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Long-term precise timing of Galactic millisecond pulsars holds great promise for measuring the long-period (months-to-years) astrophysical gravitational waves. Several gravitational-wave observational programs, called Pulsar Timing Arrays…

Astrophysics · Physics 2009-11-13 Rutger van Haasteren , Yuri Levin , Patrick McDonald , Tingting Lu

We study linear cosmological perturbations in the most general teleparallel gravity setting, where gravity is mediated by the torsion and nonmetricity of a flat connection alongside the metric. For a general linear perturbation of this…

General Relativity and Quantum Cosmology · Physics 2023-12-22 Lavinia Heisenberg , Manuel Hohmann

Despite the rapid development of computational hardware, the treatment of large and high dimensional data sets is still a challenging problem. This paper provides a twofold contribution to the topic. First, we propose a Gaussian Mixture…

Sequential algorithms are popular for experimental design, enabling emulation, optimisation and inference to be efficiently performed. For most of these applications bespoke software has been developed, but the approach is general and many…

Computation · Statistics 2021-10-18 Matthew A. Fisher , Onur Teymur , Chris. J. Oates

Mining useful clusters from high dimensional data has received significant attention of the computer vision and pattern recognition community in the recent years. Linear and non-linear dimensionality reduction has played an important role…

Computer Vision and Pattern Recognition · Computer Science 2016-05-25 Nauman Shahid , Nathanael Perraudin , Vassilis Kalofolias , Gilles Puy , Pierre Vandergheynst

The CP tensor decomposition is used in applications such as machine learning and signal processing to discover latent low-rank structure in multidimensional data. Computing a CP decomposition via an alternating least squares (ALS) method…

Numerical Analysis · Mathematics 2021-12-22 Rachel Minster , Irina Viviano , Xiaotian Liu , Grey Ballard

We discuss cosmological perturbation theory at third order, deriving the gauge transformation rules for metric and matter perturbations, and constructing third order gauge invariant quantities. We present the Einstein tensor components, the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Adam J. Christopherson , Karim A. Malik

Gaussian processes are popular and flexible models for spatial, temporal, and functional data, but they are computationally infeasible for large datasets. We discuss Gaussian-process approximations that use basis functions at multiple…

Methodology · Statistics 2020-12-22 Matthias Katzfuss , Wenlong Gong

To address the common problem of high dimensionality in tensor regressions, we introduce a generalized tensor random projection method that embeds high-dimensional tensor-valued covariates into low-dimensional subspaces with minimal loss of…

Methodology · Statistics 2025-10-03 Roberto Casarin , Radu Craiu , Qing Wang

Cylindrical algebraic decomposition (CAD) is an important tool for the study of real algebraic geometry with many applications both within mathematics and elsewhere. It is known to have doubly exponential complexity in the number of…

Symbolic Computation · Computer Science 2013-07-10 Russell Bradford , James H. Davenport , Matthew England , David Wilson

Scientific computations or measurements may result in huge volumes of data. Often these can be thought of representing a real-valued function on a high-dimensional domain, and can be conceptually arranged in the format of a tensor of high…

Numerical Analysis · Mathematics 2019-09-24 Mike Espig , Wolfgang Hackbusch , Alexander Litvinenko , Hermann G. Matthies , Elmar Zander

The decomposition of tensors into simple rank-1 terms is key in a variety of applications in signal processing, data analysis and machine learning. While this canonical polyadic decomposition (CPD) is unique under mild conditions, including…

Optimization and Control · Mathematics 2024-04-17 Nico Vervliet , Andreas Themelis , Panagiotis Patrinos , Lieven De Lathauwer

We study the degrees of freedom of the metric in a general class of higher derivative gravity models, which are interesting in the context of quantum gravity as they are (super)renormalizable. First, we linearize the theory for a flat…

General Relativity and Quantum Cosmology · Physics 2019-04-05 Patric Hölscher

Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of…

High Energy Astrophysical Phenomena · Physics 2015-05-12 Bin Chen , Ronald Kantowski , Xinyu Dai , Eddie Baron , Prasad Maddumage

Gravitational waves provide a new probe into the strong-field regime of gravity. It is thus essential to identify the predictions of General Relativity on the nature of the two-body problem, and to contrast them to alternative theories.…

General Relativity and Quantum Cosmology · Physics 2020-10-14 Adrien Kuntz

Canonical Polyadic Decomposition (CPD) of a third-order tensor is decomposition in a minimal number of rank-$1$ tensors. We call an algorithm algebraic if it is guaranteed to find the decomposition when it is exact and if it only relies on…

Spectral Theory · Mathematics 2014-05-20 Ignat Domanov , Lieven De Lathauwer

We use computational algorithms recently developed by us to study completely four index divergence free quadratic in Riemann tensor polynomials in GR. Some results are new and some other reproduce and/or correct known ones. The algorithms…

General Relativity and Quantum Cosmology · Physics 2009-10-31 X. Jaen , A. Balfagon

The quest for a consistent theory for quantum gravity is one of the most challenging problems in theoretical high-energy physics. An often-used approach is to describe the gravitational degrees of freedom by the metric tensor or related…

General Relativity and Quantum Cosmology · Physics 2023-10-19 Dennis Obster

The models of New General Relativity have recently got attention of research community, and there are some works studying their dynamical properties. The formal aspects of this investigation have been mostly restricted to the primary…

General Relativity and Quantum Cosmology · Physics 2024-01-03 Alexey Golovnev , A. N. Semenova , V. P. Vandeev

We derive the exact gravitational wave solutions in a general class of quadratic Poincar\'e gauge gravity models. The Lagrangian includes all possible linear and quadratic invariants constructed from the torsion and the curvature, including…

General Relativity and Quantum Cosmology · Physics 2017-04-18 Yuri N. Obukhov