arXiv subjects

Marija Šindik

Publications and source records attributed to Marija Šindik.

4 recordsLinked to original sources

arXiv2025

Anomalous Doppler effect in superfluid and supersolid atomic gases

By employing the formalism of hydrodynamics, we derive novel analytic predictions for the Doppler effect in superfluids with broken Galilean invariance and hosting persistent currents at zero temperature. We consider two scenarios: when Galilean invariance is broken explicitly (by external potentials) and spontaneously, as it happens in a supersolid. In the former case, the presence of a stationary current affects the propagation of sound via an anomalous Doppler term proportional to the density derivative of the superfluid fraction. In supersolids, where, according to Goldstone theorem, distinct sounds of hybrid superfluid and crystal nature can propagate, the Doppler effect can be very different for each sound. Quantitative estimates of the Doppler shifts are obtained for Bose-Einstein condensed atomic gases, described by Gross-Pitaevskii theory. The estimates are obtained both calculating the thermodynamic parameters entering the hydrodynamic results, and from full time-dependent simulations.

cond-mat.quant-gas↗

arXiv2024

Sound, superfluidity and layer compressibility in a ring dipolar supersolid

We propose a protocol to excite the Goldstone modes of a supersolid dipolar Bose-Einstein condensed gas confined in a ring geometry. By abruptly removing an applied periodic modulation proportional to cos($φ$), where $φ$ is the azimuthal angle, we explore the resulting oscillations of the gas, by solving the extended Gross-Pitaevskii equation. The value of the two longitudinal sound velocities exhibited in the supersolid phase are analyzed using the hydrodynamic theory of supersolids at zero temperature. This approach allows for the determination of the layer compressibility modulus as well as of the superfluid fraction $f_S$, in agreement with the Leggett estimate of the non-classical moment of inertia.

cond-mat.quant-gas↗

arXiv2022

Creation and robustness of quantized vortices in a dipolar supersolid when crossing the superfluid-to-supersolid transition

Experiments on dipolar Bose-Einstein condensates have recently reported the observation of supersolidity. Although quantized vortices constitute a key probe of superfluidity, their observability in dipolar supersolids is largely prevented by the strong density depletion caused by the formation of droplets. We present a novel approach to the nucleation of vortices and their observation, based on the quenching of the s-wave scattering length across the superfluid-supersolid transition. Starting from a slowly rotating, vortex-free, configuration in the superfluid phase, we predict vortex nucleation as the system enters the supersolid phase, due to the strong reduction of the critical angular velocity in the supersolid. Once a vortex is created, we show that it is robustly preserved when the condensate is brought back to the superfluid phase, where it may be readily observed.

cond-mat.quant-gas↗

arXiv2018

Periodic three-body orbits in the Coulomb potential

We numerically discovered around 100 distinct nonrelativistic collisionless periodic three-body orbits in the Coulomb potential in vacuo, with vanishing angular momentum, for equal-mass ions with equal absolute values of charges. These orbits are classified according to their symmetry and topology, and a linear relation is established between the periods, at equal energy, and the topologies of orbits. Coulombic three-body orbits can be formed in ion traps, such as the Paul, or the Penning one, where one can test the period vs topology prediction.

physics.comp-ph↗