The Infrared Universe Demonstrates Horizon-coupled Semiclassical Fluctuations Restore Entropy Via Long-wavelength Geometric Modes

The nature of the universe at its largest scales remains a fundamental question in cosmology, and new research explores a connection between horizon thermodynamics, baryon balance, and the observed expansion rate. Jonathan Holland from University, along with colleagues, investigates how energy and matter behave near cosmological horizons, effectively treating the universe as an open system coupled to a vast reservoir. This work demonstrates that the conservation of physical quantities requires compensating excitations arising from long-wavelength infrared fluctuations, identifying a return channel for energy and matter that restores balance across horizons. By linking these principles to a unique geometric framework, the team reveals a unified infrared structure that explains both the equilibrium of photons and the observed flatness of galactic rotation curves, offering a novel perspective on the fundamental properties of the cosmos.

Horizons, Thermodynamics, and Cosmological Alternatives

Scientists propose a new cosmological model that eliminates the need for dark matter and dark energy, explaining observed phenomena like the Hubble expansion, galactic rotation curves, and the cosmic microwave background. This model treats the universe as an open thermodynamic system due to cosmological and black hole horizons, linking its geometry to its thermodynamic properties. What appears as dark matter and dark energy are proposed to be manifestations of this underlying geometric structure and thermodynamic behavior. The universe is treated as an open quantum system exchanging energy and information with regions beyond the horizon, governed by non-equilibrium thermodynamics.

Carnot-Carathéodory geometry, arising in sub-Riemannian geometry, characterizes the universe with anisotropic properties. A central mesoscopic scale doesn’t represent a constant but emerges from the interplay of horizon thermodynamics and Carnot-Carathéodory geometry, governing the rate at which entropy returns to the observable universe. This builds upon the established idea that horizons possess thermodynamic properties, extending the Bekenstein-Hawking entropy of black holes to cosmological horizons. The research develops a mathematical framework based on Carnot-Carathéodory geometry and non-equilibrium thermodynamics, successfully explaining several observed phenomena without invoking dark matter or dark energy.

The expansion rate is linked to the mesoscopic scale, while the anomalous rotation curves of galaxies are explained by the modified geometry. The temperature of the cosmic microwave background is also linked to this scale, providing a mechanism for recycling entropy and charge across horizons. This alternative model offers a fundamentally new understanding of the universe, based on thermodynamics and non-commutative geometry, requiring a reinterpretation of cosmological parameters. While the mathematical framework is complex and requires further observational testing, this model presents a promising alternative to the standard Lambda-CDM model. Future research will focus on making detailed predictions testable against observational data and connecting the model to a theory of quantum gravity. This bold attempt to construct a new cosmological model, based on thermodynamics and non-commutative geometry, could lead to a deeper understanding of the universe.

Horizon Thermodynamics and Baryon Number Conservation

Scientists have developed a framework exploring the connections between cosmology, thermodynamics, and geometry, treating the universe as an open system interacting with a horizon reservoir. This research pioneers a method for tracking baryon number conservation, demonstrating that any loss of baryons across a horizon necessitates their sequestration into inaccessible modes, depleting the exterior sector and requiring compensating source terms. Relativity dictates these compensating excitations arise specifically from long-wavelength geometric modes, ensuring entropy and charge are conserved while remaining outside the causal influence of infalling matter. The research employs a Carnot-Carathéodory geometry, establishing its mesoscopic scale as a governing factor for both the excitation of these infrared modes and the propagation of photons and matter.

Photon trajectories are modeled as recurrent horizontal geodesics, creating an effective cosmic cavity whose stationary state exhibits a Planck spectrum determined by the scale. This same scale modifies large-radius circular motions in a manner consistent with observed flattened rotation curves. Through horizon thermodynamics and mesoscopic balance laws, the study links this geometric scale to the cosmic expansion rate, yielding a unified infrared structure governing photon equilibrium, baryon balance, and large-scale kinematics. By integrating the conserved U(1)B−L current over a comoving volume, the team reveals a balance equation where baryon loss across horizons is offset by source terms generated by horizon-induced chemical potentials.

This source term doesn’t violate baryon number conservation but represents an open-system effect necessary to maintain global conservation during horizon accretion. Furthermore, the research imposes a thermodynamic balance condition, demonstrating that entropy flowing into horizons through accretion is offset by the production of long-wavelength gravitational modes associated with cosmic expansion, stabilizing both radiation and baryon densities in a steady-state configuration. The study also reveals a connection between Modified Newtonian Dynamics (MOND) and sub-Riemannian geometry, interpreting MOND as a phenomenological approximation of the deeper geometric structure inherent in their framework.

Horizon Coupling Restores Cosmological Entropy and Charge

This work establishes a framework treating the cosmological exterior as an open system coupled to a horizon reservoir, revealing a fundamental connection between entropy, charge, and the cosmic expansion. Scientists demonstrate that when baryon number is lost across a horizon, conserved numbers are sequestered, effectively depleting the exterior sector and necessitating compensating source terms in the continuity equations. Crucially, relativity dictates these excitations manifest as long-wavelength geometric modes, effectively creating an infrared return channel that maintains balance across horizons. The study introduces a Carnot-Carathéodory geometry, where the mesoscopic scale governs both the excitation of these infrared modes and the kinematics of photon and matter propagation.

Photon trajectories follow recurrent horizontal geodesics, producing an effective cosmic cavity with a stationary state defined by a Planck spectrum. This scale also modifies large-radius circular motions in a manner consistent with observed flattened rotation curves. Horizon thermodynamics and mesoscopic balance laws are then linked to the cosmic expansion rate, yielding a unified infrared structure underlying photon equilibrium, baryon balance, and large-scale kinematics. This framework provides a coherent and highly constrained alternative to standard cosmological models. The research establishes a direct connection between horizon thermodynamics, infrared geometry, and local conservation laws, offering a novel perspective on the universe’s fundamental properties. The team’s work demonstrates a robust theoretical foundation for understanding the interplay between entropy, charge, and the expansion of the universe, paving the way for future investigations into a fully dynamical theory and compatibility with increasingly precise observational data.

Horizon Thermodynamics and Mesoscopic Geometry

This research establishes a framework for understanding cosmology, treating the observable universe as an open system interacting with a horizon reservoir. The team demonstrates that the conservation of quantities like baryon number and entropy, when considered alongside the principles of quantum field theory and the presence of horizons, necessitates compensating excitations within the observable universe. Crucially, relativity dictates these excitations manifest as long-wavelength geometric modes, effectively creating an infrared return channel that maintains balance across horizons. The work further introduces a Carnot-Carathéodory geometry, where a mesoscopic scale governs both the excitation of these infrared modes and the propagation of photons and matter. This geometry links horizon thermodynamics and balance laws.