Article
Physics, Multidisciplinary
Chao Zhang, Barbara Capogrosso-Sansone, Massimo Boninsegni, Nikolay V. Prokofev, Boris V. Svistunov
Summary: We present results of numerically exact simulations of the Bose one-component plasma, i.e., a Bose gas with pairwise Coulomb interactions among particles and a uniform neutralizing background. We compute the superconducting transition temperature for a wide range of densities, in two and three dimensions, for both continuous and lattice versions of the model. The Coulomb potential causes the weakly interacting limit to be approached at high density, but gives rise to no qualitatively different behavior, vis-à-vis the superfluid transition, with respect to short-ranged interactions. Our results are of direct relevance to quantitative studies of bipolaron mechanisms of (high-temperature) superconductivity.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Matteo Barborini, Matteo Calandra, Francesco Mauri, Ludger Wirtz, Pierluigi Cudazzo
Summary: This work investigates the purely electronic instability in one-dimensional semimetals independent of a lattice distortion by accurate ab initio calculations on one-dimensional carbon chain and monatomic hydrogen chain based on quantum Monte Carlo and hybrid density functional theory.
Article
Physics, Multidisciplinary
Ivan P. Christov
Summary: The time-dependent quantum Monte Carlo method is used to calculate the entanglement of electrons in one-dimensional quantum dots with various spin configurations. The study finds that the spatial entanglement differs in parallel-spin and spin-compensated cases, with outermost opposite-spin electrons behaving like bosons in the latter case. The results are consistent with numerically exact results where comparison is possible.
Article
Physics, Multidisciplinary
Shuhui Yang, Tao Ying, Xiudong Sun
Summary: This study investigates the quantum behaviors of hardcore bosons with finite-range interactions in one-dimensional optical lattices using the Quantum Monte Carlo algorithm. It reveals a phase transition from superfluid to supersolid and finally to CDW phase as the interaction strength increases, while also examining the effects of finite temperature and finite size.
Article
Optics
Tobias Ilg, Hans Peter Buechler
Summary: We study the behavior of the excitation spectrum across the quantum phase transition from a superfluid to a supersolid phase of a dipolar Bose gas in one dimension. Using an effective Hamiltonian that includes beyond-mean-field effects, we analyze the system based on Bogoliubov theory with multiple order parameters. Our results show that the supersolid phase exhibits a stable excitation spectrum with Goldstone modes and an amplitude mode in the low-energy regime, and the transition into the supersolid phase is driven by the roton instability in a parameter regime achievable for dysprosium atoms.
Article
Materials Science, Multidisciplinary
Jiangyong Yu, Ethan Lauricella, Mohamed Elsayed, Kenneth Shepherd, Nathan S. Nichols, Todd Lombardi, Sang Wook Kim, Carlos Wexler, Juan M. Vanegas, Taras Lakoba, Valeri N. Kotov, Adrian Del Maestro
Summary: An effective Bose-Hubbard model is constructed for a system of bosons, such as helium adsorbed on graphene, taking into account strong correlations and the precise lattice structure for tuning quantum phase transitions in the solid-state system.
Article
Materials Science, Multidisciplinary
Massimo Boninsegni
Summary: Theoretical studies through computer simulations on metastable liquid mixtures of parahydrogen and orthodeuterium show no reduced propensity for crystallization compared to pure liquid parahydrogen, and no demixing of the two species as a precursor of crystallization.
RESULTS IN PHYSICS
(2021)
Article
Mechanics
M. Beljin-Cavic, I Loncarevic, Lj Budinski-Petkovic, Z. M. Jaksic, S. B. Vrhovac
Summary: This study uses Monte Carlo simulations to investigate the random sequential adsorption of mixtures of objects with varying shapes on a three-dimensional cubic lattice. The research focuses on the influence of geometrical properties of the shapes on the jamming coverage and temporal evolution of density. The results show that the coverage approaches the jamming limit exponentially and the relaxation time is determined by the number of orientations the objects can take on the lattice. The jamming coverage of a mixture can be greater than or in between the jamming coverages of the single-component shapes, depending on the local geometry.
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2022)
Article
Physics, Multidisciplinary
Yaoqi Tian, Junqiao Pan, Tao Shi, Su Yi
Summary: We investigate the ground-state properties and dynamics of quasi-one-dimensional quantum droplets of binary Bose condensates using Gaussian state theory. The study shows the presence of three quantum phases in the ground state, including a coherent state and two macroscopic squeezed states. It is also found that by tuning the reduced scattering length to a negative value, a significant fraction of atoms can be transferred from a coherent state to a macroscopic squeezed state. This research opens up the possibility of generating macroscopic squeezed states using binary condensates.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Jun Hui See Toh, Katherine C. McCormick, Xinxin Tang, Ying Su, Xi-Wang Luo, Chuanwei Zhang, Subhadeep Gupta
Summary: In this study, the evolution of dynamically localized states in an interacting one-dimensional ultracold gas periodically kicked by a pulsed optical lattice was experimentally studied. The interaction was found to lead to the emergence of dynamical delocalization and many-body quantum chaos.
