Quantum simulation of parity-time symmetry breaking with a superconducting quantum processor

TL;DR

This paper demonstrates quantum simulation of parity-time symmetry breaking on a superconducting quantum processor, revealing phase transitions, critical exponents, and entanglement modifications, advancing understanding of non-Hermitian quantum systems.

Contribution

It introduces a method to simulate non-Hermitian Hamiltonians using a superconducting quantum processor with an ancillary qubit, enabling exploration of $ ext{PT}$-symmetry breaking in the quantum regime.

Findings

Observation of $ ext{PT}$-symmetry breaking phase transition at exceptional points

Measurement of the critical exponent associated with the transition

Demonstration of entanglement modification via local operations

Abstract

The observation of genuine quantum effects in systems governed by non-Hermitian Hamiltonians has been an outstanding challenge in the field. Here we simulate the evolution under such Hamiltonians in the quantum regime on a superconducting quantum processor by using a dilation procedure involving an ancillary qubit. We observe the parity-time ($\mathcal{PT}$)-symmetry breaking phase transition at the exceptional points, obtain the critical exponent, and show that this transition is associated with a loss of state distinguishability. In a two-qubit setting, we show that the entanglement can be modified by local operations.