Based on two kinds of epistemology and world, both deeply effects on Science and technology and open new application of Laser discussed briefly. The observed superluminal light pulse propagation is not at odds with causality, being a direct consequence of classical interference between its different frequency components in an anomalous dispersion region. Yet, as shown here, these very premises lead to the conflicting finding that light has an ultra-superluminal speed relative to the light source in the direction of recession. Another kind of ultra-fast phenomenon, superluminal transmission of light pulsewas proposed, its velocity can faster than the infinite that was proved in theory and experiment. We measure a group-velocity index of n g = -310(+/-5) in practice, this means that a light pulse propagating through the atomic vapour cell appears at the exit side so much earlier than if it had propagated the same distance in a vacuum that the peak of the pulse appears to leave the cell before entering it. Therefore, a wave could travel through a gamma-ray burst jet at superluminal speeds without breaking relativity. The group velocity of a laser pulse in this region exceeds c and can even become negative, while the shape of the pulse is preserved. We know that when light is travelling through a medium (such as gas or plasma), its phase velocity is slightly slower than c - the speed of light in a vacuum, and, as far as we know, the ultimate speed limit of the Universe. Here we use gain-assisted linear anomalous dispersion to demonstrate superluminal light propagation in atomic caesium gas. However, in all previous experimental demonstrations, the light pulses experienced either very large absorption or severe reshaping, resulting in controversies over the interpretation. Nevertheless, there exist various proposals for observing faster-than- c propagation of light pulses, using anomalous dispersion near an absorption line, nonlinear and linear gain lines, or tunnelling barriers. Putz and Svozil themselves suggest that a vacuum filled with either electrons or positrons would do the trick.Einstein's theory of special relativity and the principle of causality imply that the speed of any moving object cannot exceed that of light in a vacuum (c). Various physicists have proposed such materials made of things like metamaterials. This process happens instantaneously, allowing the photon to effectively “jump” across space.Ī material in which this kind of pair formation and recombination was promoted would have a refractive index less than one, they say. For example, light travelling through a vacuum can be made to spontaneously form into an electron-positron pair–an entangled pair–which then recombine to form a photon again. How might such a machine work? Putz and Svozil point out that nonlocal phenomenon can lead to materials in which the index of refraction is less than one, thereby allowing superluminal speeds. They say there is no reason why not, provided the processing does not lead to any time travel paradoxes. So-called “nonlocal” phenomenon cannot be used to transmit information faster than the speed of light but Putz and Svozil today ask whether it can be used to process it, to carry out computational tasks at superluminal speeds. The researchers generated a short pulse of light in the form of a so-called Bessel beam. These particles can be separated by the diameter of the universe and yet a measurement on one will instantaneously influence the other. This brings us back to the superluminal paper published in 2000 This research, which involves a pulse of light traveling faster than c, seems like it would be immune to the earlier criticism. For example, the quantum phenomenon of entanglement occurs when two quantum particles are described by the same wave function. Harbin Institute of Technology, Harbin, China. They say there are several ways that signals can cross the superluminal line, although none of them allow the kind of time travel paradoxes beloved of science fiction writers. Observation of Superluminal in Doppler Broadened Two-Level Atomic Systems in Magnetic Field() Shuangqiang Liu, Yundong Zhang, Hao Wu, Ping Yuan. A new theoretical paper, published in the journal Classical and Quantum Gravity, reignites the debate about the possibility of superluminal (faster-than-light) travel based on conventional physics. Well, yes and no, say Volkmar Putz and Karl Svozil at the Vienna University of Technology in Austria. Nothing can travel faster than the speed of light, right? The speed of light represents one of the fundamental limits of the laws of physics. For those who enjoy science fact as well as science fiction, a leading expert on quantum theory imaginatively explains how faster-than-light communication and travel are actually being explored by.
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