90 citations · 953 across the 58 of their papers we have counts for
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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…
Vacuum energy, the Casimir effect, and Newton's non-constant
Benjamin Koch, Christian Käding, Mario Pitschmann +1
We explore two hypotheses. First, the possibility that the quantum vacuum energy density of the Casimir effect contributes to a (local) gravitational vacuum energy density. Second,…
Density matrix formalism for interacting quantum fields
Christian Käding, Mario Pitschmann
We provide a description of interacting quantum fields in terms of density matrices for any occupation numbers in Fock space in a momentum basis. As a simple example, we focus on a…
A new method for directly computing reduced density matrices
Christian Käding, Mario Pitschmann
We demonstrate the power of a first principle-based and practicable method that allows for the perturbative computation of reduced density matrix elements of an open quantum system…
On renormalizability of the massless Thirring model
H. Bozkaya, A. N. Ivanov, M. Pitschmann
We discuss the renormalizability of the massless Thirring model in terms of the causal fermion Green functions and correlation functions of left-right fermion densities. We obtain…
On the renormalization of the sine-Gordon model
H. Bozkaya, M. Faber, A. N. Ivanov +1
We analyse the renormalizability of the sine-Gordon model by the example of the two-point Green function up to second order in alpha_r(M), the dimensional coupling constant defined…
Space/time noncommutative field theories and causality
H. Bozkaya, P. Fischer, H. Grosse +4
As argued previously, amplitudes of quantum field theories on noncommutative space and time cannot be computed using naive path integral Feynman rules. One of the proposals is to u…