The computation of observables in general interacting theories, be them quantum
mechanical, field, gauge or string theories, is a non-trivial problem which in many cases can …

We present a broad conceptual introduction to some new ideas in nonperturbative quantum
field theory (QFT) that have led to progress toward an understanding of quark confinement in …

In a classically scale-invariant quantum field theory, tunneling rates are infrared divergent
due to the existence of instantons of any size. While one expects such divergences to be …

A possible solution of the notorious sign problem preventing direct Monte Carlo calculations
for systems with nonzero chemical potential is to deform the integration region in the …

We introduce a new method for evaluating the oscillatory integrals which describe natural
interference patterns. As an illustrative example of contemporary interest, we consider …

In recent work [J. Feldbrugge et al. Phys. Rev. D 95, 103508 (2017). PRVDAQ 2470-0010
10.1103/PhysRevD. 95.103508 and J. Feldbrugge et al. Phys. Rev. Lett. 119, 171301 …

Tunneling in quantum field theory is worth understanding properly, not least because it
controls the long-term fate of our Universe. There are, however, a number of features of …

Monte Carlo studies involving real time dynamics are severely restricted by the sign problem
that emerges from a highly oscillatory phase of the path integral. In this Letter, we present a …

A bstract There are two well-known approaches to studying nonperturbative aspects of
quantum mechanical systems: saddle point analysis of the partition functions in Euclidean …

A bstract We make use of Borel resummation to extract the exact time dependence from the
divergent series found in the context of stochastic inflation. Correlation functions of self …