U.S. - Uruguay Cooperative Research: Knot Theory and the Dynamics of Quantum Gravity

9811610 PullinThis Americas Program award will support a collaborative research project on quantum gravity between Dr. Jorge Pullin，the Pennsylvania州立大学and Dr. Rodolfo Gambini，Universidad de la Republicica，Montevideo，Uruguay. 本研究将使用连接和环技术处理广义相对论的非微扰量子化。 特别是，他们希望探索的哈密顿约束的定义中使用的循环导数，并找到物理状态的理论，将被消灭的所有约束。一个重要的问题是宇宙常数在空间中的作用发挥的状态的理论的研究。 到目前为止，他们已经发现具有宇宙学常数的状态是框架依赖的结不变量，而没有宇宙学常数的状态是框架无关的。 无论这是一个一般的行为或仅限于某些状态，将被调查。这两个群体的方法对这个问题是互补的。 该方法结合了宾夕法尼亚州立大学研究人员在广义相对论和引力物理学方面的背景，以及蒙得维的亚粒子物理学小组的专业知识。***

9811610PullinThis Americas Program award will support a collaborative research project on quantum gravity between Dr. Jorge Pullin, the Pennsylvania State University and Dr. Rodolfo Gambini, Universidad de la Republica, Montevideo, Uruguay. The research will deal with nonperturbative quantization of general relativity using connection and loop techniques. In particular, they wish to explore the definition of a Hamiltonian constraint in terms of the use of the loop derivative, and find physical states for the theory that would be annihilated by all constraints.An important question to be addressed by this study is the role that the cosmological constant plays in the space of states of the theory. Up to now, they have found that states with a cosmological constant are framing-dependent knot invariants, whereas states without a cosmological constant are framing-independent. Whether this is a generic behavior or is confined to certain states only, will be investigated.The approach of both groups to the subject is complementary. The approach combines the background in general relativity and gravitational physics of the researchers at Penn State with the expertise of the Montevideo group in particle physics. ***