Article
Optics
Manuele Tettamanti, Alberto Parola
Summary: The study investigates the existence and stability of solitonic states in one-dimensional repulsive Bose-Einstein condensates by considering the limit of infinite repulsion. A class of stationary, shape-invariant states propagating at constant velocity are found and compared to the known solution of the Gross-Pitaevskii equation. The results show that typical nonlinear features can be recovered in a purely linear theory when the full many-body physics is correctly taken into account.
Article
Materials Science, Multidisciplinary
Patrycja Lydzba, Janez Bonca
Summary: The study investigates the unitary time evolution of a symmetry-broken state in a finite system of interacting hard-core bosons, which can be mapped onto the XXZ Heisenberg chain. A spatially homogeneous and time-dependent vector potential is introduced to mimic a short laser pulse, allowing control over the onset of charge density wave order. Nonthermal long-lived states with nonzero charge density wave order, translated by one lattice site, are found to have lifetimes significantly longer than typical times given by the system parameters, although they are suppressed by integrability-breaking perturbations. The existence of these long-lived nonthermal states in the thermodynamic limit is speculated based on the findings.
Article
Optics
Francois Riggio, Yannis Brun, Dragi Karevski, Alexandre Faribault
Summary: The local-density approximation (LDA) is a commonly used technique in modeling quantum gases, but it has large approximation errors in the ground state of one-dimensional Bose gases. In this study, we propose a method to correct LDA by treating the local density as a functional of the trapping potential and applying a gradient expansion. The correction coefficients are determined through perturbative calculations and can be evaluated numerically or analytically. The corrected LDA shows significant improvement compared to the zeroth-order LDA.
Article
Optics
Masaya Kunimi, Ippei Danshita
Summary: By investigating the one-dimensional Bose-Hubbard model under a trapping potential, nonergodic behavior was found through calculating level spacing statistics, time evolution of number imbalance, and entanglement entropy. The trapping potential enhances nonergodicity even when it is weak compared to the hopping energy, and an effective spin-1/2 XXZ Hamiltonian demonstrates how the trapping potential is strengthened by on-site interactions to enhance nonergodic behavior. Real-time dynamics calculations under the effective Hamiltonian show a logarithmic growth of entanglement entropy over time.
Article
Materials Science, Multidisciplinary
Rebecca Kraus, Titas Chanda, Jakub Zakrzewski, Giovanna Morigi
Summary: In this article, a theoretical analysis of the phase diagram of a quantum gas of bosons interacting via repulsive dipolar interactions is conducted. Numerical techniques are used to evaluate the phase diagram for unit density, revealing a significant impact of correlated tunneling on the parameter range of the topological insulator phase.
Editorial Material
Physics, Multidisciplinary
Tim Keller, Thomas Fogarty, Thomas Busch
Summary: The study demonstrates that a Tonks-Girardeau gas in a Bose-Einstein condensate can transition to a crystal-like Mott state without an externally imposed lattice potential. The phase transition depends on the interspecies interaction and temperature of the TG gas and can be measured through accessible observables in cold atom experiments. An effective model was also developed to accurately describe the system in the pinned insulator state and derive the critical temperature of the transition.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Yabo Li, Dominik Schneble, Tzu-Chieh Wei
Summary: We investigate dynamically coupled one-dimensional Bose-Hubbard models and solve for the wave functions and energies of two-particle eigenstates. Our study reveals the existence of four different continua and three doublon dispersions in the two-particle spectrum of a system with generic interactions. The presence of doublons and their energies depend on the coupling strength between two species of bosons and the interaction strengths. We provide details on the spectrum and properties of two-particle states, and analyze the difference in time evolution under different coupling strengths and the relation between the long-time behavior of the system and the doublon dispersion. These dynamics can be observed in cold atoms and potentially simulated by digital quantum computers.
