基于线性与非线性干涉仪的量子精密测量研究进展

Research progress in quantum precision measurements based on linear and nonlinear interferometers

量子精密测量根据量子力学的基本原理,利用光、原子、磁之间的相互作用对待测物理量进行测量.随着实验条件和技术的成熟,如何利用干涉仪进一步提高位相信号这一物理量的测量精度从而打破散粒噪声的限制、突破标准量子极限并逼近海森伯极限成为研究的前沿课题.本文阐述了利用线性干涉仪(包括原子/光子干涉仪)与非线性干涉仪调用不同阶段的量子资源在测量过程中提高参数评估精度的几种方法,通过向干涉仪中输入非经典态来实现高精度测量,如压缩态、双数态、NOON态等,还介绍了为直接观测量子态而发展出的弱测量及其在非厄米系统中的应用和为消除参数之间精度制衡而提出的多参数测量.最后,对几种测量方法进行了分析比较,并展望了量子精密测量的发展前景.

Quantum precision measurement is based on the basic principle of quantum mechanics by using the interaction between light,atoms and magnetism to measure physical quantities,also known as precision measurements based on microscopic particle systems and their quantum states.As an important means of quantum precision measurement,interferometer precision measurement technology has great application value in quantum communication.The linear interferometer measures the magnitude of the physical quantity by using the phase change obtained from the measurements,but measurement accuracy is limited and unable to meet the requirements of today's scientific problems for the precision measurement of some physical quantities.On this basis,nonlinear interferometer is able to take advantage of the quantum entangled state,that is,using the two light fields of quantum correlation characteristics to realize quantum enhanced precision measurement,thus greatly improving the measurement sensitivity,Therefore,the scope of application is wider,but the preparation of quantum entangled states has many limitations in practical manipulation.With the maturity of experimental conditions and technology,how to use both of these interferometers to further improve the measurement accuracy of the phase signal so as to break the limitation to shot noise,breaking the standard quantum limit and even approaching to the Heisenberg limit has become a frontier research topic.In this paper,we introduce several methods to improve the accuracy of parameter evaluation in the measurement process by using linear(including an atomic/photon interferometer)and nonlinear interferometer to call quantum resources at different stages.High-precision measurement can be achieved by inputting non-classical states into the interferometer,such as compressed state,bi-fock state,and NOON state.And we also introduce the weak measurement developed for the direct observation of quantum states and its application to non-Hermitian systems,and the multiparameter measurement proposed to eliminate the accuracy balance between parameters.Compared with the first two measurement methods,weak measurement method is based on the weak value amplification principle of an indirect measurement.Measurements are performed virtually without perturbing the quantum system,which does not lead the wave function to collapse,the weak value of the real and virtual part have different physical significance,The combination of weak measurement theory and non-Hermitian system also further improves the measurement sensitivity.Multi-parameter measurement uses quantum entanglement,quantum control and other quantum resources to make the measurement progress reach the Heisenberg limit,which is the current research hotspot in the field of precision measurement.Furthermore,we present a conjecture whether there will be multi-atomic mixing measurements based on atomic spin effects or ultra-high sensitivity measurement instruments with precision of fT or even aT by using other particles detection.Finally,several measurement methods are analyzed and compared with each other,and the development prospect of quantum precision measurement is forecasted.