Research on Quantum Theories of Gravity and Spacetime (Physics)

雅各布森博士的计划主要是关于量子引力的。这项研究涉及以下几个方面：1)将量子理论的概率解释扩展到量子引力的概念性问题；2)借助一类简单的模型分析将通常的量子化框架应用于哈密顿量为零的系统的困难；3)研究使广义相对论哈密顿量为正的时空切片；4)将从两个角度研究离散时空模型：a)从各个方面寻求关于离散时空的可能性质的线索，包括黑洞热力学、能量动量守恒要求和量子理论的解释要求；B)特定离散时空模型的性质(自旋网络、因果集等)将会被探索。广义地说，这项研究的动机是这样一种信念，即量子引力问题从根本上需要时空的量子理论，而不是经典引力的量子化。

The program of Dr. Jacobson is primarily on quantumgravity. The research involves several facets of that subject: 1) Conceptual problems of extending the probabilisticinterpretation of quantum theory to quantum gravity will bestudied; 2) The difficulty of applying the usual framework ofquantization to a system with vanishing hamiltonian will beanalyzed with the help of a class of simple models; 3) Spacetime slicings which render the hamiltonian of general relativity positive will be studied; 4) Discrete models of spacetime will be studied from two points of view: a) Hints will be sought from all quarters as to the possible nature of discrete spacetime, including black hole thermodynamics, energy-momentum conservation requirements and interpretive requirements of quantum theory; b) The properties of specific discrete spacetime models (spin networks, causal sets,...) will be explored. Broadly speaking, this research is motivated by the belief that the problem of quantum gravity fundamentally requires a quantum theory of spacetime itself, as opposed to aquantization of classical gravity.