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Recent research show that the cosmological components of the Universe should influence on the propagation of Gravitational Waves (GWs) and even it has been proposed a new way to measure the cosmological constant using Pulsar Timing Arrays…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-08 Jorge Alfaro , Mauricio Gamonal

Space-time structuring of light - where spatial and temporal degrees of freedom are deliberately coupled and controlled - is an emerging area of optics that enables novel configurations of electromagnetic fields. Of particular importance…

With the aid of a Fermi-Walker chart associated with an orthonormal frame attached to a time-like curve in spacetime, a discussion is given of relativistic balance laws that may be used to construct models of massive particles with spin,…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Robin W. Tucker

Pulsar timing arrays (PTAs) are searching for nanohertz-frequency gravitational waves (GWs) through cross-correlation of pulse arrival times from a set of radio pulsars. PTAs have relied upon a frequency-shift formula of the pulse, where…

High Energy Astrophysical Phenomena · Physics 2024-07-03 Ryousuke Kubo , Kakeru Yamahira , Hideki Asada

Magnetic nulls are ubiquitous in space plasmas, and are of interest as sites of localized energy dissipation or magnetic reconnection. As such, a number of methods have been proposed for detecting nulls in both simulation data and in situ…

We present a matrix formalism, inspired by the Minkowski four-vectors of special relativity, useful to solve classical physics problems related to both mechanics and thermodynamics. The formalism turns out to be convenient to deal with…

Classical Physics · Physics 2014-02-11 Julio Güémez , Manuel Fiolhais

Current GNSS systems rely on global reference frames which are fixed to the Earth (via the ground stations) so their precision and stability in time are limited by our knowledge of the Earth dynamics. These drawbacks could be avoided by…

General Relativity and Quantum Cosmology · Physics 2014-01-27 Uroš Kostić , Martin Horvat , Sante Carloni , Pacôme Delva , Andreja Gomboc

Starting from a discussion of the concrete representations of the coordinates of the k-Minkowski spacetime (in 1+1 dimensions, for simplicity), we explicitly compute the associated Weyl operators as functions of a pair of Schroedinger…

High Energy Physics - Theory · Physics 2010-02-22 Ludwik Dabrowski , Gherardo Piacitelli

Pulsar timing arrays act to detect gravitational waves by observing the small, correlated effect the waves have on pulse arrival times at Earth. This effect has conventionally been evaluated assuming the gravitational wave phasefronts are…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Xihao Deng , Lee Samuel Finn

We consider the dynamics of tensor and scalar gravitational fields in the Relativistic Theory of Gravitation with the Minkowskian vacuum metric and generalize the formulation to the massless graviton. The potential of scalar field is…

High Energy Physics - Phenomenology · Physics 2007-05-23 V. V. Kiselev

After briefly reviewing the relativistic approach to positioning systems based on the introduction of the emission coordinates, we show how explicit maps can be obtained between the Cartesian coordinates and the emission coordinates, for…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Matteo Luca Ruggiero , Angelo Tartaglia

Extended phase space of an elementary (relativistic) system is introduced in the spirit of the Souriau's definition of the `space of motions' for such system. Our formulation is generally applicable to any homogeneous space-time (e.g. de…

High Energy Physics - Theory · Physics 2009-10-28 S. Zakrzewski

We present de Sitter Teukolsky waves -- linearised quadrupolar gravitational waves in the transverse-traceless gauge in de Sitter spacetime. In the cosmological constant $\Lambda$ going to zero limit, our solutions match to Teukolsky…

General Relativity and Quantum Cosmology · Physics 2024-05-20 Harsh , Sk Jahanur Hoque , Sitender Pratap Kashyap , Amitabh Virmani

In our previous works, we have proposed a quantum description of relativistic orientable objects by a scalar field on the Poincar\'{e} group. This description is, in a sense, a generalization of ideas used by Wigner, Casimir and Eckart back…

General Physics · Physics 2024-06-04 D. M. Gitman , A. L. Shelepin

I conjecture that a flat 10D compact universe emerged out of nothing (By ``nothing'' I mean no notion of space and time) with all it's symmetries intact: Poincare invariance, conformal invariance and supersymmetry, it's massless moduli…

High Energy Physics - Theory · Physics 2007-06-13 E. Tetteh-Lartey

To date, the most precise tests of general relativity have been achieved through pulsar timing, albeit in the weak-field regime. Since pulsars are some of the most precise and stable "clocks" in the Universe, present observational efforts…

General Relativity and Quantum Cosmology · Physics 2018-09-27 Mariafelicia De Laurentis , Ziri Younsi , Oliver Porth , Yosuke Mizuno , Luciano Rezzolla

We study the geometry of curves in the Minkowski space and in the de Sitter space, specially at points where the tangent direction is lightlike (i.e. has length zero) called lightlike points of the curve. We define the focal sets of these…

Differential Geometry · Mathematics 2015-08-28 Ana Claudia Nabarro , Andrea de Jesus Sacramento

The de Sitter manifold admits a wide variety of interesting coordinatizations. The 'atlas' is a compilation of the coordinate charts referenced throughout the literature, and is presented in the form of tables, the starting point being the…

General Relativity and Quantum Cosmology · Physics 2012-11-13 Gabriel Pascu

Whether the space where we live is a globally orientable manifold $M_3$, and whether the local laws of physics require that $M_3$ be equipped with a canonical orientation, are among the unsettled questions in cosmology and quantum field…

General Relativity and Quantum Cosmology · Physics 2021-11-09 N. A. Lemos , M. J. Reboucas

Obtaining pulsar parallaxes via relative astrometry (also known as differential astrometry) yields distances and transverse velocities that can be used to probe properties of the pulsar population and the interstellar medium. Large programs…

Solar and Stellar Astrophysics · Physics 2011-10-13 A. T. Deller , W. F. Brisken , S. Chatterjee , J. M. Cordes , W. M. Goss , G. H. Janssen , Y. Y. Kovalev , T. J. W. Lazio , L. Petrov , B. W. Stappers