1,028 research outputs found

    Coupled Ferromagnetic and Nematic Ordering of Fermions in an Optical Flux Lattice

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    Ultracold atoms in Raman-dressed optical lattices allow for effective momentum-dependent interactions among single-species fermions originating from short-range s-wave interactions. These dressed-state interactions combined with very flat bands encountered in the recently introduced optical flux lattices push the Stoner instability towards weaker repulsive interactions, making it accessible with current experiments. As a consequence of the coupling between spin and orbital degrees of freedom, the magnetic phase features Ising nematic order.Comment: 5 pages, 4 figures (published version

    The spiritual value of ecosystem services: an initial Christian exploration

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    An analysis of conceptualisations of spiritual value in the ecosystem services literature and of nature in Christian, biblical thought. Plus suggestions on how Christian approaches to decision-making could contribute to this field

    Composite fermion dynamics in half-filled Landau levels of graphene

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    We report on exact-diagonalization studies of correlated many-electron states in the half-filled Landau levels of graphene, including pseudospin (valley) degeneracy. We demonstrate that the polarized Fermi sea of non-interacting composite fermions remains stable against a pairing transition in the lowest two Landau levels. However, it undergoes spontaneous depolarization, which is unprotected owing to the lack of single-particle pseudospin splitting. These results suggest the absence of the Pfaffian phase in graphene.Comment: 3 pages, 4 figures (revision: reference update

    Neutral Fermion Excitations in the Moore-Read state at \nu=5/2

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    We present evidence supporting the weakly paired Moore-Read phase in the half-filled second Landau level, focusing on some of the qualitative features of its excitations. Based on numerical studies, we show that systems with odd particle number at the flux Nϕ=2N−3N_\phi=2N-3 can be interpreted as a neutral fermion mode of one unpaired fermion, which is gapped. The mode is found to have two distinct minima, providing a signature that could be observed by photoluminescence. In the presence of two quasiparticles the same neutral fermion excitation is shown to be gapless, confirming expectations for non-Abelian statistics of the Ising model with degenerate fusion channels 1 and ψ\psi.Comment: 4 pages, 4 figures; v2: final published versio
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