# Electric field control of emergent electrodynamics in quantum spin ice

## TL;DR

This paper explores how applying electric fields influences the emergent electrodynamics in quantum spin ice, revealing tunable phases, anisotropic light propagation, and potential experimental detection of phase transitions.

## Contribution

It demonstrates electric field control over quantum spin ice phases, inducing birefringence, phase transitions, and emergent radiation, advancing understanding of emergent gauge fields in quantum materials.

## Key findings

- Electric fields induce anisotropic emergent light in quantum spin ice.
- Strong electric fields can trigger phase transitions to new $U(1)$ spin liquid phases.
- Emergent pinch points appear near phase transitions, indicating changes in spin correlations.

## Abstract

We study the coupling between conventional (Maxwell) and emergent electrodynamics in quantum spin ice, a 3+1-dimensional $U(1)$ quantum spin liquid. We find that a uniform electric field can be used to tune the properties of both the ground state and excitations of the spin liquid. In particular, it induces emergent birefringence, rendering the speed of the emergent light anisotropic and polarization-dependent. A sufficiently strong electric field triggers a quantum phase transition into new $U(1)$ quantum spin liquid phases which trap emergent electric $\pi$-fluxes. The flux patterns of these new phases depend on the direction of the electric field. Strikingly, some of the canonical pinch points in the spin structure factor, characteristic of classical spin ice, emerge near the phase transition, while they are absent in the quantum spin liquid phases. Estimating the electric field strength required, we find that this transition is potentially accessible experimentally. Finally, we propose a minimal mechanism by which an oscillating electric field can generate emergent radiation inside a quantum spin ice material with non-Kramers spin doublets.