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We follow the evolution of fermion pairing in the dimensional crossover from three-dimensional to two-dimensional as a strongly interacting Fermi gas of ^{6}Li atoms becomes confined to a stack of two-dimensional layers formed by a one-dimensional optical lattice. Decreasing the dimensionality leads to the opening of a gap in radio-frequency spectra, even on the Bardeen-Cooper-Schrieffer side of a Feshbach resonance. The measured binding energy of fermion pairs closely follows the theoretical two-body binding energy and, in the two-dimensional limit, the zero-temperature mean-field Bose-Einstein-condensation to Bardeen-Cooper-Schrieffer crossover theory.
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http://dx.doi.org/10.1103/PhysRevLett.108.045302 | DOI Listing |
Commun Math Phys
September 2025
Institute of Mathematics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
We give a rigorous derivation of the Hartree equation for the many-body dynamics of pseudo-relativistic Fermi systems at high density , on arbitrarily large domains, at zero temperature. With respect to previous works, we show that the many-body evolution can be approximated by the Hartree dynamics locally, proving convergence of the expectation of observables that are supported in regions with fixed volume, independent of . The result applies to initial data describing fermionic systems at equilibrium confined in arbitrarily large domains, under the assumption that a suitable local Weyl-type estimate holds true.
View Article and Find Full Text PDFNano Lett
September 2025
Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy.
Exciton-to-trion conversion in two-dimensional semiconductors defines the transition from an optoelectronics based on neutral bosons to one based on charged fermions, with a huge impact on the transport and spin/valley-related properties. This process has been successfully induced in field-effect transistors under gate voltage, chemically doped samples, and nonuniformly nanoscale-strained materials. Here, we study the evolution of the photoluminescence spectrum of monolayer WS under high pressure, decoupling exciton and trion contributions by their responses to laser-power variations.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
Los Alamos National Laboratory, Theoretical Division, Los Alamos, New Mexico 87545, USA.
In nuclei with an odd nucleon number the nonvanishing spin number density is the source of a pseudomagnetic field, which favors the splitting of the nucleon Cooper pairs. Such a pseudomagnetic field is generated always in the dynamics of any nucleus, but its effects on Cooper pairs are significantly enhanced in the dynamic evolution of nuclei with an odd number of nucleons. We present for the first time a microscopic study of the induced fission of the odd neutron compound nuclei ^{239}U, ^{241,243}Pu, and the odd proton, odd neutron compound nucleus ^{238}Np, performed within the time-dependent density functional theory extended to superfluid fermion systems, without any simplifying assumptions, with controlled numerical approximations, and for a very large number of initial conditions.
View Article and Find Full Text PDFAdv Mater
August 2025
PSI Center for Neutron and Muon Sciences CNM, 5232, Villigen PSI, Switzerland.
Chiral crystals, whose key feature is the structural handedness, host exotic quantum phenomena driven by the interplay of band topology, spin-orbit coupling (SOC), and electronic correlations. Due to the limited availability of suitable chiral-crystal materials, their unconventional superconductivity (SC) remains largely unexplored. Here, the discovery of unconventional SC in the La(Rh,Ir)Si family of materials is reported by combining muon-spin spectroscopy, band-structure calculations, and perturbation theory.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
University of California, Department of Physics, Santa Barbara, California 93106, USA.
We demonstrate that, starting with a simple fermion wave function, the steady mixed state of the evolution of a class of Lindbladians, and the ensemble created by strong local measurement of fermion density without postselection can be mapped to the "Gutzwiller projected" wave functions in the doubled Hilbert space-the representation of the density matrix through the Choi-Jamiołkowski isomorphism. A Gutzwiller projection is a broadly used approach of constructing spin liquid states. For example, if one starts with a gapless free Dirac fermion pure quantum state, the constructed mixed state corresponds to an algebraic spin liquid in the doubled Hilbert space.
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