Observation of quantum superposition of topological defects in a trapped ion quantum simulator

TL;DR

This paper reports the first experimental observation of quantum superposition of topological defects in a trapped-ion quantum simulator, demonstrating non-locality and quantum interference in such states.

Contribution

It experimentally realizes and observes quantum superpositions of topological defects, advancing understanding of quantum phase transitions and non-equilibrium dynamics.

Findings

Observation of a superposition of spin kinks at different positions

Demonstration of quantum interference and non-locality in superposed states

Verification of quantum coherence through wave packet propagation

Abstract

Topological defects are discontinuities of a system protected by global properties, with wide applications in mathematics and physics. While previous experimental studies mostly focused on their classical properties, it has been predicted that topological defects can exhibit quantum superposition. Despite the fundamental interest and potential applications in understanding symmetry-breaking dynamics of quantum phase transitions, its experimental realization still remains a challenge. Here, we report the observation of quantum superposition of topological defects in a trapped-ion quantum simulator. By engineering long-range spin-spin interactions, we observe a spin kink splitting into a superposition of kinks at different positions, creating a ``Schrodinger kink'' that manifests non-locality and quantum interference. Furthermore, by preparing superposition states of neighboring kinks with different phases, we observe the propagation of the wave packet in different directions, thus unambiguously verifying the quantum coherence in the superposition states. Our work provides useful tools for non-equilibrium dynamics in quantum Kibble-Zurek physics.