Article
Physics, Multidisciplinary
Florian Schafer, Yuki Haruna, Yoshiro Takahashi
Summary: We conducted experimental research on the interspecies Feshbach spectrum in a mixture of 167Er (F = 19/2, mF =-19/2)-6Li (F = 1/2, mF = 1/2) atoms at microkelvin temperatures. These temperatures were achieved through sympathetic cooling with 174Yb as a third species. By investigating the inelastic collisional properties of Er-Li, interspecies Feshbach resonances were identified, including numerous narrow resonances and six resonances with widths above 1 G. These broader resonances hold great promise for future research on novel superfluid states and Efimov states in large mass-imbalanced, all-fermionic two-component systems.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Physics, Multidisciplinary
Bugra Tuzemen, Tomasz Zawislak, Gabriel Wlazlowski, Piotr Magierski
Summary: We investigate the properties of spin-imbalanced ultracold Fermi gas at low temperatures over a wide range of spin polarizations. We employ microscopic calculations using mean-field and density functional theory approaches without any symmetry constraints. At low polarization values, the system is predicted to consist of multiple spin-polarized droplets. As the polarization increases, the system self-organizes into disordered structures resembling liquid crystals and can energetically compete with ordered structures like grid-like domain walls. Further increasing polarization leads to the development of regularities that can be considered as supersolid, where periodic density modulation and pairing correlations coexist. The robustness of the results has been verified against temperature effects, dimensionality, and the presence of a trapping potential. Dynamical stability has also been investigated.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
Marcel Duda, Xing-Yan Chen, Andreas Schindewolf, Roman Bause, Jonas von Milczewski, Richard Schmidt, Immanuel Bloch, Xin-Yu Luo
Summary: The interplay of quantum statistics and interactions in atomic Bose-Fermi mixtures results in a phase transition from a polaronic to a molecular phase, leading to the emergence of a molecular Fermi gas. This represents a new phenomenon complementary to the Bose-Einstein condensate/Bardeen-Cooper-Schrieffer crossover observed in Fermi systems. By tuning interspecies interactions, heteronuclear molecules can be generated in the quantum-degenerate regime.
Article
Physics, Multidisciplinary
Zhen Su, Huan Yang, Jin Cao, Xin-Yao Wang, Jun Rui, Bo Zhao, Jian-Wei Pan
Summary: We have demonstrated the resonant control of elastic scattering cross sections near Feshbach resonances between (NaK)-Na-23-K-40 molecules and K-40 atoms by studying their thermalization. The scattering cross sections show a variation of more than 2 orders of magnitude near the resonance, and can be accurately described by an asymmetric Fano profile. This observation opens up possibilities for studying strongly interacting atom-molecule mixtures and improving our understanding of complex atom-molecule Feshbach resonances.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Kevin Keiler, Simeon Mistakidis, Peter Schmelcher
Summary: This study reveals the polaronic properties of impurities in a correlated trapped one-dimensional Bose-Bose mixture. By varying the coupling of the impurities to bosonic components, the impurity residue peak and induced interactions can be controlled, maintaining quasiparticle character for larger interaction strengths. The findings pave the way for continuously changing the quasiparticle character, capturing bipolaron formation under strong attractive impurity-medium couplings.
Article
Optics
Jakub Kopycinski, Wojciech R. Pudelko, Gabriel Wlazlowski
Summary: The study explores the properties of a spin-imbalanced and rotating unitary Fermi gas, particularly focusing on the competition between Abrikosov lattice formation, spatial phase separation, and the emergence of the FFLO state. Experimental data show qualitative agreement with theoretical predictions. Changes in trap conditions lead to different behaviors in the gas state.
Article
Materials Science, Multidisciplinary
Philip Zechmann, Alvise Bastianello, Michael Knap
Summary: In this study, we developed a quantum Boltzmann approach applicable to weakly interacting systems, and investigated transport in a one-dimensional Hubbard model with different masses of fermionic species. We found excellent agreement between the quantum Boltzmann equation and numerically exact results, and observed distinct transport behaviors in different scenarios.
