Article
Optics
Liang Mao, Yajiang Hao, Lei Pan
Summary: In this paper, the non-Hermitian skin effect (NHSE) is extended from noninteracting systems to interacting many-body systems by studying an exactly solvable non-Hermitian model, the Lieb-Liniger Bose gas with imaginary vector potential. The NHSE is characterized quantitatively through solving the Bethe ansatz equations and calculating the model's density profiles and momentum distributions. It is found that the NHSE is enhanced for bound-state solutions on the attractive side, while it shows a nonmonotonic behavior for the scattering state. This work provides an example of NHSE in exactly solvable many-body systems and suggests its extension to other non-Hermitian many-body systems, particularly integrable models.
Article
Physics, Multidisciplinary
J. Settino, N. Lo Gullo, F. Plastina, A. Minguzzi
Summary: The study introduces a method to accurately evaluate the spectral function of a gas of one-dimensional bosons, showing three main singularity lines in the spectral function under lattice confinement, with the Lieb-II mode exhibiting divergence, providing a way to probe this mode in experiments with ultracold atoms.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Applied
Yajiang Hao, Yiwang Liu, Xiangguo Yin
Summary: In this study, the correlation properties of the ground state of Tonks-Girardeau gases are investigated in momentum space. The ground state wavefunction in coordinate space is obtained using the Bose-Fermi mapping method based on the wavefunction of spin-polarized fermions. Fourier transformation is then applied to obtain the ground state wavefunction, pair correlation, and reduced one-body density matrix in momentum space. The correlations in momentum space exhibit larger values only in small momentum regions and vanish in most other regions. Additionally, the lowest natural orbital and occupation distribution in momentum space are obtained.
INTERNATIONAL JOURNAL OF MODERN PHYSICS B
(2023)
Article
Optics
M. Beau, A. del Campo, D. J. Frantzeskakis, T. P. Horikis, P. G. Kevrekidis
Summary: This article investigates the interplay of repulsive short-range and same-sign long-range interactions in the dynamics of dark solitons in a trapped one-dimensional Bose gas. The study shows that single- and multiple-dark-soliton states can exist and are generically robust in the presence of long-range interactions. The frequencies of the soliton oscillations are significantly upshifted as the strength of the long-range interactions is increased.
Article
Quantum Science & Technology
Thomas Fogarty, Thomas Busch
Summary: This study demonstrates that a quantum Otto cycle involving a transition of an ultracold gas between superfluid and insulating phases can outperform single particle cycles. Utilizing the energy gap and the interplay between lattice forces and particle distribution can lead to a many-body cooperative effect. Introducing an approximate shortcut to adiabaticity for efficient cycling around a critical point can help mitigate unwanted non-equilibrium dynamics.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
Article
Optics
Pawel Zin, Maciej Pylak, Mariusz Gajda
Summary: We describe a quantum droplet of a Bose-Bose mixture squeezed by an external harmonic force in one spatial direction. We investigate the droplet's profile and chemical potential using both numerical and analytic methods.
Article
Physics, Multidisciplinary
Bjoern Schrinski, Anders S. Sorensen
Summary: Photons strongly coupled to material systems provide a new approach to realize nonlinear optics at the level of individual photons and study the dynamics of non-equilibrium quantum many-body systems. By using a simple physical polariton-picture, we can analytically describe the dynamics of photons coupled to a one-dimensional array of two-level atoms, including polariton scattering inside the medium and reflections of polaritons from the array's edge. We show that inelastic collisions, observed in small systems, also occur in infinite systems due to the existence of multiple bands in the dispersion relation. The developed theory serves as an effective field theory for studying nonlinear optics and many-body dynamics.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
H. A. J. Middleton-Spencer, N. G. Parker, L. Galantucci, C. F. Barenghi
Summary: A method to detect the presence and depth of dark solitons in repulsive one-dimensional harmonically trapped Bose-Einstein condensates is presented. The shift of density in Fourier space directly maps onto the depth of the soliton in single soliton systems, and combining spectral methods with imaging techniques allows for determination of soliton characteristics in multi-soliton systems. The detection of solitons by spectral shift is verified to work in the presence of waves induced by density engineering methods, with implications discussed for vortex detection in three-dimensional Bose-Einstein condensates.
Article
Engineering, Mechanical
Emmanuel Kengne
Summary: In this study, we used the similarity transformation technique to build exact and approximate rogue wave (RW) solutions for a quasi-one-dimensional Gross-Pitaevskii equation. These solutions were applied to the study of matter rogue waves and superposed rogue waves in Bose-Einstein condensates (BECs), considering different forms of the interatomic interaction strength. The results show that the solution parameters can be used to control the formation and manipulation of first- and second-order RWs in BEC systems. Additionally, the effects of changing the parameters of the interatomic interaction strength were investigated, revealing the reduction of RWs to single solitons or multiplets. The control and free parameters in the RW solutions were found to influence the splitting of rogue wave components into multi-peak solutions. Furthermore, the linear superposition of different rogue wave solutions resulted in four types of coherent structures, which were analyzed in detail, along with the effects of solution parameters and intra-component strength.
NONLINEAR DYNAMICS
(2023)
Article
Mathematics, Applied
D. Weaire, A. Mughal, J. Ryan-Purcell, S. Hutzler
Summary: This study focuses on the buckling instability of a linear chain of hard spheres confined by a transverse harmonic potential. By utilizing Jacobi functions, exact analytic solutions are provided for the displacement profile of the chain, and the variations of these solutions with changing system parameters are explored. The findings enrich the understanding of buckling instability and may offer insights into more complex experiments involving ion chains.
PHYSICA D-NONLINEAR PHENOMENA
(2022)
Article
Environmental Sciences
Rafail Abramov
Summary: In recent works, the researchers developed a model of balanced gas flow which can produce turbulent flows and Kolmogorov energy spectra in a two-dimensional setting. This discovery provides a new perspective for studying turbulent motions in Earth's atmosphere.
Article
Physics, Multidisciplinary
Oleksandr Marchukov, Artem G. Volosniev
Summary: In this study, the Gross-Pitaevskii equation is used to investigate acoustic emission generated in a uniform Bose gas by a static impurity, exploring the shape of the sound-wave packet and its potential in extracting impurity properties. The results are general for all one-dimensional systems and can be applied to non-atomic systems, such as analyzing light propagation in nonlinear optical media.
Article
Physics, Multidisciplinary
J. M. Zhang, H. F. Song, Y. Liu
Summary: We study the performance of permanent states as approximating functions for bosons, with the aim of developing variational methods based on them. We find that permanent states can well approximate the exact ground state for the one-dimensional Bose-Hubbard model. For a generic model, a greedy algorithm is devised to find the optimal set of single-particle orbitals. It is found that permanent states are effective variational wave functions for bosonic systems.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2022)
Article
Physics, Fluids & Plasmas
Deepak Dhar, R. Rajesh
Summary: The study investigates the asymptotic behavior of entropy when fully covering a square lattice with rods of specific sizes in the limit of large k. The research reveals the conditions under which full coverage is possible and the basic flip moves between configurations. In the large k limit, per-site entropy tends towards a specific mathematical function.
Article
Optics
Rui Liu, Yajie Yang
Summary: This study focuses on the exact dark soliton solutions of the coupled Gross-Pitaevskii equation and analyzes the dynamical behaviors of matter-wave dark solitons. The results show that time-dependent nonlinearity can support exact matter-wave dark solitons in two-component Bose-Einstein condensates. A special type of matter-wave dark solitons is discovered, with backgrounds decaying to zero as time approaches infinity.
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.