General relativity and quantum mechanics are the two fundamental theories of modern physics. It is natural to expect that the two cornerstones will be organically combined by constructing a quantum theory of spacetime. To solve the problem of the quantization of gravity would undoubtedly bring about a new revolution on the viewpoints of spacetime and the quantum. The traditional perturbative quantization methods have encountered the difficulty of non-renormalizability when applied to the gravitational field and cannot reflect the essential idea of general relativity, namely the background independence. Among the various approaches to non-perturbative quantum gravity, the most influential one at present is the loop quantum gravity. The study in this approach has made great progress since 1986 when Ashtekar et al. proposed the connection-dynamical formulation of general relativity. Unlike string theory, the main physical assumptions of loop quantum gravity are based on general relativity and quantum mechanics, without any additional structure attached. As a mathematically rigorous and backgound-independent theoretical framework, it succeeds in implementing the essential ideas of general relativity, predicts the discreteness of space-time, gives finite results for coupling with matter fields, and provides a rigorous theoretical framework for the study of quantum black hole physics and quantum cosmology. Of course, due to the fundamental nature and complexity of the problems involved, more progress is still needed in this area of research. The core of the current research is the low-energy approximation of the theory and the quantum dynamics problem.

Representative Works of the Center：

1. Xiangdong Zhang, Gaoping Long, and Yongge Ma, “Loop quantum gravity and cosmological constant”, Phys. Lett. B 823 (2021), 136770.

2. Cong Zhang, Yongge Ma, Shupeng Song, Xiangdong Zhang, "Loop quantum Schwarzschild interior and black hole remnant", Phys. Rev. D 102 (2020), 041502 ( Rapid Communication).

3. Xiangdong Zhang and Yongge Ma, "Extension of loop quantum gravity to f(R) theories", Phys. Rev. Lett. 106 (2011), 171301.

4. You Ding, Yongge Ma, and Jinsong Yang, "Effective scenario of loop quantum cosmology", Phys. Rev. Lett. 102 (2009), 051301.

5. Jinsong Yang, You Ding, and Yongge Ma, “Alternative quantization of the Hamiltonian in loop quantum cosmology”, Phys. Lett. B 682 (2009), 1.