arXiv subjects

Arindam Lala

Publications and source records attributed to Arindam Lala.

14 recordsLinked to original sources

arXiv2023

Integrability and non-integrability for marginal deformations of 4d $\mathcal N = 2$ SCFTs

We study integrability and non-integrability for marginal deformations of 4d $\mathcal N =2$ SCFTs. We estimate various chaos indicators for the bulk theory which clearly shows the onset of a chaotic string dynamics in the limit of large deformations. On the other hand, for small values of the deformation parameter, the resulting dynamics exhibits a non-chaotic motion and therefore presumably an underlying integrable structure. Our analysis reveals that the $γ$-deformation in the type-IIA theory could be interpreted as an interpolation between a class of integrable $\mathcal N =2$ SCFTs and a class of non-integrable $\mathcal N =1$ SCFTs at strong coupling. We also generalise our results in the presence of the flavor branes.

hep-th↗

arXiv2022

Non-chaotic dynamics for Yang-Baxter deformed $\text{AdS}_{4}\times \text{CP}^{3}$ superstrings

We explore a novel class of Yang-Baxter deformed AdS$_{4}$ $\times$ CP$^{3}$ backgrounds [Jour. High Ener. Phys. \textbf{01} (2021) 056] which exhibit a non-chaotic dynamics for (super)strings propagating over it. We explicitly use the \textit{Kovacic's algorithm} in order to establish non-chaotic dynamics of string $ \sigma $ models over these deformed backgrounds. This analysis is complemented with numerical techniques whereby we probe the classical phase space of these (semi)classical strings and calculate various chaos indicators, such as, the Poincar\'{e} sections and the Lyapunov exponents. We find compatibility between the two approaches. Nevertheless, our analysis does not ensure integrability; rather, it excludes the possibility of non-integrability for the given string embeddings.

hep-th↗

arXiv2021

Analytic (non)integrability of Arutyunov-Bassi-Lacroix model

We use the notion of the gauge/string duality and discuss the Liouvillian (non) integrability criteria for string sigma models in the context of recently proposed Arutyunov-Bassi-Lacroix (ABL) model [JHEP \textbf{03} (2021), 062]. Our analysis complements those previous results due to numerical analysis as well as Lax pair formulation. We consider a winding string ansatz for the deformed torus $T^{\qty(λ_{1},λ_{2},λ)}_{k}$ which can be interpreted as a system of coupled pendulums. Our analysis reveals the Liouvillian nonintegrablity of the associated sigma model. We also obtain the \emph{generalized} decoupling limit and confirm the analytic integrability for the decoupled sector.

hep-th↗

arXiv2020

Entanglement measures for non-conformal D-branes

We study various entanglement measures associated with certain non-conformal field theories. We consider non-conformal D$p$-brane backgrounds, which are dual to these field theories, for our holographic analysis. Restricting our interests in $p=1,2,4$, we explicitly compute properties of holographic entanglement entropy and entanglement wedge cross section, $\text{E}_{W}$, corresponding to two parallel strip shaped boundary subregions in these set ups. We study low and high temperature behaviours of these quantities analytically as well as using numerical methods. In all cases, the $\text{E}_{W}$ decrease monotonically with temperature. We observe discontinuous jumps in $\text{E}_{W}$ while the width of (as well as the separation between) the subregions reach critical values in all the cases considered. However, the corresponding holographic mutual information $\texttt{I}_{M}$ continuously decreases to zero for the aforementioned configurations. We also notice that the conjectured inequality $\text{E}_{W} \geq \texttt{I}_{M}/2$ still holds for non-conformal field theories as well. We analytically determine the critical separation between these subregions that triggers a phase transition in the holographic mutual information.

