手征对称性是量子色动力学最重要的对称性之一。它在真空中的自发破缺和在有限温度密度时的恢复已经广为人知。但是，在强电磁场中手征性质如何改变是一个没有解决的问题，也是当前高能核物理理论和实验研究的焦点问题之一。本项目研究夸克系统在电磁场中的手征相结构。采用的方法是利用圈图求和以及泛函重整化群的流方程来包含量子涨落的超出平均场方法。主要内容包括 ：1）保证对称性质的超出平均场方法，2）电磁场对手征相结构的影响，3）在相对论重离子碰撞和致密星体中电磁场效应的敏感信号。

Chiral symmetry is one of the most import symmetries of Quantum Chromodynamics. It is well known that chiral symmetry is spontaneously broken in vacuum and will be restored at finite temperature and density. However, how the electromagnetic field changes the chiral symmetry restoration is an interesting and as of yet unsolved question in theoretical and experimental studies. We plan to investigate the chiral phase structure under external electromagnetic fields. The quantum fluctuations are considered by loop expansion method and functional renormalization group method. We focus on the three issues: 1) appropriate beyond-mean-field techniques, respecting the symmetry of the system. 2) The electromagnetic field effects on the chiral phase structure. 3) The signals in relativistic heavy-ion collisions and compact stars.