Observation of Kardar-Parisi-Zhang universal scaling in two dimensions
Summary
Equilibrium and nonequilibrium states of matter can exhibit fundamentally different behavior. A key example is the Kardar-Parisi-Zhang universality class in two spatial dimensions (2D KPZ), where microscopic deviations from equilibrium give rise to macroscopic scaling laws without equilibrium counterparts. Although extensively studied theoretically, experimental evidence of 2D KPZ scaling has remained limited to interface growth. Here, we report the observation of KPZ universal scaling in
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# Observation of Kardar-Parisi-Zhang universal scaling in two dimensions
*Published: 2026 Apr 9*
Equilibrium and nonequilibrium states of matter can exhibit fundamentally
different behavior. A key example is the Kardar-Parisi-Zhang universality class
in two spatial dimensions (2D KPZ), where microscopic deviations from
equilibrium give rise to macroscopic scaling laws without equilibrium
counterparts. Although extensively studied theoretically, experimental evidence
of 2D KPZ scaling has remained limited to interface growth. Here, we report the
observation of KPZ universal scaling in 2D exciton-polariton condensates-quantum
fluids of light that inherently break equilibrium conditions. Using spectroscopy
and Michelson interferometry, we probed the phase correlations across
microscopically different systems. Our analysis revealed correlation dynamics
and scaling exponents in excellent agreement with 2D KPZ predictions. These
results establish exciton-polariton condensates as an experimental platform for
exploring 2D nonequilibrium universality.
DOI: 10.1126/science.aeb4154