Article
Multidisciplinary Sciences
Michele Pisarra, Cristian Vacacela Gomez, Antonello Sindona
Summary: This article investigates the electronic states in atomically thin crystals and their potential applications in optoelectronics and plasmonics.
SCIENTIFIC REPORTS
(2022)
Article
Physics, Multidisciplinary
Diego Hernandez-Rajkov, Jose Eduardo Padilla-Castillo, Alejandra del Rio-Lima, Andres Gutierrez-Valdes, Freddy Jackson Poveda-Cuevas, Jorge Amin Seman
Summary: By modulating the radial trap frequency and utilizing a Feshbach resonance, Faraday waves were observed in a cigar-shaped Fermi superfluid of Li-6. The study characterized the phenomenon by extracting parameters such as the speed of sound, showing a reduction in visibility of the Faraday pattern near unitarity. Additionally, the effects of finite sample size were discussed, and a novel model based on Floquet theory was introduced for stability analysis, revealing the emergence of Faraday waves as unstable solutions to a Mathieu-like equation.
NEW JOURNAL OF PHYSICS
(2021)
Article
Physics, Multidisciplinary
S. N. Klimin, J. Tempere, T. Repplinger, H. Kurkjian
Summary: This study investigates collective excitations in the superfluid state of Fermi condensed charged gases. It examines the dispersion and damping of collective excitations at nonzero temperatures, and considers the coexistence and interaction of different branches of collective excitations: plasma oscillations, pair-breaking Higgs modes, and Carlson-Goldman phonon-like excitations. The path integral methods for superfluid Fermi gases and for Coulomb gas are combined into a unified formalism to account for plasmonic modes. The spectra of collective excitations are determined in two ways: from the spectral functions and from the complex poles of the fluctuation propagator. A resonant avoided crossing of different modes is shown, accompanied by resonant enhancement of the response provided by the pair-breaking modes due to their interaction with plasma oscillations, which may facilitate the experimental observation of the pair-breaking modes.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Zhenyu Ge, Dong Huang, Shaoyu Lu, Chen Liang, Matteo Baggioli, Yan Feng
Summary: Equilibrium molecular dynamics simulations were used to investigate 2D dusty plasma liquids. The phonon spectra and dispersion relations of the longitudinal and transverse waves were calculated based on the stochastic thermal motion of the simulated particles. It was found that the longitudinal sound speed of the 2D dusty plasma liquid exceeds its adiabatic value for wavenumbers beyond the hydrodynamic regime, indicating the presence of fast sound. The analytical derivation of the ratio of the longitudinal to the adiabatic sound speeds, using previous studies and the Frenkel theory, agreed quantitatively with the simulation results.
Article
Multidisciplinary Sciences
Biswaroop Mukherjee, Airlia Shaffer, Parth B. Patel, Zhenjie Yan, Cedric C. Wilson, Valentin Crepel, Richard J. Fletcher, Martin Zwierlein
Summary: The dominance of interactions plays a crucial role in strongly correlated quantum matter, leading to transitions between liquid and crystalline phases. In this study, a spontaneous crystallization driven by magnetic spin softening was observed and compared with hydrodynamic instability. At longer timescales, the condensate self-organizes into a stable array of droplets separated by vortex streets.
Article
Chemistry, Physical
Soyeun Kim, Yinchuan Lv, Xiao-Qi Sun, Chengxi Zhao, Nina Bielinski, Azel Murzabekova, Kejian Qu, Ryan A. Duncan, Quynh L. D. Nguyen, Mariano Trigo, Daniel P. Shoemaker, Barry Bradlyn, Fahad Mahmood
Summary: Using time-domain terahertz emission spectroscopy, we observe coherent and narrowband terahertz radiation emitted from (TaSe4)(2)I material under transient photoexcitation at low temperatures, indicating the existence of a phason coupled to long-range Coulomb interactions. These findings highlight the role of long-range interactions in determining the nature of collective excitations in materials with modulated charge or spin order.
Article
Optics
P. Sturmer, M. Nilsson Tengstrand, R. Sachdeva, S. M. Reimann
Summary: This study investigates the stationary structures and breathing mode behavior of a two-dimensional self-bound binary Bose droplet using both an analytical approach and numerical solutions. It is found that the super-Gaussian ansatz is more effective in describing the system properties compared to the Gaussian ansatz. The preference for the breathing mode over the self-evaporating process is observed for large nonrotating droplets, while the results differ based on the ansatz for small self-bound systems.
