Unraveling the quantum structure of spacetime with gravitational waves

LSU physicists Ivan Agullo, and Jorge Pullin, in collaboration with European researchers, are investigating the potential of gravitational wave astronomy to enlighten us on the quantum aspects of black holes.

Recently published in Physical Review Letters, “Potential Gravitational Wave Signatures of Quantum Gravity, ”I. Agullo, V. Cardoso, A. del Rio, M. Maggiore, and J. Pullin, have shown how to use the gravitational waves emitted by colliding black holes to obtain information about the underlying quantum structure of spacetime. 

“One of the lessons that we learned in the past century is that Nature obeys the laws of quantum mechanics,” said Agullo. “All known forces have been successfully described within the quantum framework, except gravity. The precise quantum nature of gravitation still persists as one of the long-standing problems in modern physics.” 

The current lack of experimental data is certainly among the main reasons why a formulation of quantum gravity has remained so elusive.   

“Our results also highlight the need to derive predictions from specific quantum gravity proposals,” said Agullo.

In their article, Agullo, Vitor Cardoso, Instituto Superior Tecnico, University of Lisbon, Adrian del Rio, Instituto Superior Tecnico, University of Lisbon, Michele Maggiore, University of Geneva and Pullin found different channels in gravitational-wave astronomy carrying direct information about  quantum gravity. Most importantly, these observable imprints are within reach of future detectors, in the form of  gravitational wave echoes and suppressed tidal heating. 

“Among the unique properties of  black holes, we noticed that they act as a sort of magnifying lenses: black holes have the ability to make the microscopic structure of their surface, which involves length scales much smaller than what is accessible in normal circumstances, to get imprinted in the long wavelength gravitational waves they emit,” said Agullo. 

“This new work shows that gravitational wave astronomy provides a promising observational window to understand quantum aspects of gravity and black holes,” said Agullo.




Mimi LaValle

LSU Department of Physics & Astronomy