scholarly journals Non-linear plane gravitational waves as space-time defects

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
F. L. Carneiro ◽  
S. C. Ulhoa ◽  
J. W. Maluf ◽  
J. F. da Rocha-Neto
Keyword(s):  
Gravitational Waves ◽  
Present Article ◽  
Space Time ◽  
Atomic Scale ◽  
Burgers Vector ◽  
Non Linear ◽  
The Waves ◽  
Continuum Systems ◽  
Plane Gravitational Waves

AbstractWe consider non-linear plane gravitational waves as propagating space-time defects, and construct the Burgers vector of the waves. In the context of classical continuum systems, the Burgers vector is a measure of the deformation of the medium, and at a microscopic (atomic) scale, it is a naturally quantized object. One purpose of the present article is ultimately to probe an alternative way on how to quantize plane gravitational waves.

4. Gravitational waves

2017 ◽  
pp. 46-57
Author(s):  
Timothy Clifton
Keyword(s):  
Gravitational Field ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Laser Interferometer ◽  
Space Time ◽  
Binary Pulsar ◽  
Set Up ◽  
The Waves

As stars collapse they eject huge amounts of mass and energy; their gravitational field changes rapidly and, therefore, so does the curvature of the space-time around them. If the curvature of space-time is pushed out of equilibrium, by the motion of mass or energy, this disturbance travels outwards as waves. ‘Gravitational waves’ explains the effect of a gravitational wave: in a binary pulsar, the waves carry energy away from the system so that the two neutron stars slowly circle in towards each other. Gravitational waves were first detected in 2015 by the Laser Interferometer Gravitational-Wave Observatory in America. There are also plans to set up a detector in space.

scholarly journals PHENOMENOLOGY FOR AN EXTRA DIMENSION FROM GRAVITATIONAL WAVES PROPAGATION ON A KALUZA–KLEIN SPACE–TIME

2005 ◽  
Vol 14 (01) ◽  
pp. 1-21 ◽  
Author(s):  
EMANUELE ALESCI ◽  
GIOVANNI MONTANI
Keyword(s):  
Gravitational Waves ◽  
Extra Dimension ◽  
Electromagnetic Waves ◽  
Degrees Of Freedom ◽  
Background Field ◽  
Space Time ◽  
Tensor Fields ◽  
Dynamical Degree ◽  
The Waves ◽  
Kaluza Klein

In the present work we analyze the behavior of 5-dimensional (5-d) gravitational waves propagating on a Kaluza–Klein background. We face separately the two cases in which the waves are generated before and after the process of dimensional compactification respectively. We show that if the waves are originated on a 5-d space–time which fulfills the principle of general relativity, then the process of compactification cannot reduce the dynamics to the pure 4-d scalar, vector and tensor degrees of freedom. In particular, while the electromagnetic waves evolve independently, the scalar and tensor fields couple to each other; this feature appears because when the gauge conditions are split, the presence of the scalar ripple prevents the 4-d gravitational waves from becoming traceless. The phenomenological issue of this scheme consists of an anomalous relative amplitude of the two independent polarizations which characterize the 4-d gravitational waves. Such profile of polarization amplitudes, if detected, would outline the extra dimension in a very reliable way, because a wave with non-zero trace cannot arise from ordinary matter sources. We discuss the above mentioned phenomenon either in the case of a unit constant value of the background scalar component (when the geodesic deviation is treated with precise outputs), or assuming such background field as a dynamical degree. Only qualitative conclusion are provided here, because the details of the polarization amplitudes depend on the choice of specific metric forms. Finally, we perturb a real Kaluza–Klein theory showing that in this context, while the electromagnetic waves propagate independently, the 4-d gravitational waves preserve their ordinary structure, while the scalar plays for the role of source.

scholarly journals Black holes and gravitational waves sourced by non-linear duality rotation-invariant conformal electromagnetic matter

2021 ◽  
Vol 812 ◽  
pp. 136011
Author(s):  
Daniel Flores-Alfonso ◽  
Blanca Angélica González-Morales ◽  
Román Linares ◽  
Marco Maceda
Keyword(s):  
Black Holes ◽  
Gravitational Waves ◽  
Rotation Invariant ◽  
Non Linear

Magnetised Wave Collapse in Solar System Plasmas

1993 ◽  
Vol 10 (4) ◽  
pp. 283-286 ◽  
Author(s):  
Andrew Melatos ◽  
Peter Robinson
Keyword(s):  
Solar System ◽  
Wave Packets ◽  
Particle Interactions ◽  
Coherent Wave ◽  
Wave Collapse ◽  
Non Linear ◽  
Acceleration Zone ◽  
The Waves ◽  
Linear Plasma

AbstractClumpy, intense wave packets observed in situ in the Jovian and terrestrial electron foreshocks, and in the Earth’s auroral acceleration zone, point to the existence of non-linear plasma turbulence in these regions. In non-linear turbulence, wave packets collapse to short scales and high fields, stopping only when coherent wave-particle interactions efficiently dissipate the energy in the waves. The purpose of this paper is to examine the shortest scales and highest fields achieved during collapse in a strongly magnetised plasma, and identify parts of the solar system where the magnetised aspects of wave collapse are important.

