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Exploiting
Zero-Point
Energy
by Philip Yam
Scientific American, December 1997,
pp. 82-85
from
TheInstituteForNewEnergy Website
.
Energy fills empty
space,
but is there a lot to be tapped, as some propound?
Probably not.
.
Something for nothing. That's the reason
for the gurgling water, ultrasonic transducers, heat-measuring
calorimeters, data-plotting software and other technological
trappings-some seemingly of the backyard variety--inside the
Institute for Advanced Studies in Austin, Tex. One would not
confuse this laboratory with the similarly named but far more
renowned one in Princeton, N.J., where Albert Einstein and
other physicists have probed fundamental secrets of space and time.
The one in Austin is more modestly appointed, but its goals are no
less revolutionary. The researchers here test machinery that,
inventors assert, can extract energy from empty space.
Claims for perpetual-motion machines and other free-energy devices
still persist, of course, even though they inevitably turn out to
violate at least one law of thermodynamics. Energy in the vacuum,
though, is very much real. According to modern physics, a vacuum
isn't a pocket of nothingness. It churns with unseen activity even
at absolute zero, the temperature defined as the point at which all
molecular motion ceases.
Exactly how much "zero-point energy" resides in the vacuum is
unknown. Some cosmologists have speculated that at the beginning of
the universe, when conditions everywhere were more like those inside
a black hole, vacuum energy was high and may have even triggered the
big bang. Today the energy level should be lower. But to a few
optimists, a rich supply still awaits if only we knew how to tap
into it.
These maverick proponents have
postulated that the zero-point energy could explain "cold fusion,"
inertia and other phenomena and might someday serve as pan of a
"negative mass" system for propelling spacecraft. In an interview
taped for PBS's Scientific American Frontiers, which aired in
November, Harold E. Puthoff, the director of the Institute
for Advanced Studies, observed: "For the chauvinists in the field
like ourselves, we think the 21st century could be the
zero-point-energy age."
That conceit is not shared by the majority of physicists; some even
regard such optimism as pseudoscience that could leech funds from
legitimate research. The conventional view is that the energy in the
vacuum is minuscule. in fact, were it infinite, the nature of the
universe would be vastly different: you would not be able to see in
a straight line beyond a few kilometers. "The vacuum has some
mystique about it," remarks Peter W. Milonni, a physicist at
Los Alamos National Laboratory who wrote a text on the subject in
1994 called The Quantum Vacuum. "One has to be really careful about
taking the concept too naively." Steve K. Lamoreaux, also at
Los Alamos, is harsher: "The zero-point-energy community is more
successful at advertising and selfpromotion than they are at
carrying out bona fide scientific research."
[Picture of a virtual particle and virtual antiparticle.]
QUANTUM FLUCTUATIONS, ripples that form the basis for energy in a
vacuum, pervade the fabric of space and time.
The concept of zero-point energy derives from a well-known idea in
quantum mechanics, the science that accounts for the behavior of
particles near the atom's size. Specifically, zeropoint energy
emerges from Heisenberg's uncertainty principle, which limits the
accuracy of measurements. The German physicist Werner Heisenberg
determined in 1927 that it is impossible to learn both the position
and the momentum of a particle to some high degree of accuracy: if
the position is known perfectly, then the momentum is completely
unknown, and vice versa.
That's why at absolute zero,
a particle must still be littering about: if it were at a complete
standstill, its momentum and position would both be known precisely
and simultaneously, violating the uncertainty principle.
Energy
and Uncertainty
Like position and momentum, energy L and time also obey Heisenberg's
rule. Residual energy must therefore exist in empty space: to be
certain that the energy was zero, one would have to take energy
measurements in that volume of space forever. And given the
equivalence of mass and energy expressed by Einstein's E = mc^2, the
vacuum energy must be able to create particles. They flash briefly
into existence and expire within an interval dictated by the
uncertainty principle.
This zero-point energy (which comes from all the types of force
fields--electromagnetic, gravitational and nuclear) makes itself
felt in several ways, most of them obvious only to a physicist. One
is the Lamb shift, which refers to a slight frequency alteration in
the light emitted by an excited atom. Another is a particular kind
of inescapable, low-level noise that registers in electronic and
optical equipment.
