I will begin the talk with a brief introduction to quantum gravity and why there is a genuine scientific curiosity that drives this endeavour. I will then discuss the “forks on the road” that present themselves in deciding what route to take. There is strong evidence suggesting that causality is not violated in nature. If this is true, the causal relations between events in a spacetime capture the entire geometry of the spacetime, upto an overall scale. This observation due to Hawking, Malament and others provides the basis for an approach to quantum gravity called causal set theory. I will review what is meant by the causal order poset and its close relationship to “Lorentzian” geometry. In the causal set approach, it is this underlying poset structure of spacetime that replaces geometry. In addition it assumes a fundamental atomicity of spacetime which renders it discrete. I will then review some aspects of this proposal, highlighting the cosmological constant prediction. I will end with recent results on the subject which emphasise the connection to causality.
ABOUT THE SPEAKER:
Prof. Sumati Surya did her PhD from Syracuse University under Prof. Rafael Sorkin. She went on to postdoctoral positions in IUCAA, TIFR, University of British Columbia, and University of Alberta. During this time she worked on broad aspects of quantum gravity including the role of topology in canonical quantum gravity, the role of causality in topology change, as well as geometric aspects of the adS/CFT correspondence. She has been at the Raman Research Institute since 2003. Her research in the last ten odd years have been focused the causal set approach to quantum gravity, which has deep roots in Lorentzian geometry. Her interests span various aspects of classical gravity and quantum gravity.
ABOUT DR LAKSHMI RAMAN (1947-2014):
Dr Lakshmi Raman was eduacated at Lady Sivaswamy Iyer Girl’s high school, Mylapore and Queen Mary’s college, Chennai, before undertaking a PhD in crystal dynamics in the Dept. of Physics, IITM. She did post-doctoral research at MPI, Stuttgart, ETH, Zurich and the University of Texas, Austin. Dr Raman then moved to the private sector. She had a long association with BellCore (a.k.a. Bell Labs) where she worked in the sphere of telecommunications particularly in the area of network management. She was an internationally recognized expert regarding standards in telecommunication. She was the author and coauthor of books and network management. Throughout her life she had a keen interest in the higher education of women and volunteer teaching of high-school students.