Article
Physics, Multidisciplinary
Hao Xie, Linfeng Zhang, Lei Wang
Summary: The newly developed neural canonical transformation approach provides a principled way to extract the effective mass of electron gas by calculating the thermal entropy at low temperature. Calculation reveals a suppression of effective mass in the two-dimensional spin-polarized electron gas, which is more pronounced than previous reports, and calls for experimental verification.
Article
Materials Science, Multidisciplinary
Massimo Boninsegni
Summary: The ground state of a free-standing droplet consisting of four hundred dipolar Bose particles with aligned dipole moments and an additional repulsive interaction was investigated using Quantum Monte Carlo simulations. The study identified a classical regime where binding is exclusively from the dipolar potential energy and a quantum regime of prolate droplets held together by quantum-mechanical exchanges, with an abrupt transition between the two regimes.
RESULTS IN PHYSICS
(2021)
Article
Mathematics, Applied
Argha Debnath, Ayan Khan, Boris Malomed
Summary: This study investigates the static and dynamical properties of one-dimensional quantum droplets under the influence of local potentials in the form of narrow wells and barriers. The dynamics of the droplets are described by the one-dimensional Gross-Pitaevskii equation, including meanfield and beyond-mean-field terms. Stable solutions for localized states pinned to the well are found, and approximations for the well and the collision of the droplet with the barrier are developed. Simulations analyze the collisions of droplets with the wells and barriers, identifying outcomes such as fission and rebound effects.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2023)
Article
Optics
Raul Bombin, Viktor Cikojevic, Juan Sanchez-Baena, Jordi Boronat
Summary: This study focuses on the repulsive Fermi polaron in a two-component, two-dimensional system of fermionic atoms, investigating properties such as polaron energy, quasiparticle residue, and effective mass using the diffusion Monte Carlo method. The results highlight the importance of considering the effective range and scattering length to reproduce experimental results, as well as the establishment of universality through different model potentials for the interaction between the Fermi sea and the impurity. This underscores the significance of quantum fluctuations and beyond mean-field effects in accurately describing the Fermi polaron problem.
Article
Physics, Fluids & Plasmas
A. A. Danshin, A. A. Kovalishin, M. Gurevich
Summary: The paper focuses on studying the nodal surfaces of wave functions for fermion systems. By using the quantum Monte Carlo method, implicit equations for nodal surfaces in s-electron systems with two to five electrons are obtained numerically. The obtained results are consistent with the findings of other researchers. The paper proposes an original method for constructing nodal surfaces that is convenient for implementing quantum Monte Carlo.
Article
Physics, Multidisciplinary
Ivan Morera, Grigori E. Astrakharchik, Artur Polls, Bruno Julia-Diaz
Summary: This study investigates the ground-state properties of two-component bosonic mixtures in a one-dimensional optical lattice, revealing the formation of a quantum liquid and the fermionization of dimers under certain conditions. By deriving an effective model of composite bosons and validating it against exact results, the research sheds light on the nature and stability of the quantum liquid formation.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Grigory E. Astrakharchik, Luis A. Pena Ardila, Richard Schmidt, Krzysztof Jachymski, Antonio Negretti
Summary: The authors investigate the behavior of an ionic impurity in a weakly interacting gas of bosonic atoms and identify two main phases of a polaronic regime and a strongly correlated state with many bosons bound to the ion under weak interactions. The presence of strong interactions in a many-body quantum system can lead to exotic effects, and the competition of length scales in a simple setup can give rise to a highly correlated mesoscopic state. The findings are relevant to experiments using hybrid atom-ion setups in the ultracold regime, showing vastly different polaronic properties compared to neutral quantum impurities.
COMMUNICATIONS PHYSICS
(2021)
Article
Physics, Multidisciplinary
M. Will, G. E. Astrakharchik, M. Fleischhauer
Summary: The article presents a detailed study of heavy polarons in a one-dimensional Bose gas using a nonperturbative theory and exact numerical simulations. Analytic approaches for weak boson-boson interactions and strong impurity-boson couplings were developed, and the interaction potential of heavy polarons was found to deviate substantially from the exponential form in the strong coupling limit. Calculations of bipolaron binding energies for low impurity-boson mass ratios were in excellent agreement with quantum Monte Carlo results, taking into account Born-Huang corrections.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Maxim Olshanii, Dumesle Deshommes, Jordi Torrents, Marina Gonchenko, Vanja Dunjko, Grigori E. Astrakharchik
Summary: The study focuses on the mapping between the hydrodynamic equations governing the two-dimensional triangular cold-bosonic breathers and the high-density zero-temperature triangular free-fermionic clouds. The mapping perfectly explains the phenomenon of the former but leaves the nature of the initial singularity uninterpreted, with the map becoming invalid at certain time points.
