Multi-photon nonclassical states of light based on high-gain parametric down-conversion

量子信息技术的发展，最终目标是长距离量子密码学和可扩展的量子计算，导致了对真正体现量子行为的宏观系统的搜索。有各种量子行为的迹象，其中包括纠缠，违反贝尔不等式，以及最具挑战性的负值准概率分布。目前，只观察到极少数宏观(明亮)光的非经典特征。其中之一是亮压缩真空(BSV)，这是高增益参数下转换产生的一种状态。特别是，对于BSV态，已经观察到亚散粒噪声光子数关联和宏观纠缠，甚至最近预测违反Bell不等式。该项目的目标是利用高增益的参数下转换来产生新型的非经典非高斯态。这项研究计划为期36个月，将包括关于BV的产生、检测和非线性转换的实验。这项研究将与莫斯科国立大学Lomonosov理论团队合作，由Farid Khalili教授指导。该项目的基础是在DFG研究启动补助金的框架下，在Khalili教授最后一次在弗里德里希-亚历山大大学埃尔兰根-纽伦堡停留期间建立的。

The development of quantum information technologies, with the ultimate goals being long-distance quantum cryptography and scalable quantum computation, led to the search for macroscopic systems manifesting truly quantum behavior. There are various signs of quantum behavior, among them entanglement, violation of Bell inequalities and, most challenging, negative valued quasi-probability distributions. Currently, nonclassical features have been observed for very few macroscopic (bright) states of light. One of them is bright squeezed vacuum (BSV), a state produced as a result of high-gain parametric down-conversion. In particular, for the BSV state sub-shot-noise photon-number correlations and macroscopic entanglement have been observed, and even violation of the Bell inequality has been recently predicted.The project is aimed at producing novel nonclassical and, as an ultimate goal, non-Gaussian states of light using high-gain parametric down-conversion. The research is planned for 36 months and will consist of experiments on the generation, detection, and nonlinear conversion of BSV.The research will be performed in collaboration with the theoretical team from Lomonosov Moscow State University, guided by Prof. Farid Khalili. The basis for the project was founded during the last stay of Prof. Khalili in Friedrich-Alexander Universität Erlangen - Nürnberg in the framework of the DFG Research Initiation Grant.