Frontiers of Quantum Gravity: shared challenges, converging directions

Abstract

Understanding the quantum nature of spacetime and gravity remains one of the most ambitious goals of theoretical physics. It promises to provide key new insights into fundamental particle theory, astrophysics, cosmology and the foundations of physics. Despite this common goal, the community of quantum gravity researchers is sometimes seen as divided into sub-communities working on different, mutually exclusive approaches. In practice however, recent years have shown the emergence of common techniques, results and physical ideas arising from different sub-communities, suggesting exciting new prospects for collaboration and interaction between traditionally distinct approaches. In this White Paper we discuss some of the common themes which have seen a growing interest from various directions, and argue that focusing on them will help the quantum gravity community as a whole towards shared objectives.

No invariant perfect qubit codes

“…From the perspective of quantum gravity, holography and the entanglement/geometry correspondence are two important open questions [12], and the models referred to contain very important insights. At the same time, they are somewhat ad hoc.…”

TF1 Snowmass Report: Quantum gravity, string theory, and black holes

“…We emphasize however that some results we discuss in later sections rely only on low-energy effective field theory, and thus should hopefully be valid in any self-consistent theory of quantum gravity. See [1][2][3][4][5][6] for white papers on other approaches to quantum gravity.…”

Modified measures as an effective theory for causal fermion systems

“…The hope is that such a set of dictionaries of ideas helps the exchange across approaches and thereby catalyzes progress in the foundations of physics. This addresses a distinctly different goal from overview articles such as [15,66,69] or [2] (which originated the present work) that try to cover the development across many approaches simultaneously. By focusing on two sets of ideas at a time, a greater level of depth can be covered and more specific issues addressed.…”