Quantum tomography of a third-order exceptional point in a dissipative trapped ion
Abstract
The requirement for Hermiticity in quantum mechanics ensures the reality of energies, while the parity-time symmetry offers an alternative route to achieve this goal. Interestingly, in a three-level system, the parity-time symmetry-breaking can lead to a third-order exceptional point with distinctive topological properties and enhanced sensitivity. To experimentally implement this in open quantum systems, it is essential to introduce two well-controlled loss channels. However, the requirement for these two loss channels presents a challenge in experimental implementation due to the lack of methods to realize the dynamics governed by an effective non-Hermitian Hamiltonian. Here we address the challenge by employing two approaches to eliminate the effects of quantum jump terms so that the dynamics is governed by an effective non-Hermitian Hamiltonian in a dissipative trapped ion with two loss channels. Based on this, we experimentally observe the parity-time symmetry-breaking-induced third-order exceptional point through non-Hermitian absorption spectroscopy. In particular, we perform quantum state tomography to directly demonstrate the coalescence of three eigenstates into a single eigenstate at the exceptional point. Finally, we identify an intrinsic third order Liouvillian exceptional point associated with a parity-time symmetry breaking via quench dynamics. Our experiments can be extended to observe other non-Hermitian phenomena involving more than two levels and potentially find applications in quantum information technology.
Keywords
Cite
@article{arxiv.2412.05870,
title = {Quantum tomography of a third-order exceptional point in a dissipative trapped ion},
author = {Y. -Y. Chen and K. Li and L. Zhang and Y. -K. Wu and J. -Y. Ma and H. -X. Yang and C. Zhang and B. -X. Qi and Z. -C. Zhou and P. -Y. Hou and Y. Xu and L. -M. Duan},
journal= {arXiv preprint arXiv:2412.05870},
year = {2025}
}