It is a pleasure to announce the fourth edition of our summer school Solstice of Foundations! It will take place at the University of Zurich, 16-20 June 2025.

We encourage you to send your PhD and Masters students to the school - they will return with a consolidated understanding of quantum foundations and an academic network of peers interested in the same topics.

This year’s edition will focus on the importance of agents, relativity and correlations in the foundations of quantum mechanics.This includes quantum reference frames, modelling observers as explicit physical systems, the motility of the Heisenberg cut, multi-agent paradoxes, and the role of the observer and boundaries in novel approaches to relativity and quantum gravity. More on the programme below.

Information and registration: http://foundations.squids.ch

• 15th May: Deadline for student support applications
• 20th May: Notification for student support applications
• 31st May: Registration deadline for in-person participants

Format: Hybrid. Both in-person and online participation are possible; in-person participation is encouraged. Registration fee: CHF 150 for Masters students, 200 for PhD students, 250 non-students. Online attendance is free for students, but registration is mandatory. Students based in Zurich may volunteer to help with the school and have the fee waived.

Required background: The school is aimed at participants familiar with basics of quantum mechanics, and ideally introductory courses on quantum information theory.