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Navonil Neogi

Publications and source records attributed to Navonil Neogi.

4 recordsLinked to original sources

Information Spreading in Diffusion Models from Effective Field Theory

We study score-matching diffusion models with a convolutional architecture. We argue that the inductive bias of locality means that the machinery of effective field theory from physics can be usefully applied to describe the denoising dynamics. We apply this formalism first to a simple toy example which permits an analytical description, and thereafter to MNIST, and show that in both cases, the mutual information between two points grows in a manner predicted by a simple effective field theory of Brownian motion.

hep-th

Measuring qualitative change: A variational score for tracking dynamical shifts in partial differential equations

Partial differential equations (PDEs) regulate the behaviour of countless spatiotemporal systems in the physical and life sciences. In many cases, they encode the coupling between the system's degrees of freedom, leading to nonlinear equations whose solution space is challenging to explore exhaustively. Systematic approaches to PDE model exploration are a holy grail of computational science. In this article, we formulate a criterion for increasing the diversity of a search campaign, based on the PDE residual behaviour under solution deformation. We develop a practical formalism to compute this property and illustrate its role in a few cases of interest.

physics.comp-ph

Wilson lines with endpoints in 3d CFT

In Abelian gauge theories with dynamical matter, Wilson lines can end on the insertions of charged fields. We study the endpoints of Wilson lines in large $N$ bosonic QED$_3$. at its critical point. We first study the stability of an infinite Wilson line in the $\mathbb{CP}^{N-1}$ model by computing the appropriate functional determinant at large $N$. We also compute the conformal dimension of the lowest-dimension endpoint of the line to first order in $N^{-1}$. Along the way we calculate the field-strength tensor $F_{\mu\nu}$ in the presence of the line with endpoint and discuss a state-operator correspondence for the endpoints, as well as the existence of an OPE that allows two open-ended Wilson lines to be glued together into a single line.

hep-th

AdS Black Holes with a Bouncing Interior

We construct planar black hole solutions of AdS gravity minimally coupled to a scalar field with an even, super-exponential potential. We show that the evolution of the black hole interior exhibits an infinite sequence of Kasner epochs, as the scalar field rolls back and forth in its potential. We obtain an analytic expression for the `bounces' between each Kasner epoch and also give an explicit formula for the times and strengths of the bounces at late interior times, thereby fully characterizing the interior evolution. In this way we show that the interior geometry approaches the Schwarzschild singularity at late times, even as the scalar field is driven higher up its potential with each bounce.

hep-th