arXiv subjects

Robin Raj

Publications and source records attributed to Robin Raj.

4 recordsLinked to original sources

arXiv2026

On $\sqrt{T\overline{T}}$ deformed pathways: CFT to CCFT

We discuss the marginal $\sqrt{T\overline{T}}$ deformation of massless scalar field theories in two dimensions from a dynamical perspective. The operator flow equations for such deformations induce a particular Legendre Transformation between flowed Lagrangians and flowed Hamiltonians. The marginal deformation does not change the conformal symmetries of the theory, until some special points in the moduli space are reached, and the relativistic conformal algebra smoothly changes to the Carrollian conformal (equivalently BMS) one. We investigate this change of symmetry from both configuration space and phase space point of view, while keeping the notion of Legendre Transformation unchanged during the flow. By expanding the actions, in the extreme limits of the flow parameter, we recover the usual ``Electric'' Carroll theory and further uncover a novel ``Magnetic'' counterpart. We discuss the intriguing geometric understanding of such dynamical maps for the deformed theories, and also provide a concrete example for the same from a deformed string theory in flat space.

hep-th↗

arXiv2022

Can our spacetime emerge from anti -- de Sitter space?

We present a model showing that our four-dimensional spacetime with the signature $(+,-,-,-)$ and almost vanishing positive curvature may have originated from a $b$-ary tree-like branching of a single discrete entity, and the $AdS_5$ space related to this branching process.

gr-qc↗

arXiv2021

Multiresolution quantum field theory in light-front coordinates

We analyse the use of wavelet transform in quantum field theory models written in light-front coordinates. In a recent paper [W.N Polyzou, Phys. Rev. D 101(2020) 096004] W.N.Polyzou used $x^+$ variable as 'time', and applied wavelet transform to the 'spatial' coordinates only. This makes the theory asymmetric with respect to space and time coordinates. In present paper we generalise the concept of continuous causal path, which is the basis of path integration, to the sequences of causally ordered spacetime regions, and present evaluation rules for Feynman path integrals over such sequences in terms of wavelet transform. Both the path integrals and the wavelet transform in our model are symmetric with respect to the light-front variables ($x^+,x^-$). The definition of a spacetime event in our generalization is very much like the definition of event in probability theory.

hep-th↗

arXiv2020

Wavelet regularization of Euclidean QED

The regularization of quantum electrodynamics in the space of functions $\psi_a(x)$, which depend on both the position $x$ and the scale $a$, is presented. The scale-dependent functions are defined in terms of the continuous wavelet transform in $\mathbb{R}^4$ Euclidean space, with the derivatives of Gaussian served as basic wavelets. The vacuum polarization and the dependence of the effective coupling constant on the scale parameters are calculated in one-loop approximation in the limit $p^2 \gg 4m^2$.

hep-th↗