סמינר קוואנטום: The pseudo-density matrix formulation of quantum physics
Prof. Vlatko Vedral, Department of Physics at the University of Oxford
The pseudo-density matrix (PDM) is a generalization of the quantum mechanical density operator to include temporal quantum correlations. The resulting picture of quantum physics is timeless, although it is different to the Page-Wootters “dynamics without dynamics” formulation. Moreover, while the Page-Wootters formalism can be understood as a mere reparametrisation of the usual quantum dynamics, PDMs might well be necessary in the domain where quantum physics and general relativity hold an equal sway. I will introduce the basic features of PDMs and show how they are designed to treat spatial and temporal correlations on an equal footing, thereby being suitable in the domain where the spacelike and timelike intervals cannot physically even be discriminated. I will present some recent experiments on PDMs that implement simulations showing how PDMs could be useful in the presence of closed time-like loops as well as how quantum dynamics could be seen as a quantum teleportation “in time” using the temporal entanglement in PDMs.