2020/06/30 by A. V. Lunkin, Alexei Kitaev, A. Yu. Kitaev +2 · 24 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Cold Atom Physics and Bose-Einstein Condensates #Exponent #Instanton #Lyapunov exponent #Mathematical physics #Order (exchange) #Physics #Physics of Superconductivity and Magnetism #Polaron #Quantum mechanics #cond-mat.str-el #hep-th
paper · pdf · doi:10.1103/physrevlett.125.196602
published in Physical Review Letters 125(19), 196602 (American Physical Society) · 12 pages
arxiv created 2020/11/03 · openalex publication_date 2020/11/03 · arxiv updated 2020/11/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the Sachdev-Ye-Kitaev (SYK4) model with a weak SYK2 term of magnitude \mathrm\ensuremathΓ beyond the simplest perturbative limit considered previously. For intermediate values of the perturbation strength, J/N\ensuremath≪\mathrm\ensuremathΓ\ensuremath≪J/√(N), fluctuations of the Schwarzian mode are suppressed, and the SYK4 mean-field solution remains valid beyond the timescale t0\ensuremath∼N/J up to t*\ensuremath∼J/\mathrm\ensuremathΓ2. The out-of-time-order correlation function displays at short time intervals exponential growth with maximal Lyapunov exponent 2\ensuremathπT, but its prefactor scales as T at low temperatures T\ensuremath≤\mathrm\ensuremathΓ.