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Ferran Mazzanti

Bio: Ferran Mazzanti is an academic researcher from Polytechnic University of Catalonia. The author has contributed to research in topics: Diffusion Monte Carlo & Ground state. The author has an hindex of 14, co-authored 66 publications receiving 693 citations. Previous affiliations of Ferran Mazzanti include Johannes Kepler University of Linz & Ramon Llull University.


Papers
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Journal ArticleDOI
08 Nov 2019
TL;DR: In this article, the authors used a model based on the Gross-Pitaevskii equation and quantum Monte-Carlo simulations combined with experimental results to show that quantum correlations in dipolar quantum droplets are not negligible and play a role in the onset of an observable shift in the critical atom number of the self-bound state.
Abstract: The authors use a model based on the Gross-Pitaevskii equation and quantum Monte-Carlo simulations, combined with experimental results, to show that quantum correlations in dipolar quantum droplets are not negligible and play a role in the onset of an observable shift in the critical atom number of the self-bound state.

92 citations

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TL;DR: By adding a repulsive two-body potential, this work finds a narrow window of interaction parameters leading to stable ground-state configurations of droplets in a crystalline arrangement without resorting to additional stabilizing mechanisms or specific three-body forces.
Abstract: Strongly interacting systems of dipolar bosons in three dimensions confined by harmonic traps are analyzed using the exact path integral ground-state Monte Carlo method. By adding a repulsive two-body potential, we find a narrow window of interaction parameters leading to stable ground-state configurations of droplets in a crystalline arrangement. We find that this effect is entirely due to the interaction present in the Hamiltonian without resorting to additional stabilizing mechanisms or specific three-body forces. We analyze the number of droplets formed in terms of the Hamiltonian parameters, relate them to the corresponding s-wave scattering length, and discuss a simple scaling model for the density profiles. Our results are in qualitative agreement with recent experiments showing a quantum Rosensweig instability in trapped Dy atoms.

74 citations

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TL;DR: In this article, a variational hypernetted-chain Euler-Lagrange method was used to study liquid Bose mixtures with uniform density and showed that these mixtures are stable only in a narrow range near an optimal ratio near the total energy minimum.
Abstract: Recent experiments confirmed that fluctuations beyond the mean-field approximation can lead to self-bound liquid droplets of ultradilute binary Bose mixtures. We proceed beyond the beyond-mean-field approximation and study liquid Bose mixtures by using the variational hypernetted-chain Euler--Lagrange method, which accounts for correlations nonperturbatively. Focusing on the case of a mixture of uniform density, as realized inside large saturated droplets, we study the conditions for stability against evaporation of one of the components (both chemical potentials need to be negative) and against liquid-gas phase separation (spinodal instability), the latter being accompanied by a vanishing speed of sound. Dilute Bose mixtures are stable only in a narrow range near an optimal ratio ${\ensuremath{\rho}}_{1}/{\ensuremath{\rho}}_{2}$ and near the total energy minimum. Deviations from a universal dependence on the $s$-wave scattering lengths are significant despite the low density.

58 citations

Journal ArticleDOI
TL;DR: This work calculates the dynamic structure function in the gas phase which shows the anisotropic dispersion of the excitations and finds that the energy of roton excitations in the strongly interacting direction decreases with increasing polarization angle and almost vanishes close to the instability.
Abstract: We present calculations of the ground state and excitations of an anisotropic dipolar Bose gas in two dimensions, realized by a nonperpendicular polarization with respect to the system plane. For sufficiently high density, an increase of the polarization angle leads to a density instability of the gas phase in the direction where the anisotropic interaction is strongest. Using a dynamic many-body theory, we calculate the dynamic structure function in the gas phase which shows the anisotropic dispersion of the excitations. We find that the energy of roton excitations in the strongly interacting direction decreases with increasing polarization angle and almost vanishes close to the instability. Exact path integral ground state Monte Carlo simulations show that this instability is indeed a quantum phase transition to a stripe phase, characterized by long-range order in the strongly interacting direction.

55 citations

Journal ArticleDOI
TL;DR: In this paper, the Bose gas with contact interaction in optical lattices at zero temperature is investigated by means of the exact diffusion Monte Carlo algorithm, and the results obtained from the fundamental continuous model are compared with those obtained from lattice (discrete) Bose-Hubbard model, using exact diagonalization, and from the quantum sine-Gordon model.
Abstract: One-dimensional Bose gas with contact interaction in optical lattices at zero temperature is investigated by means of the exact diffusion Monte Carlo algorithm. The results obtained from the fundamental continuous model are compared with those obtained from the lattice (discrete) Bose-Hubbard model, using exact diagonalization, and from the quantum sine-Gordon model. We map out the complete phase diagram of the continuous model and determine the regions of applicability of the Bose-Hubbard model. Various physical quantities characterizing the systems are calculated, and it is demonstrated that the sine-Gordon model used for shallow lattices is inaccurate.

54 citations


Cited by
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Proceedings Article
14 Jul 1996
TL;DR: The striking signature of Bose condensation was the sudden appearance of a bimodal velocity distribution below the critical temperature of ~2µK.
Abstract: Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

3,530 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the recent theoretical and experimental advances in the study of ultra-cold gases made of bosonic particles interacting via the long-range, anisotropic dipole-dipole interaction, in addition to the short-range and isotropic contact interaction usually at work in ultracold gases is presented.
Abstract: This paper reviews the recent theoretical and experimental advances in the study of ultra-cold gases made of bosonic particles interacting via the long-range, anisotropic dipole–dipole interaction, in addition to the short-range and isotropic contact interaction usually at work in ultra-cold gases. The specific properties emerging from the dipolar interaction are emphasized, from the mean-field regime valid for dilute Bose–Einstein condensates, to the strongly correlated regimes reached for dipolar bosons in optical lattices. (Some figures in this article are in colour only in the electronic version)

1,230 citations

Journal ArticleDOI
TL;DR: The physics of one-dimensional interacting bosonic systems is reviewed in this paper, where the effects of various perturbations on the Tomonaga-Luttinger liquid state are discussed as well as extensions to multicomponent and out of equilibrium situations.
Abstract: The physics of one-dimensional interacting bosonic systems is reviewed. Beginning with results from exactly solvable models and computational approaches, the concept of bosonic Tomonaga-Luttinger liquids relevant for one-dimensional Bose fluids is introduced, and compared with Bose-Einstein condensates existing in dimensions higher than one. The effects of various perturbations on the Tomonaga-Luttinger liquid state are discussed as well as extensions to multicomponent and out of equilibrium situations. Finally, the experimental systems that can be described in terms of models of interacting bosons in one dimension are discussed.

907 citations

Journal ArticleDOI
TL;DR: Baranov et al. as mentioned in this paper proposed a method for quantum Optics and Quantum Information of the Austrian Academy of Sciences (A-6020 Innsbruck, Austria).
Abstract: M. A. Baranov,†,‡,§ M. Dalmonte,†,⊥ G. Pupillo,†,‡,∇ and P. Zoller*,†,‡ †Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria ‡Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria RRC “Kurchatov Institute”, Kurchatov Square 1, 123182, Moscow, Russia Dipartimento di Fisica dell’Universita di Bologna, via Irnerio 46, 40126 Bologna, Italy ISIS (UMR 7006) and IPCMS (UMR 7504), Universite de Strasbourg and CNRS, Strasbourg, France

492 citations