Complex Quantum Systems and The Quantum Universe

A QuantISED Collective

Exciting recent developments have unearthed deep connections between Quantum Information Science and Quantum Gravity. Many fundamental questions in quantum field theory and quantum gravity, simply are questions about the distribution and dynamics of quantum information. For example, recent progress on the black hole information loss problem, the holographic emergence of spacetime from strongly coupled quantum field theories, thermodynamics in closed quantum systems, and phase transitions without classical order parameters have relied heavily on ideas and methods from the theory of quantum information and computing.

The central role of complex entanglement patterns, complex operators, and complex time evolution has been a recurring theme in these developments. The concepts quantifying these notions are rooted in the field of quantum computational complexity, the study of which tasks are easy and and which tasks are hard for a quantum computer. The basic idea of work at the interface of quantum complexity and quantum graivty is that computational complexity is a resource that can also be used to ensure the robustness of spacetime to perturbation by computationally-bounded agents. This robustness is an essential feature of holographic duality in gravity: complexity “hides” the inherent non-locality of quantum gravity from obvious experimental detection. This picture has opened  a host of new questions in black hole physics, computer science, cryptography, condensed matter physics, and more.  We aim to shed light on these connections.

Thus, we bring together researchers in Quantum Information and Quantum Gravity, to develop the study of quantum complexity — broadly defined to include computational complexity, multipartite quantum correlations, and exotic forms of entanglement — via quantum gravity, and to develop the study of quantum gravity via quantum complexity.

As befits the interdisciplinary nature of these problems, our consortium includes world-leading experts in both quantum information theory and quantum gravity.  We are pursuing investigations on: (1) multi-party quantum correlations; (2) the dynamics of complexity in quantum theories and holography; (3) the dynamics of open quantum systems; (4) entanglement across energy and momentum scales; (5) the information-theoretic basis of cosmology and black holes; and (6) tractable but still complex models of quantum gravity. In all  these areas, we  use high energy physics as a guide to develop new tools in quantum information science for complex systems. Conversely, we will use insights  from quantum information science to guide our investigations in high energy physics.