Nikodem J. Poplawski
We show that it is possible to formulate the classical Einstein-Maxwell-Dirac theory of spinors interacting with the gravitational and electromagnetic fields as the Einstein-Cartan-Kibble-Sciama theory with the Ricci scalar of the traceless torsion, describing gravity, and the torsion trace acting as the electromagnetic potential.
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New Insight into the Relation between Torsion and Electromagnetism
在几种统一的场论中，挠率迹被设定为等于电磁势。使用纤维束技术，我们表明，这是没有主导原则，但另一个时空和电磁学之间的几何关系的正式后果。
Geometric Interpretation of Electromagnetism in a Gravitational Theory with Torsion and Spinorial Matter
研究了引力和电磁学统一理论的可能几何框架：通过允许任意复线性联系和基于复联系构造扩展旋量导数来扩展广义相对论。因此，时空挠率不仅与费米子的自旋耦合，导致四费米子接触相互作用，而且挠率的非度规矢量部分也与电磁势有关。然而，这个长期存在的关系被证明只在特殊的U（1）规范中有效，并且它是潜在的扩展几何的形式结果。
Two Lagrangian functions are used to construct geometric field theories. One of these Lagrangians depends on the curvature of space, while the other depends on curvature and torsion. It is shown that the theory constructed from the first Lagrangian gives rise to pure gravity, while the theory constructed using the second Lagrangian gives rise to both gravity and electromagnetism. The two theories are constructed in a version of absolute parallelism geometry in which both curvature and torsion are, simultaneously, non-vanishing. One single geometric object, {\it W-tensor}, reflecting the proper…
Recently much controversy has been shed on BICEP 2 experiments for the concerning this validity or not and a possible set of new experiments to detect primordial inflation and gravitational waves. Since gravitational waves imply the existence of primordial magnetic fields in this context, C Bonvin, R Durrer and R Marteens [Phys Rev Lett (2014)] have tried to associate the presence of primordial magnetic fields to BICEP 2 by making use of CMB tensor modes. Here we show that by considering torsion dilatonic lagrangean one obtains cosmological magnetic fields of the order of $B\sim{10^{-10}G}$ wh…
Coupling Electromagnetism to Torsion: Black Holes and Spin-Charge Interactions
本文研究了电磁场与 torsion 的非最小耦合，推导了扩展的 Reissner-Nordstr{ö}m 黑洞解，并揭示了自旋电荷与电荷的新相互作用。
The metric-affine Lagrangian of Ponomarev and Obukhov for the unified gravitational and electromagnetic field is linear in the Ricci scalar and quadratic in the tensor of homothetic curvature. We apply to this Lagrangian the variational principle with the tetrad and spin connection as dynamical variables and show that, in this approach, the field equations are the Einstein-Maxwell equations if we relate the electromagnetic potential to the trace of the spin connection. We also show that, as in the Ponomarev-Obukhov formulation, the generally covariant Dirac Lagrangian gives rise to the standar…
It is shown the antisymmetric part of the metric tensor is the potential for the spin field. Various metricity conditions are discussed and comparisons are made to other theories, including Einstein's. It is shown in the weak field limit the theory reduces to one with a symmetric metric tensor and totally antisymmetric torsion. It is also shown, due to gauge invariance, the electromagnetic field must be present.
Geometrical formulation of classical electromagnetism
一般的仿射联络有足够的自由度来描述引力的度量仿射公式中的经典引力场和电磁场。引力场在拉格朗日量中由里奇张量的对称部分表示，而经典电磁场则由位似曲率张量几何表示。我们引入的四速度场的运动学约束，其中的拉格朗日乘子代表的能量密度的问题。四速度和非度规张量的迹之间的耦合表示电荷密度。我们表明，最简单的度量仿射拉格朗日依赖于Ricci张量和位似曲率张量产生的爱因斯坦-麦克斯韦场方程，而Bianchi恒等式给出洛伦兹运动方程。如果四速度耦合到挠率矢量，爱因斯坦方程就被一个在普朗克尺度下很重要的项所修正，这可能会阻止时空奇点的形成。
We show that a non-minimal coupling of electromagnetism with background torsion can produce birefringence of the electromagnetic waves. This birefringence gives rise to a B-mode polarization of the CMB. From the bounds on B-mode from WMAP and BOOMERanG data, one can put limits on the background torsion at $ξ_{1}T_{1}=(-3.35 \pm 2.65) \times 10^{-22} GeV^{-1}$.
