应用于医疗的量子传感芯片：

       量子传感器利用物质的极小单元：原子、分子、电子、光子等进行传感，这些极小单元对外界物理量如磁场、电场、角速度等及其敏感，因此，量子传感器具有超高灵敏度的特性。当前量子传感器的体积庞大，限制了量子传感器的应用，因此，将微光机电系统和量子传感技术结合，研制量子传感芯片，扩大量子传感器的应用范围。

 芯片原子磁强计

      原子磁强计利用原子自旋对磁场的敏感特性进行磁场测量，并且对磁场以的测量具有超高灵敏的特性，灵敏度可以达到fT量级，有望对大脑磁场进行成像，服务于阿尔兹海默症的早期诊断、抑郁、癫痫术前定位、脑机接口等。 将原子磁强计和芯片技术结合有望突破现有传感器的体积，提升脑磁等极弱磁的空间分辨率，降低传感器的成本。相比较脑电信号而言，脑磁信号可以穿透头皮而不发生信号畸变，因此可以对脑部深处的信号进行检测，对癫痫术前的致病部位进行定位等。本研究部分将聚焦于传感器核心敏感元件以及整个脑磁系统的搭建，研制新一代的脑磁影像设备（具有广阔的市场前景），本研究基于西安交通大学医工交叉产教融合平台，对本研究进行了很好的支持。

Chip-scale quantum sensors for medical and power grid system:

Quantum sensors utilize the smallest units of matter, such as atoms, molecules, electrons, and photons, for sensing. These minute units are highly sensitive to external physical quantities like magnetic fields, electric fields, angular velocity, etc. Therefore, quantum sensors exhibit extremely high sensitivity. The current limitation lies in the bulky size of quantum sensors, restricting their applications. To address this, a quantum sensing chip is developed by integrating optomechanical systems and quantum sensing technology, aiming to broaden the scope of quantum sensor applications.

Atomic magnetometer:

The atomic magnetometer measures magnetic fields by utilizing the sensitivity of atomic spins to magnetic fields. It demonstrates super high sensitivity, reaching the order of femtoteslas (fT), making it potentially applicable to imaging brain magnetic fields. This could serve in early diagnosis of Alzheimer's disease, preoperative localization for deppression and epilepsy, brain-machine interfaces, etc. Integrating atomic magnetometers with chip technology is expected to break through the size limitations of current sensors, enhance the spatial resolution of weak magnetic fields like brain magnetism, and reduce sensor costs. Unlike brain electrical signals, brain magnetic signals can penetrate the scalp without distortion, allowing for the detection of signals deep within the brain and preoperative localization of epileptic foci. This research focuses on the core sensitive components of sensors and the construction of the entire brain magnetic system, developing a new generation of brain magnetic imaging devices with broad market prospects. This study received significant support from the collaborative platform of medical engineering at Xi'an Jiaotong University.

 基于核自旋补偿的运动脑磁测量：

      在人体运动状态下进行脑磁测量具有很大的挑战，核心在于如何对由于运动造成的背景干扰磁场进行抑制；脑磁信号的强度一般在100fT量级，磁屏蔽房内部的剩磁通过补偿可以到1nT以内，虽然已经对磁场进行了较好的抑制，但是运动造成的磁场仍然较大。为此，开发一种基于核自旋的干扰磁场子补偿技术。如下图所示，利用超极化的核自旋可以实现运动状态下背景干扰磁场的补偿。

Background magnetic field noise compensation based on hyper-polarized nuclear spins for moving MEGs recording.

Measuring brain magnetism during human motion poses significant challenges, mainly in suppressing background interference magnetic fields caused by movement. The strength of brain magnetic signals is generally on the order of 100 femtoteslas (fT), and although magnetic shielding rooms can reduce residual magnetism to within 1 nanotesla (nT), the magnetic fields caused by motion remain substantial. Therefore, a compensation technique based on nuclear spin interference is developed. As illustrated in the figure below, compensating for background interference magnetic fields during motion is achieved using hyperpolarized nuclear spins.

利用此磁强计，实现了灵敏度为3.2fT/Hz^(1/2) 的灵敏度。3.2fT/Hz^(1/2) magnetic field sensitivity has been achieved.

下一步拟通过3He进行核自旋自补偿研究，研制小型化的原子磁强计探头，对运动脑磁进行测量。Next step, hyper-polarized 3He unclear spins will be used for the compensation. Compact sensor head design will be achieved.

            基于He3的小型化原子磁强计探头

     本课题组还研制了原子磁强计所需的各项关键核心技术，比如碱金属气室，无磁加热芯片等：

Some key components have been developed by MEMS technology such as alkali vapor cell, non-magnetic heating chips:

                无磁加热芯片(non-magnetic heating)                                  双平面调制线圈（bi-planar coil）

                                         MEMS碱金属气室(MEMS vapor cell)

MEMS碱金属气室制作供气装置(MEMS vapor cell fabrication platform for gas handling.)

电力市场用的芯片原子磁强计

       本课题组和国家电网合作，正在开发电力市场应用的电流传感器。在新能源产业的发展下，电力行业电网系统等对电流传感器的需求越来越大，为此，开发用于电网大电流监测的量子电流传感器，服务于未来智能电网智能调度的需求。

       超极化核自旋量子电流传感器是一种新型电流测量传感器，当前并未看到将其应用于电网大电流测量的相关研究报道，本项目的实施将有望在电网大电流测量方面进行原始创新。超极化核自旋量子电流传感器使用核自旋进行磁场测量，由于核自旋的旋磁比是电子自旋的千分之一且基于³He核自旋，其相干时间远远大于电子自旋，可以预见，基于³He核自旋可以对磁场进行更高精度的测量。

Chip-scale atomic magnetometer for state grid market:

Our research group, in collaboration with the State Grid Corporation of China, is currently developing a current sensor for applications in the power market. With the growing demand for current sensors in the power industry and grid systems due to the development of renewable energy, there is a need for quantum current sensors designed for large current monitoring in power grids. This aims to cater to the future requirements of intelligent grid management.

