paper

Oscillating fidelity susceptibility near a quantum multicritical point

arXiv:1010.4446 · doi:10.1103/PhysRevB.83.075118

Abstract

We study scaling behavior of the geometric tensor and the fidelity susceptibility in the vicinity of a quantum multicritical point (MCP) using the example of a transverse XY model. We show that the behavior of the geometric tensor (and thus of ) is drastically different from that seen near a critical point. In particular, we find that is highly non-monotonic function of along the generic direction when the system size is bounded between the shorter and longer correlation lengths characterizing the MCP: , where are the two correlation length exponents characterizing the system. We find that the scaling of the maxima of the components of is associated with emergence of quasi-critical points at , related to the proximity to the critical line of finite momentum anisotropic transition. This scaling is different from that in the thermodynamic limit , which is determined by the conventional critical exponents. We use our results to calculate the defect density following a rapid quench starting from the MCP and show that it exerts a step-like behavior for small quench amplitudes. Study of heat density and diagonal entropy density also show signatures of quasi-critical points.

12 pages, 9 figures

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Oscillating fidelity susceptibility near a quantum multicritical point · wovepaper