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Different formulations of Einstein's equations used in numerical relativity can affect not only the stability but also the accuracy of numerical simulations. In the original Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation, the loss of…

General Relativity and Quantum Cosmology · Physics 2015-08-06 Hwei-Jang Yo , Zhoujian Cao , Chun-Yu Lin , Hsing-Po Pan

GWs from BNS associated with SGRBs have drawn considerable attention due to their prospect in cosmology. For such events, the sky locations of sources can be pinpointed with techniques such as identifying the host galaxies. However, the…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-22 Minghui Du , Lixin Xu

Motivated by the increasing use of and rapid changes in array technologies, we consider the prediction problem of fitting a linear regression relating a continuous outcome $Y$ to a large number of covariates $\mathbf {X}$, for example,…

Applications · Statistics 2014-01-13 Philip S. Boonstra , Bhramar Mukherjee , Jeremy M. G. Taylor

The idea that we live in a Universe undergoing a period of acceleration is a strongly held notion in cosmology. As this can, potentially, be explained with a modification to General Relativity we look at current cosmological data with the…

Astrophysics · Physics 2010-11-11 Shaun A. Thomas , Filipe B. Abdalla , Jochen Weller

We propose a way to construct manifestly gauge independent quantities out of the gauge dependent quantities occurring in the linearized Einstein equations. Thereupon, we show that these gauge-invariant combinations can be identified with…

General Relativity and Quantum Cosmology · Physics 2007-05-23 P. G. Miedema , W. A. van Leeuwen

The Sequential Linear Quadratic (SLQ) algorithm is a continuous-time variant of the well-known Differential Dynamic Programming (DDP) technique with a Gauss-Newton Hessian approximation. This family of methods has gained popularity in the…

Robotics · Computer Science 2021-03-29 Jean-Pierre Sleiman , Farbod Farshidian , Marco Hutter

We consider a class of Boussinesq systems of Bona-Smith type in two space dimensions approximating surface wave flows modelled by the three-dimensional Euler equations. We show that various initial-boundary-value problems for these systems,…

Classical Physics · Physics 2009-07-29 Vassilios Dougalis , Dimitrios Mitsotakis , Jean-Claude Saut

As is well known, there exist some Lorentz breaking scenarios which explain the smallness of the cosmological constant in the present era. An important aspect to analyze is the propagation of gravitational waves and the screening or…

General Relativity and Quantum Cosmology · Physics 2017-11-01 O. Santillan , M. Scornavacche

Modified gravity theories generically predict a violation of Lorentz invariance, which may lead to a modified dispersion relation for propagating modes of gravitational waves. We construct a parametrized dispersion relation that can…

General Relativity and Quantum Cosmology · Physics 2014-12-02 Saeed Mirshekari , Nicolas Yunes , Clifford M. Will

The GW170817 event opened a new window to test modifications to General Relativity with the aim of discard or impose strong constraints in extra dimension theories of gravity. Concerning these theories, the Randall-Sundrum brane-world…

General Relativity and Quantum Cosmology · Physics 2020-05-20 Miguel A. García-Aspeitia , Celia Escamilla-Rivera

We consider chance constrained optimization where it is sought to optimize a function while complying with constraints, both of which are affected by uncertainties. The high computational cost of realistic simulations strongly limits the…

Optimization and Control · Mathematics 2022-04-18 Julien Pelamatti , Rodolphe Le Riche , Céline Helbert , Christophette Blanchet-Scalliet

Regression with the lasso penalty is a popular tool for performing dimension reduction when the number of covariates is large. In many applications of the lasso, like in genomics, covariates are subject to measurement error. We study the…

Methodology · Statistics 2017-01-04 Øystein Sørensen , Arnoldo Frigessi , Magne Thoresen

Reasoning about the physical world requires models that are endowed with the right inductive biases to learn the underlying dynamics. Recent works improve generalization for predicting trajectories by learning the Hamiltonian or Lagrangian…

Machine Learning · Computer Science 2020-10-27 Marc Finzi , Ke Alexander Wang , Andrew Gordon Wilson

Understanding the properties of transient gravitational waves and their sources is of broad interest in physics and astronomy. Bayesian inference is the standard framework for astro-physical measurement in transient gravitational-wave…

General Relativity and Quantum Cosmology · Physics 2020-10-07 Rory Smith , Gregory Ashton , Avi Vajpeyi , Colm Talbot

Neural networks are increasingly used in complex (data-driven) simulations as surrogates or for accelerating the computation of classical surrogates. In many applications physical constraints, such as mass or energy conservation, must be…

Computational Physics · Physics 2020-02-25 Jim Magiera , Deep Ray , Jan S. Hesthaven , Christian Rohde

As the size of quantum devices continues to grow, the development of scalable methods to characterise and diagnose noise is becoming an increasingly important problem. Recent methods have shown how to efficiently estimate Hamiltonians in…

Quantum Physics · Physics 2019-12-18 Tim J. Evans , Robin Harper , Steven T. Flammia

With the continuous upgrade of detectors, more and more gravitational wave (GW) events were captured by the LIGO Scientific Collaboration and Virgo Collaboration (LVC), which offers a new avenue to test General Relativity and explore the…

General Relativity and Quantum Cosmology · Physics 2021-11-17 Rui Niu , Xing Zhang , Bo Wang , Wen Zhao

Many challenging tasks in sensor networks, including sensor calibration, ranking of nodes, monitoring, event region detection, collaborative filtering, collaborative signal processing, {\em etc.}, can be formulated as a problem of solving a…

Numerical Analysis · Computer Science 2009-01-20 Danny Bickson , Ezra N. Hoch , Harel Avissar , Danny Dolev

In this paper we study two multidimensional nonlinear dispersive systems: the Serre-Green-Naghdi (SGN) equations describing dispersive shallow water flows, and Iordanskii-Kogarko-Wijngaarden (IKW) equations describing fluids containing…

Numerical Analysis · Mathematics 2023-02-01 Sergey Tkachenko , Sergey Gavrilyuk , Jacques Massoni

We study the evolution of cosmological perturbations, using a hybrid approximation scheme which upgrades the weak-field limit of Einstein's field equations to account for post-Newtonian scalar and vector metric perturbations and for…

Astrophysics · Physics 2007-05-23 Carmelita Carbone , Sabino Matarrese