标题： 排斥的卡西米尔-波德尔力来自宇宙弦 显示英文标题

标题： Repulsive Casimir-Polder forces from cosmic strings

摘要： 我们研究了作用于极化微粒上的卡西米尔-波德力在直宇宙弦几何中的表现。为了发展这一分析，我们在虚频轴上评估了电磁场的Green张量。卡西米尔-波德力的表达式在各向异性极化率的一般情况下被推导出来。依赖于极化率张量的特征值和其主轴的方向，卡西米尔-波德力可以是排斥的也可以是吸引的。此外，在某些情况下，力会随着距离而改变方向。我们证明，对于各向同性的极化率张量，力总是排斥的。在微粒与弦之间距离较大时，力随距离的五次方反比变化。在非推迟阶段，即分离小于相关跃迁波长的情况下，力随距离的四次方反比衰减。在各向异性极化率的情况下，卡西米尔-波德势对极化率张量主轴方向的依赖性也导致了作用在粒子上的力矩。 显示英文摘要

摘要： We investigate the Casimir-Polder force acting on a polarizable microparticle in the geometry of a straight cosmic string. In order to develop this analysis we evaluate the electromagnetic field Green tensor on the imaginary frequency axis. The expression for the Casimir-Polder force is derived in the general case of anisotropic polarizability. In dependence of the eigenvalues for the polarizability tensor and of the orientation of its principal axes, the Casimir-Polder force can be either repulsive or attractive. Moreover, there are situations where the force changes the sign with separation. We show that for an isotropic polarizability tensor the force is always repulsive. At large separations between the microparticle and the string, the force varies inversely as the fifth power of the distance. In the non-retarded regime, corresponding to separations smaller than the relevant transition wavelengths, the force decays as the inverse fourth power of the distance. In the case of anisotropic polarizability, the dependence of the Casimir-Polder potential on the orientation of the polarizability tensor principal axes also leads to the moment of force acting on the particle.