We observe spin rotations caused by atomic collisions in a nonequilibrium Bose-condensed gas of ^{87}Rb. Reflection from a pseudomagnetic barrier creates counterflow in which forward- and backward-propagating matter waves have partly transverse spin directions. Even though inter-atomic interaction strengths are state independent, the indistinguishability of parallel spins leads to spin dynamics. A local magnetodynamic model, which captures the salient features of the observed spin textures, highlights an essential connection between four-wave mixing and collisional spin rotation. The observed phenomenon is commonly thought not to occur in Bose condensates; our observations and model clarify the nature of these effective-magnetic spin rotations.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1103/PhysRevLett.132.173401 | DOI Listing |
Adv Mater
December 2024
Department of Physics, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, 462066, India.
Weyl semimetals are a novel class of topological materials with unique electronic structures and distinct properties. HfRhGe stands out as a noncentrosymmetric Weyl semimetal with unconventional superconducting characteristics. Using muon-spin rotation and relaxation (µSR) spectroscopy and thermodynamic measurements, a fully gapped superconducting state is identified in HfRhGe that breaks time-reversal symmetry at the superconducting transition.
View Article and Find Full Text PDFPolarization ellipses are well-known as the result of coherent superposition of photonic spin states. As orbital counterparts, in this Letter, we introduce centroid ellipses that are geometrically mapped from optical orbital angular momentum (OAM) superpositions on a modal Poincaré sphere (PS) by coaxial interference. Different from not easily observable polarization ellipses, these centroid ellipses can be directly observed from dynamical interferograms with broken rotational symmetry.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
The nonintegrable higher spin Kitaev honeycomb model has an exact Z_{2} gauge structure, which exclusively identifies quantum spin liquid in the half-integer spin Kitaev model. But its constraints for the integer-spin Kitaev model are much limited, and even trivially gapped insulators cannot be excluded. The physical implications of exact Z_{2} gauge structure, especially Z_{2} fluxes, in integer-spin models remain largely unexplored.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology, Kaiserstraße 12, 76131 Karlsruhe, Germany.
The formalism to calculate excited state properties from the GW-Bethe-Salpeter equation (BSE) method is introduced, providing convenient access to excited state absorption, excited state circular dichroism, and excited state optical rotation in the framework of the GW-BSE method. This is achieved using the second-order transition density, which can be obtained by solving a set of auxiliary equations similar to time-dependent density functional theory (TD-DFT). The proposed formulation therefore leads to no increase in the formal computational complexity when compared to the corresponding ground state properties.
View Article and Find Full Text PDFMagn Reson Med
December 2024
Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA.
Purpose: To implement and evaluate the feasibility of brain spin-lattice relaxation in the rotating frame (T1ρ) mapping using a novel optimized pulse sequence that incorporates weighted spin-lock acquisitions, enabling high-resolution three-dimensional (3D) mapping.
Methods: The optimized variable flip-angle framework, previously proposed for knee T1ρ mapping, was enhanced by integrating weighted spin-lock acquisitions. This strategic combination significantly boosts signal-to-noise ratio (SNR) while reducing data acquisition time, facilitating high-resolution 3D-T1ρ mapping of the brain.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!