Gravity, Holography and Spacetime

This award funds the research activities of Professor Elena Caceres at The University of Texas at Austin.

Quantum mechanics is a cornerstone of modern physics; it describes how the subatomic world works, and experiments have verified the accuracy of its predictions for more than a century. One fascinating phenomenon predicted by quantum mechanics is "quantum entanglement". Entanglement occurs when initially independent systems interact and separate.

After interacting, the systems cannot be described independently even if they are very far apart; they have become entangled. In the last decade, physicists have discovered a surprising connection between quantum entanglement --- an intrinsically subatomic phenomenon --- and the geometry of space and time. This discovery points to the possibility that space and time emerge from quantum mechanics and is one of the most significant theoretical developments of the last decade.

Research in this area advances the national interest by promoting the progress of science in a fundamental direction: understanding the microscopic nature of space and time. Many foundational questions in this area are still unanswered. Professor Caceres’ research aims to contribute to our understanding of how to reconstruct space and time from quantum mechanics.

Her research will use a two-pronged approach: 1) studying a specific formulation of entanglement known as “bit threads”; and 2) investigating a class of promising quantum systems, known as “sparse SYK models.” This project will also have significant broader impacts. Professor Caceres will involve graduate students and postdocs in her research, contributing to their scientific training.

She will also develop a mentoring program for minority undergraduate students and focus her outreach efforts on disadvantaged communities and underrepresented groups in physics.

More technically, one of Professor Caceres’ goals is to create a framework for metric reconstruction using bit threads. She plans to study bit threads in time-dependent backgrounds, investigate bit threads in states with entanglement shadows, and work towards obtaining the full non-linear Einstein’s equations from a bit thread construction. Another thrust of this project is the study of sparse SYK.

More concretely, Professor Caceres will investigate two coupled sparse SYKs, the degree of sparseness for which the two coupled sparse SYKs display features consistent with a traversable wormhole and a teleportation protocol in this model. The results will establish to what extent sparse SYKs are good quantum gravity models and can lead to a wealth of computationally efficient quantum models with black hole dynamics.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.