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Related papers: Rigid motion revisited: rigid quasilocal frames

200 papers

The notion of a rigid quasilocal frame (RQF) provides a geometrically natural way to define a system in general relativity, and a new way to analyze the problem of motion. An RQF is defined as a two-parameter family of timelike worldlines…

General Relativity and Quantum Cosmology · Physics 2013-07-09 Richard J. Epp , Robert B. Mann , Paul L. McGrath

In this thesis, I examine in detail the properties of rigid quasilocal frames (RQF), which have been proposed as a geometrically natural way to define spatially extended reference frames in general relativity. I also explore their…

General Relativity and Quantum Cosmology · Physics 2014-02-07 Paul L. McGrath

We construct a general relativistic conservation law for linear and angular momentum for matter and gravitational fields in a finite volume of space that does not rely on any spacetime symmetries. This work builds on our previous…

General Relativity and Quantum Cosmology · Physics 2015-06-16 Richard J. Epp , Paul L. McGrath , Robert B. Mann

We develop, in the context of general relativity, the notion of a geoid -- a surface of constant "gravitational potential". In particular, we show how this idea naturally emerges as a specific choice of a previously proposed, more general…

General Relativity and Quantum Cosmology · Physics 2016-06-10 Marius Oltean , Richard J. Epp , Paul L. McGrath , Robert B. Mann

We analyze the necessary conditions for a body to remain rigid in an expanding cosmological Universe. First, we establish the main theorems and definitions for having a rigid body in a general spacetime as well as the new concept of…

General Relativity and Quantum Cosmology · Physics 2020-08-28 Luciano Combi , Gustavo E. Romero

In this thesis, a non-standard geometric framework, the "quasi-metric" framework (QMF), is used to define relativistic space-time. The QMF consists of a 4-dimensional space-time manifold equipped with two one-parameter families of…

General Relativity and Quantum Cosmology · Physics 2024-03-27 Dag Østvang

In general relativity, the description of spacetime relies on idealised rods and clocks, which identify a reference frame. In any concrete scenario, reference frames are associated to physical systems, which are ultimately quantum in…

Quantum Physics · Physics 2021-07-28 Flaminia Giacomini

This is a survey of a new type of relativistic space-time framework; the so-called quasi-metric framework. The basic geometric structure underlying quasi-metric relativity is quasi-metric space-time; this is defined as a 4-dimensional…

General Relativity and Quantum Cosmology · Physics 2024-03-20 Dag Østvang

We present a theoretical foundation for relativistic astronomical measurements in curved space-time. In particular, we discuss a new iterative approach for describing the dynamics of an astronomical N-body system. To do this, we generalize…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Slava G. Turyshev

This work introduces a novel three-fold classification of reference frames in General Relativity, distinguishing between Idealised Reference Frames (IRFs), Dynamical Reference Frames (DRFs), and Real Reference Frames (RRFs). By defining a…

History and Philosophy of Physics · Physics 2025-10-03 Nicola Bamonti

Choice of an appropriate (3+1)-foliation of spacetime or a (2+1)-foliation of the Cauchy space, leads often to a substantial simplification of various mathematical problems in General Relativity Theory. We propose a new method to construct…

General Relativity and Quantum Cosmology · Physics 2013-08-22 Hans-Peter Gittel , Jacek Jezierski , Jerzy Kijowski , Szymon Łȩski

Newtonian mechanics has the concept of an absolute inertial rest frame. Special relativity eliminates the absolute rest frame but continues to require the absolute inertial frame. General relativity solves this for gravity by requiring…

Mathematical Physics · Physics 2007-05-23 Stephen G. Low

Presented is description of kinematics and dynamics of material points with internal degrees of freedom moving in a Riemannian manifold. The models of internal degrees of freedom we concentrate on are based on the orthogonal and affine…

Mathematical Physics · Physics 2010-03-17 J. J. Sławianowski , V. Kovalchuk , B. Gołubowska , A. Martens , E. E. Rożko

We consider the motion of several rigid bodies immersed in a two-dimensional incompress-ible perfect fluid, the whole system being bounded by an external impermeable fixed boundary. The fluid motion is described by the incompressible Euler…

Analysis of PDEs · Mathematics 2019-04-15 Olivier Glass , Christophe Lacave , Alexandre Munnier , Franck Sueur

We consider the motion of a two-dimensional body of arbitrary shape in a planar irrotational, incompressible fluid with a given amount of circulation around the body. We derive the equations of motion for this system by performing…

Mathematical Physics · Physics 2011-08-04 Joris Vankerschaver , Eva Kanso , Jerrold E. Marsden

Viewing frames of reference as physical systems, subject to the same laws as the systems they describe, is central to the relational approach in physics. Under the assumption that quantum mechanics universally governs all physical entities,…

Quantum Physics · Physics 2025-04-22 Michael Suleymanov , Avishy Carmi , Eliahu Cohen

The gravitational field exterior respectively interior to a spherically symmetric, isolated body made of perfect fluid is examined within the quasi-metric framework (QMF). It is required that the gravitational field is "metrically static",…

General Relativity and Quantum Cosmology · Physics 2024-03-21 Dag Østvang

This research establishes an operational measurement way to express the quantum field theory in a geometrical form. In four-dimensional spacetime continuum, the orthogonal rotation is defined. It forms two sets of equations: one set is…

General Physics · Physics 2007-05-23 Jianhua Xiao

Special relativity theory is well established and confirmed by experiments. This research establishes an operational measurement way to express the great theory in a geometrical form. This may be valuable for understanding the underlying…

General Physics · Physics 2007-05-23 Xiao Jianhua

A reference frame consists of: a reference space, a time scale and a spatial metric. The geometric structure induced by these objects in spacetime is developed. The existence of a class of spatial metrics that are rigid, have free mobility…

General Relativity and Quantum Cosmology · Physics 2008-11-26 J. Llosa , D. Soler
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