With recent advances in experimental tools and wearable devices, it has become increasingly easy to collect large volumes of time-series data. In this talk, I will demonstrate how such data can be utilized to uncover the hidden structures within complex systems. First, I will introduce GOBI (General Model-based Inference), a simple yet scalable method designed for inferring regulatory networks...
Dark matter makes up the majority of matter in the Universe and plays a central role in the formation of cosmic structures. Under appropriate conditions, it may also form compact, self-gravitating objects analogous to stars. In this talk, I will examine the possibility that such “dark stars” arise in scenarios where dark matter possesses self-interactions in addition to gravity. These...
Cosmic halo formation is typically expected to begin deep in the matter-dominated epoch of the Universe. However, this expectation rests on assuming standard initial conditions and dark matter properties. In this talk I will discuss two situations which relax these assumptions. In the first, I will discuss initial conditions with larger than anticipated small scale fluctuations, leading to...
The very beginning of our universe is believed to be a rapid and silent expansion, called Inflation, during which the universe stayed cold, empty, and dark without heat or light. However, before the familiar hot and dense universe (the Hot Big Bang) begins, something extraordinary had to happen: the universe needs to get ignition. This brief but turbulent transition, known as reheating,...
It was first observed by Witten and soon proved by Kontsevich that the two-point correlation function of the 2d quantum gravity theory is a solution of the KdV hierarchy. Since then, relationships between 2d topological field theories coupling with gravity and integrable hierarchies have been studied in a great detail. In this talk, I will explain a canonical correspondence between semisimple...
Divergence in perturbative expansions is where interesting physics takes place. Particle production on time-dependent backgrounds, as one such example, is interpreted as transition from one vacuum to another. In this talk, I establish that several conceptual issues in the conventional approach to particle production in cosmology may be eliminated by fully employing the exact WKB methodology, a...
Dynamical phenomena in purely chiral fermionic theories remain an open challenge across a wide range of fields, from condensed matter to high-energy physics. In this talk, I will discuss how dynamical symmetry breaking can be studied in a class of chiral gauge theories that includes the Georgi–Glashow model originally proposed in the context of grand unification. This family of theories is...
During seasons with little or no food, hibernators enter inactive states to survive in harsh environments. Due to its complexity, the mechanism of hibernation remains largely unknown. Recent advances in experimental technology have enabled monitoring of body temperature in hibernators for more than 100 days. In this study, we aim to reveal the mechanisms of hibernation by analyzing body...
The correlation functions of primordial cosmological perturbations encode valuable information about the early universe. In particular, higher-order correlations, known as non-Gaussianities, can reveal additional insights, including the mass and spin of heavy particles, through characteristic oscillatory signatures. Remarkably, such particles can have masses as large as the Hubble scale during...
Reticulate evolution is a major driver of genetic and phenotypic diversity in the natural world. With the proliferation of genomic data, interest in detecting historical reticulation has grown rapidly, coinciding with advances in statistical methods for identifying complex evolutionary histories. Phylogenetic networks provide a probabilistic framework for representing such processes (e.g.,...
The statistical properties of the CMB anisotropies, reflecting the curvature inhomogeneities in the early Universe, are very well accounted for by assuming that they emerged from amplified vacuum fluctuations. Being the result of a genuine quantum process, it is natural to wonder which properties of these primordial inhomogeneities are quantum, and which, if any, persisted until their...
Carrollian physics has recently emerged as a powerful framework for describing gravitational subsystems with null boundaries, playing a central role in settings such as flat-space holography and black-hole horizons. In this talk, I will review the development of Carrollian structures, beginning with their algebraic formulation and then connecting it to the geometric viewpoint of null...
In Turing’s study of reaction–diffusion systems, phyllotactic pattern formation was one of his motivations, especially in his later unpublished notes. His work introduced continuous and dynamic approaches to discretely given phyllotactic patterns, inspiring extensive analytical and numerical studies in reaction–diffusion systems. However, Turing himself did not investigate phyllotaxis on...
Quantum effects in general induce scale dependence in the coupling constants. When applied to Kerr black holes with a running Newton coupling, the consistency of black hole thermodynamics requires that the Newton coupling have a specific dependence on the black hole parameters. In this work, we consider such a class of Newton couplings and look for the possible observational implications on...
In this talk we review various axiomatic approaches to quantum field theory and the known connections between them.
Imagine that you are in a room without information of time. The room is in a cave so that temperature and light-intensity are constant over time. Can you wake up tomorrow or day after tomorrow? In fact, most humans can wake up tomorrow and day after tomorrow almost regularly. It is because we have daily rhythms in our body. Biological experiments have shown that not only humans but also other...