Torsional Weyl-Dirac Electrodinamics
从具有非度规性和挠率的几何出发，建立了经典的引力和电磁理论。该理论是坐标协变的，也是Weyl规范协变的。无质量和大质量的光子、内禀电流和磁电流都存在于这个框架中。运动的场EQ-s和EQ-s是从基于几何的动作导出的。结果表明，大质量的相互作用是由大质量的光子传递的。磁电荷不能与电电荷同时存在。在没有挠率和爱因斯坦规范的情况下，我们得到爱因斯坦-麦克斯韦理论。
The Coupling of Gravity to Spin and Electromagnetism
研究了两个费米子在单重旋量态下的静态球对称系统的耦合Einstein-Dirac-麦克斯韦方程组。稳定的类孤子的解决方案被证明是存在的，我们讨论了正则化的影响，从费曼图的角度来看重力。
The new spinor-unit field representation of the electromagnetism \cite{Nash2010} (with quark and lepton sources) is integrated via minimal coupling with standard Einstein gravitation, to formulate a Lagrangian model of the very early universe. The solution of the coupled Euler-Lagrange field equations yields a scale factor $a(t)$ (comoving coordinates) that initially exponentially increases $N$ e-folds from $a(0) \approx 0$ to $a_{1} = a(0) {e}^{N} $ ($N$ = 60 is illustrated), then exponentially decreases, then exponentially increases to $a_{1}$, and so on almost periodically. (Oscillatory cos…
We present a framework in which the projective symmetry of the Einstein-Hilbert action in metric-affine gravity is used to induce an effective coupling between the Dirac lagrangian and the Maxwell field. The effective $U(1)$ gauge potential arises as the trace of the non-metricity tensor $Q_{μa}{}^a$ and couples in the appropriate way to the Dirac fields to in order to allow for local phase shifts. On shell, the obtained theory is equivalent to Einstein-Cartan-Maxwell theory in presence of Dirac spinors.
An assessment of Evans' unified field theory II
埃文斯在时空服从黎曼-嘉当几何的背景下发展了引力和电磁的经典统一场论。在第一篇论文中，我们分析了这个理论，并将其总结为九个方程。我们现在提出一个适用于Evans理论的变分原理，并证明它产生两个场方程。第二个场方程在挠率中是代数的，我们可以用挠率来解它。事实证明，对于所有的物理情况下，扭转消失，第一场方程，连同埃文斯的统一场论，崩溃到一个普通的爱因斯坦方程。
It is well known that a theory of the (i) Lorentz invariant and (ii) locally interacting (iii) two degrees of freedom of a massless spin 1 particle, the photon, leads uniquely to electromagnetism at large distances. In this work, we remove the assumption of (i) Lorentz boost invariance, but we still demand (ii) and (iii). We consider several broad classes of theories of spin 1, which in general explicitly violate Lorentz symmetry. We restrict to the familiar two degrees of freedom of the photon. We find that most theories lead to non-locality and instantaneous signaling at a distance. By deman…
Dynamics of charged spin-$\frac{1}{2}$ particles in superposed states minimally coupled to electromagnetism in curved spacetime within the WKB approximation
本文利用WKB近似研究弯曲时空中最小耦合电磁场的带电自旋-1/2粒子叠加态动力学，通过提取二阶微分方程处理质量本征态不同固有时间问题，获得自旋动力学及测地线偏离。
A geometric formalism is developed which allows to describe the non-linear regime of higher-spin gravity emerging on a cosmological quantum space-time in the IKKT matrix model. The vacuum solutions are Ricci-flat up to an effective vacuum energy-momentum tensor quadratic in the torsion, which arises from a Weitzenböck-type higher spin connection. Torsion is expected to be significant only at cosmic scales and around very massive objects, and could behave like dark matter. A non-linear equation for the torsion tensor is found, which encodes the Yang-Mills equations of the matrix model. The metr…
Classical electrodynamics and spin-torsion coupling effects
本文在庞加莱规范引力框架下研究轴向挠率与电磁场的耦合，指出磁螺旋密度和自旋密度构成挠率场源，并证明外部正交电磁场可导致线偏振光的偏振旋转效应。
