Fidelity susceptibility and general quench near an anisotropic quantum critical point

Article

关键词: PHASE-TRANSITIONS;    DYNAMICS;    SYSTEMS;   

DOI  :  10.1103/PhysRevB.83.214302

来源: SCIE

【 摘 要 】

We study the scaling behavior of fidelity susceptibility density (chi(f)) at or close to an anisotropic quantum critical point (AQCP) characterized by two different correlation length exponents nu(parallel to) and nu(perpendicular to) along parallel and perpendicular spatial directions, respectively. Our studies show that the response of the system due to a small change in the Hamiltonian near an AQCP is different from that seen near an isotropic QCP. In particular, for a finite system with linear dimension L-parallel to (L-perpendicular to) in the parallel (perpendicular) directions, the maximum value of chi(f) is found to increase in a power-law fashion with L-parallel to for small L-parallel to, with an exponent depending on both nu(parallel to) and nu(perpendicular to) and eventually crosses over to a scaling with L-perpendicular to for L-parallel to(1/nu parallel to) greater than or similar to L-perpendicular to(1/nu perpendicular to). We also propose scaling relations of heat density and defect density generated following a quench starting from an AQCP and connect them to a generalized fidelity susceptibility. These predictions are verified exactly both analytically and numerically taking the example of a Hamiltonian showing a semi-Dirac band-crossing point.

【 授权许可】

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