Perhaps the most dramatic example, though, is the Casimir effect. In
1948 the Dutch physicist H.B.G. Casimir calculated that two
metal plates brought sufficiently close together will attract each
other very slightly. The reason is that the narrow distance between
the plates allows only small, high-frequency electromagnetic "modes"
of the vacuum energy to squeeze in between. The plates block out
most of the other, bigger modes. In a way, each plate acts as an
airplane wing, which creates low pressure on one side and high
pressure on the other. The difference in force knocks the plates
toward each other.
While at the University of Washington, Lamoreaux conducted
the most precise measurement of the Casimir effect. Helped by his
student Dev Sen, Lamoreaux used gold-coated quartz surfaces
as his plates. One plate was attached to the end of a sensitive
torsion pendulum; if that plate moved toward the other, the pendulum
would twist. A laser could measure the twisting of the pendulum down
to O.Ol-micron accuracy. A current applied to a stack of
piezoelectric components moved one Casimir plate; an electronic
feedback system countered that movement, keeping the pendulum still.
Zero-point-energy effects showed up as changes in the amount of
current needed to maintain the pendulum's position. Lamoreaux found
that the plates generated about 100 microdynes (one nanonewton) of
force. That "corresponds to the weight of a blood cell in the
earth's gravitational field," Lamoreaux states. The result falls
within 5 percent of Casimir's prediction for that particular plate
separation and geometry.
[Picture of virtual particles disappearing in a time internal
h/(4*Pi).]
VIRTUAL PARTICLES can spontaneously flash into existence from the
energy of quantum fluctuations. The particles, which arise as
matter-antimatter twins, can interact but must, in accordance with
Heisenberg's uncertainty principle, disappear within an interval set
by Planck's constant, h.
Zero for
Zero-Point Devices
Demonstrating the existence of zero-point energy is one thing;
extracting useful amounts is another. Puthoff's institute, which he
likens to a mini Bureau of Standards, has examined about 10 devices
over the past 10 years and found nothing workable.
One contraption, whose Russian inventor claimed could produce
kilowatts of excess heat, supposedly relied on sonoluminescence,
the conversion of sound into light. Bombarding water with sound to
create air bubbles can, under the right conditions, lead to bubbles
that collapse and give off flashes of light. Conventional thinking
explains sonoluminescence in terms of a shock wave launched within
the collapsing bubble, which heats the interior to a flash point.
Following up on the work of the late Nobelist Julian Schwinger,
a few workers cite zero-point energy as the cause. Basically, the
surface of the bubble is supposed to act as the Casimir force
plates; as the bubble shrinks, it starts to exclude the bigger modes
of the vacuum energy, which is converted to light. That theory
notwithstanding, Puthoff and his colleague Scott Little tested the
device and changed the details a number of times but never found
excess energy.
Puthoff believes atoms, not bubbles, offer a better approach. His
idea hinges on an unproved hypothesis: that zeropoint energy is what
keeps electrons in an atom orbiting the nucleus. In classical
physics, circulating charges like an orbiting electron lose energy
through radiation; what keeps the electron zipping around the
nucleus is, to Puthoff, zero-point energy that the electron
continuously absorbs. (Quantum mechanics as originally formulated
simply states that an electron in an atom must have some minimum,
ground-state energy.)
Physicists have demonstrated that a small enough cavity can suppress
the natural inclination of a trapped, excited particle to give up
some energy and drop to a lower energy state [see "Cavity Quantum
Electrodynamics," by Serge Haroche and Jean-Michel
Raimond; SCIENTIFIC AMERICAN, April 1993]. Basically, the cavity
is so small that it can exclude some of the lower-frequency vacuum
fluctuations, which the excited atom needs to emit light and drop to
a lower energy level. The cavity in effect controls the vacuum
fluctuations.
