Quantum dynamics of two $XX$ interacting PT-symmetric non-Hermitian qubits: enhancement of quantum annealing

TL;DR

This paper proposes a network of interacting PT-symmetric non-Hermitian qubits for quantum annealing, showing that small non-Hermitian terms can significantly improve ground state reachability.

Contribution

It introduces a theoretical model of interacting PT-symmetric qubits and demonstrates enhanced quantum annealing performance through non-Hermitian term addition.

Findings

Adding tiny PT-symmetric non-Hermitian terms enhances ground state probability.

Analysis of symmetry-preserving and symmetry-broken regimes.

The minimal model provides insights into interacting non-Hermitian quantum systems.

Abstract

Quantum information platforms enable analog quantum simulations, such as quantum annealing, offering a promising route to solving complex combinatorial optimization problems. Here, we propose a quantum information architecture based on networks of interacting parity-time (PT)-symmetric non-Hermitian qubits. While the dynamics of individual PT-symmetric qubits have been experimentally demonstrated across multiple platforms including NV centers, superconducting circuits, and trapped-ion systems yet coherent dynamics in interacting systems remain largely unexplored. To address this issue we theoretically investigate stationary and time-dependent Hamiltonians relevant to quantum annealing using a minimal model of two interacting XX-coupled PT-symmetric non-Hermitian qubits. We analyze both symmetry-preserving and symmetry-broken regimes and demonstrate that adding even tiny PT-symmetric non-Hermitian terms in the qubits Hamiltonian allows to greatly enhance the probability of reaching the ground state after annealing.