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arXiv · 1611.04550

On the equivalence of models with similar low-energy quasiparticles

Mirko M. Möller·Mona Berciu
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Abstract

We use a Metropolis algorithm to calculate the finite temperature spectral weight of three related models that have identical quasiparticles at $T=0$, if the exchange favors the appearance of a ferromagnetic background. The low-energy behavior of two of the models remains equivalent at finite temperature, however that of the third does not because its low-energy behavior is controlled by rare events due to thermal fluctuations, which transfer spectral weight well below the $T=0$ quasiparticle peaks and generate a pseudogap-like phenomenology. Our results demonstrate that having $T=0$ spectra with similar quasiparticles is not a sufficient condition to ensure that two models are equivalent, {\em i.e.} that their low-energy properties are similar. We also argue that the pseudogap-like phenomenology is quite generic for models of $t$-$J$ type, appearing in any dimension and for carriers injected into both ferromagnetic and antiferromagnetic backgrounds.

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Mirko M. Möller, Mona Berciu. 2016-11-14. On the equivalence of models with similar low-energy quasiparticles. https://doi.org/10.1103/physrevb.92.214422

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