Spin fluctuations and density fluctuations are studied for a two-component gas of strongly interacting fermions along the Bose-Einstein condensate-BCS crossover. This is done by in situ imaging of dispersive speckle patterns. Compressibility and magnetic susceptibility are determined from the measured fluctuations. This new sensitive method easily resolves a tenfold suppression of spin fluctuations below shot noise due to pairing, and can be applied to novel magnetic phases in optical lattices.
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http://dx.doi.org/10.1103/PhysRevLett.106.010402 | DOI Listing |
J Am Chem Soc
January 2025
Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris Saclay, 91400 Orsay, France.
Ni(II) complexes with an integer spin = 1 that behave as clock transition spin qubits at zero magnetic field are resilient to magnetic fluctuations of the spin bath, while Co(II) complexes with a half-integer spin ( = 3/2) lose their coherence when they are subject to the same fluctuating magnetic field as the Ni(II) ones. These findings demonstrate that adequately designed Ni(II) complexes are excellent candidates for spin qubits.
View Article and Find Full Text PDFJ Pharm Biomed Anal
January 2025
Institute of Chemistry, University of Silesia in Katowice, 9 Szkolna Street, Katowice 40-006, Poland; SPIN-Lab Centre for Microscopic Studies on Matter, University of Silesia in Katowice, 75 Pulku Piechoty Street 1, Chorzow 41-500, Poland. Electronic address:
Near-infrared hyperspectral imaging (NIR-HSI) integrated with expert systems can support the monitoring of active pharmaceutical ingredients (APIs) and provide effective quality control of tablet formulations. However, existing quality control methods usually test a limited number of variability sources affecting the final product. This study examines the potential of NIR-HSI (in the spectral range of 935.
View Article and Find Full Text PDFNature
January 2025
Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
A particle current generated by pumping in the absence of gradients in potential energy, density or temperature is associated with non-trivial dynamics. A representative example is charge pumping that is associated with the quantum Hall effect and the quantum anomalous Hall effect. Spin pumping, the spin equivalent of charge pumping, refers to the emission of a spin current by magnetization dynamics.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Johns Hopkins University, Institute for Quantum Matter and Department of Physics and Astronomy, Baltimore, Maryland 21218, USA.
The tetragonal heavy-fermion superconductor CeRh_{2}As_{2} (T_{c}=0.3 K) exhibits an exceptionally high critical field of 14 T for B∥c. It undergoes a field-driven first-order phase transition between superconducting states, potentially transitioning from spin-singlet to spin-triplet superconductivity.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Ens de Lyon, Université Lyon, CNRS, Laboratoire de Physique, F-69342 Lyon, France.
We introduce a new paradigm for the preparation of deeply entangled states useful for quantum metrology. We show that, when the quantum state is an eigenstate of an operator A, observables G which are completely off diagonal with respect to A have purely quantum fluctuations, as quantified by the quantum Fisher information, namely, F_{Q}(G)=4⟨G^{2}⟩. This property holds regardless of the purity of the quantum state, and it implies that off-diagonal fluctuations represent a metrological resource for phase estimation.
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