The hyperpolarized nuclear spin quantum current sensor is a novel current measurement sensor. Currently, there is no reported research on its application in large current measurements for power grids. The implementation of this project is expected to bring about original innovations in the field of large current measurements for power grids. The hyperpolarized nuclear spin quantum current sensor utilizes nuclear spin for magnetic field measurements. Due to the fact that the gyromagnetic ratio of nuclear spin is one-thousandth of that of electron spin and is based on 3He nuclear spin, its coherence time is much longer than that of electron spin. It is foreseeable that based on 3He nuclear spin, higher precision measurements of magnetic fields can be achieved.

芯片原子陀螺仪

       原子陀螺仪利用原子自旋在惯性空间保持定轴的特性进行角速度的测量，并且对转动角速度的测量具有超高灵敏的特性， 将原子陀螺仪传感器和芯片技术结合有望突破现有传感器的体积，降低传感器的成本，在自动驾驶、无人机、无人潜器等领域得到广泛应用。

Chip scale atomic spin gyroscope:

The atomic gyroscope utilizes the characteristic of atomic spin to maintain a fixed axis in inertial space for measuring angular velocity. It exhibits super high sensitivity in measuring rotational angular velocity. Combining atomic gyroscope sensors with chip technology is expected to overcome the size limitations of current sensors and reduce sensor costs. This has the potential for widespread applications in areas such as autonomous driving, unmanned aerial vehicles (drones), and unmanned submersibles.

参考文献：

1.Chen Y*, Zhao L*, Ma Y, Yu M, Wang Y, Zhang N, Wei K, Jiang Z. Spin exchange optically pumped nuclear spin self compensation system for moving magnetoencephalography measurement. Biomedical Optics Express 2022, 13(11): 5937-5951.

2.Ma Y, Qiao Z, Yu M, Wang Y, Chen Y*, Luo G*, Yang P, Lin Q, Zhao L, Zhang Y, Sun J, Qin G, Jiang Z. Single-beam integrated hybrid optical pumping spin exchange relaxation free magnetometer for biomedical applications. Applied Physics Letters 2022, 121(11): 114001. link

3.Chen Y, Yu M, Ma Y, et al. Quadrupolar interaction induced frequency shift of 131Xe nuclear spins on the surface of silicon[J]. Journal of Physics D: Applied Physics, 2022.

实验平台图：

Penning离子阱技术——量子机械振子和转子

        (1) Penning 离子阱量子精密测量

        机械振子和转子是经典力学里边的常见物理系统，相对应的，量子机械振子和转子其能级是量子化的，利用Penning离子阱可以构建此类量子机械振子和转子系统。Penning离子阱通过电磁场将离子进行囚禁，离子组成二维平面，通过构建二维平面的量子谐振子可以用来进行极微弱力的测量，极限灵敏度可以达到10^(-24)N。

        传统的经典机械振子系统可以对加速度、角速度、压力等物理量 进行测量从而应用于惯性导航，并且此类系统可以进行微型化，所研制的传感器体积很小。相对应的，量子机械振子和转子可以应用于极微弱力测量、加速度测量、量子计算等，通过Penning离子阱构建二维离子平面晶体是研究此类问题很好的一个系统。

        此外，利用离子体系对暗物质进行探测等，对超出标准模型的新物理进行探测。

 (2) Penning 离子阱量子模拟

参考文献：Chen Y, Zhao L, Jiang Z. Rotation sensing with a compact Penning trapped calcium ion crystal system[J]. Bulletin of the American Physical Society, 2022. 链接

2. Penning trapped ions:Quantum Mechanical Oscillators and Rotors:

(1)Precision quantum measurement in Penning trapped ions:

Mechanical oscillators and rotors are common physical systems in classical mechanics. Correspondingly, the energy levels of quantum mechanical oscillators and rotors are quantized. Penning ion traps are utilized to construct such quantum mechanical oscillator and rotor systems. In a Penning ion trap, ions are confined by electromagnetic fields, forming a two-dimensional plane. By constructing a two-dimensional quantum harmonic oscillator, extremely weak forces can be measured with a sensitivity limit reaching 10^(-24) Newtons.

Traditional classical mechanical oscillator systems are used for measuring physical quantities such as acceleration, angular velocity, and pressure, making them applicable in inertial navigation. Moreover, these systems can be miniaturized, resulting in sensors with very small volumes. In contrast, quantum mechanical oscillators and rotors can be applied in the measurement of extremely weak forces, acceleration, quantum computing, etc. Constructing a two-dimensional ion crystal in a Penning ion trap proves to be an excellent system for researching such phenomena.

Additionally, utilizing ion systems for detecting dark matter and exploring new physics beyond the standard model is another application.

(2) Quantum simulation in Penning trapped ions:

Penning ion traps also find applications in quantum simulation.

实验平台图：

Penning trapped ions

We also focus on studying penning trapped ions. These ions are trapped in a cylendrical penning trap. They could form an ion plane as well as rotating around the magnetic field. They just looks like a rotating disk. Quantum hamonic oscillators are studied in the system. We are very intrested in using these quantum oscillators for force sensing.