Matter Creation Dynamics in Cosmological Models

Matter creation dynamics in cosmology examines mechanisms by which the expanding Universe may generate particles through purely gravitational or geometric interactions. In this framework, the cosmic medium is treated as an open thermodynamic system in which the non-conservation of the energy–momentum tensor gives rise to a particle production rate that can drive inflationary and late-time accelerating phases without invoking an explicit dark energy component. Approaches range from semi-classical quantum field theory in curved spacetime to macroscopic descriptions based on irreversible thermodynamics. Many models introduce an effective creation pressure associated with particle production, modifying the Friedmann equations and permitting unified accounts of early inflation, matter domination and current acceleration. Extensions include multi-fluid cosmologies, curvature–matter couplings and torsion–matter couplings, each predicting subtle departures from the standard ΛCDM expansion history. This body of work addresses cosmological tensions—such as discrepancies in the Hubble constant and structure growth rate—as well as offering observational tests via cosmic microwave background anisotropies, Sunyaev–Zeldovich cross-correlations and Supernova distance measurements.

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Matter Creation Dynamics in Cosmological Models publication trend

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Technical terms

Particle production rate (Γ): The rate at which the gravitational field generates new particles per unit volume and time.

Open thermodynamic system: A system exchanging energy or matter with its surroundings, allowing non-conservation of particle number.

Creation pressure: Effective negative pressure arising from particle production, modifying cosmic expansion dynamics.

ΛCDM model: The standard cosmological paradigm featuring cold dark matter and a cosmological constant as drivers of structure formation and acceleration.

Torsion–matter coupling: A theoretical interaction linking spacetime torsion to matter fields, leading to nonconservation of the energy–momentum tensor and induced particle creation.

References

1. Gravitational matter creation, multi-fluid cosmology and kinetic theory. European Physical Journal C (2023).
2. Gravitational induced particle production through a nonminimal curvature–matter coupling. European Physical Journal C (2015).
3. Two-fluid solutions of particle-creation cosmologies. European Physical Journal C (2019).
4. Gravitationally Induced Particle Production through a Nonminimal Torsion–Matter Coupling. Universe (2021).