11 papers
Time Machines and the Breakdown of Unitarity
Frank Antonsen, Karsten Bormann
We present a generic way of thinking about time machines from the view of a far away observer. In this model the universe consists of three (or more) regions: One containing the en…
Zeta-Functions and Star-Products
Frank Antonsen
We use the definition of a star (or Moyal or twisted) product to give a phasespace definition of the -function. This allows us to derive new closed expressions for the coefficie…
Casimir driven evolution of the universe
Frank Antonsen, Karsten Bormann
For a Friedman-Robertson-Walker space-time in which the only contribution to the stress-energy tensor comes from the renormalised zero-point energy (i.e. the Casimir energy) of the…
Wigner Functions in Curved Spacetimes and Deformation Quantisation of Constrained Systems
Frank Antonsen
We first generalise the standard Wigner function to Dirac fermions in curved spacetimes. Secondly, we turn to the Moyal quantisation of systems with constraints. Gravity is used as…
The Heat-Kernel in a Schwarzschild Geometry and the Casimir Energy
Frank Antonsen
We obtain an hybrid expression for the heat-kernel, and from that the density of the free energy, for a minimally coupled scalar field in a Schwarzschild geometry at finite tempera…
Deformation Quantisation of Constrained Systems
Frank Antonsen
We study the deformation quantisation (Moyal quantisation) of general constrained Hamiltonian systems. It is shown how second class constraints can be turned into first class quant…