2001/03/21 by Malcolm P. Kennett, Claudio Chamon, Jinwu Ye · 42 citations
Materials Science · Mathematics · Physics and Astronomy · #Condensed matter physics #Dynamics (music) #Material Dynamics and Properties #Materials science #Physics #Quantum #Quantum mechanics #Random Matrices and Applications #Spin (aerodynamics) #Spin glass #Statistical physics #Theoretical and Computational Physics #Thermodynamics #cond-mat.dis-nn
paper · pdf · doi:10.1103/physrevb.64.224408
published in Physical review. B, Condensed matter 64(22) (American Physical Society) · 14 pages, 4 figures
arxiv created 2001/03/21 · openalex publication_date 2001/11/20 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the long time dynamics of quantum spin glasses of rotors using the nonequilibrium Schwinger-Keldysh formalism. These models are known to have a quantum phase transition from a paramagnetic to a spin-glass phase, which we approach by looking at the divergence of the spin-relaxation rate at the transition point. In the aging regime, we determine the dynamical equations governing the time evolution of the spin response and correlation functions, and show that all terms in the equations that arise solely from quantum effects are irrelevant at long times under time reparametrization group (RPG) transformations. At long times, quantum effects enter only through the renormalization of the parameters in the dynamical equations for the classical counterpart of the rotor model. Consequently, quantum effects only modify the out-of-equilibrium fluctuation-dissipation relation (OEFDR), i.e. the ratio X between the temperature and the effective temperature, but not the form of the classical OEFDR.