Article
Physics, Multidisciplinary
Tomohiro Tanaka, Yusuke Nishida
Summary: The study shows that one-dimensional Bose and Fermi gases exhibit weak-strong duality under contact interactions, extending beyond thermodynamics to the frequency-dependent complex bulk viscosity.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
T. O. Puel, Stefano Chesi, Stefan Kirchner, P. Ribeiro
Summary: Bosons in one dimension exhibit quasicondensation, where correlations decay in a power-law manner. We investigate the fate of this state in an open-system setup driven by two macroscopic leads with different chemical potentials. We find that a finite bias destroys the quasicondensation and introduces exponential-decay correlations with bias-dependent subleading power-law corrections. Near equilibrium, we observe a diverging correlation length and determine the critical properties and scaling of correlations.
Article
Quantum Science & Technology
Olli Mansikkamaeki, Sami Laine, Atte Piltonen, Matti Silveri
Summary: This article presents a framework for describing the effective unitary dynamics of highly excited states of coupled transmons based on high-order degenerate perturbation theory. It accurately describes various collective phenomena and enables transmon arrays to be used to study and explore other lattice models.
Article
Optics
Asaad R. Sakhel, William J. Mullin, Roger R. Sakhel
Summary: This study investigates the fluid insulator transition in one-dimensional disordered bosons. The behavior of the bosons is studied under changes in the average particle number and temperature. The width of path fluctuations increases with decreasing repulsion between bosons and the gain in mobility. The compressibility shows fluid behavior at lower gamma values and a proposed Bose-glass phase at higher gamma values.
Article
Physics, Multidisciplinary
Yong Zheng
Summary: The study investigates the one-dimensional Bose-Hubbard model in the large-U limit by reducing and mapping the Hamiltonian to a simpler form. Exact eigenstates and eigenvalues have been obtained in subspaces with fixed numbers of single- and double-occupancies, excluding multiple-occupancies, and the thermodynamic properties of the system have been calculated. Furthermore, the development of a new perturbation treatment for the model based on these eigenstates and eigenvalues has also been discussed.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Physics, Multidisciplinary
R. S. Watson, S. A. Simmons, K. V. Kheruntsyan
Summary: Generalized hydrodynamics (GHD) is a theoretical approach used to characterize non-equilibrium phenomena in integrable and near-integrable quantum many-body systems. In this study, we compare its performance with alternative theoretical methods in describing an interacting one-dimensional Bose gas described by the Lieb-Liniger model. We find that GHD performs well at high temperatures or strong interactions, but for low temperatures and weak interactions, it can still provide a coarse-grained description based on convolution averaging that mimics finite imaging resolution in ultracold atom experiments.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Optics
Yajiang Hao
Summary: In this study, we investigate the dynamics of the hard-core Bose gas in a harmonic trap with a periodic drive using the Bose-Fermi mapping method. The time-dependent wavefunction is constructed based on the solution of the single-particle Schrodinger equation under the periodic drive. It is found that both the density distribution and momentum distribution maintain their initial profiles during the time evolution, behaving as if the hard-core Bose gas is a single entity particle. When the frequency of the driving force is close to the trap frequency of the harmonic potential, both the density distribution and momentum distribution exhibit classical beats behavior, similar to the behavior of the composition of two classical harmonic oscillators with similar frequencies.
EUROPEAN PHYSICAL JOURNAL D
(2023)
Article
Optics
Smitha Vishveshwara, David M. Weld
Summary: In the presence of nearest-neighbor pairing, the Bose-Hubbard chain exhibits an unusual gapped Z(2) Ising phase with number fluctuation but no off-diagonal long range order. This phase has a strongly correlated many-body doubly degenerate ground state that can be viewed as a gap-protected macroscopic qubit. The system can be mapped to an anisotropic transverse spin chain in the strongly interacting limit, which is further mapped to the fermionic sister, the Kitaev chain, with zero-energy Majorana bound states. The cold-atom realization of the paired Bose-Hubbard model in a biased zigzag optical lattice with reservoir-induced pairing provides a possible route for experimental Kitaev chain spectroscopy.
