'Fantastic Voyage' to Approach Sci-Fi Realm
LEICESTER, England, July 7, 2006 -- A three-nation consortium is planning a "fantastic voyage" to explore empty space -- with potential benefits that have previously been explored only in science fiction.
The program, Nanocase, will use the ultrahigh vacuum atomic force microscope at the University of Leicester Physics and Astronomy Department to make very high-precision Casimir force measurements in nonsimple cavities and to assess the utility of the force in providing a method for contactless transmission in nanomachines.
The project, which will be lead by the University of Leicester, aims to delve into a "void" -- an empty space in which atoms move -- that has a large intrinsic energy density known as zero-point energy. The university will have a lead role in performing Casimir force measurements in novel geometries, it said in a statement. The Casimir force is a mysterious interaction between objects that arises directly from the quantum properties of the so-called void.
The research team carrying out this work has received a grant of 800,000 euros (about $1 million) from the European framework 6 NEST (New and Emerging Science and Technology) program to lead a consortium from three countries the UK, France and Sweden. The other Nanocase partner institutions are the University of Birmingham, England; Université Pierre et Marie Curie, France; and Linköping University, Sweden.
Chris Binns, a professor of nanoscience at the University of Leicester, said, "In classical physics, the void is a simple absence of all matter and energy, while quantum theory tells us that in fact it is a seething mass of quantum particles that constantly appear into and disappear from our observable universe. This gives the void an unimaginably large energy density."
He said the research will help to overcome a fundamental problem of all nanomachines, the individual components of whiuchare the size of molecules: At that size, everything is "sticky," and any components that come into contact stick together. If a method can be found to transmit force across a small gap without contact, then it may be possible to construct nanomachines that work freely without gumming up.
Such machines are the stuff of science fiction at present, and a long way off, but possible uses include the ability to rebuild damaged human cells at the molecular level, Binns said.
"In a sense, the actual value of the zero-point energy is not important, because everything we know about is on top of it. According to quantum field theory, every particle is an excitation (a wave) of an underlying field (for example, the electromagnetic field) in the void, and it is only the energy of the wave itself that we can detect," he said.
"A useful analogy is to consider our observable universe as a mass of waves on top of an ocean, whose depth is immaterial. Our senses and all our instruments can only directly detect the waves, so it seems that trying to probe whatever lies beneath, the void itself, is hopeless. Not quite so. There are subtle effects of the zero-point energy that do lead to detectable phenomena in our observable universe."
For example, he said, Dutch physicist Hendrik Casimir predicted a force in 1948 that arises from the zero-point energy. "If you place two mirrors facing each other in empty space, they produce a disturbance in the quantum fluctuations that results in a pressure pushing the mirrors together," Blinn said.
"Detecting the Casimir force, however, is not easy, as it only becomes significant if the mirrors approach to within less that 1 micrometer (about a 50th the width of a human hair). Producing sufficiently parallel surfaces to the precision required has had to wait for the emergence of the tools of nanotechnology to make accurate measurements of the force."
The instrumentation at the University of Leicester will enable researchers to extend measurements to yet more complex shapes and, for the first time, to search for a way to reverse the Casimir force.
This would be a ground-breaking discovery, Blinn said, since the Casimir force is a fundamental property of the void, and reversing it is akin to reversing gravity. Technologically, this would only have relevance at very small distances, but it would revolutionize the design of micromachines and nanomachines.
For more information, visit: www.le.ac.uk
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