Reviewed by Danielle Ellis, B.Sc.Sep 17 2024
Scientists from the Cluster of Excellence at the University of Würzburg have devised a technique for laboratory modeling of a central theory of quantum gravity. Their mission was to unravel mysteries from the quantum realm that had hitherto remained unsolved. The journal Physical Review Letters published the study.
Illustration of the theory used to model quantum gravity: The lattice simulates a curved space-time – near the boundary, the lattice is denser due to the curvature. The interacting electrical signals (yellow, red, and blue lines) in the bulk simulate the gravitational dynamics. The dynamics in the bulk and at the outer boundary correspond to each other. They are consistent with the AdS/CFT correspondence. Image Credit: Erdmenger/JMU, Böttcher/Alberta
Because of science, scientists can now precisely calculate planet orbits, predict tides, and launch rockets into space. Science has also made gravity less mysterious, at least when it comes to great distances. However, at the level of the tiniest particles, the so-called quantum level, the theoretical description of gravity breaks down.
To explain the Big Bang or the interior of black holes, we have to understand the quantum properties of gravity. At very high energies, the classical laws of gravity fail. Therefore, our goal is to contribute to the development of new theories that can explain gravity at all scales, including at the quantum level.
Johanna Erdmenger, Professor and Chair, Theoretical Physics, University of Würzburg
Researchers Focus on the Central Theory of Quantum Gravity
One of the key theories of quantum gravity, the “AdS/CFT correspondence,” is crucial to the creation of new models. It asserts that simpler quantum theories at the boundary of a high-dimensional space can describe complicated gravitational theories within that region.
This sounds very complicated at first, but it is easy to explain. The AdS/CFT correspondence allows us to understand difficult gravitational processes, such as those that exist in the quantum world, using simpler mathematical models. At its heart is a curved spacetime, which can be thought of as a funnel.
Johanna Erdmenger, Professor and Chair, Theoretical Physics, University of Würzburg
Erdmenger said, “The correspondence states that the quantum dynamics at the edge of the funnel must correspond to the more complex dynamics inside similar to a hologram on a banknote, which generates a three-dimensional image even though it is only two-dimensional itself.”
Proof of Concept for Realizing Gravitational Dynamics in the Laboratory
Erdmenger’s team has now created a way to experimentally test the predictions of the previously unproven AdS/CFT correspondence. The method involves simulating curved space-time with a branched electrical circuit, where the electrical signals at each branch point correspond to the gravitational dynamics that would be present at different points in space-time.
According to the study team's theoretical calculations, the suggested circuit can achieve a central prediction of the AdS/CFT correspondence since the dynamics at the border of the imitated spacetime also match those insides.
The Würzburg research team now intends to implement the experimental setting detailed in the research as a subsequent step. This could result in major advancements in gravitational studies and technological breakthroughs.
Practical Implementation and Possible Technical Applications
Our circuits also open up new technological applications. Based on quantum technology, they are expected to transmit electrical signals with reduced loss, since the simulated curvature of space bundles and stabilizes the signals. This would be a breakthrough for signal transmission in neural networks used for artificial intelligence, for example.
Johanna Erdmenger, Professor and Chair, Theoretical Physics, University of Würzburg
The University of Alberta, Canada; the Max Planck Institute for the Physics of Complex Systems in Dresden, Germany; the University of Alabama in Tuscaloosa, USA; and the Chair of Theoretical Physics I at the University of Würzburg, Germany collaborated on this study. The Würzburg-Dresden Cluster of Excellence “ct. qmat - Complexity and Topology in Quantum Materials” supported the research.
Journal Reference:
Dey, S., et al. (2024) Simulating Holographic Conformal Field Theories on Hyperbolic Lattices. Physical Review Letters. doi.org/10.1103/physrevlett.133.061603.