Hi all,
Tomorrow Maria Radisch will tell us about her master thesis "The Page-Wootters Formalism and Multipartite Clock Systems". See below for the abstract. The talk will take place at 2pm in HIT E 41.1
Best, Ladina
**** Title: The Page-Wootters Formalism and Multipartite Clock Systems
Abstract: The Wheeler-DeWitt Equation states that within a theory of Quantum Gravity the physical quantum states of our universe are annihilated by the Hamiltonian of the theory and thus do not evolve in time. So how come we are able to observe evolution in our universe? The Page-Wootters formalism provides a way to regain the dynamical description of a subsystem of the universe with respect to an internal temporal reference frame – a quantum clock. In my talk, I will present this formalism in its simplest form and discuss how we can construct a time observable for such a clock. Next, we will see that when we consider the quantum clock to be a physical system consisting of multiple subsystems, applying the Page-Wootters formalism as before raises a few problems. Using the main results from my Master’s thesis, I will show that a notion of subsystems can only be maintained with respect to a subclock if the total clock Hamiltonian has energy degeneracies. We will see that such a degenerate clock Hamiltonian prevents us from constructing a time observable on the multipartite clock system in the way it is usually done in the Page-Wootters formalism.
itp-quantumseminare@lists.phys.ethz.ch