56 citations · 99 across the 7 of their papers we have counts for
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Explicit finite-time illustration of improper unitary evolution for the Klein--Gordon field in de Sitter space
William T. Emond, Christian Käding, Peter Millington
It is known that quantum field theories in curved spacetime suffer from a number of pathologies, including the inability to relate states on different spatial slices by proper unit…
Directly computing Wigner functions for open quantum systems
Nick Huggett, Christian Käding, Mario Pitschmann +1
The Wigner function is a well-known phase space distribution function with many applications in quantum mechanics. In this article, we consider an open quantum system consisting of…
Density matrices in quantum field theory: Non-Markovianity, path integrals and master equations
Christian Käding, Mario Pitschmann
Density matrices are powerful mathematical tools for the description of closed and open quantum systems. Recently, methods for the direct computation of density matrix elements in…