M-Theory, Cosmology and Quantum Field Theory

The STFC research programme of the Theoretical Physics Group at Imperial College London is focused the interrelated fundamental problems of M-theory, quantum field theory and cosmology. M-theory, which subsumes string theory and supergravity theory, is our central approach to unify Einstein's theory of General Relativity with the Standard Model of particle physics. One of the most interesting features of M-theory is that it incorporates dual descriptions of non-perturbative Yang-Mills theories in terms of strings leading to profound connections between black holes and thermal quantum field theory and also to new insights into strong coupling phenomena such as quark confinement. These connections will continue to be explored in a number of different ways, including using novel geometric techniques and exactly integrable quantum field theory models. Exploration of string theory on backgrounds which cannot be described by conventional geometry will be carried out, both to deepen our understanding of the structure of the space of vacua of M-theory, with applications to particle physics phenomenology, and also to provide hints as to the fundamental degrees of freedom of M-theory. There has been a great deal of progress in understanding the quantum properties of black holes in M-theory. Using both analytical and numerical techniques we will construct and study black hole solutions with novel properties that have possible applications to both the quark gluon plasma and poorly understood systems in condensed matter such as high temperature superconductors. Connections between M-theory black holes and measures of quantum entanglement will also be explored. In the area of cosmology and related aspects of quantum field theory, key clues to the structure of the Big Bang origin of the universe are to be found in the non-Gaussian corrections to the cosmic microwave background. This provides an important indication about the origin of density perturbations in the early universe and of the formation of galactic structures. Over the course of the grant there will be a wealth of new data arriving most notably from the Planck and Spider experiments. We will analyse this data and explore the detailed implications for a host of cosmological models. In parallel with the analysis of observational microwave background data, we will pursue our diverse model building activities, both based around inflationary scenarios and also alternatives. Computational modelling of early-universe field dynamics and structure formation will be carried out and we will also explore the possibility of imprints of quantum gravity on cosmological data. We will also investigate how astrophysical black holes can be used to test modified theories of gravity that have been proposed as alternatives to dark matter. There is a deep synergy between the broad strands of our research, with work on the non-perturbative aspects of Yang-Mills gauge theories informing both supergravity and superstring theory on the one hand and the study of high-temperature fields in the early universe and the computational modelling of early-universe density fluctuations on the other.