Marten REEHORST

Post-Doc

Research group: Mathematical Physics

Research interests

Quantum field theory (QFT) has been successfully used to describe particle physics and condensed matter systems. Perturbation theory can predict particle interactions to astounding precision. Yet, these perturbative approaches are known to break down when the involved coupling constants become strong. Many interesting physical phenomena are described by such strongly coupled systems. Developing non-perturbative methods to solve these systems is essential and one of my main research interests.

An especially promising non-perturbative approach is available for conformal field theories (CFTs). CFTs are ubiquitous in theoretical physics. They describe second order phase transitions in condensed matter systems, as well as the start and end points of the renormalization group flow of QFTs. They also appear in quantum gravity both directly as the theory describing the string worldsheet and indirectly through the AdS/CFT correspondence. I work on the conformal bootstrap, a program consisting of mapping out the allowed regions for the data describing the CFT, using non-perturbative consistency conditions that follow from the associativity of the operator product expansion. This yields exact bounds on physical observables, such as the most accurate determinations of the critical exponents in the 3d Ising model. I have repeatedly pushed forward the numerical bootstrap technology, for example when I performed the first bootstrap involving spinning and scalar fields, and when I invented a new method of numerical conformal bootstrap using a "navigator" function. The latter removes an important bottleneck in the numerical conformal bootstrap enabling many new lines of research such as the bootstrap of gauge theories such as QED_3, ARP_N and O(N)xO(2) models. It also allows us to study non-perturbative effects such as level-repulsion and the annihilation and merger of CFTs.

Link to my publications: https://inspirehep.net/literature?q=a%20M.J.Reehorst.1