4 citations · 13 across the 7 of their papers we have counts for
12 papers
Coalgebras and quantization
Christian Brouder
Two coalgebra structures are used in quantum field theory. The first one is the coalgebra part of a Hopf algebra leading to deformation quantization. The second one is a co-module…
Non-commutative Hopf algebra of formal diffeomorphisms
Christian Brouder, Alessandra Frabetti, Christian Krattenthaler
The subject of this paper are two Hopf algebras which are the non-commutative analogues of two different groups of formal power series. The first group is the set of invertible ser…
Many-body theory of degenerate systems: A simple example
Christian Brouder
The hierarchy of Green functions for (quasi)degenerate systems, presented in cond-mat/0308058, is calculated in detail for the case of a system with closed shells plus a single ele…
Many-body theory of degenerate systems
Christian Brouder
The many-body theory of degenerate systems is described in detail. More generally, this theory applies to systems with an initial state that cannot be described by a single Slater…
Quantum field theory of degenerate systems
Christian Brouder
To set up a self-consistent quantum field theory of degenerate systems, the unperturbed state should be described by a density matrix instead of a pure state. This increases the co…
Quantum groups and interacting quantum fields
Christian Brouder
If C is a cocommutative coalgebra, a bialgebra structure can be given to the symmetric algebra S(C). The symmetric product is twisted by a Laplace pairing and the twisted product o…