Zenith Grant Awardee
Dr. Alexander Maloney
McGill University
Co-Investigators
Robert Brandenberger, <i>McGill University</i><br>Jim Cline, <i>McGill University</i><br>Keshav Dasgupta, <i>McGill University</i>
Project Title
The Holographic Wave Function of the Universe
Project Summary
Current models of cosmology, which are based on Einstein's theory of general relativity, successfully describe many features of our universe at its largest scales. However, in order to describe the dynamics of the universe at very early times – times shortly after the big bang – a quantum theory of gravity is necessary. String theory, one of the most promising theories of quantum gravity, provides a host of powerful techniques, which can be used to attack problems in quantum cosmology. Moreover, many of these techniques allow us to understand quantum gravity in regimes where intuitive notions of space and time cease to apply. For example, the holographic principle – which relates a theory of quantum gravity in four dimensions to a simpler theory living in three dimensions – provides deep insights into quantum cosmology, which challenge traditional notions of classical space-time. As more realistic cosmologies are studied using these powerful holographic techniques, we both address basic conceptual puzzles in quantum gravity and face the exciting prospect of contact with observational data.
Technical Abstract
We propose to use non-perturbative techniques in string theory to address basic conceptual puzzles in quantum cosmology. Many of the most important problems in cosmology, involving the wave function of the universe and the quantum resolution of the big bang singularity, are not amenable to the effective field theory techniques typically used in string cosmology. For example, holography – and its specific implementation as gauge/gravity duality – provides a mechanism to address basic issues in quantum cosmology at the non-perturbative level. The AdS/CFT correspondence allows us to compute the wave function of locally Anti-de Sitter universes in terms of a dual conformal field theory. Other, less well understood, implementations of the holographic principle can be developed to study more interesting – and more realistic – cosmologies, such as those involving inflation. We propose to investigate and generalize these and other related non-perurbative approaches to quantum cosmology. Further, we propose to apply the results to realistic four-dimensional cosmologies of observational significance.
QSpace Latest
PressRelease: Precision experiment puts pressure on quantum collapse theories
Quantum mechanics, the theory governing the microscopic world, is famously counterintuitive. A particle can exist in a superposition of multiple states, such as different positions, until a measurement is performed. At that point, the wavefunction describing that particle appears to ‘collapse’ to a single outcome. This puzzle lies at the heart of the measurement problem, famously illustrated by Schrödinger’s cat, suspended between life and death until observed. The XENONnT detector, which was designed to be sensitive to rare physics events, has tightened constraints on one family of possible solutions to the measurement problem, known as ‘collapse theories.’ The work, which was partially funded by FQxI, was reported in Physical Review Letters in March 2026. Image credit: XENON Collaboration.