Article
Optics
G. Bougas, S. I. Mistakidis, P. Giannakeas, P. Schmelcher
Summary: A scheme is proposed to dynamically excite distinct eigenstate superpositions in three-body Bose-Fermi mixtures, which can be achieved in current experiments by adjusting the scattering lengths to span from weak to strong interactions.
Article
Materials Science, Multidisciplinary
Ruipeng Li, Jonas von Milczewski, Atac Imamoglu, Rafal Oldziejewski, Richard Schmidt
Summary: We study induced pairing between two identical fermions mediated by an attractively interacting quantum impurity in two-dimensional systems. Based on a stochastic variational method (SVM), we investigate the influence of confinement and finite interaction range on the ground state of the quantum three-body problem. We find that confinement and a finite interaction range can enhance trimer stability and overcome Coulomb repulsion, opening possibilities for electron pairing beyond conventional paradigms.
Article
Materials Science, Multidisciplinary
M. Pini, P. Pieri, G. Calvanese Strinati
Summary: This study analyzes the evolution of an attractive polarized two-component Fermi gas at zero temperature as its polarization is gradually decreased from full polarization to a critical polarization where superfluidity occurs. The critical polarization and the associated superfluid instability are determined using a fully self-consistent t-matrix approach at zero temperature, constructing the polarization-vs-coupling phase diagram throughout the BCS-BEC crossover. The superfluid instability can lead to either a Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) phase or a standard polarized BCS phase depending on the interparticle interaction strength between the two components. The behavior of the quasiparticle parameters in the normal Fermi gas varies significantly between the two cases.
Article
Physics, Multidisciplinary
Heron Caldas, S. Rufo, M. A. R. Griffith
Summary: The effects of impurities on the induced interactions corrections are detrimental for the transition temperature and tricritical point in both balanced and imbalanced Fermi gases. Impurities strongly suppress particle-hole fluctuations for large impurity parameter. The Chandrasekhar-Clogston limit of an imbalanced Fermi gas with induced interactions has been determined for both pure and impure regimes at unitarity.
ANNALEN DER PHYSIK
(2022)
Article
Physics, Multidisciplinary
N. Darkwah Oppong, G. Pasqualetti, O. Bettermann, P. Zechmann, M. Knap, I Bloch, S. Foelling
Summary: This study observes constrained dynamics in a one-dimensional mass-imbalanced Fermi-Hubbard model. By displacing the trap potential and monitoring the dynamical response of the system, suppressed transport and slow relaxation are identified, with a strong dependence on mass imbalance and interspecies interaction strength.
Article
Optics
Jeff Maki, Tilman Enss
Summary: The scattering properties of spin-polarized Fermi gases are mainly influenced by p-wave interactions, which differ from s-wave interactions due to their angular dependence and the necessity of an effective range. This article investigates the dependence of shear viscosity and thermal conductivity on the effective range and scattering volume in both weakly and strongly interacting limits for a three-dimensional spin-polarized Fermi gas in the normal phase. The study reveals that, while the shear viscosity and thermal conductivity depend on the effective range near resonance, the Prandtl number, which represents the ratio of momentum to thermal diffusivity, does not exhibit an explicit interaction dependence at resonance or for weak interactions in the low-energy range. Unlike s-wave systems, p-wave scattering shows an additional resonance at weak attraction, resulting in a significant dip in shear viscosity at specific temperatures.
Article
Chemistry, Multidisciplinary
Ruijin Liu, Cheng Peng, Xiaoling Cui
Summary: In this study, various crystalline few-body correlations smoothly emerged from mass-imbalanced Fermi polarons in two dimensions were revealed. When the fermion-impurity mass ratio exceeds a certain critical value, the Fermi polaron undergoes a smooth transition from the polaronic to trimer and tetramer regimes.
CELL REPORTS PHYSICAL SCIENCE
(2022)
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.