Under the right circumstances, Puthoff reasons, one could
effectively manipulate the vacuum so that a new, lower ground state
appears. The electron would then drop to the lower ground state--in
effect, the atom would become smaller--and give up some energy in
the process. "It implies that hydrogen or deuterium injected into
cavities might produce excess energy," Puthoff says. This
possibility might explain cold-fusion experiments, he notes--in
other words, the occasional positive results reported in cold-fusion
tests might really be indicators of zero-point energy (rather than,
one would assume, wishful thinking).
[Picture of a piezoelectric stack within a suspended device to
measure the Casimir Effect.]
[Picture of vacuum fluctuations flowing between the Casimir Plates.]
Work in cavity quantum electrodynamics is experimentally challenging
in its own right, however, so it is not clear how practical an
energy supply from "shrinking atoms" could be. The Austin institute
is testing a device that could be interpreted as manipulating the
vacuum, although Puthoff declines to provide details, citing
proprietary nondisclosure agreements with its designers.
How Much
in Nothing?
Underlying these attempts to tap the vacuum is the assumption that
empty space holds enough energy to be tapped. Considering just the
fluctuations in the electromagnetic force, the mathematics of
quantum mechanics suggest that any given volume of empty space could
contain an infinite number of vacuum-energy frequencies--and hence,
an infinite supply of energy. (That does not even count the
contributions from other forces.) This sea of energy is largely
invisible to us, according to the zeropoint-energy chauvinists,
because it is completely uniform, bombarding us from all directions
such that the net force acting on any object is zero.
But just because equations produce an infinity does not mean that an
infinity exists in any practical sense. In fact, physicists quite
often "renormalize" equations to get rid of infinities, so that they
can ascribe physical meaning to their numbers. An example is the
calculation of the electron's mass from theoretical principles,
which at face value leads to an unrealistic, infinite mass. The same
kind of mathematical sleight-of-hand might need to be done for
vacuum-energy calculations. "Somehow the notion that the energy is
infinite is too naive," Milonni says.
In fact, several signs indicate that the amount of energy in the
vacuum isn't worth writing home about. Lamoreaux's experiment could
roughly be considered to have extracted 10^-15 joule. That paltry
quantity would seem to be damning evidence that not much can be
extracted from empty space. But Puthoff counters that Casimir plates
are macroscopic objects. What is needed for practical energy
extraction are many plates, say, some 10^23 of them. That might be
possible with systems that rely on small particles, such as atoms.
"What you lose in energy per interaction, you gain in the number of
interactions;" he asserts.
Milonni replies by noting that Lamoreaux's plates themselves
are made of atoms, so that effectively there were 10^23 particles
involved. The low Casimir result still indicates, by his figures,
that the plates would need to be kilometers long to generate even a
kilogram of force. Moreover, there is a cost in extracting the
energy of the plates coming together, Milonni says: "You have to
pull the plates apart, too.
Another argument for a minuscule vacuum energy is that the fabric of
space and time, though slightly curved near objects, is pretty much
flat overall. Draw a triangle in space and the sum of its angles is
180 degrees, as it would be on a flat piece of paper. (The angles of
a triangle on a sphere, conversely, sum to more than 180 degrees.)
Because energy is equivalent to matter, and matter exerts a
gravitational force, cosmologists expect that an energy-rich vacuum
would create a strong gravity field that distorts space and time as
it is seen today. The whole universe would be evolving in a
different manner.
CASIMIR EFFECT is the motion of two parallel plates because
of quantum fluctuations in a vacuum. The plates are so dose together
that only small fluctuations fit in between; the bigger modes are
excluded (above). They exert a total force greater than that by the
smaller modes and hence push the plates together. The effect was
observed by Steve K. Lamoreaux, now at Los Alamos National
Laboratory, who relied on a torsion pendulum (left). A current
applied to the piezoelectric stack tried to move the Casimir plate
on the pendulum; the compensator plates held the pendulum still. The
voltage needed to prevent any twisting served as a measure of the
Casimir effect.
