Emerging (2+1)D electrodynamics and topological instanton in pseudo-Hermitian two-level systems

• URL: http://arxiv.org/abs/2505.07791v1
• Date: Mon, 12 May 2025 17:43:54 GMT
• Title: Emerging (2+1)D electrodynamics and topological instanton in pseudo-Hermitian two-level systems
• Authors: Kuangyin Deng, Ran Cheng,
• Abstract summary: Even when the Hamiltonian does not explicitly depend on time, the Berry curvature can be mapped onto a $2+1$ dimensional electromagnetic field.<n>The instanton appearing as a spacetime singularity carries a topological charge that quantizes the jump of magnetic flux of the Berry curvature at the time origin.
• Score: 8.937248059172983
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We reveal a hidden electrodynamical structure emerging from a general $2\times2$ pseudo-Hermitian system that exhibits real spectra. Even when the Hamiltonian does not explicitly depend on time, the Berry curvature can be mapped onto a $2+1$ dimensional electromagnetic field arising from an artificial spacetime instanton, in sharp contrast to the Hermitian systems where the Berry curvature is equivalent to the static magnetic field of a magnetic monopole in three spatial dimensions. The instanton appearing as a spacetime singularity carries a topological charge that quantizes the jump of magnetic flux of the Berry curvature at the time origin. Our findings are demonstrated in a simple example related to antiferromagnetic magnons.

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