipulation capabilities. The setup includes dynamically controllable telescope, which we use vary tweezer beam waist. A D1...

The authors investigate the dynamics involved in formation of atomic quantum droplets. By performing numerical simulations, they analyze so-called self-evaporation mechanism that allows dissipation initial excitations, as well effect other losses mechanisms.

A class of systems exists in which dissipation, external drive and interactions compete give rise to non equilibrium phases that would not exist without the drive. There, phase transitions could occur breaking any symmetry, yet with a local order parameter, contrast Landau theory at equilibrium. One simplest driven dissipative quantum consists two-level atoms enclosed volume smaller than wavelength atomic transition cubed, by light field. The competition between collective coupling driving...

We investigate the evolution of second-order temporal coherence during emission a superradiant burst by an elongated cloud cold Rb atoms in free space. To do so, we measure two-times intensity correlation function $g_N^{(2)}(t_1, t_2)$ following pulsed excitation cloud. By monitoring $g_N^{(2)}(t, t)$ burst, observe establishment coherence, and contrast it with situation where is initially prepared steady state. compare our findings to predictions Dicke model, using effective atom number...

We study the ultimate bounds on sensitivity of a Bloch-oscillation atom interferometer where external force is estimated from measurement on-site atomic density. For forces such that energy difference between lattice sites smaller than tunneling energy, wave function spreads over many sites, increasing separation occupied modes and naturally enhancing interferometer. To investigate applicability this scheme we estimate effect uncontrolled fluctuations finite resolution detection. Our...

We report experimental measurements of the second-order coherence function $g^{(2)}(\tau)$ light emitted by a laser-driven dense ensemble $^{87}$Rb atoms. observe clear departure from Siegert relation valid for Gaussian chaotic light. Measuring intensity and first-order coherence, we conclude that violation is not due to emergence coherent field. This indicates obeys non-Gaussian statistics, stemming correlations in atomic medium. More specifically, steady-state this driven-dissipative...

We study the ultimate bounds on sensitivity of a Bloch-oscillation atom interferometer where external force is estimated from measurement on-site atomic density. For forces such that energy difference between lattice sites smaller than tunneling energy, wave-function spreads over many sites, increasing separation occupied modes and naturally enhancing interferometer. To investigate applicability this scheme we estimate effect uncontrolled fluctuations finite resolution detection. Our...