Observation of the ground-state-geometric phase in a Heisenberg XY model

TL;DR

This paper reports the first experimental observation of the ground-state geometric phase in a Heisenberg XY model, demonstrating its connection to quantum phase transitions through NMR interferometry.

Contribution

It provides the first experimental measurement of the ground-state geometric phase as a topological indicator of quantum phase transitions in a spin model.

Findings

Measured geometric phase for different adiabatic circuits.

Confirmed the geometric phase's role as a topological marker.

Demonstrated the connection between geometric phase and quantum transitions.

Abstract

Geometric phases play a central role in a variety of quantum phenomena, especially in condensed matter physics. Recently, it was shown that this fundamental concept exhibits a connection to quantum phase transitions where the system undergoes a qualitative change in the ground state when a control parameter in its Hamiltonian is varied. Here we report the first experimental study using the geometric phase as a topological test of quantum transitions of the ground state in a Heisenberg XY spin model. Using NMR interferometry, we measure the geometric phase for different adiabatic circuits that do not pass through points of degeneracy.