Article
Nanoscience & Nanotechnology
S. Kuru, J. Negro, L. M. Nieto, L. Sourrouille
Summary: This work investigates the confinement properties of charged particles in a Dirac material in an electric quantum dot. The study focuses on the influence of mass and angular momenta on the confinement properties. The results show that the resonances for massive particles are not significantly influenced by angular momenta, while for massless particles such as graphene, the resonances are quite sensitive to angular momenta.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Review
Physics, Multidisciplinary
Nir Navon, Robert P. Smith, Zoran Hadzibabic
Summary: The development of optical box traps has led to breakthroughs in the study of quantum atomic and molecular gases, simplifying interpretation of experimental results and providing more direct connections with theory. Box trapping has allowed for the creation of homogeneous samples in various dimensionalities and for different types of gases, leading to new experiments previously thought impossible. Optically trapped quantum gases in box traps create a potential landscape close to the ideal homogeneous theoretical conditions, highlighting the breakthroughs in experimental many-body physics.
Article
Physics, Applied
V. Ya. Aleshkin, A. O. Rudakov, S. V. Morozov
Summary: This work aims to find the optimal parameters of the HgTe/CdHgTe multi-quantum-well structure for generating two-dimensional plasmon-phonons under optical excitation. The study shows that decreasing the bandgap and increasing the number of quantum wells can lead to a decrease in carrier threshold concentration and an improvement in plasmon-phonon radiation output.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Particles & Fields
Bo-Ting Chen
Summary: This study focuses on non-BPS amplitudes (Z<2m), constructing three-point amplitudes of two equal-mass particles and one massless particle using on-shell methods, where the two massive particles are non-BPS states. The results are verified through matching with N=2 supersymmetry, and a non-BPS coupling for N=4 super-Maxwell and supergravity is derived as an application.
Article
Physics, Multidisciplinary
Wei-Feng Zhuang, Yue-Xin Huang, Ming Gong
Summary: By introducing the influence of the Zeeman field, trapped Bose gases can exhibit angular momentum Josephson effect, generating oscillations with different periods and characteristics. The dynamics in the self-trapping regime are explained by the time-dependent evolution of constant-energy trajectories in phase space, which has superior performance compared to previous models.
CHINESE PHYSICS LETTERS
(2021)
Article
Physics, Fluids & Plasmas
Conrad Bertrand Tabi, Etienne Wamba, Emmanual Nare, Timoleon Crepin Kofane
Summary: This study investigates the nonlinear dynamics induced by the modulation instability of a binary mixture in an atomic Bose-Einstein condensate, considering the effects of higher-order residual nonlinearities and helicoidal spin-orbit coupling. The analysis is based on modified coupled Gross-Pitaevskii equations, and the stability of plane-wave solutions is studied to obtain the modulation instability gain. Parametric analysis reveals regions of instability and the effects of higher-order interactions and spin-orbit coupling under different combinations of interaction strengths. Numerical calculations support the analytical predictions, showing that the residual nonlinearity can preserve and reinforce the stability of miscible pairs of condensates with spin-orbit coupling.
Article
Physics, Multidisciplinary
Jingxin Sun, Pengju Zhao, Zhongshu Hu, Shengjie Jin, Ren Liao, Xiong-Jun Liu, Xuzong Chen
Summary: We report the observation of a 2D quantum phase transition from Mott insulator to π superfluid in a shaking optical lattice. Through a shaking technique, we experimentally observe the transition between the S and p(x,y) bands, resulting in a quantum phase transition from 2D s-orbital Mott phase to p(x,y) orbital superfluid condensed at (π,π) momentum. Using the band-mapping method, we observe the changes of atomic population in different energy bands during the transition, which are consistent with theoretical expectations.
CHINESE PHYSICS LETTERS
(2023)
Article
Physics, Multidisciplinary
Axel U. J. Lode, Sunayana Dutta, Camille Leveque
Summary: The dynamics of two-dimensional interacting ultracold bosons in an artificial gauge field were studied, revealing the implantation of angular momentum and emergence of fragmentation in the system. The experimental assessment of fragmentation and angular momentum was demonstrated to be possible through statistical analysis of image entropy variance.
