More than three centuries ago, Isaac Newton in his Principia stated that for any action there is an equal and opposite reaction. The ramifications of this law of motion are now being reconsidered by a team of researchers from the University of Central Florida and Germany who recently carried out an optical experiment that one day may help lead to new propulsion systems.
麻豆精品 S淭his counterintuitive process, which involves the concept of negative mass, mimics the behavior of a diametric drive, 麻豆精品 S� said Professor Demetrios Christodoulides of UCF 麻豆精品 S檚 College of Optics and Photonics. 麻豆精品 S淓ven though ideas of this sort have been around for several years, they have never been successfully pursued because mass in nature is always a positive quantity. 麻豆精品 S� Diametric drive refers to the possibility of a self-contained, space-propulsion engine that operates without the need for any external fuel.
The study 麻豆精品 S淥ptical diametric drive acceleration via action-reaction symmetry breaking 麻豆精品 S� recently published on the website of Nature Physics and was part of a project with other partner universities. Mohammad-Ali Miri, a UCF graduate student in the Center for Research and Education in Optics and Lasers (CREOL), also participated in this work.
As everyone in introductory physics courses knows, Newton 麻豆精品 S檚 third law of motion states that the forces two bodies exert on each other are equal and opposite. As a result, two bodies of positive mass tend to accelerate toward each other when this pair of forces happens to be attractive.
However, if one of the two particles were to have a negative mass, this hypothetical arrangement would set up a system where the leading particle would constantly be 麻豆精品 S渃hased 麻豆精品 S� by the trailing particle.
麻豆精品 S淯nder these conditions, two interacting bodies will indefinitely accelerate in the same direction while keeping a constant distance between themselves, 麻豆精品 S� the study says. 麻豆精品 S淥f course, given that in real life the mass of a particle is always positive, no such acceleration behavior that breaks the action-reaction symmetry has ever been reported. 麻豆精品 S�
In their experiment with the University of Erlangen-Nuernberg in Germany, the researchers used light pulses in a figure 8, fiber-optic platform to create the effect of attractive and repulsive forces.
麻豆精品 S淚n the lab, one can create photon pulses with effective positive or negative masses, 麻豆精品 S� Ali Miri said. 麻豆精品 S淭hey [pulses] could start chasing each other until reaching relativistic limits. 麻豆精品 S�
He said the concept of negative mass is not restricted to photons. Similar experiments can be performed in other settings, for example with electrons in crystalline solids.
麻豆精品 S淲hile a realization of a Star Trek warp drive space-propulsion engine still remains a dream, the demonstrated optical diametric drive can provide new strategies in accelerating and steering optical pulses, 麻豆精品 S� Christodoulides said. 麻豆精品 S淭his may have an impact on how one can control light in tomorrow 麻豆精品 S檚 optical networks. 麻豆精品 S�
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