The merger of neutron stars provides a distinct scenario to check this hypothesis because gravity around them is pushed to the extreme. In this research study, released in Physical Review Letters, SISSA researchers in collaboration with physicists from Universitat de les Illes Balears in Palma de Mallorca, produced the first simulation of merging binary neutron stars in theories of modified gravity appropriate for cosmology: “This type of simulations is incredibly tough,” clarifies Miguel Bezares, very first author of the paper, “because of the extremely non-linear nature of the problem. Thanks to these simulations, scientists are lastly able to compare basic relativity and modified gravity. “Surprisingly, we found that the dark gravity hypothesis is equally good as basic relativity at explaining the information acquired by the LIGO and Virgo interferometers throughout previous binary neutron star crashes.
SISSA researchers offer the first simulation of neutron star crashes in extensions of basic relativity pertinent for cosmology, offering a new technique to evaluate gravity.
A substantial quantity of mysterious dark energy is necessary to discuss cosmological phenomena, such as the sped up growth of the Universe, with Einsteins theory. However what if dark energy was just an impression and basic relativity itself had to be customized? A new SISSA study, published in Physical Review Letters, offers a new approach to answer this question. Thanks to huge computational and mathematical effort, scientists produced the first simulation ever of combining binary neutron stars in theories beyond basic relativity that reproduce a dark- energy like habits on cosmological scales. This permits the contrast of Einsteins theory and customized versions of it, and, with adequately precise data, might solve the dark energy secret.
For about 100 years now, basic relativity has actually been very effective at describing gravity on a range of regimes, passing all speculative tests on Earth and the solar system. To discuss cosmological observations such as the observed sped up expansion of the Universe, we need to present dark components, such as dark matter and dark energy, which still remain a mystery.
Simulated merger of a neutron star binary. Credit: Miguel Bezares– GRAMS group SISSA
Enrico Barausse, astrophysicist at SISSA (Scuola Internazionale Superiore di Studi Avanzati) and primary investigator of the ERC grant GRAMS (GRavity from Astrophysical to Microscopic Scales) concerns whether dark energy is real or, rather, it may be interpreted as a breakdown of our understanding of gravity. “The existence of dark energy might be just an illusion,” he states, “the accelerated growth of the Universe might be triggered by some yet unidentified adjustments of basic relativity, a sort of dark gravity.”.
The merger of neutron stars offers a distinct circumstance to test this hypothesis due to the fact that gravity around them is pushed to the extreme. We can use the information acquired throughout such occasions to study the operations of gravity and test Einsteins theory in a new window.”.
Simulated merger of a neutron star binary. Credit: Miguel Bezares– GRAMS group SISSA.
In this study, published in Physical Review Letters, SISSA researchers in collaboration with physicists from Universitat de les Illes Balears in Palma de Mallorca, produced the very first simulation of merging binary neutron stars in theories of modified gravity pertinent for cosmology: “This type of simulations is very challenging,” clarifies Miguel Bezares, very first author of the paper, “due to the fact that of the highly non-linear nature of the problem. It requires a substantial computational effort– months of run in supercomputers– that was enabled also by the contract in between SISSA and CINECA consortium as well as unique mathematical solutions that we established. These represented significant obstructions for numerous years till our first simulation.”.
Thanks to these simulations, researchers are finally able to compare basic relativity and modified gravity. “Surprisingly, we found that the dark gravity hypothesis is similarly great as general relativity at explaining the information acquired by the LIGO and Virgo interferometers throughout previous binary neutron star accidents. Undoubtedly, the distinctions between the two theories in these systems are quite subtle, however they might be detectable by next-generation gravitational interferometers, such as the Einstein telescope in Europe and Cosmic Explorer in USA. This opens the interesting possibility of utilizing gravitational waves to discriminate in between dark energy and dark gravity,” Barausse concludes.
Referral: “No Evidence of Kinetic Screening in Simulations of Merging Binary Neutron Stars beyond General Relativity” by Miguel Bezares, Ricard Aguilera-Miret, Lotte ter Haar, Marco Crisostomi, Carlos Palenzuela and Enrico Barausse, 1 March 2022, Physical Review Letters.DOI: 10.1103/ PhysRevLett.128.091103.