Einstein-Cartan-Heisenberg Theory of Gravity with Dynamical Torsion
基于挠率与经典旋量场之间的代数关系，给出了爱因斯坦-嘉当引力与经典旋量场相互作用的一种新解释。在这种方法中，旋量场变成了一个辅助场，而这个场的动力学方程（海森堡方程）是一个动力学的、关于挠率的引力方程。这个理论的最简单的版本进行检查的度量自由度被冻结，只有扭转起作用。一个球对称的解决方案，这个理论进行了检查。这个解可以用惠勒的“不带电荷的电荷”和“没有质量的质量”的思想来解释，作为一个不带电荷和没有质量的粒子的几何模型，但有自旋（“没有自旋的自旋”）。
Search for manifestations of spin-torsion coupling
本文在庞加莱规范引力框架下研究轴矢量挠率-自旋耦合，推导修正麦克斯韦方程并分析电磁波在均匀挠率场中的法拉第偏振旋转，从而利用天体物理数据对宇宙轴矢量挠率场给出强约束。
Berry phase for spin--1/2 particles moving in a spacetime with torsion
在Einstein-Cartan-Dirac模型下研究了自旋为1/2的粒子在有挠平坦时空中运动时的Berry相位.结果表明，如果扭转是由于一个密集的极化背景，那么只有当费米子是无质量的，它的动量是垂直于背景极化的方向，有一个Berry相。在其他理论框架中讨论了这个Berry相位的数量级。
We develop a many-particle quantum-hydrodynamical model of fermion matter interacting with the external classical electromagnetic and gravitational/inertial and torsion fields. The consistent hydrodynamical formulation is constructed for the many-particle quantum system of Dirac fermions on the basis of the nonrelativistic Pauli-like equation obtained via the Foldy-Wouthuysen transformation. With the help of the Madelung decomposition approach, the explicit relations between the microscopic and macroscopic fluid variables are derived. The closed system of equations of quantum hydrodynamics enc…
Sources of torsion in Poincare gauge theory
本文研究庞加莱规范理论中挠率的来源，发现非杨-米尔斯玻色子场的对称动能项及自旋3/2场等均驱动挠率，并发展了任意自旋场的系统记号，揭示了挠率与旋量场的新耦合。
On de Sitter gravitationally from the spin-torsion primordial density
利用COBE观测数据得到的物质密度、原始密度涨落、自旋-扭转密度涨落和物质密度涨落，得到了Einstein-Cartan场方程de Sitter解的涨落. Einstein-de Sitter解即使在没有挠率的情况下也是不稳定的。自旋-挠率密度涨落是由Einstein-Cartan方程和COBE数据计算的。
Torsion-induced spin precession
本文在爱因斯坦-嘉当理论的框架下研究了自旋粒子在空间平坦的FRW型时空中的运动。时空有一个扭曲，它是由充满时空的旋转流体引起的。我们发现，对于自旋粒子与非零的横向自旋分量，扭转引起的进动的粒子自旋周围的方向的流体自旋。我们还表明，带电自旋粒子在无挠空间平坦的FRW时空中运动的均匀磁场的存在下，经历了一个不同的字符的进动。
On de Sitter deflationary cosmology from the spin-torsion primordial fluctuations and COBE data
利用COBE观测数据得到的物质密度、原始密度涨落、自旋-扭转密度涨落和物质密度涨落，得到了Einstein-Cartan场方程de Sitter解的涨落. Einstein-de Sitter解即使在没有挠率的情况下也是不稳定的。
Spherically Symmetric Solution for Torsion and the Dirac equation in 5D spacetime
考虑了5D时空中的挠率。在这种情况下，引力由5D度规和挠率定义。证明了挠率与旋量场有关。在这种情况下，狄拉克方程变成了非线性海森堡方程。证明了该方程有一个解的离散谱，每个解在整个空间上都是正则的，并且具有有限的能量。每一个解都集中在普朗克区域，因此我们可以说，在时空泡沫的气泡形成过程中，挠率应该在量子引力中起重要作用。根据挠率与爱因斯坦-嘉当引力中经典旋量场之间的代数关系，将旋量场的几何解释看作挠率的“平方根”。
We investigate the hidden symmetries of the Kerr-Newman, of the D=5 minimal gauged supergravity which admits a Killing-Maxwell system in the sense of Carter and of higher dimensional spacetimes in the presence of Killing-Yano torsion. We note that when an electromagnetic tensor is present and an associated Killing-Maxwell system can be constructed in the sense of Carter, the Killing- Maxwell field becomes a PCKY (primary conformal Killing-Yano) tensor or a PGCKY (primary generalized conformal Killing-Yano) tensor, the latter in the presence of torsion. We point out the structure of the Dirac-t…
We consider the most general torsional completion of gravitation together with electrodynamics for the Dirac spinorial material fields, and we show that consistency arguments constrain torsion to be completely antisymmetric and the dynamics to be parity-invariant and described by actions that are either least-order derivative or renormalizable.
