对“增益辅助超光速光传播”的评论

增益辅助的纳米波导慢至超光速群速度操纵

Gain-assisted slow to superluminal group velocity manipulation in nano-waveguides

我们研究了亚波长波导中的能量传播，并证明了先前提出的用于损耗补偿的材料增益机制也是在纳米尺度上操纵电磁脉冲的色散和传播特性的有力工具。我们从理论上表明，在有损纳米波导的群速度可以控制从慢超光速值的材料增益和波导的几何形状，并制定了相关的物理分析描述。我们利用发达的形式主义表明，增益辅助色散管理可以用来控制之间的过渡“光子漏斗”和“光子压缩机”制度在锥形纳米波导。亚波长结构中群速度的强调制现象可以在不同几何形状的波导中实现，并且存在于体模和面模中。

Avoidance of instability of a superluminal Gaussian light pulse via control of nonlinear coherence Kerr effect in a gain-assisted medium

We investigate nonlinear Kerr-induced coherence effect on a superluminal probing light pulse in a gain-assisted N-type 4-level atomic system via an intense monochromatic laser field. The dispersion exhibits a novel, interesting and useful two-paired double gain lines processes. The system displays lossless characteristics similar to [L. J. Wang, A. Kuzmich, A. Dogariu, Nature \textbf{406}, 277 (2000)] but with advantages of \emph{multiple} \textbf{controllable} anomalous regions, \emph{significantly enhanced} superluminal behavior and \textbf{relaxed} temperature, states of matter regardless o…

Gain-assisted superluminal light propagation through a Bose-Einstein condensate cavity system

The propagation of a probe laser field in a cavity optomechanical system with a Bose-Einstein condensate is studied. The transmission properties of the system are investigated and it is shown that the group velocity of the probe pulse field can be controlled by Rabi frequency of the pump laser field. The effect of the decay rate of the cavity photons on the group velocity is studied and it is demonstrated that for small values of the decay rates, the slope of phase dispersion switches from positive to negative just by changing the Rabi frequency of the pump field. Then, the gain-assisted super…

旋转超光速源产生的非球形衰减辐射的形态学：对评论的答复

Morphology of the nonspherically decaying radiation generated by a rotating superluminal source: reply to comment

汉内在他的评论中使用的公式是“来自电动力学的标准文本”，这一事实既不能保证它是普遍适用的，也不能保证它是明确正确的。我们已经明确显示[J。A 25，543（2008）]，因为它不包括对场值的边界贡献，所以当源被扩展并且具有比真空中的光旋转更快的分布图案时，所讨论的公式不适用。在控制电磁场的波动方程的延迟解中，被忽略的边界项构成了衍射理论的基础。如果该项为零，根据汉内给出的理由，电磁波通过一个表面上的孔的衍射将是不可能的。如果这一项是相同的零，由于汉内给出的原因，衍射的电磁波通过孔径表面上包围一个源将是不可能的。

Superluminal Motion-Assisted 4-Dimensional Light-in-Flight Imaging

Advances in high speed imaging techniques have opened new possibilities for capturing ultrafast phenomena such as light propagation in air or through media. Capturing light-in-flight in 3-dimensional xyt-space has been reported based on various types of imaging systems, whereas reconstruction of light-in-flight information in the fourth dimension z has been a challenge. We demonstrate the first 4-dimensional light-in-flight imaging based on the observation of a superluminal motion captured by a new time-gated megapixel single-photon avalanche diode camera. A high resolution light-in-flight vid…

对Nimtz和Stahlhofen“狭义相对论的宏观破坏“的评论[ arXiv：0708.0681v1]

Comment on "Macroscopic violation of special relativity" by Nimtz and Stahlhofen [arXiv:0708.0681v1]

