论文标题
Weyl型$ f（q，t）$重力及其宇宙学的影响
Weyl type $f(Q,T)$ gravity, and its cosmological implications
论文作者
论文摘要
我们考虑了一个$ f（q，t）$类型的重力模型，其中时空的标量$ q_ {αμν} $以其标准Weyl形式表示，并且由矢量字段$W_μ$确定。该理论的场方程是在消失的总标数曲率的假设下获得的，该条件通过Lagrange乘数添加到重力作用中。重力场方程是从变分原理获得的，它们明确取决于标量非赞誉和Lagrange乘数。还确定了物质能量量张量的协变差异，因此得出的是非对象 - 偶联导致能量和动量的不受影。明确计算了能量和动量平衡方程，并发现能源项和额外力的表达式。我们研究了该理论的宇宙学意义，并获得了平坦，均匀和各向同性几何形状的宇宙进化方程，从而概括了标准一般相对性的弗里德曼方程。我们通过施加一些函数$ f（q，t）$的简单功能形式来考虑几种宇宙学模型，并将理论的预测与标准$λ$ CDM模型进行比较。
We consider an $f(Q,T)$ type gravity model in which the scalar non-metricity $Q_{αμν}$ of the space-time is expressed in its standard Weyl form, and it is fully determined by a vector field $w_μ$. The field equations of the theory are obtained under the assumption of the vanishing of the total scalar curvature, a condition which is added into the gravitational action via a Lagrange multiplier. The gravitational field equations are obtained from a variational principle, and they explicitly depend on the scalar nonmetricity and on the Lagrange multiplier. The covariant divergence of the matter energy-momentum tensor is also determined, and it follows that the nonmetricity-matter coupling leads to the nonconservation of the energy and momentum. The energy and momentum balance equations are explicitly calculated, and the expressions of the energy source term and of the extra force are found. We investigate the cosmological implications of the theory, and we obtain the cosmological evolution equations for a flat, homogeneous and isotropic geometry, which generalize the Friedmann equations of standard general relativity. We consider several cosmological models by imposing some simple functional forms of the function $f(Q,T)$, and we compare the predictions of the theory with the standard $Λ$CDM model.
