Laboratory of High Energy Physics

The Standard Model of particle physics is a beautiful and complete theory, the last brick of which was the triumphant discovery of the Higgs boson at the Large Hadron Collider at CERN in 2012. However, at the moment it is quite obvious that it is not a theory of everything. For example, according to the Standard Model, there are three generations of massless neutral leptons: electron, muon and tau neutrinos. However, in the 21st century, the existence of neutrino oscillations was discovered (Nobel Prize in Physics 2015), when neutrinos of one generation pass into another, which contradicts the hypothesis of masslessness of neutrinos (and, therefore, goes beyond the Standard Model). Other popular problems of the Standard Model – the presence of baryon asymmetry and dark matter in the Universe – may also be related to the presence of non–zero mass in neutral leptons, which is why the search for New Physics – effects beyond the Standard Model - in the field of neutrino physics is very relevant in the modern world community. The three problems mentioned above, which are not explained by the Standard Model, can be solved by introducing a new type of neutrino – a heavy sterile neutrino that does not interact with ordinary matter, but has a large mass and can oscillate into ordinary neutrinos of the Standard Model.

Over the past fifty years, the modern theory of fundamental particles, the Standard Model (CM), has been theoretically developed and experimentally confirmed, the last brick of which was the triumphant discovery of the Higgs boson at the Large Hadron Collider at CERN in 2012. Despite its beauty and accuracy in describing processes at colliders, there are a number of cosmological observations that require the expansion of CM (i.e., the creation of models that do not contradict it, but go beyond it). Particles, processes, or models that go beyond CM are often called New Physics, and its search is the most urgent task of modern particle physics. Unfortunately, in the field of so-called "high–pt" physics – the search for dark matter, supersymmetric particles, exotic resonances, neutral leptons - the "big experiments" of ATLAS and CMS at the LHC have not made any significant progress in finding deviations from CM in the 10 years since the discovery of the Higgs boson.

We investigate the properties of correlation functions in quantum field theory in strong external fields of various natures, as well as the dynamics of the initial state in nonstationary situations. When considering symmetric spaces such as Minkowski, de Sitter and anti de Sitter spaces and states invariant with respect to the corresponding isometries, it is important to study the analytical properties of correlators and loop corrections to them as functions of geodetic distances. In the case of more general, non-invariant states and background fields, it is important to study the dynamics of the initial state. Namely, the study of non-stationary phenomena, when, for example, the background depends on time, requires the inclusion of states with non-zero abnormal mean and population levels, since these quantities are generated dynamically in loops in many models with interaction in external fields, and in the presence of moving mirrors. Also, from an applied point of view, the most urgent problem is the dynamics of fermions in models with interaction and in a strong magnetic field at high density or at low temperatures. Among other things, the study of dynamics in these systems can shed light on the physics of dynamic condensate formation and answer the question of the existence of islands of stability in high-density plasma.

Since the discovery of the AdS/KTP correspondence in the second half of the 90s, string theory, together with its nonperturbative formulation, M-theory, have attracted great interest as powerful tools for the study of gauge theories. The point of application is not only phenomenologically interesting theories such as supersymmetric QCD or theories describing strongly correlated systems, but also models related to more fundamental issues such as the definition and calculation of microscopic degrees of freedom of black holes. In this context, solution generation methods are particularly useful, allowing us to study the properties of families of gauge field theories, generate new gauge theories and obtain information about non-Lagrangian operators using the geometric properties of solutions to supergravity, which is the low-energy limit of string theory and M-theory. A well-known example is the bivector Yang-Baxter deformation of the AdS5xS5 background, a dual of the so-called beta Lee-Strassler deformations of the N=4 super Yang-Mills theory, preserving N=1 supersymmetry. This project is dedicated to the development and application to specific solutions of the methods of generating solutions proposed within the framework of the 2020 project. The developed methods are based on the U-covariant formalism of exceptional field theory, which describes the low-energy dynamics of M-theory and, generally speaking, goes beyond the standard 11-dimensional supergravity. It is expected that, having successfully been tested on the simplest examples, these methods will become an effective tool for the controlled generation of new non-supersymmetric families of conformal field theories, the study of the corresponding dynamics of membranes and the expansion of the space of self-consistent vacuums of M-theory.

The project is aimed at studying the dynamics of exotic branes, which, despite the name, are the same fundamental objects in string theory as, for example, D-branes and the string itself. It is proposed to study these objects both from a fundamental point of view and in the field-theoretic limit. In the first case, the effective action for exotic branes is in focus, in the second — the geometric properties of the corresponding configurations of space and fields. The main tool in the framework of the project is supposed to be the so-called dual (exceptional) field theory, in the formalism of which symmetry with respect to T(U)-duality turns out to be explicit, which allows us to develop a unified approach to exotic and ordinary branes. Exotic branes are partners of standard D- and NS-branes under the action of T-duality transformations. At the supergravity level, they manifest themselves in the form of special solutions that are globally defined only up to the transformation of T(U)-duality, and in the simplest cases correspond to T(U)-images. In addition, it is known that exotic branes interact with a special kind of potentials, the flows of which make it possible to obtain vacuums with a small positive cosmological constant. The so-called non-geometric compactifications

The duality of gauge gravity, and in particular the AdS/CFT correspondence, is probably the most successful application of string theory methods to the analysis of gauge theories. These dualities are of great interest in the context of phenomenological applications to multiparticle systems such as superconductivity, non-Fermi fluids, entanglement entropy, and many others. The rich symmetry of the vacuum space of string theories allows us to go far beyond the standard weak/strong coupling. matching and describing theories with fewer symmetries than N = 4 SYM. Among such symmetries, the most important for the proposed project are transformations generating solutions based on non-Abelian T-dualities, Yang-Baxter deformations of ten-dimensional supergravity backgrounds and, more generally, Poisson-Lee T-duality. This project aims to advance the solution generation methods developed for string sigma models and 10-dimensional supergravity to the level of 11-dimensional supergravity. The ten-dimensional background of supergravity describes very limited loci in the vacuum module space of string theory, where the string coupling constant is small and a perturbative description is acceptable. However, in general, the 11th direction is observed, and constant string vacuums correspond to the background of 11-dimensional supergravity. To some extent, it is possible to advance the duality of gauge gravity into an 11-dimensional theory and gauge theories describing brane systems of M-theory. Recently, an 11-dimensional generalization of Yang-Baxter deformations of the supergravity background has been proposed in the literature, however, despite very few toy examples, not much information is available about such deformations. In particular, it is known that they are related to the procedure of non-Abelian transformations of U-duality, proposed recently in the literature. Therefore, they are naturally interested in the same issues as in the 10-dimensional case: preservation of integrability, explicit deformations of the 11-dimensional background, generation of new field theories using non-Abelian U-duality, spectrum analysis, proponents of deformed theories, etc. The main objectives of the project are: to develop tools for generating solutions for the basis of M-theory, to analyze the properties of dual superconformal field theories, including RG behavior, noncommutativity and operator spectrum, to search for classifications regulating the algebraic basis of methods. As for the calibration theory, we expect to obtain new results and/or new interpretations of known results based on the developed tools. As for the sigma model, we expect to gain insight into the recently proposed deformations of 11-dimensional backgrounds and gain access to their integrability properties. The problems will be solved using new methods developed as applications of the exceptional approach of field theory: non-Abelian and U-Nambuli duality, exceptional Drinfeld algebra, exceptional Kaluza-Klein spectroscopy, polyvector deformations.