标题： R-引力中具有挠率的狄拉克场 显示英文标题

标题： Dirac fields in f(R)-gravity with torsion

摘要： 我们研究了具有挠率的 f(R)-引力，并且在狄拉克大质量场存在的条件下进行了探讨。 利用比安基恒等式，我们制定了理论的守恒定律，并验证了其与物质场方程的一致性。 此外，我们将场方程分解为无挠率项和挠率项：我们证明引力拉格朗日量的非线性归结为一个依赖于旋量场的标量场的存在；这个附加的标量场产生了有效的应力-能量张量，并扮演着修改狄拉克场归一化的比例因子的角色。 关于费米子的能量正定性和粒子-反粒子二象性问题进行了讨论。 显示英文摘要

摘要： We study f(R)-gravity with torsion in presence of Dirac massive fields. Using the Bianchi identities, we formulate the conservation laws of the theory and we check the consistency with the matter field equations. Further, we decompose the field equations in torsionless and torsional terms: we show that the non-linearity of the gravitational Lagrangian reduces to the presence of a scalar field that depends on the spinor field; this additional scalar field gives rise to an effective stress-energy tensor and plays the role of a scale factor modifying the normalization of Dirac fields. Problems for fermions regarding the positivity of energy and the particle-antiparticle duality are discussed.