We discuss aspects of non-perturbative unitarity in quantum field theory. The additional
ghost degrees of freedom arising in “truncations” of an effective action at a finite order in …

Quantum Field Theory (QFT) has proved to be the most useful strategy for the description of
elementary particle interactions and as such is regarded as a fundamental part of modern …

A new approach to the construction of interacting quantum field theories on two-dimensional
Minkowski space is discussed. In this program, models are obtained from a prescribed …

We present a general construction of KMS states in the framework of perturbative algebraic
quantum field theory (pAQFT). Our approach may be understood as an extension of the …

The infrared problem in quantum electrodynamics consists of intriguing difficulties in
scattering theory appearing at large scales and low energies. Although they can be …

Several related operator-algebraic constructions for quantum field theory models on
Minkowski spacetime are reviewed. The common theme of these constructions is that of a …

We consider translation invariant gapped quantum spin systems satisfying the Lieb–
Robinson bound and containing single-particle states in a ground state representation …

The recent construction of integrable quantum field theories on two-dimensional Minkowski
space by operator-algebraic methods is extended to models with a richer particle spectrum …

It is shown that there are significant conceptual differences between QM and QFT which
make it difficult to view the latter as just a relativistic extension of the principles of QM. At the …

A major obstacle facing interpreters of quantum field theory (QFT) is a proliferation of
different theoretical frameworks. This article surveys three of the main available options …