Upcoming and planned experiments combining increasingly intense lasers and energetic
particle beams will access new regimes of nonlinear, relativistic, quantum effects. This …

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 the perturbative renormalization group functions of O (n)-symmetric ϕ 4 theory in
4-2 ϵ dimensions to the sixth loop order in the minimal subtraction scheme. In addition, we …

In these lectures I present a review of non‐perturbative instanton effects in quantum
theories, with a focus on large N gauge theories and matrix models. I first consider the …

Electronic resonances are states that are unstable towards loss of electrons. They play
critical roles in high-energy environments across chemistry, physics, and biology but are …

These lecture notes give an introduction to the functional renormalisation group and
asymptotically safe quantum gravity. We cover the basics of generating functionals in …

Expansions of physical functions are controlled by their singularities, which have special
structure because they themselves are physical, corresponding to instantons, caustics or …

Nonperturbative effects in string theory are usually associated to D-branes. In many cases it
can be explicitly shown that D-brane instantons control the large-order behavior of string …

This highly pedagogical textbook for graduate students in particle, theoretical and
mathematical physics, explores advanced topics of quantum field theory. Clearly divided into …

We develop techniques to compute multi-instanton corrections to the 1/N expansion in
matrix models described by orthogonal polynomials. These techniques are based on finding …