Magnetochiral eigenstate of the Heisenberg chain with spontaneous symmetry breaking

TL;DR

This paper introduces a method to generate high-energy eigenstates in quantum systems using deformed Hamiltonians, demonstrating an exact solution for a chiral Heisenberg chain that exhibits spontaneous symmetry breaking and ballistic transport.

Contribution

It presents a novel protocol for constructing atypical eigenstates via Hamiltonian deformation and provides an exact Bethe ansatz solution for a chiral Heisenberg chain with spontaneous symmetry breaking.

Findings

Ground state is a magnetized, current-carrying eigenstate.

State breaks SU(2), time-reversal, and parity symmetries.

Exhibits ballistic spin and chirality transport.

Abstract

We propose a protocol to construct atypical high-energy eigenstates in quantum systems by using ground states of Hamiltonians deformed by conserved charges. For the spin-1/2 Heisenberg XXX chain we study a chiral Hamiltonian built from the scalar-chirality charge and total magnetization and solve it exactly by Bethe ansatz. Its ground state is a magnetized, current-carrying XXX eigenstate that breaks SU(2), time-reversal, and parity yet stays critical. This zero-entropy macrostate shows ballistic spin and chirality transport and admits realistic cold-atom and Rydberg platforms.