#general-relativity

[stevensaus]

Magnetars drag spacetime to power superluminous supernovae

Frame-dragging may explain an odd pattern seen in the brightest supernovae.

Magnetars drag spacetime to power superluminous supernovae

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[pastdaily]

Albert Einstein Has A Few Words For You – (March 14, 1879) – Happy Birthday – Past Daily – Albert Einstein - Speaking at the Opening of the Museum Of Science and Industry, New York - April 1936 - Gordon Skene Sound Collection - Albert Einstein - born on this day in 1879, turning 137 today. One of the greatest scientific minds of the 20th century, Einstein's work on the general...

[einstein-in-verse-blog]

Introduction

Hop in with me, a time machine we ride, Intent on chasing space-time concepts wild, To fathom Einstein’s insights into Reality, In his Special and General Relativity.

Like Wordsworth, a lonely cloud wandering,[2] Through space and time we will be winging, Not to appreciate the “daffodils” of Nature; But to understand Nature’s Architecture.

We start with Special Relativity; We’ll meet the strangest thing in memory; It is the constancy of the speed of light; Scientists puzzled with all their might.

The fact is contrary to our expectations; Scientists tried all sorts of explanations; For such a strange behaviour, Unsatisfactory were all conjectures.

The constancy of the speed of light, Is not an ordinary fact, in hindsight; Indeed, it is an intrinsic, primary behaviour; Unexplainable by other features of Nature.

Common sense, which includes us all, Treats this fact of light to be as usual; Instead, with “uncommon” sense, Einstein saw The constancy of the speed of light is Nature’s Law.

From this, Einstein deduced strange consequences; On elements, like time and space, in our experiences: The key components in the design of the Cosmos, The topics in Book I, in detail we will discuss.

We cannot get over this feeling strange; In mind, we yield; yet our intuition, unmoved, remains; A dog can never comprehend Quantum Mechanics;[3] It’s hard: our intuitive understanding has its limits.

We then move on to General Relativity; Einstein’s theory on the phenomenon of gravity; For ten years after Special Relativity, he struggled; Between confidence and misgivings, he wobbled.

A key idea inspired his imagination: letting go in gravity; One banishes gravity, by yielding to it completely! Einstein says, it is his life’s happiest thought; The field equation was the culmination of his effort.

Say, we jump out a window; we are “weightless”; However, Tidal Gravity remains; as we will see, this is What Einstein eventually realized: the Spacetime Curvature; on this, in Book II, we will spend our time.

We’ll be discussing implications and impacts too: such as, What do the two theories, reveal about the Cosmos? Facts of Nature and theories: what is their connection? What do the theories imply, on the mind-Nature relation?

With the map of what’s ahead laid out, A ready mind and a heart so stout, And each a seat in the time machine, It is time for our journey to begin…

About the author

Feliciano Bantilan lives in Hyderabad, India with his career-busy wife, home-bound due to Parkinson's; free from the usual distractions, his mind turns time into writings in poetry and prose. So far, he has published three books. 

He earned his PhD in Physics from Duke University, USA in 1983.

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[retagin-blog-blog]

Quantum gravity takes singularity out of black holes - space - 29 May 2013

Falling into a black hole may not be as final as it seems. Apply a quantum theory of gravity to these bizarre objects and the all-crushing singularity at their core disappears. In its place is somethin... http://dlvr.it/3RTF7g

[gr-qc]

Authors: Fabrizio Canfora, Francisco Correa, Alex Giacomini, Julio Oliva

In this paper an intrinsically non-Abelian black hole solution for the SU(2) Einstein-Yang-Mills theory in four dimensions is constructed. The gauge field of this solution has the form of a meron whereas the metric is the one of a Reissner-Nordström black hole in which, however, the coefficient of the term is not an integration constant. Even if the stress-energy tensor of the Yang-Mills field is spherically symmetric, the field strength of the Yang-Mills field itself is not. A remarkable consequence of this fact, which allows to distinguish the present solution from essentially Abelian configurations, is the Jackiw, Rebbi, Hasenfratz, 't Hooft mechanism according to which excitations of bosonic fields moving in the background of a gauge field with this characteristic behave as Fermionic degrees of freedom.

[gr-qc]

Authors: Liu Zhao, Wei Xu, Pengfei Yu

Every classical Newtonian mechanical system can be equipped with a nonstandard Hamiltonian structure, in which the Hamiltonian is the square of the canonical Hamiltonian up to a constant shift, and the Poisson bracket is nonlinear. In such a formalism, time translation symmetry can be spontaneously broken, provided the potential function becomes negative. A nice analogy between time translation symmetry breaking and the Landau theory of second order phase transitions is established, together with several example cases illustrating time translation breaking ground states. In particular, the CDM model of FRW cosmology is reformulated as the time translation symmetry breaking ground states.

[gr-qc]

Authors: Biju Patla

An approximate analytical formula for the capacitance of a non-parallel plate capacitor with small values of inclination angles and distance separations of the plates is presented. Most applications involving position sensing that are employed in precision experiments and micromechanical devices often use a parallel plate approximation for modeling the capacitance. The analytical approximation presented here is based on the more general, but hard to implement formalism for small angles, and that may be used directly to compute the forces acting on the proof masses by taking the derivative of the capacitance.

Effects of varying the inclination angle, plate dimension and separation on the value of the capacitance per unit length are analyzed in detail. We use the formula derived in this paper to compute the acceleration of the proof mass due to the presence of sensing electrodes (used for positioning the proof masses) with an assumed tilt of rad as applicable to SR-POEM: an experiment aiming to test the weak equivalence principle -- a fundamental postulate of general relativity.

[gr-qc]

Authors: Saskia Grunau, Valeria Kagramanova, Jutta Kunz, Claus Lämmerzahl

We present analytical solutions of the geodesic equations of test particles and light in the five dimensional singly spinning black ring spacetime for special cases, since it does not appear possible to separate the Hamilton-Jacobi-equation for singly spinning black rings in general. Based on the study of the polynomials in the equations of motion we characterize the motion of test particles and light and discuss the associated orbits.