Finite-temperature crossover from coherent magnons to energy superdiffusion in the PXP model
Year: 2026
Type: article
Abstract: The PXP chain was recently shown to exhibit superdiffusive energy transport with Kardar-Parisi-Zhang-like scaling, $z\approx3/2$, joining a growing number of spin chains with this exponent. An understanding of how this anomalous hydrodynamics emerges from microscopics is, however, still lacking. In this work, we show that finite-temperature energy transport in this model provides a window into the emergence of superdiffusion. At finite temperature, the energy autocorrelation function exhibits a crossover from short-time coherent dynamics to long-time hydrodynamics. The short-time behavior is dominated by a single magnon band and can be understood analytically. In momentum space, this regime is characterized by spectral weight near $q=π$. The damping time $τ$, which separates the short-time magnon-dominated behavior from the late-time hydrodynamics, grows rapidly upon cooling, consistent with an activated form $τ(β)\sim βe^{Δβ}$ with a gap scale set by the magnon band. At longer times, the spectral weight transfers to $q=0$ and the running decay exponent drifts toward the superdiffusive value $z=3/2$. Finite-temperature energy transport therefore provides a bridge between microscopic magnon physics and late-time superdiffusion in the PXP model.
DOI: 10.1103/mx9k-1mc6
Language: English
Topic: Quantum many-body systems
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1229526393, G1286251239, G1768993395, G1849965876, G2371548206, G2396176815, G2586477669, IST-BRIDGE: International postdoctoral program, G4711507462, G498139845, G5405102689, G5570207115, G6550344761, G7283024673, G8204283603, G8382000481, EXC 2111: Munich Center for Quantum Science and Technology (MCQST), G8945569637, G911061179, G969889393
OpenAlex ID: W7201842646