G. Nimtz和A. A. Stahlhofen [arXiv：0708.0681v1]提出了以下主张：（1）作者观察到了狭义相对论的宏观违反，（2）他们已经证明了在米长尺度上消逝模式的量子力学行为，（3）在零时间内跨越障碍，这意味着超光速（比光快），实际上，无限的隧穿速度。在这里，我认为所有这些说法都是错误的，并且是基于对麦克斯韦方程精确描述的纯经典测量的误解。

对“真空对重力辅助光的负光的折射”的评论

Comment on 'Towards gravitationally assisted negative refraction of light by vacuum'

参考文献arXiv：physics/0408021声称时空的无物质区域可以支持电磁波，对于电磁波，相速度3矢量与功率流3矢量方向相反。这是\cite{ML}中采用的负屈光定义。我们在这里表明，这不可能发生在电磁能量密度为正的时空区域。

Theoretical analysis on quantum interference effect in fast-light media

We make a systematic theoretical analysis on the quantum interference (QI) effects in various fast-light media (including gain-assisted $N$, gain-assisted ladder-I, and gain-assisted ladder-II atomic systems). We show that such fast-light media are capable of not only completely eliminating the absorption but also suppressing the gain of signal field, and hence provide the possibility to realize a stable propagation of the signal field with a superluminal velocity. We find that there is a destructive (constructive) QI effect in gain-assisted ladder-I (gain-assisted N) system, but no QI in the …

切伦科夫辐射与X形局域波无关（“X波的切伦科夫-瓦维洛夫公式”一文评述）

Cherenkov radiation has nothing to do with X-shaped Localized Waves (Comments on "Cherenkov-Vavilov Formulation of X-Waves")

局域波是波动方程的无衍射（“类孤子”）和自重构解，并且已知以亚光速、光速和超光速的峰值速度存在。研究得最多的是“X形”超光速波;它与锥体有关，因此一些作者[例如，Walker和Kuperman，PRL 99（Dec.2007）244802]已经试图将它们与切伦科夫辐射联系起来。然而，“X波”属于不同的领域，并且甚至独立于任何介质存在于真空中，如在许多论文中所验证的[例如，在“Localized Waves”（J.Wiley; Jan.2008）中列出的]。我们希望在严格的形式主义和明确的物理考虑的基础上澄清整个问题。特别地，通过仅基于麦克斯韦方程组的显式计算，我们证明了：（i）X波也存在于其双锥的前部和后部（这与切伦科夫的无关）;（ii）它们不是通过特别的假设找到的，而是通过使用严格的数学公式。（或实验）程序;（iii）理想的X波拥有无限的能量，但有限能量的X波可以很容易地构建（即使没有时空截断）：我们确实构造了精确的有限能量解（完全没有后向行波）;（iv）将切伦科夫辐射与X波进行比较的实际尝试将导致人们考虑非常不同的情况，由超光速点电荷产生的（也是X形）场，这是以前的论文[Recami等人，PRE 69（2004）027602]：我们在这里明确地表明，点电荷在真空中不会损失能量，它的场也不需要不断地由入射的边波供给（实际上，对于理想的普通X波来说就是这样）。

在具有超光速相速度的直接激光加速过程中通过高阶共振增强能量增益

Enhanced energy gain through higher-order resonances during direct laser acceleration with superluminal phase velocity

本文研究超光速相速度下的直接激光加速，揭示其产生的非单调频率比可在宽能区内维持高阶共振匹配，使高阶共振取代基频电子感应加速器共振成为增强电子能量增益的主导机制。

Physical limitations on broadband invisibility based on fast-light media

This note is a comment on a recent article [Tsakmakidis, et al., Nat Commun 10 (2019)] that presents a thought-provoking proposal to overcome the bandwidth restrictions of invisibility cloaks based on using media that support superluminal (faster than light in free space) group and phase velocities. As illustrated in Fig. 1 of the original article, a wave packet propagating through such a fast-light cloak is alleged to be able to reach the side behind the cloaked object simultaneously with a corresponding wave packet propagating through the shorter, direct route in free space without the objec…