Zero Point Energy doc
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| ZP OWER C ORPORATION PAGE OF 352 Z ERO P OINT E NERGY F ILLING THE VOID T HE E CONOMIST , F EBRUARY 1 ST , 1997 Nature, famously, abhors a vacuum. People are generally just bored by vacuurns, because they believe them to be empty spaces in which, almost by definitlon, nothing ever happens. For nearly 50 years, however, quantum physicists have had a very different view. A branch of quantum theory known as quantum electrodynamics (QED) says that a vacuum, far from being static or empty, teems with transient "birtual" particles (especially photons, the particles of light) that keep popping weirdly into existence and then disappearing again. But for all their theoretical confidence, physicists have found it hard to demonstrate this. Until now, that is. Steve Lamoreaux, who works at the Los Alarnos National Laboratory In New Mexico, has just done something perculiar. Ashe reported in a recent issue of Physical Review Letters, he has shown that if you take two electrically conducting plates and put them close together in a vacuum, they are pushed toward each other by a force conjured up out of the nothingness -- the Casimir force. Hendrik Casimir is a Dutch physicist. IN 1948, when QED was still anew theory, he suggested that it would be possible to get Nature to give you something for nothing, despite her being a well-known skinflint. Commonsense suggests that a vacuum, being empty, has zero energy. But Heisenberg's uncertainty principle, a mainstay of quantum theory, says that zero is not a precise quantity.The vacuum is filled with short-lived bursts of energy. And, QED predicted, these energy bursts can turn into particles such as photons that exist fora very short period-so short that they are not directly observable. But their presence is keenly felt. According to QED, they carry the forces that hold real particles -- and hence the material world -- together. Dr Casimir suggested that their effects could be more permanent in another way too. Quantum theory holds that particles in general (and photons in particular) have a simultaneous existence as waves. And as waves, they need space in which to vibrate. Just as the short strings of a violin cannot produce the deep, long-wavelength notes of a double bass, so photons -- which are vibrations not of string but electromagnetic fields -- are constrained by things that conduct electricity. A photon can exist between two conducting plates only if its wavelength is less than twice the distance between the plates. As a consequence, the longest virtual wavelengths are missing from the gap between the plates used in Dr Lamoreaux's experiment. |