We investigate the possibility of gravitationally generated particle production via the mechanism of nonminimal torsion–matter coupling. An intriguing feature of this theory is that the divergence of the matter energy–momentum tensor does not vanish identically. We explore the physical and cosmological implications of the nonconservation of the energy–momentum tensor by using the formalism of irreversible thermodynamics of open systems in the presence of matter creation/annihilation. The particle creation rates, pressure, and the expression of the comoving entropy are obtained in a covariant formulation and discussed in detail. Applied together with the gravitational field equations, the thermodynamics of open systems lead to a generalization of the standard $\Lambda$CDM cosmological paradigm, in which the particle creation rates and pressures are effectively considered as components of the cosmological fluid energy–momentum tensor. We consider specific models, and we show that cosmology with a torsion–matter coupling can almost perfectly reproduce the $\Lambda$CDM scenario, while it additionally gives rise to particle creation rates, creation pressures, and entropy generation through gravitational matter production in both low and high redshift limits.

中文翻译：

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通过非最小扭转-物质耦合产生引力诱导粒子

我们研究了通过非最小扭转-物质耦合机制产生引力产生的粒子的可能性。该理论的一个有趣特征是，物质能量-动量张量的散度不会完全消失。我们通过在物质创造/湮灭的情况下使用开放系统的不可逆热力学的形式主义来探索能量-动量张量不守恒的物理和宇宙学意义。粒子产生速率、压力和共动熵的表达式在协变公式中获得并详细讨论。与引力场方程一起应用，开放系统的热力学导致标准的推广$\Lambda$CDM 宇宙学范式，其中粒子产生率和压力被有效地视为宇宙学流体能量-动量张量的组成部分。我们考虑了特定的模型，并且证明了具有扭转-物质耦合的宇宙学几乎可以完美地再现$\Lambda$CDM 情景，同时它还通过在低红移和高红移极限下产生的引力物质来增加粒子产生率、产生压力和熵产生。