Spin-torsion in Chaotic Inflation
在混沌膨胀模型的背景下，自旋扭转耦合引力的作用进行了分析。从爱因斯坦-嘉当方程和暴胀子场方程构造的方程组进行了研究，它表明，自旋扭转相互作用是有效的，只有在非常第一个e-折叠的通货膨胀，变得很快可以忽略不计，因此，不影响标准的通货膨胀的情况下，也没有密度扰动谱预测。
A notion of distorted torsion tensor was introduced by Okubo, in the establishment of the Nijenhuis-Bianchi identity and of BRST-like operators. These quantities are constructed with the help of the Nijenhuis tensor, which in turn is defined in terms of a (1,1) tensor $S^λ_μ$. This tensor enters the construction of the distorted torsion tensor. We use this tensor to extend the teleparallel equivalent of general relativity (TEGR) into a theory defined by the tetrad fields and by the tensor $S^λ_μ$. The ordinary TEGR is recovered if $S^λ_μ=δ^λ_μ$. We consider the flat space-time formulation of t…
The static spherically symmetric traversable wormholes are analysed in the Einstein- Cartan theory of gravitation. In particular, we computed the torsion tensor for matter fields with different spin S = 0; 1/2; 1; 3/2. Interestingly, only for certain values of the spin the torsion contribution to Einstein-Cartan field equation allows one to satisfy both faring-out condition and Null Energy Condition. In this scenario traversable wormholes can be produced by using usual (non-exotic) spinning matter.
Distributional torsion of charged domain walls with spin
本文从黎曼分布理论出发，得到了由畴壁上的电荷和自旋密度的跃变给出的带电畴壁的Einstein-Cartan-Maxwell（ECM）场方程的精确解。利用高斯-科达兹方程表明自旋、电荷和Cartan挠率增加了畴壁的排斥性。陶布和Vilenkin墙进行了讨论，以及它们的关系，虫洞几何。电场和扭转场在壁面处为常数。
Coupling of Gravitation and Electromagnetism in the Weak Field Approximation
利用弱场近似，我们可以用一种类似电磁学的麦克斯韦型结构来表达广义相对论。我们发现，每一个电磁场耦合到一个重力电场和重力磁场。承认这两个场都起源于同一个源，即粒子，我们可以通过它们各自的引力类似物，用比例系数k来表示磁场和电场。该系数取决于质量和电荷的比率以及电磁和重力-重力磁介电常数和磁导率之间的比率。虽然这个系数很小，但物质介质中的电磁场可以用来产生重力场和重力磁场，反之亦然的事实并不为人所知。我们发现，大质量离子流、电子和核自旋排列可以增加耦合系数。材料科学、低温技术和材料介质中的高频电磁场的进步可能导致导出的关系的应用。
We show that the intrinsic angular momentum of matter in curved spacetime requires the metric-affine formulation of gravity, in which the antisymmetric part of the affine connection (the torsion tensor) is not constrained to be zero but is a variable in the principle of stationary action. Regarding the tetrad and spin connection (or the metric and torsion tensors) as independent variables gives the correct generalization of the conservation law for the total (orbital plus intrinsic) angular momentum to the presence of the gravitational field. The metric-affine formulation extends general relat…
We study Weyssenhoff spin fluids in Bianchi type-I cosmological models, within the framework of torsional f(R)-gravity; the resulting field equations are derived and discussed in both Jordan and Einstein frames, clarifying the role played by the spin and the non-linearity of the gravitational Lagrangian f(R) in generating the torsional dynamical contributions. The general conservation laws holding for f(R)-gravity with torsion are employed to provide the conditions needed to ensure the preservation of the Hamiltonian constraint and the consequent correct formulation of the associated initial v…
Universality Principle for Orbital Angular Momentum and Spin in Gravity with Torsion
我们认为，与基本粒子物理学的兼容性要求有挠率的引力理论不能区分轨道角动量和自旋。这一原理的一个重要结果是，无自旋粒子必须沿着自平行轨道运动，而不是沿着测地线运动。