Article
Physics, Multidisciplinary
Cui-Xian Guo, Chun-Hui Liu, Xiao-Ming Zhao, Yanxia Liu, Shu Chen
Summary: The study reveals the sensitivity of systems with non-Hermitian skin effects to boundary conditions and lattice size. In one-dimensional non-Hermitian models, the existence of non-Hermitian skin effects is identified even when one of the boundary hopping terms vanishes. However, it is shown that in the thermodynamic limit, this skin effect is fragile to any tiny boundary perturbations.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Cui-Xian Guo, Shu Chen
Summary: We study one-dimensional general non-Hermitian models with asymmetric long-range hopping and analytically solve the systems under specific boundary conditions. We find exact solutions when the boundary parameters fulfill certain constraint relations, resulting in specific boundary conditions. Our analysis reveals simple forms of wave functions that are independent of hopping range, while the eigenvalue spectra exhibit diverse, model-dependent structures. Particularly, we identify a special point called pseudo-periodic boundary condition, where the eigenvalues are identical to those of a periodic system under certain hopping parameter conditions, but the eigenstates display the non-Hermitian skin effect.
Article
Physics, Multidisciplinary
Zhi-Hao Xu, Xu Xia, Shu Chen
Summary: A two-dimensional quasicrystal model with exact mobility edges is discovered, displaying time-reversal symmetry. In the thermodynamic limit, it is found that the extended-localized transition point observed at the breaking point of time-reversal symmetry is topologically characterized by a hidden winding number in dual space.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Materials Science, Multidisciplinary
Yu-Guo Liu, Shu Chen
Summary: In this study, the effects of the Liouvillian flat band on the relaxation dynamics of open quantum systems were investigated using the Lindblad master equation scheme. Three types of Liouvillian band dispersion were observed: a flat band, a dispersionless band in the real part, and a dispersionless band in the imaginary part, and their respective dynamical signatures were captured. It was found that when the Liouvillian rapidity spectrum is flat, the particle numbers in different sites relax to their steady-state value with the same decay rate, while a dispersionless real or imaginary part of the rapidity spectrum leads to oscillating or forked relaxation behaviors. Furthermore, the Liouvillian flat band was shown to induce dynamical localization, characterized by a halt in the propagation of local perturbation in the steady state.
Article
Materials Science, Multidisciplinary
Luhong Su, Hui Jiang, Zhan Wang, Shu Chen, Dongning Zheng
Summary: We report the experimental observation of the non-Hermitian skin effect (NHSE) in non-Hermitian systems. By constructing one-dimensional circuits using linear components and varying their parameter values, we achieve nonreciprocity and observe the presence of NHSE through the voltage response. Additionally, we simulate the interplay between NHSE and Anderson localization, observing a transformation from the skin effect phase to the localized phase with increasing disorder strength.
Article
Materials Science, Multidisciplinary
Yumeng Zeng, Bozhen Zhou, Shu Chen
Summary: The dynamical quantum phase transition refers to the emergence of nonanalytic behaviors in the rate function, indicating the exact zero points of the Loschmidt echo. Generally, these exact zeros are inaccessible in finite-size quantum systems, except for finely tuned quench parameters. In this study, we investigate the realization of the dynamical singularity of the rate function in finite-size systems under the twist boundary condition, introduced by applying a magnetic flux. We demonstrate that exact zeros of the Loschmidt echo can always be achieved when the postquench parameter crosses the underlying equilibrium phase transition point, leading to a series of critical times where the rate function diverges.
Article
Materials Science, Multidisciplinary
Yu Zhang, Bozhen Zhou, Haiping Hu, Shu Chen
Summary: This study investigates the combined effect of quasiperiodic disorder, driven, and interaction in the periodically kicked Aubry-Andre model. The research verifies the existence of a dynamical localization transition in the high-frequency region in the noninteracting limit, and demonstrates the intricate spectrum statistics in the low-frequency region due to the emergence of extended/localized-to-multifractal edges. The introduction of interaction leads to a transition from the ergodic to many-body localization phase in the high-frequency region, but this many-body localization phase vanishes in the low-frequency region even with strong quasiperiodic disorder.
