A team of researchers reports they have succeeded in disproving a long-held tenet of modern physics–that useful work cannot be obtained from random thermal fluctuations–thanks in part to the unique properties of graphene.
The microscopic motion of particles within a fluid, otherwise known as Brownian motion for its discovery by Scottish scientist Robert Brown, has long been considered an impossible means of attempting to generate useful work.
The idea had been most famously laid to rest decades ago by physicist Richard Feynman, who proposed a thought experiment in May 1962 involving an apparent perpetual motion machine, dubbed a Brownian ratchet.
In theory, this device would consist of a gear and a rachet that vibrates while immersed in a heat bath, allowing motion only in one direction. The premise is that the unidirectional motion would produce a force in the absence of any heat gradient, seemingly defying the second law of thermodynamics. However, Feynman argued that since the machine’s components will also undergo Brownian motion, there will inevitably be faults in the way it functions, thereby canceling out any useful work it might generate.
Now, a team of researchers with the University of Arkansas Department of Physics argues that they have demonstrated thermal fluctuations in freestanding graphene can indeed be used as part of a novel new method that allows the creation of useful work, upending more than a century of conventional thinking in modern physics.
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