hep-th↗

arXiv2020

JT gravity and the models of Hawking-Page transition for 2D black holes

We propose a top down construction for Jackiw-Teitelboim (JT) gravity using compactification of $ D=5 $ gravity theories in the presence of Abelian ($ U(1) $) as well as $ SU(2) $ Yang-Mills (YM) fields. The background solutions corresponding to $ D=2 $ model have been obtained in the perturbative regime of the theory where the corrections have been estimated over the uncharged JT solutions while treating the gauge couplings as the parameters of the expansion. Our analysis reveals the existence of two classes of solutions namely, (i) the \emph{interpolating} vacuum solution with AdS$_2$ in the IR and Lifshitz$_2$ in the UV (which serves as the thermal radiation background for our analysis) and (ii) the charged 2D black hole solution exhibiting Lifshitz$_2$ asymptotics. The analysis on thermal stability reveals the onset of a first order phase transition at $ T \sim T_0 $ such that for $ T < T_0 $ the only possible state is the thermal radiation background without any black hole. On the other hand, as the temperature is gradually increased beyond certain \emph{crossover} value $ T\sim T_2 (>T_0 )$, an emerging \emph{globally} stable black hole dominated phase has been observed which clearly indicates the onset of Hawking-Page (HP) transition in 2D gravity models.

hep-th↗

arXiv2019

Models of phase stability in Jackiw-Teitelboim gravity

We construct solutions within Jackiw-Teitelboim (JT) gravity in the presence of nontrivial couplings between the dilaton and the Abelian $1$-form where we analyse the asymptotic structure as well as the phase stability corresponding to charged black hole solutions in $1+1$ D. We consider the Almheiri-Polchinski (AP) model as a specific example within $1+1$ D JT gravity which plays a pivotal role in the study of Sachdev-Ye-Kitaev (SYK)/anti-de Sitter (AdS) duality. The corresponding vacuum solutions exhibit a rather different asymptotic structure than their uncharged counterpart. We find interpolating vacuum solutions with AdS$_2$ in the IR and Lifshitz$_2$ in the UV with dynamical exponent $z_{\text{dyn}}=3/2$. Interestingly, the presence of charge also modifies the black hole geometry from asymptotically AdS to asymptotically Lifshitz with same value of the dynamical exponent. We consider specific examples, where we compute the corresponding free-energy and explore the thermodynamic phase stability associated with charged black hole solutions in $1+1$ D. Our analysis reveals the existence of a universal thermodynamic feature that is expected to reveal its immediate consequences on the dual SYK physics at finite density and strong coupling.

hep-th↗

arXiv2018

SYK/AdS duality with Yang-Baxter deformations

In this paper, based on the notion of SYK/AdS duality we explore the effects of Yang-Baxter (YB) deformations on the SYK spectrum at strong coupling. In the first part of our analysis, we explore the consequences of YB deformations through the Kaluza-Klein (KK) reduction on $ (AdS_2)_η\times (S^1)/Z_2 $. It turns out that the YB effects (on the SYK spectrum) starts showing off at \textit{quadratic} order in $ 1/J $ expansion. For the rest of the analysis, we provide an interpretation for the YB deformations in terms of bi-local/collective field excitations of the SYK model. Using large $ N $ techniques, we evaluate the effective action upto quadratic order in the fluctuations and estimate $ 1/J^2 $ corrections to the correlation function at strong coupling.

hep-th↗

arXiv2018

Enhanced Symmetry of the $p$-adic Wavelets

Wavelet analysis has been extended to the $p$-adic line $\mathbb{Q}_p$. The $p$-adic wavelets are complex valued functions with compact support. As in the case of real wavelets, the construction of the basis functions is recursive, employing scaling and translation. Consequently, wavelets form a representation of the affine group generated by scaling and translation. In addition, $p$-adic wavelets are eigenfunctions of a pseudo-differential operator, as a result of which they turn out to have a larger symmetry group. The enhanced symmetry of the $p$-adic wavelets is demonstrated.

math-ph↗

arXiv2017

On the Exchange Interactions in Holographic p-adic CFT

There is a renewed interest in conformal field theories (CFT) on ultrametric spaces (p-adic field and its algebraic extensions) in view of their natural adaptability in the holographic setting. We compute the contributions from the exchange interactions to the four-point correlator of the CFT using Witten diagrams with three-scalar interaction vertex. Together with the contributions from the bulk four-point interaction, the contact term, these provide a complete answer. We remark on the singularity structure in Mellin space, and argue that all these models are analogues of adS_2/CFT_1.