We report the first experimental upper bound to our knowledge on possible in-matter torsion interactions of the neutron from a recent search for parity violation in neutron spin rotation in liquid He-4. Our experiment constrains a coefficient $ζ$ consisting of a linear combination of parameters involving the time components of the torsion fields $T^μ$ and $A^μ$ from the nucleons and electrons in helium which violates parity. We report an upper bound of $|ζ|<9.1x10^{-23}$ GeV at 68% confidence level and indicate other physical processes that could be analyzed to constrain in-matter torsion.
We study systems analogous to binary black holes with spin in order to gain some insight into the origin and nature of "bobbing" motion and "kicks" that occur in this system. Our basic tool is a general formalism for describing the motion of extended test bodies in an external electromagnetic field in curved spacetime and possibly subject to other forces. We first show that bobbing of exactly the type as observed in numerical simulations of the binary black hole system occurs in a simple system consisting of two spinning balls connected by an elastic band in flat spacetime. This bobbing may be…
Axial Torsion-Dirac spin Effect in Rotating Frame with Relativistic Factor
在有挠无曲率时空框架下，研究了转动系统中Dirac粒子的自旋进动。在极坐标系中，考虑相对论性，给出了旋转标架的等效四元组，得到的等效度规是平坦的Minkowski度规。所得的旋转耦合公式适用于高速旋转情况，与理论预期一致。
Effect of Spin-Torsion Interaction on Raychaudhuri Equation
在参数化绝对平行几何中推广了Raychaudhuri方程。这个版本的绝对平行比传统的更一般。一般化考虑了运动基本粒子的量子自旋和背景引力场的扭转之间的相互作用。所得到的广义Raychaudhuri方程包含了一些依赖于时空挠率的额外项，这些额外项对广义相对论的奇异性定理有一定的影响。在一定条件下，该方程可化为原Raychaudhuri方程，而不需要零挠。
We consider the most general renormalizable theory of propagating torsion in Einstein gravity for the Dirac matter distribution and we demonstrate that in this case torsion is a massive axial-vector field whose coupling to the spinor gives rise to conditions in terms of which gravitational singularities are not bound to form; we discuss how our results improve those that are presented in the existing literature, and that no further improvement can be achieved unless one is ready to re-evaluate some considerations on the renormalizability of the theory.
In this paper we generalize our previous results on spin connection for the linear scalar cosmological perturbation in $f(T)$ theory to wider class of theories which includes a scalar field $Φ$ non-minimally coupled to torsion, and allows $Φ$-dependence of the function $f$. The case of $f_{TT}=0$, with a scalar field non-minimally coupled to torsion needs a special treatment. In both considered cases we derive self-consistent equations of motion for cosmological perturbation using a solution for non-trivial spin connection.
In this paper, the recently-introduced ELKO and the well-known Dirac spinor fields will be compared; however, instead of comparing them under the point of view of their algebraic properties or their dynamical features, we will proceed by investigating the analogies and similarities in terms of their geometrical character viewed from the perspective of torsion. The paper will be concluded by sketching some consequences for the application to cosmology and particle physics.
