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arXiv · 1807.09184

Strong randomness criticality in the scratched-XY model

Tobias Pfeffer·Zhiyuan Yao·Lode Pollet
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Abstract

We study the finite-temperature superfluid transition in a modified two-dimensional (2D) XY model with power-law distributed "scratch"-like bond disorder. As its exponent decreases, the disorder grows stronger and the mechanism driving the superfluid transition changes from conventional vortex-pair unbinding to a strong randomness criticality (termed scratched-XY criticality) characterized by a non-universal jump of the superfluid stiffness. The existence of the scratched-XY criticality at finite temperature and its description by an asymptotically exact semi-renormalization group theory, previously developed for the superfluid-insulator transition in one-dimensional disordered quantum systems, is numerically proven by designing a model with minimal finite size effects. Possible experimental implementations are discussed.

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Tobias Pfeffer, Zhiyuan Yao, Lode Pollet. 2018-07-24. Strong randomness criticality in the scratched-XY model. https://doi.org/10.1103/physrevb.99.104514

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