Simulating a Topological Transition in a Superconducting Phase Qubit by Fast Adiabatic Trajectories

TL;DR

This paper demonstrates a fast adiabatic simulation of topological phase transitions in a superconducting phase qubit using shortcut to adiabaticity, enabling efficient probing of topological invariants like the winding number and Chern number.

Contribution

It introduces a novel application of shortcut to adiabaticity in superconducting qubits to simulate topological phases rapidly and accurately.

Findings

Successfully simulated topological transition in a superconducting qubit.

Measured the topological invariant (winding number) experimentally.

Identified the Chern number in a 2D toy model.

Abstract

The significance of topological phases has been widely recognized in the community of condensed matter physics. The well controllable quantum systems provide an artificial platform to probe and engineer various topological phases. The adiabatic trajectory of a quantum state describes the change of the bulk Bloch eigenstates with the momentum, and this adiabatic simulation method is however practically limited due to quantum dissipation. Here we apply the `shortcut to adiabaticity' (STA) protocol to realize fast adiabatic evolutions in the system of a superconducting phase qubit. The resulting fast adiabatic trajectories illustrate the change of the bulk Bloch eigenstates in the Su-Schrieffer-Heeger (SSH) model. A sharp transition is experimentally determined for the topological invariant of a winding number. Our experiment helps identify the topological Chern number of a two-dimensional toy model, suggesting the applicability of the fast adiabatic simulation method for topological systems.