ZERO-POINT ENERGY was purportedly tapped with a machine that made
use of ultrasonically generated bubbles (right). Such devices are
tested by Harold E. Puthoff (below), director of the
Institute for Advanced Studies in Austin, Tex. So far no apparatus
has been found to produce a net gain in energy.
{Picture of Hal Puthoff.]
[Picture of an ultrasonic device.]
That argument ties into the cosmological constant, a concept that
Einstein first developed, then discarded. In the equations that
describe the state of the universe, the cosmological constant--which
incorporates zeropoint energy--is in a sense a term that can
counteract gravity. Astronomical observations suggest the constant
must be nearly zero. Consequently, if the vacuum energy really is
large, then some other force that contributes to the constant must
offset it. And as physicist Steven Weinberg of the University of
Texas notes in his 1992 book Dreams of a Final Theory, that offset
feels unnatural: calculations that sidestep the infinity terms
produce a vacuum energy 120 orders of magnitude greater than the
nearly zero value of the cosmological constant, so that other force
must be opposite but identical in magnitude to the vacuum energy out
to 120 decimal places.
Puthoff replies that the connection between the cosmological
constant and zero-point energy is more complex than is often
realized. "Obviously, the zeropoint-energy problem and the
cosmological constant, though related, are really different
problems," Puthoff argues, noting that predictions of quantum
mechanics have proved correct time and again and that instead
something is still missing from cosmologists' thinking.
Such disagreements in science are not unusual, especially
considering how little is really known about zero-point energy. But
those would-be utility moguls who think tapping zero-point energy is
a worthwhile pursuit irritate some mainstream scientists. "I was
rather dismayed at the attention from what I consider a kook
community," Lamoreaux says of his celebrity status among zero-point
aficionados after publishing his Casimir effect result. "It
trivializes and abuses my work." More galling, though, is that these
"pseudoscientists secure funding, perhaps governmental, to carry on
with their research," he charges.
Puthoff's institute receives a little government money but
gets most of its funds from contracts with private firms. Others are
backed more explicitly by public money. This past August the
National Aeronautics and Space Administration sponsored a meeting
called the "Breakthrough Propulsion Physics Workshop." According to
participants, zero-point energy became a high priority among those
trying to figure out which "breakthroughs" should be pursued.
The propulsion application depends on a speculation put forth in
1994 by Puthoff, Bernhard Haisch of Lockheed Pale Alto
Research Laboratory and Alfonso Rueda of California State
University at Long Beach. They suggested that inertia--the
resistance that objects put up when they are accelerated--stems from
the drag effects of moving through the zero-point field. Because the
zeropoint field can be manipulated in quantum experiments, Puthoff
reasons, it should be possible to lessen an object's inertia and
hence, for a rocket, reduce the fuel burden. Puthoff and his
colleagues have been trying to prove this inertia-origin
hypothesis--a sensitive pendulum should be able to detect a
zero-point-energy "wake" left by a moving object--but Puthoff says
they have not managed to isolate their system well enough to do so.
More conventional scientists decried the channeling of NASA
funds to a meeting where real science was lacking. "We hardly talked
about the physics" of the proposals, complained Milonni,
adding that during one of the breakout sessions "there was a guy
talking about astral projection."
Certainly, there should be room for far-out, potentially
revolutionary ideas, but not at the expense of solid science. "One
has to keep an open mind, but the concepts I've seen so far would
violate energy conservation," Milonni concludes. In sizing up
zero-point-energy schemes, it may be best to keep in mind the old
caveat emptor: if it sounds too good to be true, it probably is.
Further
Reading
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DEMONSTRATION OF THE CASIMIR FORCE
IN THE 0.6 TO 6 MICROMETER RANGE, S. K. Lamoreaux in Physical
Review Letters, Vol. 78, No. 1, pages 5-8; January 6, 1997.
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QUANTUM FLUCTUATIONS OF EMPTY SPACE:
A NEW ROSETTA STONE IN PHYSICS? Harold E. Puthoff. Available at
http://www.livelinks.com/sumeria/free/zpe1.html on
the World Wide Web. [This all-text paper was saved on the INE
website July 16, 1998, as the file QUANTFLUX.html.]
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