Article
Physics, Multidisciplinary
Haiping Hu, Shikang Sun, Shu Chen
Summary: This article presents the characteristics and topological classification of exceptional points (EPs), discusses interesting phenomena related to non-Hermitian band degeneracy, and proposes a non-Hermitian no-go theorem. The author also provides a simple algorithm for generating a non-Hermitian Hamiltonian with a specific knot.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
Wenkui Ding, Yanxia Liu, Zhenyu Zheng, Shu Chen
Summary: We propose a dynamic quantum sensing scheme using a quantum many-spin system, which demonstrates the feasibility of achieving Heisenberg scaling. The study also investigates various effects in practical quantum systems.
Article
Materials Science, Multidisciplinary
Chun-Hui Liu, Haiping Hu, Shu Chen
Summary: The paper systematically classifies the Floquet non-Hermitian (FNH) topological bands for 54-fold generalized Bernard-LeClair (GBL) symmetry classes and arbitrary spatial dimensions using K theory. It distinguishes two different scenarios of the Floquet operator's spectrum gaps and produces two periodic tables. The framework lays the foundation for exploring unique phenomena and functionalities arising from periodic driving, non-Hermiticity, and band topology.
Article
Materials Science, Multidisciplinary
Chun-Hui Liu, Shu Chen
Summary: Information constraint is a phenomenon characterized by different decay rates of signal strengths propagating along opposite directions in open quantum systems. This concept allows for an elegant explanation of chiral and helical damping, as well as the identification of local maxima points for relative particle numbers in periodic boundary systems. Additionally, it leads to the proposal and proof of a correspondence between edge modes and damping modes, resulting in the introduction of a new damping mode called Dirac damping. Chiral/helical damping can be considered a special case of Dirac damping.
Article
Materials Science, Multidisciplinary
Bozhen Zhou, Yumeng Zeng, Shu Chen
Summary: The study reveals that exact zeros of Loschmidt echo exist in finite size quantum systems when the postquench parameter takes certain discrete values in regions with corresponding equilibrium phases different from the initial phase. As the system size increases, the discrete parameters continuously distribute in the parameter regions. The maximal value of the quantum speed limit time tau(QSL) is proportional to L and approaches infinity in the thermodynamic limit when quenching the initial noncritical state to the critical phase, while the minimal value of tau(QSL) behavior is dependent on the phase of the initial state.
Article
Optics
Yanxia Liu, Yi-Cong Yu, Shu Chen
Summary: This study investigates one-dimensional three-body systems consisting of two identical bosons and one mass-imbalanced atom with attractive two-body and three-body zero-range interactions. It reveals that additional low-lying three-body bound states emerge when the mass of the impurity particle differs from the other two identical particles. The presence of weak three-body interaction does not always induce an extra three-body bound state, but at specific parameter points, even a small three-body interaction can generate one more three-body bound state. This shows a transition in the number of three-body bound states induced solely by two-body attractive interaction.
Article
Materials Science, Multidisciplinary
Yanxia Liu, Yumeng Zeng, Linhu Li, Shu Chen
Summary: In this study, the single impurity problem in the Hatano-Nelson model and the Su-Schreieffer-Heeger model was considered, revealing a transition of bulk states and spectrum structure change when increasing impurity strength. The critical value of impurity strength was found to be size dependent, increasing exponentially with lattice size in certain conditions.
Article
Materials Science, Multidisciplinary
Yanxia Liu, Qi Zhou, Shu Chen
Summary: This study develops a rigorous scheme for the study of general non-Hermitian quasicrystals using Lyapunov exponent analysis and Avila's global theory, finding a direct relationship between winding number and acceleration of LE. The quantization of acceleration is crucial for Avila's global theory, and the results apply to models with higher winding as well. Additionally, this research successfully determines analytical phase boundaries for localization transitions and complete phase diagrams for different models in the parameter space.
