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Fermions in a random medium

Harald Kinzelbach·Michael Lassig
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Abstract

We study the continuum field theory for an ensemble of directed polymers r_i (t) in 1+d' dimensions that live in a medium with quenched point disorder and interact via short-ranged pair forces g Ψ(r_i - r_j). In the strong-disorder (or low-temperature) regime, such forces are found to be relevant in any dimension d' below the upper critical dimension for a single line. Attractive forces generate a bound state with localization length ξ_\perp \sim |g|^{-ν_\perp}; repulsive forces lead to mutual avoidance with a pair distribution function P(r_i - r_j) \sim |r_i - r_j|^θreminiscent of interacting fermions. In the experimentally important dimension d' = 2, we obtain ν_\perp \approx 0.8 and θ\approx 2.4 .

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Harald Kinzelbach, Michael Lassig. 1994-11-29. Fermions in a random medium. https://arxiv.org/abs/cond-mat/9411126

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