Project
Decoherence and Infrared Effects in Quantum Gravity
In theoretical physics, quantum field theory is extremely successful at describing the smallest building blocks of the universe, like electrons and other particles, while Einstein’s theory of general relativity describes space, time, and gravity up to cosmic scales. We still do not have a unified theory of quantum gravity that is both complete and fully understood; nevertheless, promising tools, such as information theory, give us insight into universal features of quantum gravity.
Because both quantum systems and gravitational systems can store and process information, the mathematical theory of information is an important common language between the two. As such, we can use information theory to translate quantum principles into novel gravitational insights, and vice versa.
A concept from quantum information theory that remains largely unexploited in gravity is decoherence. This is the process through which uncontrolled quantum systems naturally lose their "quantumness" over time and start behaving like classical systems. Recently, massive progress has been made in understanding decoherence caused by extremely low-energy radiation in quantum field theory. By translating these advances to gravity, the aim of the proposed research is to use decoherence to explain how space, time, and classical relativistic behaviour emerge from highly quantum configurations, like the Big Bang. Understanding space-time emergence is a problem of paramount importance for quantum gravity.