hep-th↗

arXiv2015

Holographic $s$-wave condensation and Meissner-like effect in Gauss-Bonnet gravity with various non-linear corrections

In this paper we have studied the onset of holographic $s$-wave condensate in the $(4+1)$ dimensional planar Gauss-Bonnet-AdS black hole background with several non-linear corrections to the gauge field. In the probe limit, performing explicit analytic computations, with and without magnetic field, we found that these higher order corrections indeed affect various quantities characterising the holographic superconductors. Also, performing a comparative study of the two non-linear electrodynamics it has been shown that the exponential electrodynamics has stronger effects on the formation of the scalar hair. We observe that our results agree well with those obtained numerically [Z. Zhao et. al., Nucl. Phys. B 871 [FS] (2013) 98].

hep-th↗

arXiv2014

Magnetic response of holographic Lifshitz superconductors:Vortex and Droplet solutions

In this paper a holographic model of $s$-wave superconductor with anisotropic Lifshitz scaling has been considered. In the presence of an external magnetic field our holographic model exhibits both vortex and droplet solutions. Based on analytic methods we have shown that the anisotropy has no effect on the vortex and droplet solutions whereas it may affect the condensation. Our vortex solution closely resembles the Ginzburg-Landau theory and a relation between the upper critical magnetic field and superconducting coherence length has been speculated from this comparison. Using Sturm-Liouville method, the effect of anisotropy on the critical parameters in insulator/superconductor phase transitions has been analyzed.

hep-th↗

arXiv2013

Critical phenomena in higher curvature charged AdS black holes

In this paper we have studied the critical phenomena in higher curvature charged black holes in the anti-de Sitter (AdS) space-time. As an example we have considered the third order Lovelock-Born-Infeld black holes in AdS space-time. We have analytically derived the thermodynamic quantities of the system. Our analysis revealed the onset of a higher order phase transition in the black hole leading to an infinite discontinuity in the specific heat at constant charge at the critical points. Our entire analysis is based on the canonical framework where we have fixed the charge of the black hole. In an attempt to study the behavior of the thermodynamic quantities near the critical points we have derived the critical exponents of the system explicitly. Although the values of the critical points have been determined numerically, the critical exponents are calculated analytically. Our results fit well with the thermodynamic scaling laws. The scaling hypothesis is also seen to be consistent with these scaling laws. We find that all types of AdS black holes, studied so far, indeed belong to the same universality class. Moreover these results are consistent with the mean field theory approximation. We have derived the suggestive values of the other two critical exponents associated with the correlation function and correlation length on the critical surface.

gr-qc↗

arXiv2013

Holographic s-wave condensate with non-linear electrodynamics: A nontrivial boundary value problem

In this paper, considering the probe limit, we analytically study the onset of holographic s-wave condensate in the planar Schwarzschild-AdS background. Inspired by various low energy features of string theory, in the present work we replace the conventional Maxwell action by a (non-linear) Born-Infeld (BI) action which essentially corresponds to the higher derivative corrections of the gauge fields. Based on a variational method, which is commonly known as the Sturm-Liouville (SL) eigenvalue problem and considering a non-trivial asymptotic solution for the scalar field, we compute the critical temperature for the s-wave condensation. The results thus obtained analytically agree well with the numerical findings\cite{hs19}. As a next step, we extend our perturbative technique to compute the order parameter for the condensation. Interestingly our analytic results are found to be of the same order as the numerical values obtained earlier.

hep-th↗

arXiv2012

Ehrenfest's scheme and thermodynamic geometry in Born-Infeld AdS black holes

In this paper we analyze the phase transition phenomena in Born-Infeld AdS black holes using Ehrenfest's scheme of standard thermodynamics. The critical points are marked by the divergences in the heat capacity. In order to investigate the nature of the phase transition, we analytically check both the Ehrenfest's equations near the critical points. Our analysis reveals that this is indeed a second order phase transition. Finally, we analyze the nature of the phase transition using state space geometry approach. This is found to be compatible with the Ehrenfest's scheme.

gr-qc↗