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Maciej Lewkowicz

Publications and source records attributed to Maciej Lewkowicz.

3 recordsLinked to original sources

Three-dimensional Bose-Fermi droplets at nonzero temperatures

Using numerical methods, we study the formation of self-bound quantum Bose-Fermi droplets at nonzero temperatures. We describe an attractive atomic Bose-Fermi mixture using quantum hydrodynamics enriched by beyond-mean-field corrections and thermal fluctuations, together with a simplified self-consistent Hartree-Fock model. With these models, we determine that low-temperature droplets with finite lifetimes can exist in free space when the attraction between bosons and fermions is sufficiently strong. Additionally, Bose-Fermi droplets at nonzero temperatures can exist in a box potential in equilibrium with bosonic and fermionic vapor. We discuss the properties of Bose-Fermi droplets at nonzero temperatures in terms of the initial condensate fraction, total atom number, and interspecies attraction strength.

cond-mat.quant-gas

Dynamic formation of supersolid phase in a mixture of ultracold bosonic and fermionic atoms

We numerically study the dynamical properties of a mixture consisting of a dipolar condensate and a degenerate Fermi gas in a quasi-one-dimensional geometry. In particular, we focus on the system's response to a temporal variation in the interaction strength between bosons and fermions. When the interspecies attraction becomes sufficiently strong, we observe a phase transition to a supersolid state. This conclusion is supported by the emergence of an out-of-phase Goldstone mode in the excitation spectrum.

cond-mat.quant-gas

Supersolidity of dipolar Bose-Einstein condensates induced by coupling to fermions

We study a mixture of a repulsive dipolar condensate and a degenerate Fermi gas in a quasi-one-dimensional geometry. We demonstrate that the presence of fermions, which attract bosons, drastically changes the behavior of the dipolar condensate. For strong enough boson-fermion attraction, a dipolar Bose-Fermi droplet appears in the mixture, and as the attraction becomes stronger, a roton excitation develops in the Bogoliubov spectrum, leading to the formation of a supersolid, and eventually a crystal of isolated droplets. We describe the system by coupled extended Gross-Pitaevskii (bosons) and Hartree-Fock (fermions) equations. We study the excitation spectrum of the system and identify a number of Goldstone and Higgs modes in the supersolid regime.

cond-mat.quant-gas