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arXiv · 1402.3098

Higgs amplitude mode in the vicinity of a $(2+1)$-dimensional quantum critical point

A. Rancon·N. Dupuis
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Abstract

We study the "Higgs" amplitude mode in the relativistic quantum O($N$) model in two space dimensions. Using the nonperturbative renormalization group we compute the O($N$)-invariant scalar susceptibility in the vicinity of the zero-temperature quantum critical point. In the zero-temperature ordered phase, we find a well defined Higgs resonance for $N=2$ with universal properties in agreement with quantum Monte Carlo simulations. The resonance persists at finite temperature below the Berezinskii-Kosterlitz-Thouless transition temperature. In the zero-temperature disordered phase, we find a maximum in the spectral function which is however not related to a putative Higgs resonance. Furthermore we show that the resonance is strongly suppressed for $N\geq 3$.

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A. Rancon, N. Dupuis. 2014-05-20. Higgs amplitude mode in the vicinity of a $(2+1)$-dimensional quantum critical point. https://doi.org/10.1103/physrevb.89.180501

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