Monthly Archives: March 2016

TianQin: a space-borne gravitational wave detector

Posted on by
Attendees at the third workshop on the TianQin science mission

Attendees at the third workshop on the TianQin science mission

Gravitational waves can paint a completely new picture of the Universe. Promising advances in technology may make it possible to detect the minute wobbling of spacetime in the next few years. Estimates show that ground-based gravitational wave detectors, such as Advanced LIGO (Laser Interferometer Gravitational-wave Observatory) or Advanced Virgo will probably see several hundred events by 2020. These ground-based instruments will be complemented by space-borne detectors. These are sensitive to a much richer set of sources, including compact binary star systems in our own Milky Way, supermassive black holes consuming stars, and binary supermassive black holes in distant galactic nuclei. Dozens of proposals have been put forward for space-borne gravitational wave detectors, among which the most studied are LISA (Laser Interferometric Space Antenna) and its evolved version, eLISA. The European space agency has picked “Gravitational Universe” as the science theme for its 3rd large science mission L3; if chosen, eLISA might be launched in 2034.

In our paper, we describe the preliminary concept of a newly proposed space-borne gravitational wave detector, TianQin. In old Chinese legend, the lives of the gods in heaven are very similar to the lives of people on the ground (apart from the fact that they can fly, perform other miracles, and are presumably much happier). They also play music using instruments such as a Chinese zither. A zither on the ground is called “Qin”, and one in heaven is “TianQin”. Bearing this name, our experiment is metaphorically seen as Continue reading →

Perfect accordance of the gravitational and the electromagnetic field in 3D

Posted on by
Maro Cvitan (assistant professor at the University of Zagreb) (left), Predrag Dominis Prester (associate professor at the University of Rijeka) (centre) and Ivica Smolić (assistant professor at the University of Zagreb) (right)

Maro Cvitan (assistant professor at the University of Zagreb) (left), Predrag Dominis Prester (associate professor at the University of Rijeka) (centre) and Ivica Smolić (assistant professor at the University of Zagreb) (right)

Does a physical field have to share the symmetries of the ambient spacetime?

Open a typical textbook on classical electrodynamics and you will find numerous examples of wrinkled and twisted electromagnetic fields, in a sheer contrast with the maximally symmetric Minkowski spacetime they inhabit. These, however, are the weak fields which do not “bend” the spacetime “fabric”. Once we allow the field to interact with the spacetime geometry via gravitational field equations, the symmetry constraints become much more stringent. When the answer to the opening question is affirmative we say that the field inherits the spacetime symmetries. Symmetry inheritance is not only used as a convenient assumption in a choice of the ansatz, but is also an important ingredient of Continue reading →

Black-hole laboratories in the era of gravitational-wave astronomy

Posted on by
Paolo Pani and Helvi Witek

Helvi and Paolo visiting Toronto during the International Conference on Black Holes at the Fields Institute last year.
Helvi is Research Fellow in the School of Mathematical Sciences at the University of Nottingham. Paolo is Assistant Professor at Sapienza University of Rome and Research Scientist at the Instituto Superior Técnico in Lisbon.

We are proud to present the completed Focus Issue on “Black holes and Fundamental Fields” one year after its first contribution has been published online.

This issue appears serendipitously at the same time as LIGO’s historic detection of gravitational waves which, simultaneously, provided us with the first direct observational evidence for the existence of black holes (BHs). We wish to take this opportunity to congratulate the LIGO/VIRGO Scientific Collaboration and everyone involved on  their breakthrough discovery!

The true excitement around this discovery arises from the fact that it marks the beginning of the long-sought-for era of gravitational-wave astronomy. As Kip Thorne recently put it, “Recording a gravitational wave […] has never been a big motivation for LIGO, the motivation has always been to open a new window to the Universe”. The outstanding observation of a BH binary coalescence — and the expectation of Continue reading →