The scientists found that the precursor wave front of a single photon always travels at c, like the signalvelocity of large groups of photons.
科学家发现,单个光子的前驱波头一般以光速c传播,就像由大量光子携带的信号的传播速度一样。
2
Although previous studies have found that the "group velocity" of light can travel faster than c, the "signalvelocity" -the speed at which information travels -cannot.
Although previous studies have found that the "group velocity" of light can travel faster than c, the "signalvelocity" - the speed at which information travels - cannot.