PT -symmetric quantum sensing: Advantages and restrictions

Quantum sensing utilizing unique quantum properties of non-Hermitian systems to realize ultraprecision measurements has been attracting increasing attention. However, the debate on whether non-Hermitian systems are superior to Hermitian counterparts in sensing remains an open question. Here, we investigate the quantum information in PT-symmetric quantum sensing utilizing two experimental schemes based on the trapped-ion platform and explore the relationship between PT-symmetric quantum sensors and quantum resources. It turns out that the existence of advantages of non-Hermitian quantum sensing heavily depends on additional information resources carried by the extra degrees of freedom introduced to construct PT-symmetric quantum sensors. Moreover, the practical application of non-Hermitian quantum sensing with superior performance is primarily restricted by the extra resource consumption accompanied by the postselection, while the superiority of non-Hermitian quantum sensing can be efficiently achieved in the presence of reasonable quantum resources. Our study provides theoretical references for the efficient construction of non-Hermitian quantum sensors with superior performance based on quantum resources and has potential applications in the research field of quantum precision measurement.