Adam Day is the former publisher of Classical and Quantum Gravity. His background is mostly in publishing, where he thoroughly enjoyed working with the gravitational physics community. He now works as a Data Scientist for SAGE Publishing.
Kazuya Koyama is a Reader in Cosmology in the Institute of Cosmology and Gravitation, at the University of Portsmouth,
I am very pleased to bring you this focus issue summarising the recent developments in computing relativistic effects in cosmology.
The issue consists of two parts, with the first part examining general relativistic formulations of the observed over-density of galaxies.
The second part discusses relativistic effects on the formation of large scale structures.
The authors pioneered the development of our understanding of general relativistic effects in cosmological observations and we hope that this focus issue will be a basis for further advancement of the field. Continue reading →
Image copyright Warner Bros and Paramount Pictures
CQG has never published a movie review before. It is therefore with appropriate humility that I offer a review of Interstellar. This scifi epic wins the historic honor because it lists a physicist, Kip Thorne, as an executive producer, and is advertised as based on his theories. Indeed, the movie plot and graphics do involve ideas of relativity in very important ways.
In the spirit of disclosure I state, right up front, that I am not a fan of science fiction, but am a fan of Kip Thorne; like many of his former students I have remained a friend. My fan/antifan biases should cancel and leave me to do the objective job that a scientist is expected to do.
This is not, of course, a review for the general public. CQG is seldom found in the waiting room of dentists. If you Continue reading →
Dr Obinna Umeh is a postdoctoral researcher at the University of the Western Cape in Cape Town, supported by the Square Kilometre Array project in South Africa
The accurate determination of cosmological distances is the most important probe in cosmology. Observations of type Ia supernovae imply dark energy exists because we know the relation between the distance of an object and its redshift – this changes with the relative amount of matter to dark energy, for example. But intervening matter between the supernovae and us cause fluctuations in this relationship. To a first approximation this is just normal gravitational lensing, an integrated contribution from the wobbly path the light takes to us.
Is this an accurate enough picture? Maybe at the moment, but not Continue reading →
Miguel, a postdoc at the Raman Research Institute (RRI), enjoying a traditional south Indian dish: masala dosa. Madhavan (professor at RRI) not enjoying traditional South American drink: mate.
It is of great physical interest to construct a canonical quantization of asymptotically flat spacetimes. The classical phase space variables are subject to delicate boundary conditions at spatial infinity and the first challenge is to construct a quantum kinematics which carries an imprint of these boundary conditions.
Paul Campsie completed his Ph.D. in the Institute for Gravitational Research at the University of Glasgow. He now works as a Product & Test Engineer for Freescale Semiconductor.
A direct measurement of the fluctuating force noise created by surface charge on dielectrics
It has been known that future interferometric gravitational wave detectors could have their low frequency sensitivity limited by excess surface charges on the detector optics. Though it is suspected that the limiting effects of this noise source have been observed in initial detectors, this was never directly verified because there was no measurement of the charge on the optic.
In our recent CQG article we present a direct measurement of the fluctuating force noise created by excess surface charges (charging noise) on a dielectric. This measurement is Continue reading →
James Dacey is multimedia projects editor for Physics World
The Square Kilometre Array (SKA) promises to usher in a new era in radio astronomy. Astronomers will use the telescope to probe the early universe by looking as far back in time as the first 100 million years after the Big Bang. It will also be employed to search for life and planets, as well as to study the nature of dark energy, and to examine theories of gravity and general relativity.
I recently travelled to the global headquarters of the SKA Organisation at the Jodrell Bank observatory in the north of England, along with a small film crew. We met scientists and engineers involved with the SKA, and we produced this short film about what the project is designed to achieve. The video takes you on a tour of the sites in Australia and southern Africa that will host the SKA, featuring artists’ impressions of the impressive telescope equipment.
It was inspiring to hear the SKA representatives talk about the unprecedented scale of the project and the range of scientific fields that stand to benefit from the new tool. But it was also interesting to learn about the economic and social considerations that underpin a scientific project of such vast scale. The hope is that it can inspire the next generation of scientists and engineers in Australia and the African continent.
Martin Reiris is Junior Scientist at the Max Planck Institute for Gravitational Physics (Golm-Germany) since 2009. He received the PHD in pure math in 2005 at SUNYSB, and held a Moore Instructor in Math at MIT from 2006 to 2009. His interests are mainly in geometry and the mathematical structure of general relativity
In the extraordinary manuscript The Foundation of the Generalised Theory of Relativity, printed in 1916 in Annalen der Physics, Einstein begins addressing what he calls an epistemological defect of classical mechanics, (as well as of special relativity), whose dignity he attributes to E Mach. He imagined two bodies, A and B, made of the same fluid material and sufficiently separated from each other that none of the properties of one could be attributed to the existence of the other. Observers at rest in one body, he continues, see the other body rotating at a constant angular velocity, yet these same observers measure a perfect round surface in one case and an ellipsoid of rotation in the other case. It is then asked: “Why is this difference between the two bodies?”. Continue reading →
Marie-Anne Bizouard is a research fellow at CNRS, Laboratoire de l’Accélérateur Linéaire, Orsay, France. She is an experimental physicist working on gravitational wave searches with ground based interferometric detectors.
The numerical relativity breakthrough in 2005 has provided waveforms of the gravitational wave signal emitted by a compact binary sources that describe the coalescence, the merger of the two compact objects and the ring-down of the newborn object. These waveforms are now more and more often used in gravitational wave searches carried out with interferometric detectors (LIGO, Virgo, GEO and eventually KAGRA), instead of analytical waveforms from Post Newtonian expansion that Continue reading →
Parampreet Singh is an Assistant Professor of Physics at Louisiana State University
Whether the gravitational collapse of an astrophysical object leads to a black hole or a naked singularity is one of the most intriguing issues in Einstein’s theory of General Relativity. In many astrophysical situations, the initial conditions are such that a trapped region forms and the gravitational collapse ends in a black hole, in confirmation with the Cosmic Censorship conjecture. However, in recent years Continue reading →
Our primary goal with CQG+ is to raise the visibility of some of the best papers in CQG.
Take a look at the table below this post: it shows the 20 most downloaded papers in CQG since the launch of CQG+. At the time that the data was collected, 15 papers had been promoted by CQG+. 13 of those are to be found in the top 20 (and the other 2 are not far behind).
This leaves no doubt in my mind that CQG+ is achieving its goal – but what does this mean for you? Continue reading →
CQG+ 
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