# Quantum Gravity Unit (Yasha Neiman)

The Quantum Gravity Unit is a theoretical group driven by an interest in the laws of nature. Our work is at the interface of three pillars of fundamental physics: gravitation, particle physics and cosmology. Each of the three provides us with a glimpse into the underlying structure of our world. With some artistic license, these can be associated with particular physical constants: Newton's constant G, Planck's constant ħ, and the positive cosmological constant Λ>0.

A central task of fundamental theory is to reconcile these fragments of reality within a single consistent picture. Thus, we must learn to describe a world that is quantum (ħ), with geometry that fluctuates due to gravity (G), and of which only finite portions are accessible due to cosmic horizons (Λ>0). If the 20^{th} century is any guide, this task will involve a revision of our most basic notions, such as time and quantum mechanics.

The main line of work in the group (Yasha + students) follows a program of constructing an idealized, controlled theoretical model that nevertheless incorporates the above key features of our Universe. The model builds on the application of higher-spin gravity to dS/CFT – holography in de Sitter space. The goal is to extract quantum-gravitational physics inside a cosmic horizon from the holographic description at infinity. This project involves several lines of research, combining de Sitter physics with foundational work on higher-spin theory itself and its more standard application to anti-de Sitter holography.

Other research directions in the group include the relationship between entanglement and geometry in AdS/CFT (Tomonori Ugajin), black hole information puzzles and cosmology (Henry Stoltenberg), as well as seeking new quantum observables for characterizing dynamical systems with non-negligible quantum gravity effects (Linqing Chen).

Click here for some lectures and presentations by group members.

Our students and postdocs mostly sit in Lab 2, B614 (Yasha's office is at A628).

We hold group meetings every Monday at 15:00 in Lab 2, A618.