Department of Physics and York Centre for Quantum Technologies, University of York, Heslington, York, YO10 5DD, UK.
Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
Sci Rep. 2017 Mar 30;7:45587. doi: 10.1038/srep45587.
Squeezed states of light are a set of nonclassical states in which the quantum fluctuations of one quadrature component are reduced below the standard quantum limit. With less noise than the best stabilised laser sources, squeezed light is a key resource in the field of quantum technologies and has already improved sensing capabilities in areas ranging from gravitational wave detection to biomedical applications. In this work we propose a novel technique for generating squeezed states of a confined light field strongly coupled to a two-level system, or qubit, in the dispersive regime. Utilising the dispersive energy shift caused by the interaction, control of the qubit state produces a time-dependent change in the frequency of the light field. An appropriately timed sequence of sudden frequency changes reduces the quantum noise fluctuations in one quadrature of the field well below the standard quantum limit. The degree of squeezing and the time of generation are directly controlled by the number of frequency shifts applied. Even in the presence of realistic noise and imperfections, our protocol promises to be capable of generating a useful degree of squeezing with present experimental capabilities.
压缩态光是非经典态的一种，其中一个正交分量的量子涨落低于标准量子极限。与最好的稳定激光源相比，压缩光具有更少的噪声，是量子技术领域的关键资源，已经提高了从引力波探测到生物医学应用等领域的传感能力。在这项工作中，我们提出了一种新的技术，用于在色散区域中产生与两能级系统（或量子位）强耦合的受限光场的压缩态。利用由相互作用引起的色散能量位移，控制量子位状态会导致光场频率随时间发生变化。通过适当的时间序列的突然频率变化，将场的一个正交分量中的量子噪声波动降低到远低于标准量子极限的水平。压缩的程度和生成时间直接由应用的频率变化次数控制。即使在存在现实噪声和不完美的情况下，我们的方案也有望在现有实验能力的基础上产生有用的压缩程度。
