Science and Technology

Técnico scientists show how gravitational waves could point to quantum gravity

The results of this research are explained in an article published in Physical Review Letters magazine.

One of the lessons from the 20th century is that Nature obeys the rules of Quantum Mechanics. While all other fundamental interactions have been assimilated into a quantum description, gravity has withstood all efforts. The “quantization” of gravity is one of the biggest and longest challenges in modern physics.

One reason for this is the absence of experimental data, but finally, an international team composed of scientists from Técnico, Louisiana and Genève, showed how we can use gravitational waves to perceive the quantum space-time structure. “What we have found was a very peculiar effect. This makes it easier to search and to find”, says Vítor Cardoso, Técnico professor and president of the Department of Physics (DF), researcher at the Center for Astrophysics and Gravitation (CENTRA) and one of the authors of this arcticle.

The article authored by professor Vítor Cardoso, professor Ivan Agullo (Louisiana State University), Adrian del Rio (University of Valencia), Michele Maggiore (professor at University of Geneva) and professor Jorge Pullin (Louisiana State University) was published in Physical Review Letters.

The authors show that gravitational wave echoes and suppressed tidal heating are signs of new physics from which the fundamental quantum of black hole area can be measured, and which are within reach of future detectors.

To reach these conclusions, the researchers used numerical simulations, that is, a mathematical study of Einstein’s field equations. “So far, the universe seems to behave as mathematically described by Einstein. So, what we do is to solve differential equations with some degree of complexity, in order to capture phenomena that we still don’t know”, explains the DF professor.

According to the researchers, the most interesting aspect is that these signals are within the reach of current detectors, such as LIGO, and can be clearly observed by detectors under construction such as LISA, which should be launched in 2034 by the European Space Agency (ESA).

“We have been looking for quantization of gravity for almost a century. Any clue will be precious and very welcome. The future of gravitational waves might be rich in scientific discoveries”, says the CENTRA researcher.