Multicomponent Kardar-Parisi-Zhang universality in degenerate coupled condensates
Abstract Gapless phase modes in non-equilibrium condensates fall within the Kardar-Parisi-Zhang (KPZ) universality class, but key single-component symmetries do not clearly generalise to the multicomponent case. We discuss the phase diagram of coupled KPZ equations describing the low-energy theory o...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-08-01
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| Series: | Communications Physics |
| Online Access: | https://doi.org/10.1038/s42005-025-02233-8 |
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| Summary: | Abstract Gapless phase modes in non-equilibrium condensates fall within the Kardar-Parisi-Zhang (KPZ) universality class, but key single-component symmetries do not clearly generalise to the multicomponent case. We discuss the phase diagram of coupled KPZ equations describing the low-energy theory of a $${{\mathbb{Z}}}_{2}$$ Z 2 degenerate driven-dissipative condensate with global U(1) × U(1) symmetry. In the homogeneous condensate regime, a dynamical renormalisation group (RG) analysis in one dimension reveals that coupled stochastic complex Ginsburg-Landau equations exhibit an emergent stationary distribution, enforcing the KPZ dynamical exponent z = 3/2 and roughness exponent χ = 1/2 for both components. In specific parameter regimes relevant to polaritons, the RG fixed point offers a transformation to decoupled KPZ equations. By tuning the intercomponent coupling, the system offers non-KPZ regimes, including a fragmentation transition, and a non-thermal spacetime vortex phase driven by the KPZ non-linear terms. Our findings have broad implications for experiments and understanding multicomponent KPZ systems in the long-wavelength limit. |
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| ISSN: | 2399-3650 |