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Ordered droplets in quantum magnets with long-range interactions

Thomas Vojta·Jose A Hoyos
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Abstract

A defect coupling to the square of the order parameter in a nearly quantum-critical magnet can nucleate an ordered droplet while the bulk system is in the paramagnetic phase. We study the influence of long-range spatial interactions of the form $r^{-(d+σ)}$ on the droplet formation. To this end, we solve a Landau-Ginzburg-Wilson free energy in saddle point approximation. The long-range interaction causes the droplet to develop an energetically unfavorable power-law tail. However, for $σ>0$, the free energy contribution of this tail is subleading in the limit of large droplets; and the droplet formation is controlled by the defect bulk. Thus, for large defects, long-range interactions do not hinder the formation of droplets.

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Thomas Vojta, Jose A Hoyos. 2008-03-04. Ordered droplets in quantum magnets with long-range interactions. https://doi.org/10.1016/j.physb.2007.10.252

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