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Related papers: Parameter Estimation Limits in Blazars

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Quantum metrology leverages quantum effects such as squeezing, entanglement, and other quantum correlations to boost precision in parameter estimation by saturating quantum Cramer Rao bound, which can be achieved by optimizing quantum…

Quantum Physics · Physics 2024-12-03 A. Naimy , A. Slaoui , A. Ali , H. El Hadfi , R. Ahl Laamara , S. Al-Kuwari

We present the results of the \textit{Fermi}-LAT 10-years-long light curves (LCs) modeling of selected blazars: six flat spectrum radio quasars (FSRQs) and five BL Lacertae (BL Lacs), examined in 7-, 10-, and 14-day binning. The LCs and…

High Energy Astrophysical Phenomena · Physics 2021-09-24 Mariusz Tarnopolski , Natalia Żywucka , Volodymyr Marchenko , Javier Pascual-Granado

A study of blazar PKS 1424-418 was carried out using multi waveband data collected by Fermi-LAT, Swift-XRT, Swift-UVOT and SMARTS telescopes between MJD 56000 to MJD 56600 (14 Mar 2012 to 4 Nov 2013). Two flaring episodes were identified by…

High Energy Astrophysical Phenomena · Physics 2021-01-18 Jayant Abhir , Jophin Joseph , Sonal R Patel , Debanjan Bose

We use the Fisher matrix formalism and semi-numerical simulations to derive quantitative predictions of the constraints that power spectrum measurements on next-generation interferometers, such as the Hydrogen Epoch of Reionization Array…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-26 Aaron Ewall-Wice , Jacqueline Hewitt , Andrei Mesinger , Joshua S. Dillon , Adrian Liu , Jonathan Pober

When training data are fragmented across batches or federated-learned across different geographic locations, trained models manifest performance degradation. That degradation partly owes to covariate shift induced by data having been…

Machine Learning · Computer Science 2025-10-07 Behraj Khan , Tahir Qasim Syed

Modern machine learning systems operating in dynamic environments often face \textit{sequential covariate shift} (SCS), where input distributions evolve over time while the conditional distribution remains stable. We introduce FADE…

Machine Learning · Computer Science 2025-07-28 Behraj Khan , Tahir Qasim Syed , Nouman Muhammad Durrani

Polarization optical fiber sensors are based on modifications of fiber birefringence by an external measurand (e.g. strain, pressure, acoustic waves). Yet, this means that different input states of polarization will result in very distinct…

Optics · Physics 2025-06-13 Catarina S. Monteiro , Tiago D. Ferreira , Nuno A. Silva

We perform a detailed spectral study of a recent flaring activity from the Flat Spectrum Radio Quasar (FSRQ), 3C\,454.3, observed simultaneously in optical, UV, X-ray and $\gamma$-ray energies during 16 to 28 August, 2015. The source…

High Energy Astrophysical Phenomena · Physics 2017-05-18 Zahir Shah , S. Sahayanathan , Nijil Mankuzhiyil , Pankaj Kushwaha , Ranjeev Misra , Naseer Iqbal

We study the scalar curvature of the Fisher information metric on the microscopic coupling-parameter manifold of lattice spin models at criticality. For a $d$-dimensional lattice with periodic boundary conditions and $n = L^d$ sites, the…

Statistical Mechanics · Physics 2026-03-10 Max Zhuravlev

Resolving frequencies in a time-dependent field is classically limited by the measurement bandwidth. Using tools from quantum metrology and quantum control may overcome this limit, yet the full advantage afforded by entanglement so far…

Quantum Physics · Physics 2025-09-03 Anirban Dey , Sara Mouradian , Cosmo Lupo , Zixin Huang

To ensure high quality outputs, it is important to quantify the epistemic uncertainty of diffusion models. Existing methods are often unreliable because they mix epistemic and aleatoric uncertainty. We introduce a method based on Fisher…

Machine Learning · Statistics 2026-02-18 Aditi Gupta , Raphael A. Meyer , Yotam Yaniv , Elynn Chen , N. Benjamin Erichson

A computable expression for the rate-distortion (RD) function proposed by Heegard and Berger has eluded information theory for nearly three decades. Heegard and Berger's single-letter achievability bound is well known to be optimal for…

Information Theory · Computer Science 2012-12-12 Roy Timo , Tobias J. Oechtering , Michèle Wigger

The Fisher information matrix (FIM) plays an important role in the analysis of parameter inference and system design problems. In a number of cases, however, the statistical data distribution and its associated information matrix are either…

Statistics Theory · Mathematics 2016-11-24 Dave Zachariah , Petre Stoica

We consider the processing of statistical samples $X\sim P_\theta$ by a channel $p(y|x)$, and characterize how the statistical information from the samples for estimating the parameter $\theta\in\mathbb{R}^d$ can scale with the mutual…

Information Theory · Computer Science 2021-07-12 Leighton Pate Barnes , Ayfer Ozgur

We present simultaneous Planck, Swift, Fermi, and ground-based data for 105 blazars belonging to three samples with flux limits in the soft X-ray, hard X-ray, and gamma-ray bands. Our unique data set has allowed us to demonstrate that the…

Locating the gamma-ray emission sites in blazar jets is a long-standing and highly controversial issue. We investigate jointly several constraints on the distance scale r and Lorentz factor Gamma of the gamma-ray emitting regions in…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Krzysztof Nalewajko , Mitchell C. Begelman , Marek Sikora

We present a study of high-cadence, high-precision, optical light curves from the TESS satellite of 67 blazars in the southern sky. We provide descriptive flux statistics, power spectral density model parameters, and characteristic…

High Energy Astrophysical Phenomena · Physics 2024-06-18 Ryne Dingler , Krista Lynne Smith

The notion of low-noise channels was recently proposed and analyzed in detail in order to describe noise-processes driven by environment [M. Hotta, T. Karasawa and M. Ozawa, Phys. Rev. A72, 052334 (2005)]. An estimation theory of low-noise…

Quantum Physics · Physics 2009-11-13 M. Hotta , T. Karasawa , M. Ozawa

Historically, the blazar population has been poorly understood at low frequencies because survey sensitivity and angular resolution limitations have made it difficult to identify megahertz counterparts. We used the LOFAR Two-Metre Sky…

In this paper we propose a way to use optical polarisation observations to provide independent constraints and guide to the modelling of the spectral energy distribution (SED) of blazars, which is particularly useful when two-zone models…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Ulisses Barres de Almeida , Fabrizio Tavecchio , Nijil Mankuzhiyil