Chiral transport of pseudo-spinors induced by synthetic gravitational field in photonic Weyl metamaterials

TL;DR

This paper demonstrates how Weyl metamaterials with spatially controlled nonlocality can simulate gravitational fields, leading to observable chiral transport phenomena akin to those predicted for Weyl particles in curved spacetime.

Contribution

It introduces a novel approach to mimic gravitational effects in Weyl metamaterials, enabling experimental study of chiral gravitational effects without real Weyl particles.

Findings

Spatial modulation induces curved spacetime analog in Weyl cones

Quantization of energy levels including chiral zero modes

Experimental platform for observing chiral gravitational effects

Abstract

Weyl particles exhibit chiral transport property under external curved space-time geometry. This effect is called chiral gravitational effect, which plays an important role in quantum field theory. However, the absence of real Weyl particles in nature hinders the observation of such interesting phenomena. In this paper, we show that chiral gravitational effect can be manifested in Weyl metamaterials with spatially controlled nonlocality. This inhomogeneous modulation results in a spatially dependent group velocity in the Weyl cone dispersion, which is equivalent to introducing a curved background space-time (or gravitational field) for Weyl pseudo-spinors. The synthetic gravitational field leads to the quantization of energy levels, including chiral zeroth order energy modes (or simply chiral zero modes) that determine the chiral transport property of pseudo-spinors. The inhomogeneous Weyl metamaterial provides an experimentally realizable platform for investigating the interaction between Weyl particles and gravitational field, allowing for observation of chiral gravitational effect in table-top experiments.