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
Materials Science, Multidisciplinary
Andrea Nava, Domenico Giuliano, Phong H. Nguyen, Massimo Boninsegni
Summary: This study investigates the low temperature structural and superfluid properties of 4He confined in cylindrical nanopores using quantum Monte Carlo simulations. The results show that when the pore length greatly exceeds its radius, the 4He fluid displays remarkably one-dimensional behavior without dimensional crossover, contrary to recent claims by other authors. This system could potentially provide a viable pathway for the experimental observation of exotic behaviors, such as the junctions of interacting Tomonaga-Luttinger liquids, in a suitably designed network of nanopores.
Article
Mechanics
Anthony M. Guenault, Peter V. E. McClintock, Malcolm Poole, Roch Schanen, Viktor Tsepelin, Dmitry E. Zmeev, David Schmoranzer, William F. Joe Vinen, Deepak Garg, Kalpana Devi
Summary: We introduce a low-frequency torsional oscillator suitable for studies of quantum fluids and solids. It operates at frequencies of similar to 100 Hz, achieves velocities of several cm s(-1,) and exhibits a quality factor of Q similar or equal to 3 x 104.
Article
Physics, Multidisciplinary
Riccardo Panico, Guido Macorini, Lorenzo Dominici, Antonio Gianfrate, Antonio Fieramosca, Milena De Giorgi, Giuseppe Gigli, Daniele Sanvitto, Alessandra S. Lanotte, Dario Ballarini
Summary: The study investigates the behavior of a lattice of vortices in a nonequilibrium polariton fluid, revealing accelerated stretching and outward bending of the lattice and vortex trajectories due to repulsive interactions. Access to full density and phase fields allows detection of a small deviation from the Feynman-Onsager rule in terms of a transverse velocity component caused by the density gradient of the fluid envelope acting on the vortex lattice.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
F. Claude, M. J. Jacquet, I. Carusotto, Q. Glorieux, E. Giacobino, A. Bramati
Summary: We use a high-resolution coherent probe spectroscopy method to study the dispersion of collective excitations in a polaritonic quantum fluid. By measuring the dispersion relation with high energy and wave-number resolution, we determine the speed of sound in the fluid and identify the contribution of an excitonic reservoir. We observe the generation of collective excitations at negative energies, on the ghost branch of the dispersion curve, and identify precursors of dynamical instabilities. Our methods enable precise study of quantum hydrodynamics in quantum fluids of light.
Article
Physics, Multidisciplinary
F. Claude, M. J. Jacquet, R. Usciati, I. Carusotto, E. Giacobino, A. Bramati, Q. Glorieux
Summary: In this study, we present an original angle-resolved coherent probe spectroscopy technique to characterize elementary excitations in polariton fluids. With unprecedented spectral and spatial resolution, we directly observe the low-energy phononic behavior and detect negative-energy modes, as well as reveal narrow spectral features precursory of dynamical instabilities due to the intrinsic out-of-equilibrium nature of the system.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Timon A. Hilker, Lena H. Dogra, Christoph Eigen, Robert P. Smith, Zoran Hadzibabic
Summary: The two sounds in a highly compressible fluid are investigated using an ultracold Bose gas. The results show that only one sound persists at different temperatures, which is consistent with the hydrodynamic theory.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Physical
Hatsuki Otani, Hiroko Nakahara, Haruka Goto, Susumu Kuma, Takamasa Momose
Summary: Cold clusters of molecular hydrogen were created using a pulsed nozzle, and their thermodynamical states were characterized by measuring cluster beam velocity and laser-induced fluorescence (LIF) spectra. Different velocity components originating from different clustering mechanisms were identified, with the possibility of the presence of a liquid phase in the clusters below 5K.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Massimo Boninsegni
Summary: The bound state of a He-3 atom at the interface between crystalline and superfluid phases of He-4 is investigated using first principle Quantum Monte Carlo simulations. The results show that the He-3 atom is sharply localized in a quasi-2D layer of He-4, located in the intermediate region between the solid and liquid states. The localization and quantum-mechanical exchanges of the He-3 atom are influenced by the attractive strength of the substrate.
RESULTS IN PHYSICS
(2022)
Article
Multidisciplinary Sciences
Charles Peretti, Jeremy Vessaire, Emeric Durozoy, Mathieu Gibert
Summary: This article demonstrates the visualization and quantification of quantum vortices in a stationary rotating superfluid bucket and verifies Feynman's rule. The researchers also induce different effects by adjusting the heat flux, providing a foundation for studying quantum turbulence in rotating He-4.
Article
Physics, Applied
Phong H. Nguyen, Massimo Boninsegni
Summary: The phase diagram of lattice hard core bosons with independently varying nearest-neighbor interactions along different crystallographic directions is studied using quantum Monte Carlo simulations. The results show the existence of a superfluid phase and two crystalline phases at half filling, either checkerboard or striped, while no supersolid phase is observed.
JOURNAL OF LOW TEMPERATURE PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Massimo Boninsegni, Saverio Moroni
Summary: The second layer of 4He adsorbed on a graphite substrate is studied using Quantum Monte Carlo simulations. The substrate's corrugation is fully taken into account in a microscopic model, and the results are compared to those obtained with a smooth substrate. The main effect of the corrugation is a 20% reduction in the superfluid fraction of the top layer at zero temperature. No evidence of any commensurate (7/12) crystalline and/or supersolid phase is found, and the superfluid transition temperature is estimated to be -0.75 K. The implications of these findings on recent experiments are discussed.
RESULTS IN PHYSICS
(2023)
Article
Multidisciplinary Sciences
Tobias Dornheim, Zhandos A. Moldabekov, Jan Vorberger, Burkhard Militzer
Summary: Research on ultracold helium using PIMC simulations reveals the differences in physical properties between bosonic He-4 and fermionic He-3. Simulations of fermionic He-3 avoid nodal constraints and demonstrate the impact of Fermi statistics on physical properties. The comparison of new results with neutron scattering measurements shows excellent agreement between theory and experiment.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Physical
Rui Su, Antonio Fieramosca, Qing Zhang, Hai Son Nguyen, Emmanuelle Deleporte, Zhanghai Chen, Daniele Sanvitto, Timothy C. H. Liew, Qihua Xiong
Summary: Lead-halide perovskites show great promise for exciton-polariton studies and polaritonic devices operating at room temperature. Recent rapid experimental advances have been made using lead-halide perovskites, but challenges and mysteries remain in pushing polaritons to room-temperature operation.
Article
Multidisciplinary Sciences
Matthew A. Norcia, Claudia Politi, Lauritz Klaus, Elena Poli, Maximilian Sohmen, Manfred J. Mark, Russell N. Bisset, Luis Santos, Francesca Ferlaino
Summary: Supersolid states combine properties of solids and superfluids, initially envisioned in solid helium but observed in ultracold atomic gases. The extension of supersolid properties into two dimensions using dysprosium atoms opens up the possibility of studying rich excitation properties.