Article
Physics, Multidisciplinary
S. Bresolin, A. Roy, G. Ferrari, A. Recati, N. Pavloff
Summary: Close to the demixing transition, the degree of freedom associated with relative density fluctuations of a two-component Bose-Einstein condensate is described by a nondissipative Landau-Lifshitz equation. In the quasi-one-dimensional weakly immiscible case, this mapping surprisingly predicts that a dark-bright soliton should oscillate when subject to a constant force favoring separation of the two components. We propose a realistic experimental implementation of this phenomenon which we interpret as a spin -Josephson effect in the presence of a movable barrier.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
V. E. Colussi, F. Caleffi, C. Menotti, A. Recati
Summary: In this study, the physics of a mobile impurity confined in a two-dimensional lattice and interacting with a Bose-Hubbard bath is investigated at zero temperature. By employing the quantum Gutzwiller formalism, a beyond-Frohlich model of the bath-impurity interaction is developed to understand the properties of the polaronic quasiparticle formed by dressing the impurity with quantum fluctuations of the bath. It is found that a stable and well-defined polaron exists in the entire phase diagram of the bath, except for the low tunneling limit of the hard-core superfluid. The properties of the polaron are highly sensitive to different universality classes of the quantum phase transition between the superfluid and Mott insulating phases, serving as a definitive probe of correlations and collective modes in a quantum critical many-body environment.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
R. Cominotti, A. Berti, C. Dulin, C. Rogora, G. Lamporesi, I. Carusotto, A. Recati, A. Zenesini, G. Ferrari
Summary: This study demonstrates a quantum phase transition from a paramagnetic to a ferromagnetic state in an extended atomic superfluid with a coherent coupling between two internal states. The nature of the transition is experimentally assessed using phase diagrams, hysteresis phenomena, magnetic susceptibility, and magnetization fluctuations. The observed features are found to be consistent with mean-field calculations, and experimental protocols are developed to generate domain walls in the ferromagnetic state.
Review
Physics, Applied
Alessio Recati, Sandro Stringari
Summary: Supersolidity is an intriguing state of matter that combines superfluid and crystal features. It has been observed in atomic gases, where density modulations, coherence effects, and new Goldstone modes have been observed. Future research will focus on issues such as the realization of quantized vortices, the role of dimensionality, and the nature of phase transitions.
NATURE REVIEWS PHYSICS
(2023)
Article
Optics
Andrea Richaud, Giacomo Lamporesi, Massimo Capone, Alessio Recati
Summary: Quantum vortices with effective inertial mass, introduced by massive particles in their cores, exhibit new phenomena beyond the standard picture of massless superfluid vortex dynamics. In this study, we propose a scheme to generate controllable and repeatable collisional events between massive vortices. We demonstrate two mass-driven fundamental processes: the annihilation of two counter-rotating vortices and the merging of two co-rotating vortices. This reveals new mechanisms for incompressible-to-compressible kinetic-energy conversion and the stabilization of doubly quantized vortices in flat superfluids.
Article
Optics
Arko Roy, Miki Ota, Franco Dalfovo, Alessio Recati
Summary: This study investigates the fate of a paramagnetic-ferromagnetic quantum phase transition in a two-dimensional coherently coupled Bose mixture of dilute ultracold atomic gases at finite temperature. Numerical simulations using the stochastic Gross-Pitaevskii formalism reveal a finite-temperature critical line for the transition by extracting the average magnetization, magnetic fluctuations, and characteristic relaxation frequency. The critical point shows a linear shift with temperature and the quantities used to probe the transition exhibit temperature power-law scaling. The critical slowing down is well approximated by the square of the spin excitation gap at zero temperature.
Article
Materials Science, Multidisciplinary
R. Cominotti, H. A. M. Leymann, J. Nespolo, J. M. Manceau, M. Jeannin, R. Colombelli, I. Carusotto
Summary: The coherent nonlinear response of electrons in semiconductor quantum wells to resonant electromagnetic radiation is theoretically studied. The study is based on the time-dependent Schrodinger-Poisson equation and the results are interpreted with approximated analytical formulas. The redshift of the resonance frequency and the competition between coherent nonlinearities and incoherent saturation effects are observed and discussed. The optical nonlinearity is estimated across different frequency ranges, which is important for ongoing experiments and the exploration of quantum optical phenomena.
Article
Optics
Louise Wolswijk, Carmelo Mordini, Arturo Farolfi, Dimitris Trypogeorgos, Franco Dalfovo, Alessandro Zenesini, Gabriele Ferrari, Giacomo Lamporesi
Summary: This study investigates the strong out-of-equilibrium dynamics occurring when a harmonically trapped ultracold bosonic gas is evaporatively cooled across the Bose-Einstein condensation transition. The results show that the cooling rate affects the timescales for the growth of the condensate order parameter and the relaxation dynamics of its spatial fluctuations.
Article
Optics
Anna Berti, Iacopo Carusotto
Summary: We propose a realistic protocol to study the robust topological dynamics of two-particle bound states in a lattice model. This protocol utilizes on-site interactions and time-dependent hoppings, and can be implemented on existing digital quantum computer platforms. Our results highlight significant differences from the topological dynamics of two independent particles and demonstrate clear signatures of entanglement between the two constituent particles.
Article
Optics
S. M. Roccuzzo, A. Recati, S. Stringari
Summary: We show that by studying the time-dependent response of a trapped gas subjected to a sudden rotation, we can determine the moment of inertia of dipolar supersolid configurations. One-dimensional arrays of droplets provide accurate access to the moment of inertia through the frequency of scissors oscillation, while two-dimensional-like configurations exhibit low-frequency resonances indicating the presence of significant rigid body components in the rotational motion.
