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A new avenue in the hunt for dark energy

Project description

Sun’s oscillations could reveal clues about new gravitational forces in the Universe

In 1998, scientists were surprised to discover that the expansion of the Universe is accelerating because this ran counter to the predictions of General Relativity. Since then, this has been dubbed as the 'dark energy' problem. Its explanation requires an extension of General Relativity. The most popular approach has been through the introduction of a new gravitational force ('fifth force'), mediated by a scalar particle. The EU-funded DhostHunt project plans to introduce a new framework of unprecedented precision in the search for new gravitational forces in the Universe by combining studies on solar evolution and helioseismology. The approach will constitute a novel and interdisciplinary line of research that will impact future research in cosmology and astrophysics. The discovery of new constraints on the fifth force from helioseismology will further our understanding of new gravitational forces in Nature, and will guide the future modelling of dark energy and scalar field theories in general.

Objective

Currently, General Relativity (GR) and the standard model of particles physics are severely challenged by their inability to explain the late-time accelerated expansion of the Universe, known as the “dark energy” problem. The most promising scenarios aiming to explain it are the so--called scalar-tensor theories, corresponding to extensions of GR where gravity is enhanced through a new gravitational force mediated by a scalar field. The quest for phenomenological imprints of new scalar gravitational forces has been a central effort in cosmology and astrophysics over the last decade.

My goal is to introduce helioseismology as a test of unprecedented accuracy in the search for new gravitational forces in Nature. The focus will be on the most general scalar-field extensions of GR, known as “DHOST” scalar-tensor theories. The unique ability of solar pulsations to probe the finest details of gravity in the solar interior, combined with the extreme accuracy of helioseismic observations, promises an orders-of-magnitude improvement of previous constraints.

I will formulate the theoretical framework for adiabatic stellar pulsations in this context, and with sophisticated numerical techniques, I will model the associated solar pulsation eigenspectrum. A systematic statistical analysis will be devised to confront the predictions against observations making use of powerful helioseismic inversions, and derive the tightest constraints on the most general scalar-tensor theories up to date. The cosmological implications will be predicted, in accordance with ESA’s upcoming Euclid satellite mission.

The project will introduce a genuinely novel, interdisciplinary line of research that will strongly impact a broad spectrum of cosmology and astrophysics. The new constraints will be pivotal for our understanding of scalar-gravity interactions in Nature, and are expected to guide the future modelling of dark energy, and scalar field theories in general.

Coordinator

AARHUS UNIVERSITET
Net EU contribution
€ 207 312,00
Address
NORDRE RINGGADE 1
8000 Aarhus C
Denmark

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Region
Danmark Midtjylland Østjylland
Activity type
Higher or Secondary Education Establishments
Links
Total cost
€ 207 312,00