%0 Journal Article %T Anti-shielding Effect and Negative Temperature in Instantaneously Reversed Electric Fields and Left-Handed Media %A Jian Qi Shen %J Physics %D 2003 %I arXiv %R 10.1238/Physica.Regular.068a00087 %X The connections between the anti-shielding effect, negative absolute temperature and superluminal light propagation in both the instantaneously reversed electric field and the left-handed media are considered in the present paper. The instantaneous inversion of the exterior electric field may cause the electric dipoles into the state of negative absolute temperature and therefore give rise to a negative effective mass term of electromagnetic field (i. e., the electromagnetic field propagating inside the negative-temperature medium will acquire an imaginary rest mass), which is said to result in the potential superluminality effect of light propagation in this anti-shielding dielectric. In left-handed media, such phenomena may also arise. %U http://arxiv.org/abs/cond-mat/0302351v1