Linear and non-linear potential-flow calculations of free-surface waves with lift and induced drag

2000 ◽  
Vol 214 (6) ◽  
pp. 801-812
Author(s):  
C-E Janson
Keyword(s):  
Free Surface ◽  
Potential Flow ◽  
Lift Force ◽  
Radiation Condition ◽  
Linear Potential ◽  
Surface Boundary ◽  
Model Approximation ◽  
Non Linear ◽  
Lifting Surfaces ◽  
The Waves

A potential-flow panel method is used to compute the waves and the lift force from surface-piercing and submerged bodies. In particular the interaction between the waves and the lift produced close to the free surface is studied. Both linear and non-linear free-surface boundary conditions are considered. The potential-flow method is of Rankine-source type using raised source panels on the free surface and a four-point upwind operator to compute the velocity derivatives and to enforce the radiation condition. The lift force is introduced as a dipole distribution on the lifting surfaces and on the trailing wake, together with a flow tangency condition at the trailing edge of the lifting surface. Different approximations for the spanwise circulation distribution at the free surface were tested for a surface-piercing wing and it was concluded that a double-model approximation should be used for low speeds while a single-model, which allows for a vortex at the free surface, was preferred at higher speeds. The lift force and waves from three surface-piercing wings, a hydrofoil and a sailing yacht were computed and compared with measurements and good agreement was obtained.

Gravitational waves: Some less discussed intriguing issues

2015 ◽  
Vol 24 (12) ◽  
pp. 1544023 ◽  
Author(s):  
C. Sivaram
Keyword(s):  
Gravitational Waves ◽  
Strong Field ◽  
Direct Detection ◽  
Recent Observation ◽  
High Redshift ◽  
Nonlinear Effects ◽  
Resonant Absorption ◽  
Compact Objects ◽  
The Waves ◽  
Very High

Attempts to detect gravitational waves is actively in progress with sophisticated devices like LIGO setup across continents. Despite being predicted almost 100 years ago, there has so far been no direct detection of these waves. In this work, we draw attention to some of the less discussed but subtle aspects arising, for example, from high orbital eccentricities, where emission near periastron could be millions of times more than that in the distant parts of the orbit. The strong field nonlinear effects close to the compact objects can substantially slow down and deflect the waves in the last (few) orbit(s) where much of the intensity is expected. Spin–orbit and other forces could be significant. There would also be plasma like resonant absorption (of kilohertz radiation) during the collapse. Recent observation of supermassive black holes at high redshift implies cluster collapse, where the gravitational wave intensity depends on very high powers of the mass. Any unambiguous claim of detection should perhaps consider several of these effects.

scholarly journals Questions and a myriad answers: Coming together and drifting apart in the historical sciences

2020 ◽  
Author(s):  
Dan Costa Baciu
Keyword(s):  
Present Article ◽  
Space Time ◽  
Harvard University ◽  
Strong Promoter ◽  
People Search

There is no end to the questions you can ask, and no end to the answers you can give. Where then, in this space of endless possibilities, can research begin; and how can researchers be expected to reach any consensus on what are useful question-answer-pairs? This present article recounts the story of Sigfried Giedion and Bruno Zevi. Space, Time and Architecture, a book printed at Harvard University ties the fates of the two Europeans. Giedion is the author, Zevi is a reader surrounded by a transatlantic group of followers. Initially a strong promoter of Giedion's book, Zevi later changed his mind and went on to propose his own, divergent theory of space and architecture. Zevi and Giedion's story of coming together and drifting apart is not unique. We all live in a world in which ideas spread and diversify as people search for questions and a myriad answers.

scholarly journals Gravitational waves and the breaking of parallelograms in space-time

2013 ◽  
Vol 45 (6) ◽  
pp. 1163-1177 ◽  
Author(s):  
J. W. Maluf ◽  
S. C. Ulhoa ◽  
J. F. da Rocha-Neto
Keyword(s):  
Gravitational Waves ◽  
Space Time
Sign in / Sign up

Export Citation Format

Share Document