Project description
Understanding axions’ role in theoretical consistency
Axions are pseudoscalar particles that play an essential part in a number of Standard Model extensions and are significant in quantum gravity and cosmology. Yet a convincing motivation for their existence remains unknown. Supported by the Marie Skłodowska-Curie Actions programme, the ACROSS project aims to advance the study of axions and their coupling to space-time, emphasising their importance from the perspective of theoretical coherence. Through the use of quantum field theory, holographic techniques and string compactifications, it will explore the properties of axions in the context of AdS/CFT duality and in de Sitter space-time. The outcomes will be beneficial for the string theory landscape and quantum gravity, serving both theoretical and experimental purposes.
Objective
Axions are pseudoscalar particles described by a periodic field, so that a shift symmetry protects their masses. They play a central role in many extensions of the Standard Model, with implications for quantum gravity, cosmology and experimental physics. As such, axion physics is ideally situated at the crossroad of fundamental theory, particle phenomenology, and experiments. Despite their growing relevance, a first-principles explanation for the presence of axions is still lacking. ACROSS aims to take crucial steps towards a deeper understanding of axions, their interplay with the background spacetimes and the necessity of their presence as an inevitable consequence for consistency, if any. Can we argue on general and model-independent grounds that an axion should exist in our Universe? Given the significant experimental effort underway to detect axions, answering this question is both timely and essential. This project will integrate tools from quantum field theory in curved spacetimes, holography and string compactifications to investigate the nature of axions. Special emphasis will be placed on their behaviour within the AdS/CFT correspondence and in de Sitter spacetime. The findings will be contextualized within the landscape of string theory vacua, and broader quantum gravity considerations, ultimately informing both theoretical and experimental communities, offering guidance for ongoing axion searches.
ACROSS will be hosted by Harvard University (outgoing phase), with a return phase at Scuola Normale Superiore in Pisa. The Fellowship will support advanced training and establish international collaboration, laying the foundation for a lasting European research programme on axions in curved backgrounds. By bridging multiple disciplines, ACROSS will deepen our understanding of axions as fundamental elements in theoretical physics and provide a novel framework for assessing their presence—or absence—in quantum gravity and, ultimately, in our Universe.
Fields of science (EuroSciVoc)
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CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
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Project’s keywords as indicated by the project coordinator. Not to be confused with the EuroSciVoc taxonomy (Fields of science)
Project’s keywords as indicated by the project coordinator. Not to be confused with the EuroSciVoc taxonomy (Fields of science)
Programme(s)
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Multi-annual funding programmes that define the EU’s priorities for research and innovation.
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HORIZON.1.2 - Marie Skłodowska-Curie Actions (MSCA)
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Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
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Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
HORIZON-TMA-MSCA-PF-GF - HORIZON TMA MSCA Postdoctoral Fellowships - Global Fellowships
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Call for proposal
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(opens in new window) HORIZON-MSCA-2025-PF
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56126 Pisa
Italy
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