Observation of parity-time symmetry breaking in a single spin system
Abstract
A fundamental axiom of quantum mechanics requires the Hamiltonians to be Hermitian which guarantees real eigen-energies and probability conservation. However, a class of non-Hermitian Hamiltonians with Parity-Time () symmetry can still display entirely real spectra. The Hermiticity requirement may be replaced by symmetry to develop an alternative formulation of quantum mechanics. A series of experiments have been carried out with classical systems including optics, electronics, microwaves, mechanics and acoustics. However, there are few experiments to investigate symmetric physics in quantum systems.Here we report the first observation of the symmetry breaking in a single spin system. We have developed a novel method to dilate a general symmetric Hamiltonian into a Hermitian one, which can be realized in a practical quantum system.Then the state evolutions under symmetric Hamiltonians, which range from symmetric unbroken to broken regions, have been experimentally observed with a single nitrogen-vacancy (NV) center in diamond. Due to the universality of the dilation method, our result opens a door for further exploiting and understanding the physical properties of symmetric Hamiltonian in quantum systems.
Keywords
Cite
@article{arxiv.1812.05226,
title = {Observation of parity-time symmetry breaking in a single spin system},
author = {Yang Wu and Wenqiang Liu and Jianpei Geng and Xingrui Song and Xiangyu Ye and Chang-Kui Duan and Xing Rong and Jiangfeng Du},
journal= {arXiv preprint arXiv:1812.05226},
year = {2019}
}