The Einstein-Cartan-Sciama-Kibble theory of gravity removes the constraint of general relativity that the affine connection be symmetric by regarding its antisymmetric part, the torsion tensor, as a dynamical variable. The minimal coupling between the torsion tensor and Dirac spinors generates a spin-spin interaction which is significant in fermionic matter at extremely high densities. We show that such an interaction averts the unphysical big-bang singularity, replacing it with a cusp-like bounce at a finite minimum scale factor, before which the Universe was contracting. This scenario also e…
It is assumed that the two-component spinor formalisms for curved spacetimes that are endowed with torsionful affine connexions can supply a local description of dark energy in terms of classical massive spin-one uncharged fields. The relevant wave functions are related to torsional affine potentials which bear invariance under the action of the generalized Weyl gauge group. Such potentials are thus taken to carry an observable character and emerge from contracted spin affinities whose patterns are chosen in a suitable way. New covariant calculational techniques are then developed towards deri…
On dilaton solutions of de Sitter inflation and primordial spin-torsion density fluctuations
本文给出了Einstein-Cartan介子暴胀de Sitter宇宙学的四类精确解。第一类是用无质量介子的状态方程代替Gasperini以前所用的非极化费米子流体得到的。当介子受到自旋的约束时，我们得到了排斥引力。第二种和第三种解分别代表了辐射时代的大质量夸克，具有大质量的势和扭转扭结，最后是自旋的尘埃本文还根据COBE数据得到的原始温度涨落计算了原始自旋密度涨落。温度涨落也可以根据暴胀过程中产生的引力波的近似平坦谱和介子质量与哈勃常数成正比的结果计算。这一结果与COBE数据一致。这一思想也被用来计算自旋密度涨落。在暴胀时代的扭转密度。
We construct the geometro-hydrodynamical formalism for a spinning particle based on the six-dimensional manifold of autoparallelism geometry which is represented as a vector bundle with a base formed by the manifold of the translational coordinates and a fibre specified at each point by the field of an orthogonal coordinate frame underlying the classical spin. We show that the geometry of oriented points leads to the existence of torsion field with the source - the classical spin. We expand the geometro-hydrodynamical representation of Pauli field developed by Takabayasi and Vigier. We show th…
Dark spinors with torsion in cosmology
我们解决了爱因斯坦-嘉当理论中的一个公开问题，即找到一个自旋角动量张量与宇宙学原理相容的自然物质源。我们分析由此产生的演化方程，并发现加速膨胀的时代是一个吸引子。在此期间，扭转场迅速衰减。我们的结果解释的背景下，宇宙学的标准模型。
Gravitational and torsion waves in linearised teleparallel gravity
在线性遥平行性中，当全斜对称的复扭曲张量产生标量扭曲波，后两个指数的对称扭曲产生引力波时，得到了具有扭曲张量的平坦时空的自旋2、自旋1和自旋0模.利用LISA GW探测器获得的数据，提出了一个利用这种引力扭转波撞击无自旋粒子环的实验，从而可以估计地球的扭曲。这个值与Nitsch在telepallelism中使用另一种类型的实验获得的先前值相吻合。
Gravitationally induced electromagnetism at the Compton scale
结果表明，爱因斯坦引力倾向于修改的电场和磁场在康普顿波长的顺序的距离明显。在那个距离上，引力场变成自旋主导而不是质量主导。引力场通过爱因斯坦-麦克斯韦方程组耦合到电磁场，在最简单的模型中，这导致带电自旋粒子的静电场获得相对于自旋方向的扁球形结构。因此，对于电子和质子，纯库仑场在康普顿尺度下可能与广义相对论不相容。在最简单的模型中，磁偶极子对应于狄拉克g因子，g=2。此外，从电场的形式可以看出，电偶极矩为零，这与目前电子的实验极限是一致的。从数量上讲，经典的爱因斯坦-麦克斯韦理论预测电子的磁偶极子和电偶极子的精度约为1/10^{-3}或更高。进入下一个多极阶，我们发现第一个非零的高多极是电四极矩，预计电子的电四极矩为-124 barn，电子或质子的电四极矩的任何非零值都是曲率的明显标志，因为这意味着违反了旋转不变性。还有一种可能的与r^{-4}成比例的库仑力的球面修正。然而，这种效应的大小远低于目前的实验极限。对氢光谱的修正预计很小，但可能是可检测的。
