arXiv:1208.3703

Quantum Geometry and Interferometry

Craig J. Hogan

Published Aug 17, 2012• 3 citations

Abstract

All existing experimental results are currently interpreted using classical geometry. However, there are theoretical reasons to suspect that at a deeper level, geometry emerges as an approximate macroscopic behavior of a quantum system at the Planck scale. If directions in emergent quantum geometry do not commute, new quantum-geometrical degrees of freedom can produce detectable macroscopic deviations from classicality: spatially coherent, transverse position indeterminacy between any pair of world lines, with a displacement amplitude much larger than the Planck length. Positions of separate bodies are entangled with each other, and undergo quantum-geometrical fluctuations that are not describable as metric fluctuations or gravitational waves. These fluctuations can either be cleanly identified or ruled out using interferometers. A Planck-precision test of the classical coherence of space-time on a laboratory scale is now underway at Fermilab.

DOI: 10.48550/arxiv.1208.3703

Related papers

Quantum Geometry in the Lab

Craig J. Hogan

Standard particle theory is based on quantized matter embedded in a classical geometry. Here, a complementary model is proposed, based on classical matter -- massive bodies, without quantum properties -- embedded in a quantum geometry. It does not describe elementary particles, but may be a better, fully consistent quantum description for position states in laboratory-scale systems. Gravitational theory suggests that the geometrical quantum system has an information density of about one qubit per Planck length squared. If so, the model here predicts that the quantum uncertainty of geometry creates a new form of noise in the position of massive bodies, detectable by interferometers.

arXiv:1303.5981Mar 24, 20130 citations

Nature does not play Dice at the Planck scale

Tejinder P. Singh

We start from classical general relativity coupled to matter fields. Each configuration variable and its conjugate momentum, as also spacetime points are raised to the status of matrices [equivalently operators]. These matrices obey a deterministic Lagrangian dynamics at the Planck scale. By coarse-graining this matrix dynamics over time intervals much larger than Planck time, one derives quantum theory as a low energy emergent approximation. If a sufficiently large number of degrees of freedom get entangled, spontaneous localisation takes place, leading to the emergence of classical spacetime geometry and a classical universe. In our theory, dark energy is shown to be a large-scale quantum gravitational phenomenon. Quantum indeterminism is not fundamental, but results from our not probing physics at the Planck scale.

arXiv:2005.06427International Journal of Modern Physics DJul 29, 20205 citations

Quantum gravitational decoherence of matter waves

Charles H.-T. Wang, R. Bingham, José Tito Mendonça

One of the biggest unsolved problems in physics is the unification of quantum mechanics and general relativity. The lack of experimental guidance has made the issue extremely evasive, though various attempts have been made to relate the loss of matter wave coherence to quantum spacetime fluctuations. We present a new approach to the gravitational decoherence near the Planck scale, made possible by recently discovered conformal structure of canonical gravity. This leads to a gravitational analogue of the Brownian motion whose correlation length is given by the Planck length up to a scaling factor. With input from recent matter wave experiments, we show that the minimum value of this factor to be well within the expected range for quantum gravity theories. This suggests that the sensitivities of advanced matter wave interferometers may be approaching the fundamental level due to quantum spacetime fluctuations and that investigating Planck scale physics using matter wave interferometry may become a reality in the near future. Physics on the large scale is based on Einstein’s theory of general relativity (GR), which interprets gravity as the curvature of spacetime. Despite its tremendous success as an isolated

Jan 1, 200640 citations

Quantum gravitational decoherence of matter waves

Charles H-T Wang, R. Bingham, J Tito Mendonça

One of the biggest unsolved problems in physics is the unification of quantum mechanics and general relativity. The lack of experimental guidance has made the issue extremely evasive, though various attempts have been made to relate the loss of matter wave coherence to quantum spacetime fluctuations. We present a new approach to the gravitational decoherence near the Planck scale, made possible by the recently discovered conformal structure of canonical gravity. This leads to a gravitational analogue of Brownian motion whose correlation length is given by the Planck length up to a scaling factor. With input from recent matter wave experiments, we show the minimum value of this factor to be well within the expected range for quantum gravity theories. This suggests that the sensitivities of advanced matter wave interferometers may be approaching the fundamental level due to quantum spacetime fluctuations, and that investigating Planck scale physics using matter wave interferometry may become a reality in the near future.

arXiv:gr-qc/0603112Classical and Quantum GravityAug 18, 200657 citations

Scale-Invariant Cosmodynamics: Historical Geometry and the Emergence of Quantum Behavior

Schäfer, Sandro

This work develops a scale-invariant, discrete-frame interpretation of quantum mechanics based on the concept of historical geometry. In this framework, space is not a static background but a layered geometric archive formed by sequential, scaled frames of reality. Macroscopic objects continuously extend their geometric structure across frames, establishing stable centers, mass, inertia, and gravitational behavior. Elementary particles, however, cannot continue their historical geometric structure independently. This loss of geometric continuation provides a mechanical explanation for core quantum phenomena: superposition as a set of compatible geometric continuation options, wave-function collapse as reattachment to a macroscopic geometry, and entanglement as shared global geometric constraints. The theory proposes that the classical–quantum boundary is defined not by size, decoherence, or measurement, but by the ability (or inability) of a system to maintain geometric continuity across frames. This work is intended as a conceptual and structural foundation for a unified scale-based description of quantum behavior and gravitation.

Dec 10, 20250 citations

Quantum Entanglement and Non-Planck Geometry: A Novel Analytical Framework

Jincheng Zhang

Quantum entanglement, a cornerstone of quantum mechanics, presents a unique challenge to traditional geometric analysis. This paper explores the potential of a non-Planck geometry to provide a deeper understanding of entanglement's non-classical properties, specifically focusing on its geometric implications. We propose a framework built upon quantum entanglement, aiming to reveal previously unacknowledged geometric features. This work seeks to address limitations of existing approaches by incorporating the fundamental entanglement properties directly into the geometric analysis. The core mechanism involves establishing a new geometric tool to analyze entanglement's non-classical behavior. The resulting analysis will pave the way for novel quantum algorithm design and a more complete understanding of entanglement's geometric landscape.

Sep 3, 20260 citations