Time Without Time: Emergent Time in Canonical Quantum Gravity
Project by Polygence alum John Paul
Project's result
The paper investigates the Problem of Time in quantum gravity and why time seems to disappear when general relativity and quantum mechanics are combined. By examining the Wheeler–DeWitt equation, semiclassical emergent time, and the Page–Wootters mechanism, I explore different ways physicists attempt to recover a notion of time from a fundamentally timeless universe.
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Summary
Despite decades of research, the Problem of Time in quantum gravity remains unresolved. Quantum mechanics treats time as an absolute external parameter governing state evolution, while general relativity describes time as a dynamic component of spacetime geometry. Canonical quantization of general relativity yields the Wheeler–DeWitt equation, which contains no explicit time parameter, giving rise to the Problem of Time. This paper reviews two major approaches to this issue: the semiclassical Wentzel-Kramers-Brillouin (WKB) approximation, in which time emerges from classical gravitational degrees of freedom, and the Page–Wootters relational model, in which time arises from quantum entanglement between subsystems. This paper compares how each framework recovers an effective notion of time evolution and examines whether time is a fundamental feature of physical law or an emergent phenomenon arising from deeper quantum relationships.
Terra
Polygence mentor
PhD Doctor of Philosophy candidate
Subjects
Biology, Quantitative, Physics, Computer Science
Expertise
All aspects of quantum computing including quantum error correction and quantum algorithms, interdisciplinary data-driven projects such as those related to bioinformatics, theoretical and computational physics
Check out their profile
John Paul
Student
Graduation Year
2028
Project review
“This project challenged me to explore one of the deepest and complicated question in physics: the nature of quantum gravity. Throughout my research process, I learned about how general relativity and quantum mechanics treat time differently and why this creates the problem of time. The project helped me investigate approaches I have never seen before such as the Page-Wootters quantum entanglement approach and the WKB approximation. This project hourney helped me develop my skills in scientific writing and independent research.”
About my mentor
“My mentor was very knowledgeable and supportive throughout the project. He helped me with the mathematical derivations of these complex ideas and provided valuable feedback on my writing.”