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arXiv 1507.07448gr-qcastro-ph.COhep-th
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具有一般曲率不变量的类标量张量引力中的局部能量动量守恒

Local energy-momentum conservation in scalar-tensor-like gravity with generic curvature invariants

David Wenjie Tian

摘要:

对于一类作用量包含标量场$ϕ(x^α)$与Ricci标量$R=R^α_{\;\;α}$以外的一般曲率不变量$\mathcal{R}$之间的非极小耦合的类标量-张量修正引力,证明了其场方程的协变不变性,并确认/证明了局部能量动量守恒.这些$ϕ(x^α)-\mathcal{R}$耦合项打破了粒子变换下的自同构不变性的对称性,这意味着当$ϕ(x^α)$是非动力学的和无质量的时,场方程的解应该满足相容性条件$\mathcal{R}\equiv 0$。根据这一事实,并基于可观测宇宙的加速膨胀,我们提出了一个初步的测试,以检查修改后的重力是一个有效的暗能量的可行性,和一个最简单的例子通过测试是“外尔/共形暗能量“。

英文摘要:

For a large class of scalar-tensor-like modified gravity whose action contains nonminimal couplings between a scalar field $ϕ(x^α)$ and generic curvature invariants $\mathcal{R}$ beyond the Ricci scalar $R=R^α_{\;\;α}$, we prove the covariant invariance of its field equation and confirm/prove the local energy-momentum conservation. These $ϕ(x^α)-\mathcal{R}$ coupling terms break the symmetry of diffeomorphism invariance under a particle transformation, which implies that the solutions of the field equation should satisfy the consistency condition $\mathcal{R}\equiv 0$ when $ϕ(x^α)$ is nondynamical and massless. Following this fact and based on the accelerated expansion of the observable Universe, we propose a primary test to check the viability of the modified gravity to be an effective dark energy, and a simplest example passing the test is the "Weyl/conformal dark energy".

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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