Gravitomagnetic effect and spin-torsion coupling
本文通过引入自由参数b，利用修正的测地线方程，研究了绝对平行条件下的重磁效应。我们计算了两个反向绕地球运行的原子钟的时间差，发现由于时空的扭曲与自由参数测量的原子钟内部结构之间的耦合，存在一个很小的修正。
Torsion and Nonmetricity Constraints From Neutron Spin Rotation in Polarized Matter
本研究应用有效场论方法表征粒子算符与时空挠率、非度量性的耦合，利用补偿铁氧体的中子自旋旋转数据，首次对相关物质内组合施加约束。
Spin polarised magnetized cylinder in torsioned spacetime
本文得到了Einstein-Cartan-Maxwell引力中具有磁场的自旋极化柱对称精确解。应用程序的匹配条件，这个内部解决方案具有外部爱因斯坦的真空解决方案表明，这类度量的黎曼-Cartan（RC）旋转消失，使解决方案静态。因此，我们最终得到一个磁化的静态自旋极化圆柱体，其中沿对称轴的压力为负。
We propose a modified gravitational action containing besides the Einstein-Cartan term some quadratic contributions resembling the Yang-Mills lagrangian for the Lorentz spin connections. We outline how a propagating torsion arises and we solve explicitly the linearised equations of motion on a Minkowski background. We identify among torsion components six degrees of freedom: one is carried by a pseudo-scalar particle, five by a tachyon field. By adding spinor fields and neglecting backreaction on the geometry, we point out how only the pseudo-scalar particle couples directly with fermions, but…
We study Dirac spinors in Bianchi type-I cosmological models, within the framework of torsional $f(R)$-gravity. We find four types of results: the resulting dynamic behavior of the universe depends on the particular choice of function $f(R)$; some $f(R)$ models do not isotropize and have no Einstein limit, so that they have no physical significance, whereas for other $f(R)$ models isotropization and Einsteinization occur, and so they are physically acceptable, suggesting that phenomenological arguments may select $f(R)$ models that are physically meaningful; the singularity problem can be avoi…
In Poincare gauge theory of gravity, in addition to mass-energy content, spin is also a source for gravitational interactions. Although the effects of spin are negligible at low energies, they can play a crucial role at very early universe when the spin density was very high. In this paper by choosing a suitable Lagrangian for Poincare gauge theory of gravity, and suitable energy-momentum and spin density tensors, we show that the effects of spin and torsion can lead to a inflationary phase without the need for any additional fields. No fine tuning of parameters is required in this setup. We a…
Spin-torsion interaction and geodesic bending
本文研究费米子自旋引起的时空扭转对球对称恒星级致密物质中零测地线和类时测地线弯曲的影响，发现扭转贡献额外偏折，其大小取决于费米子数密度、手性耦合常数和温度，在中子星等致密天体上效应显著。
Interacting spin 0 fields with torsion via Duffin-Kemmer-Petiau theory
本文研究了DKP场在挠率空间中自旋0扇区的行为。首先，我们表明，在黎曼-嘉当流形的DKP领域提出了一个相互作用与扭转时，最小的耦合进行，相反的行为的KG字段，一个结果，打破了通常的等效DKP和KG字段之间。其次，我们分析了广义相对论Weitzenbock流形的遥平行等价情形，表明在这种情形下KG场和DKP场是完全一致的。这两个结果的起源也进行了讨论。
Nonmetricity and torsion induced by dilaton gravity in two dimension
我们开发了一个理论，其中有狄拉克旋量，介子和非黎曼引力之间的耦合，并探讨连接诱导的介子耦合引力和狄拉克旋量的性质时，该理论是重新制定的列维-奇维塔连接。在给出了一些不含旋量的精确解之后，我们研究了该模型的最小旋量耦合，并得出结论，我们找不到任何非平凡的旋量耦合。
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