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arXiv · 1402.0241

Ultra-soft fermionic excitation at finite chemical potential

Jean-Paul Blaizot·Daisuke Satow
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Abstract

It has been suggested previously that an ultra-soft fermionic excitation develops, albeit with a small spectral weight, in a system of massless fermions and scalar bosons with Yukawa interaction at high temperature ($T$). In this paper we study how this excitation is modified at finite chemical potential ($μ$). We relate the existence of the ultra-soft mode to symmetries, in particular charge conjugation, and a supersymmetry of the free system which is spontaneously broken by finite temperature and finite density effects, as argued earlier by Lebedev and Smilga. A non vanishing chemical potential breaks both symmetries explicitly, and maximally at zero temperature where the mode ceases to exist. A detailed calculation indicates that the ultra-soft excitation persists as long as $T\gtrsim μ$.

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Jean-Paul Blaizot, Daisuke Satow. 2014-05-13. Ultra-soft fermionic excitation at finite chemical potential. https://doi.org/10.1103/physrevd.89.096001

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