# The Quantum Mechanics of Spherically Symmetric Causal Diamonds

### APA

He, T. (2024). The Quantum Mechanics of Spherically Symmetric Causal Diamonds. Perimeter Institute. https://pirsa.org/24100072

### MLA

He, Temple. The Quantum Mechanics of Spherically Symmetric Causal Diamonds. Perimeter Institute, Oct. 01, 2024, https://pirsa.org/24100072

### BibTex

@misc{ pirsa_PIRSA:24100072, doi = {10.48660/24100072}, url = {https://pirsa.org/24100072}, author = {He, Temple}, keywords = {Quantum Fields and Strings}, language = {en}, title = {The Quantum Mechanics of Spherically Symmetric Causal Diamonds}, publisher = {Perimeter Institute}, year = {2024}, month = {oct}, note = {PIRSA:24100072 see, \url{https://pirsa.org}} }

**Collection**

**Subject**

We construct the phase space of a spherically symmetric causal diamond in (d+2)-dimensional Minkowski spacetime. Utilizing the covariant phase space formalism, we identify the relevant degrees of freedom that localize to the d-dimensional bifurcate horizon and, upon canonical quantization, determine their commutators. On this phase space, we find two Iyer-Wald charges. The first of these charges, proportional to the area of the causal diamond, is responsible for shifting the null time along the horizon and has been well-documented in the literature. The second charge is much less understood, being integrable for d ≥ 2 only if we allow for field-dependent diffeomorphisms and is responsible for changing the size of the causal diamond.