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arXiv · 2109.06891

Topological gauge theory for mixed Dirac stationary states in all dimensions

Ze-Min Huang·Xiao-Qi Sun·Sebastian Diehl
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Abstract

We derive the universal real time $U(1)$ topological gauge field action for mixed quantum states of weakly correlated fermions in all dimensions, and demonstrate its independence of the underlying equilibrium or non-equilibrium nature of dynamics stabilizing the state. The key prerequisites are charge quantization and charge conservation. The gauge action encodes non-quantized linear responses as expected for mixed states, but also quantized non-linear responses, associated to mixed state topology and accessible in experiment. Our construction furthermore demonstrates how the physical pictures of anomaly inflow and bulk-boundary correspondence extend to non-equilibrium systems.

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Ze-Min Huang, Xiao-Qi Sun, Sebastian Diehl. 2021-09-14. Topological gauge theory for mixed Dirac stationary states in all dimensions. https://doi.org/10.1103/physrevb.106.245204

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