Gravity from Entropy A Radical New Framework for Quantum Gravity

Gravity from Entropy A Radical New Framework for Quantum Gravity
by Sophie Jenkins
London, UK (SPX) Mar 11, 2025

A groundbreaking study published in Physical Review D by Professor Ginestra Bianconi of Queen Mary University of London introduces a revolutionary approach to understanding gravity through quantum relative entropy. This innovative framework seeks to bridge the gap between quantum mechanics and Einstein's general relativity-two fundamental but historically incompatible theories in physics.

The Long-Standing Challenge of Quantum Gravity

For decades, physicists have grappled with the challenge of unifying quantum mechanics, which governs microscopic particle behavior, with general relativity, which explains gravity on a cosmic scale. Professor Bianconi's work offers a novel perspective by treating the metric of spacetime, a fundamental component of general relativity, as a quantum operator.

Her approach employs quantum relative entropy-an essential concept in quantum information theory-to describe the interaction between spacetime geometry and matter, leading to an entirely new entropic formulation of gravity.

Entropy, the G-Field, and Modified Einstein Equations

The study introduces an entropic action that measures the disparity between spacetime metrics and the metric influenced by matter fields. This formulation results in modified Einstein equations that, under conditions of weak coupling (low energy and small curvature), revert to classical general relativity. However, the theory extends beyond current models by naturally predicting a small, positive cosmological constant, aligning more closely with observations of the universe's accelerated expansion.

A crucial feature of this model is the introduction of the G-field-an auxiliary field functioning as a Lagrangian multiplier. The G-field plays a pivotal role in the modified gravitational equations and may provide a new interpretation of dark matter, an enigmatic substance believed to comprise a significant portion of the universe's mass.

Implications for Quantum Gravity and Dark Matter

By establishing a link between gravity and quantum information theory, this study paves the way for a unified theory of quantum gravity. The proposed G-field could also offer fresh insights into the nature of dark matter, a mystery that continues to perplex cosmologists.

"This work proposes that quantum gravity has an entropic origin and suggests that the G-field might be a candidate for dark matter," explains Professor Bianconi. "Additionally, the emergent cosmological constant predicted by our model could help resolve the discrepancy between theoretical predictions and experimental observations of the universe's expansion."

While further research is necessary to explore the full ramifications of this theory, it represents a significant step toward understanding the fundamental nature of the universe. By redefining spacetime as a quantum entity and leveraging entropy in spacetime metrics, this work challenges conventional theories and opens new avenues for scientific exploration.

Research Report:Gravity from Entropy