Density matrix of de Sitter JT gravity

[摘要] Jackiw-Teitelboim (JT) gravity in two-dimensional de Sitter space is an intriguing toy model for a quantum mechanical description of an inflationary phase of the universe, including initial conditions. Starting from exact solutions of the Wheeler-DeWitt equation, we study a conditional density matrix of the system. We find that the ground state is a mixed state, rather than a pure Hartle-Hawking state. Our results are consistent with the semiclassical double-trumpet amplitude, and with recent work on complex geometries containing bra-ket wormholes. We also analyse semiclassical wave functions for metric, dilaton, and an additional inflaton field. The probability distribution for the size of the universe is flat.

[发布日期] 2026-09-03

[关键词] 2D Gravity;de Sitter space;Models of Quantum Gravity