10,285 research outputs found
Non-Fermi-liquid behavior and anomalous suppression of Landau damping in layered metals close to ferromagnetism
We analyse the low-energy physics of nearly ferromagnetic metals in two
spatial dimensions using the functional renormalization group technique. We
find a new low-energy fixed point, at which the fermionic (electron-like)
excitations are non-Fermi-liquid () and the magnetic fluctuations
exhibit an anomalous Landau damping whose rate vanishes as in the low- limit. We discuss
this renormalization of the Landau-damping exponent, which is the major novel
prediction of our work, and highlight the possible link between that
renormalization and neutron-scattering data on UGe and related compounds.
Implications of our analysis for YFeAl are also discussed.Comment: 5 pages, 3 figures; action modified to include spin of fermions,
resulting in quantitative changes to exponents but same essential physic
The 2-generalized knot group determines the knot
Generalized knot groups were introduced independently by Kelly
(1991) and Wada (1992). We prove that determines the unoriented knot
type and sketch a proof of the same for for .Comment: 4 page
Evolution of virulence in opportunistic pathogens: generalism, plasticity, and control
Standard virulence evolution theory assumes that virulence factors are maintained because they aid parasitic exploitation, increasing growth within and/or transmission between hosts. An increasing number of studies now demonstrate that many opportunistic pathogens (OPs) do not conform to these assumptions, with virulence factors maintained instead because of advantages in non-parasitic contexts. Here we review virulence evolution theory in the context of OPs and highlight the importance of incorporating environments outside a focal virulence site. We illustrate that virulence selection is constrained by correlations between these external and focal settings and pinpoint drivers of key environmental correlations, with a focus on generalist strategies and phenotypic plasticity. We end with a summary of key theoretical and empirical challenges to be met for a fuller understanding of OPs
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