Article
Physics, Multidisciplinary
G. Guijarro, G. E. Astrakharchik, J. Boronat
Summary: This study demonstrates the formation of ultradilute quantum liquids with ultracold bosonic dipolar atoms in a bilayer geometry. The proposed system uses dipolar interactions alone to create a self-bound state without the need for an additional short-range potential. Quantum Monte Carlo simulations reveal a diverse ground-state phase diagram with quantum phase transitions between liquid, solid, atomic gas, and molecular gas phases. The stabilization mechanism of the liquid phase involves an effective balance between dimer-dimer attraction and three-dimer repulsion, with the equilibrium density controlled by the interlayer distance.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
G. Guijarro, G. E. Astrakharchik, J. Boronat
Summary: The research team proposed a method to experimentally realize halo states containing as many as six atoms, observing the different responses of halo structures to interlayer separations and the unusual shape of halo states close to the unbinding threshold.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
Jordi Marti, Ferran Mazzanti, Grigori E. Astrakharchik, Lluis Batet, Laura Portos-Amill, Borja Pedreno
Summary: Fusion energy is a promising alternative for a decarbonised energy system. This study investigates the behavior of lithium-helium mixtures and introduces a new microscopic model to describe the formation of helium droplets, which could impact the performance of breeding blankets in future fusion nuclear reactors.
Article
Physics, Multidisciplinary
Giulia De Rosi, Riccardo Rota, Grigori E. Astrakharchik, Jordi Boronat
Summary: We report an intriguing anomaly in the temperature dependence of the specific heat of a one-dimensional Bose gas. This anomaly resembles a superfluid-to-normal phase transition observed in higher dimensions, despite phase transitions not being allowed in one dimension. The anomaly can be attributed to unpopulated states that act as an energy gap located below the hole branch in the excitation spectrum. Furthermore, thermal fluctuations at temperatures near the anomaly threshold can become comparable to the maximum hole energy, leading to a qualitative change in the excitation structure.
Article
Physics, Multidisciplinary
Ivan Morera, Rafal Oldziejewski, Grigori E. Astrakharchik, Bruno Julia-Diaz
Summary: We propose a mechanism for liquid formation in strongly correlated lattice systems by studying dipolar bosons in one-dimensional optical lattices as an example. We present a perturbative theory and validate it through simulations for the energetic and structural properties of the system's phases. We analyze the nonequilibrium properties and calculate the dynamic structure factor.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Giulia De Rosi, Riccardo Rota, Grigori E. Astrakharchik, Jordi Boronat
Summary: In this study, the effect of thermal fluctuations on correlations in a one-dimensional Bose gas with repulsive interactions is comprehensively investigated. The pair correlation function, static structure factor, and one-body density matrix are calculated using the exact ab-initio Path Integral Monte Carlo method for various interaction strengths and temperatures. A detailed comparison with different theoretical models is provided. The Monte Carlo results agree excellently with the tractable limits and serve as an important benchmark for future experiments in different platforms.
NEW JOURNAL OF PHYSICS
(2023)
Article
Multidisciplinary Sciences
Grigory E. Astrakharchik, Luis A. Pena Ardila, Krzysztof Jachymski, Antonio Negretti
Summary: In this study, using quantum Monte Carlo methods, we investigate the static properties of two ionic impurities in a bosonic bath and identify three bipolaronic regimes. We further reveal strong bath-induced interactions between the two ionic polarons. Our findings demonstrate the necessity of numerical simulations in describing highly correlated impurity models.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Korbinian Kottmann, Andreas Haller, Antonio Acin, Grigory E. Astrakharchik, Maciej Lewenstein
Summary: Recent research has identified a new phase separated phase in the extended Bose-Hubbard model in one dimension at integer filling, with superfluid and supersolid parts generated by mechanical instability. Numerical simulations reveal peculiar spatial patterns and characteristics in different phases, which persist in the thermodynamic limit. Furthermore, the low-energy spectrum of the phase can be effectively captured by a spinless Luttinger liquid, with consistent results between different analysis methods.
Article
Optics
Giulia De Rosi, Grigori E. Astrakharchik, Pietro Massignan
Summary: This study examines the low-temperature thermodynamics of weakly interacting uniform liquids in one-dimensional attractive Bose-Bose mixtures, using the Bogoliubov approach to describe quantum and thermal fluctuations. The research delves into two different thermal mechanisms driving the liquid-to-gas transition, computes key thermodynamic quantities of the liquid, and highlights the temperature-dependent nature of these quantities for their potential use as precise temperature probes in experiments on quantum liquids.
Article
Materials Science, Multidisciplinary
Yu E. Lozovik, I. L. Kurbakov, G. E. Astrakharchik, J. Boronat
Summary: The proposed method provides an accurate estimation of the condensate fraction in strongly correlated systems under various conditions, with experimental measurements confirming its effectiveness.
Article
Materials Science, Multidisciplinary
G. E. Astrakharchik, I. L. Kurbakov, D. Sychev, A. K. Fedorov, Yu E. Lozovik
Summary: Studied the ground-state phase diagram of a 2D Bose system with quadrupolar interactions, predicting a quantum phase transition and observing strong rotonization of the collective excitation branch near the transition point. Results can be probed using advanced experimental systems like quasi-2D systems of quadrupolar excitons in transition metal dichalcogenide trilayers.