NV色心系统中的自旋压缩和宏观纠缠的理论研究

At present, the spin squeezing and macroscopic entanglement are mostly generated in atoms and quantum dot systems. The manipulation of these systems generally requires strict experimental conditions, such as ultra low temperature, high pressure and so on. While the greatest advantage of the nitrogen vacancy center (NV center) is that quantum state can be manipulated and outputted even at room temperature. In addition, the electron spin of NV center have overriding advantages for stable spin quantum state, long relaxation time and the decoherence time, and feasible quantum manipulation. Therefore, how to generate stable spin squeezing and macroscopic entanglement in the NV center system attract increasing attention. We plan to study: (1)generation of steady state spin squeezing in NV center system, and determination of the parameters that affect the spin squeezing; (2)generation of macroscopical entanglement in NV center system, and determination of all parameters which are related to entanglement; (3)creation of entanglement and spin squeezing in coupling system of NV center system and mechanical oscillator system. The research will provide important theoretical basis for macroscopic system to realize a quantum entanglement, and an important theoretical basis and experimental support for solid system at room temperature to realize quantum calculations.

目前产生的自旋压缩和宏观纠缠大多在原子和量子点系统中，这些系统的操控一般需要苛刻的实验条件，例如超低温、超高压等。而氮-空位中心（简称NV色心）最大的优势是其量子态即使在常温下都很容易被操控和输出。另外，NV色心的电子自旋具有稳定的自旋量子态、超长弛豫时间和退相干时间、量子态光学可操控性等优点。所以，如何在金刚石结构的NV色心系统中产生稳定的自旋压缩和宏观纠缠是目前研究的热点之一。本项目计划研究:（1）NV色心系统中产生稳态自旋压缩，并确定各个参数对自旋压缩的影响；（2）NV色心系统中产生宏观纠缠，通过纠缠的计算得到各个参数对纠缠的影响；（3）NV色心系统与机械振子耦合系统中的纠缠和自旋压缩。本项目的研究为宏观系统实现量子纠缠提供重要的理论依据，也为常温固态系统中实现量子计算提供重要的理论基础和实验支持。

NV色心最大的优势是其量子态即使在常温下也很容易被操控和输出。另外，NV色心的电子自旋具有稳定的自旋量子态、超长的弛豫时间和退相干时间、量子态光学可操控性等优点。所以，如何在金刚石结构的NV色心系统中产生稳定的自旋压缩和宏观纠缠是目前研究的热点之一。本项目研究了:（1）提出了在NV色心系统中产生稳态自旋压缩的方案，并给出各个参数对自旋压缩的影响；（2）提出了NV色心系统中产生宏观纠缠的方法，通过纠缠的计算确定了相关参数对纠缠的影响，同时设计了理论方案的实验实现。