Article
Multidisciplinary Sciences
Panagiotis Christodoulou, Maciej Galka, Nishant Dogra, Raphael Lopes, Julian Schmitt, Zoran Hadzibabic
Summary: The observation of first and second sound in a two-dimensional superfluid confirms the predicted jump in the superfluid density at the infinite-order Berezinskii-Kosterlitz-Thouless transition. The study also shows agreement with BKT theory, including the universal jump in superfluid density at the critical temperature.
Article
Optics
A. Tononi, A. Cappellaro, G. Bighin, L. Salasnich
Summary: The study calculates the first and second sound velocities in a two-dimensional system of ultracold fermions and analyzes the system response to external perturbations. It reproduces recent experimental results at low temperatures and shows mode mixing at high temperatures.
Article
Materials Science, Multidisciplinary
D. Belitz, T. R. Kirkpatrick
Summary: In this study, we used kinetic-theory methods to analyze the Landau Fermi-liquid theory and investigate the soft modes in Fermi liquids in the hydrodynamic and the collisionless regimes. The hydrodynamic regime shows that Fermi-liquid theory is consistent with Navier-Stokes hydrodynamics, while the collisionless regime demonstrates the soft continuous mode and the zero-sound excitations. The two families of soft modes have different physical origins and evolve differently with temperature.
Article
Chemistry, Multidisciplinary
Houssem Rezgui
Summary: This study provides an efficient framework for identifying hydrodynamic heat transport and second sound propagation in graphene. It solves the dual-phase-lag model and the Maxwell-Cattaneo-Vernotte equation using the finite element method with ab initio data. The study emphasizes the detection of thermal wave-like behavior using macroscopic quantities, going beyond Fourier's law. It also observes a crossover from the wave-like regime to diffusive heat transport, as predicted by mesoscopic equations. This research is of great importance for future experimental detection of second sound propagation above 80 K.
Article
Optics
G. Bighin, A. Cappellaro, L. Salasnich
Summary: In this study, the researchers compared recent experimental results with a thermodynamic model to investigate the properties of a superfluid unitary Fermi gas near the critical temperature. They found good agreement between experimental data and their theory for several quantities and observed mode mixing between first and second sound. They also studied the response of the gas to a density perturbation.
Article
Physics, Multidisciplinary
Vijay Pal Singh, Ludwig Mathey
Summary: We study the propagation of sound modes in two-dimensional Bose gases across the Berezinksii-Kosterlitz-Thouless transition using classical-field dynamics, and obtain two different excitation responses through experiments and numerical simulations.
NEW JOURNAL OF PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Janik Schoenmeier-Kromer, Lode Pollet
Summary: We investigate the phase diagram of a one-dimensional Bose-Fermi-Hubbard model with scalar bosons at unit filling and S=1/2 fermions at half filling using quantum Monte Carlo simulations. The fermion-fermion interaction is set to zero. The main focus of our study is to understand the induced interactions between the fermions by the bosons, both for weak and strong interspecies coupling. We find that these induced interactions can result in competing instabilities favoring phase separation, superconducting phases, and density wave structures, often occurring on length scales of more than 100 sites. Additionally, we observe marginal bosonic superfluids with faster decay of the density matrix compared to pure bosonic systems with on-site interactions.
Article
Physics, Multidisciplinary
Jia Wang, Xia-Ji Liu, Hui Hu
Summary: In this study, we investigate a heavy impurity immersed in an interacting Fermi superfluid using the exact functional determinant approach. We analyze the impact of the pairing gap on the properties of quasiparticles revealed by two spectroscopies. The results show interesting phenomena, such as dark continuum, molecule-hole continuum, and repulsive polaron, depending on the scattering conditions.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Andrea Barresi, Antoine Boulet, Gabriel Wlazlowski, Piotr Magierski
Summary: We investigate the life cycle of the large amplitude Higgs mode in strongly interacting superfluid Fermi gas. Through numerical simulations and the technique of the interaction quench, we verify the previous theoretical predictions on the mode's frequency. We also demonstrate the mode's dynamic instability against external perturbation and examine the post-decay state characterized by spatial fluctuations at scales comparable to the superfluid coherence length, showing similarities with FFLO states in higher dimensionalities and nonzero spin imbalances.
SCIENTIFIC REPORTS
(2023)
Article
Physics, Multidisciplinary
Xin Wang, Xiang Li, Ilya Arakelyan, J. E. Thomas
Summary: In this study, we measure the free decay of a spatially periodic density profile in a strongly interacting Fermi gas with a high temperature. The results provide direct measurements of the thermal conductivity and the shear viscosity, obtained from the time-dependent evolution.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Applied
P. J. Baymatov, A. G. Gulyamov, B. T. Abdulazizov, Kh Yu Mavlyanov, M. S. Tokhirjonov
Summary: The low-temperature behavior of the chemical potential of a quasi-two-dimensional electron gas near and far from the resonance point was analyzed, with analytical formulas obtained under certain conditions. It was found that near the resonance point, as temperature increases, the chemical potential decreases linearly and exponentially slowly. Analytical formulas were compared with numerical solutions.
INTERNATIONAL JOURNAL OF MODERN PHYSICS B
(2021)
Article
Chemistry, Physical
Qi Zhou, Sifan Luo, Wei Xue, Ningbo Liao
Summary: In this study, an approach for evaluating the selective NO2 sensing performance of ReS2 is proposed and investigated by first-principles calculations. It is found that ReS2 exhibits superior selective sensitivity and fast response to NO2, providing a conceptual foundation for designing nanomaterial-based gas sensors.
APPLIED SURFACE SCIENCE
(2023)
Article
Physics, Multidisciplinary
Chen-How Huang, Miguel A. Cazalilla
Summary: At temperatures below the Fermi temperature TF, the coupling of magnetic fluctuations to particle-hole excitations in a Fermi gas leads to non-analytic corrections and a first-order phase transition to itinerant ferromagnetism. However, for a Fermi gas with SU(N > 2)-symmetry in three space dimensions, the ferromagnetic phase transition is first order in agreement with Landau's mean-field theory. By performing unrestricted Hartree-Fock calculations, we find that the order parameter undergoes a finite jump across the transition and no tri-critical point is observed.
NEW JOURNAL OF PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Sreemayee Aditya, Diptiman Sen
Summary: In this study of a one-dimensional lattice model, various phenomena such as fermion interactions and Tomonaga-Luttinger liquids were observed, with a focus on understanding the influence of parameters phi and eta on the system properties.
Article
Physics, Multidisciplinary
Yadong Song, Cunxi Zhang, Yunqing Zhou
Summary: This study investigates the universal properties of mass-imbalanced highly polarized Fermi gases in one-dimensional scenarios. The binding energy, quasiparticle residue, and correlation functions of the systems are examined by treating the mass ratio as a parameter. The study demonstrates the existence of molecular states in one-dimensional polaron systems with strong attractive interactions, contrary to previous conclusions.
