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Persistent homology analysis provides means to capture the connectivity structure of data sets in various dimensions. On the mathematical level, by defining a metric between the objects that persistence attaches to data sets, we can…

Machine Learning · Computer Science 2019-06-12 Henri Riihimäki , José Licón-Saláiz

We study how the topology of a data set $M = M_a \cup M_b \subseteq \mathbb{R}^d$, representing two classes $a$ and $b$ in a binary classification problem, changes as it passes through the layers of a well-trained neural network, i.e., with…

Machine Learning · Computer Science 2020-04-14 Gregory Naitzat , Andrey Zhitnikov , Lek-Heng Lim

The bubble size distribution is a summary statistics that can be computed from the observed 21-cm signal from the Epoch of Reionization. As it depends only on the ionization field and is not limited to gaussian information, it is an…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-16 Aristide Doussot , Benoit Semelin

We present a pipeline for characterizing and constraining initial conditions in cosmology via persistent homology. The cosmological observable of interest is the cosmic web of large scale structure, and the initial conditions in question…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-08 Alex Cole , Matteo Biagetti , Gary Shiu

I review computational studies of different models of elastic network self-organization leading to the existence of a globally isostatic (rigid but unstressed) or nearly isostatic intermediate phase. A common feature of all models…

Disordered Systems and Neural Networks · Physics 2008-07-21 Mykyta V. Chubynsky

The reionization of hydrogen in the intergalactic medium (IGM) is a crucial landmark in the history of the universe, but the processes through which it occurs remain mysterious. In particular, recent numerical and analytic work suggest that…

Astrophysics · Physics 2009-11-10 Steven Furlanetto , Lars Hernquist , Matias Zaldarriaga

Recently, level crossings in the energy bands of crystals have been identified as a key signature for topological phase transitions. Using realistic models we show that the parameter space controlling the occurrence of level coincidences in…

Mesoscale and Nanoscale Physics · Physics 2012-11-19 R. Winkler , L. Y. Wang , Y. H. Lin , C. S. Chu

We complete a classification of topological phases and their topological defects in crystalline insulators and superconductors. We consider topological phases and defects described by non-interacting Bloch and Bogoliubov de Gennes…

Mesoscale and Nanoscale Physics · Physics 2014-10-15 Ken Shiozaki , Masatoshi Sato

In recent years, cosmic shear has emerged as a powerful tool to study the statistical distribution of matter in our Universe. Apart from the standard two-point correlation functions, several alternative methods like peak count statistics…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Sven Heydenreich , Benjamin Brück , Joachim Harnois-Déraps

Persistent homology computes the multiscale topology of a data set by using a sequence of discrete complexes. In this paper, we propose that persistent homology may be a useful tool for studying the structure of the landscape of string…

High Energy Physics - Theory · Physics 2019-04-24 Alex Cole , Gary Shiu

Persistent homology probes topological properties from point clouds and functions. By looking at multiple scales simultaneously, one can record the births and deaths of topological features as the scale varies. In this paper we use a…

We use the results of large-scale simulations of reionization to explore methods for characterizing the topology and sizes of HII regions during reionization. We use four independent methods for characterizing the sizes of ionized regions.…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-11 Martina M. Friedrich , Garrelt Mellema , Marcelo A. Alvarez , Paul R. Shapiro , Ilian T. Iliev

A geometric entropy is defined as the Riemannian volume of the parameter space of a statistical manifold associated with a given network. As such it can be a good candidate for measuring networks complexity. Here we investigate its ability…

Mathematical Physics · Physics 2017-12-20 D. Felice , R. Franzosi , S. Mancini , M. Pettini

Granular materials exhibit intricate force networks, often concentrated in chains rather than being uniformly distributed. These meso-scale structures are complex to characterize, owing to their heterogeneous and anisotropic nature. We…

Soft Condensed Matter · Physics 2025-08-06 S Vishali , Abrar Naseer , Vijay Natarajan , Tejas G Murthy

We develop an analytic approach to study inhomogeneous reionization on large scales by solving the equations of ionization balance and radiative transfer to first order in perturbations. Given the spatial distribution and spectrum of the…

Astrophysics · Physics 2008-11-26 Jun Zhang , Lam Hui , Zoltan Haiman

Complex networks encountered in biology are often characterized by significant structural diversity. Whether it be differences in the three-dimensional structure of allosteric proteins, or the variation among the micro-scale structures of…

Physics and Society · Physics 2020-08-19 Jason W. Rocks , Andrea J. Liu , Eleni Katifori

This study presents a numerical analysis of the topology of a set of cosmologically interesting three-dimensional Gaussian random fields in terms of their Betti numbers $\beta_0$, $\beta_1$ and $\beta_2$. We show that Betti numbers entail a…

A possible way to study the reionization of cosmic hydrogen is by observing the large ionized regions (bubbles) around bright individual sources, e.g., quasars, using the redshifted 21 cm signal. It has already been shown that matched…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-17 Raghunath Ghara , T. Roy Choudhury

Motivated by the desire to understand complex transient behaviour in fluid flows, we study the dynamics of an air bubble driven by the steady motion of a suspending viscous fluid within a Hele-Shaw channel with a centred depth perturbation.…

Transition out of a topological phase is typically characterized by discontinuous changes in topological invariants along with bulk gap closings. However, as a clean system is geometrically punctured, it is natural to ask the fate of an…

Disordered Systems and Neural Networks · Physics 2023-12-15 Saikat Mondal , Subrata Pachhal , Adhip Agarwala