Sommerfeld Theory Colloquium (ASC)

The life of a protein, from birth till death, is complex and challenging. At times, because of stresses or bad luck, it might take the wrong conformation and start aggregating. This process is intrinsic to the physics of proteins, and life has had to cope with it since its early days. The solution devised by evolution comes in the form of chaperone protein, a broad class of machines, present in al...

Electron-positron pair production in ultra-strong electric fields, the Sauter-Schwinger effect, is a long-standing theoretical prediction. In this talk the Sauter-Schwinger effect will be introduced and the related field-strength and energy scales as well as the possibility to verify this effect in upcoming multi-petawatt laser facilities will be discussed. The Dirac-Heisenberg-Wigner formalism pr...

Strongly correlated electron systems, i.e. systems where the interaction between electrons cannot be treated as an effective potential, are an extremely fascinating, but also very challenging topic in modern solid state physics. The challenge arises in parts due to the simultaneous importance of non-local kinetic and local correlation effects, which make it important to treat both at equal footing...

String theory is around 50 years old and for much of that time it has been proclaimed as a quantum theory of gravity unified with all forces and matter. However, we still don’t know its fundamental formulation, although we do now know it is not just a theory of strings. Nonetheless, it has led to many new and surprising insights, with concepts that were once seen as absolute now seen as dependent...

Perturbation theory remains one of the main tools in physics, in particular in quantum theories. However, most perturbative series diverge factorially, and it is not obvious how to extract information from them. Their divergence also suggests that, in order to obtain accurate results, one might need additional non-perturbative information. The theory of resurgence has been proposed as a general fr...

Throughout the century that has passed since Ernst Ising submitted his PhD thesis in 1924, the Ising (-Lenz) model has provided an incredibly fruitful challenge that gave rise to entirely new branches of physics and mathematics. In this colloquium I will focus on the conformal bootstrap program which was designed by Polyakov in 1974 as a mathematical method to access non-perturbative aspects of cr...

Since the discovery of the first binary black-hole merger in 2015, analytical and numerical solutions to the relativistic two-body problem have been essential for the detection and interpretation of more than 100 gravitational-wave signals from compact-object binaries. Future experiments will detect black holes at cosmic dawn, probe the nature of gravity and reveal the composition of neutron stars...

I will discuss recent progress in the study of cosmological applications of string compactifications with stabilised moduli, focusing in particular on inflation, reheating and dark energy.

Learning algorithms using deep neural networks are currently having a major impact on basic sciences. The physics of complex quantum systems is no exception, with multiple applications that constitute a new field of research. Examples include the representation and optimization of wave functions of quantum systems with large numbers of degrees of freedom (neural quantum states), the determination...

One of the simplest ways to make gauge fields massive is to add them a mass "by hand". Intuitively, one could expect that the corresponding massless theory would then be easy to recover. Yet, conventional methods indicate that such a limit is singular. In this talk, we will explore the massless limits of several massive gauge theories. We will identify the source of the apparent discontinuities an...

One of the major problems of computational chemistry is the ab initio prediction of energies and properties of molecules. The electronic Schrödinger equations provides the in-principle solution, but because of intrinsic difficulties associated with the singular and long-ranged Coulomb interaction, this remains an extremely challenging task numerically. Here we outline a formalism called transcorre...

Interesting erasure phenomena arise from interactions between lower-dimensional and higher-dimensional objects and impact cosmology and fundamental physics. In the first part of the colloquium, I will examine the case for topological defects, revealing insights into the interactions of magnetic monopoles, cosmic strings, and domain walls. For objects like cosmic or QCD flux strings, encounters wit...

I will describe recent developments on the (numerical) computation of energy levels of various systems by the quantum mechanical bootstrap. The main way the bootstrap works is by using constraints that arise from positive matrices. Part of the goal is to turn the bootstrap problem into a problem that can be solved by semi-definite programming methods. I will describe how this method leads to solut...

Understanding dark energy and black holes remain a great challenge to fundamental physics. In this talk I will review the difficulties and explore some new and speculative approaches.

Gravitational waves open a new window into our universe. In this colloquium we discuss particle theorists' perspective on calculations directly relevant for gravitational-wave emission from compact objects, which is rooted in quantum field theory and builds on the idea that gravitational interactions are mediated by spin-2 particles. After reviewing some of the remarkable advances in our understan...

Our search for a quantum theory of gravity is aided by a unique and perplexing feature of the classical theory: General Relativity already knows" about its own quantum states (the entropy of a black hole), and about those of all matter (via the covariant entropy bound). The results we are able to extract from classical gravity are inherently nonperturbative and increasingly sophisticated. Recent b...

I will discuss Effective Field Theories that can originate from microscopic unitary theories, and their relation to moment theory. I will show that massive gravity, theories with isolated massive higher-spin particles, and theories with very irrelevant interactions, don't posses healthy UV completions, and I will show how Vector Meson Dominance follows from such first principles.

In this talk, I will explore the fascinating connections between string theory and quantum field theory, focusing on what we have learned from studying string scattering amplitudes. These insights have not only deepened our understanding of particle interactions but have also led to significant advancements in quantum field theory itself. To set the stage, I will introduce string theory, highlight...

We will review the beginning of experimental and theoretical studies of moire systems and their evolution up to present. We will show how thousands of p orbitals in a moire unit cell of graphene can create single Heavy fermion at moire scale, and how the interaction between such fermions can lead to a perfect quantum simulator of an Anderson model. We will then present a catalogue of possible twis...

This talk will overview the history of primordial black hole (PBH) research from the first papers around 50 years ago to the present time. I will first discuss their possible formation mechanisms, including critical collapse from inflationary fluctuations and various types of phase transition. I will then describe the numerous constraints on the number of PBHs from various quantum and astrophysica...

In driven open quantum matter, coherent many-body quantum dynamics, drive, and dissipation play equally significant roles. These systems span a wide range of examples, including cold atomic gases, exciton-polaritons in solid state, and quantum devices designed for quantum information applications. These setups break the conditions of thermodynamic equilibrium on the microscopic scale, prompting qu...

In a simple, constant environment does evolution continue forever? Does extensive diversification via small genetic and ecological differences? What are general evolutionary consequences of organismic complexity? Hints from long term laboratory evolution experiments and findings from genomic data of extensive within-species bacterial diversity motivate considering these questions. Several simple m...

Ultra-High-Energy Cosmic Rays (UHECRs) are particles with energies up to $3\times 10^20 eV$, originating from unknown sources and producing extensive air showers in Earth's atmosphere. In this talk, I will review the current status of UHECR observations, including the energy spectrum, mass composition, and anisotropy in their arrival directions. I will highlight how the knowledge of the Galactic M...

In the development of animals, tissues self-organise starting from a single cell into lay- ers, shapes and patterns. This active mechanical process operates beyond the theoretical framework of reaction-diffusion equations such as Turing patterns. At the same time, combining active driving with careful mechanical design of a system is distinct route to pattern formation and artificial functionality...

At a singularity the continuum description of spacetime breaks down and one can hope that the microscopic constituents will be revealed. Over 50 years ago, Belinski-Khalatnikov-Lifshitz (BKL) argued that the dynamics of spacetime close to the Big Bang singularity (or inside black holes) is chaotic and inhomogeneous. I will revisit the BKL scenario within a modern understanding of quantum chaos and...