[The following article originally appeared in "Frontier Perspectives" (vol. 2
number 2, Fall/Winter 1991), the newsletter of The Center for Frontier
Sciences at Temple University, Dr. Beverly Rubik, Director. The address of
the Center is: Ritter Hall 003-00, Philadelphia, PA 19122. The e-mail
address is v2058a@templevm (Bitnet) and firstname.lastname@example.org (Internet).
This article is posted here with the permission of the Center.]
QUANTUM FLUCTUATIONS OF EMPTY SPACE: A NEW ROSETTA STONE OF PHYSICS?
October 23, 1990 Colloquium Presentation
Harold E. Puthoff
Senior Fellow in Physics
Institute for Advanced Studies
My topic is about something called nothing, the vacuum. In fact, the
so-called vacuum is not quite empty. Democritus was apparently the first
known philosopher who proposed that matter was ultimately constructed of
indivisible atoms suspended in the void, capable ofmotion by pushing aside
other atoms and moving intovoids. On the other hand, Aristotle reasoned that
nothing would affect a body in a complete void, and therefore space must be
filled with a substance. In the 19th century this ancient philosophical
discussion was raised to the level of a scientific debate that could be
experimentally investigated in the problem of the propagation of
electromagnetic waves. Scientists had invented the concept of the ether
which pervaded all of space. A series of experiments was devised to detect
the properties of the ether, the most well known of which is the Michelson-
Morley experiment. The ether was never detected experimentally, so it was
abandoned, and we were back to the notion of a true void. However, soon
quantum theory came into being and revised this notion. Today the vacuum is
not regarded as empty, but as full of energy. It is a sea of dynamical
energy where virtual particles are continually being created and then
dropping back into an unobservable state, like the spray of foam near a
The vacuum acts as a dynamical background determining the states of matter
and their interaction. The most fundamental quantum concept is that the
vacuum is fluctuating at a zero-point energy level, the ground state for
vibration of an harmonic oscillator. The main characteristic of quantum
theory is that everything is in this state of at least low level agitation.
The amount of energy associated with that fluctuation is very small, on the
order of half a photon's worth for each vibrational mode. If we consider
the universe as a whole, it is like a giant cavity with many modes, with all
directions of propagation, and having all possible frequencies. According to
quantum theory each of those modes and frequencies has a tiny amount of
zero-point energy associated with it. The sum total of all of the energy
associated with all these possible modes is enormous, and can be shown to
derive from the quantum fluctuation motion of charged particles distributed
throughout cosmological space.
Since quantum theory predicts an awesome amount of this energy, why don't we
observe many effects associated with it? The answer to this is analogous to
the following. If there is a door standing in a complete void, it would not
fall over, but just stand there. Similarly if you had two elephants come up
and push on each side of the door with equal strength, it also would just
stand there. If the elephants were invisible, you might not notice that
anything had changed. Thus, the zero-point energy is so completely in
balance that under ordinary circumstances its effects are unobservable.
However, the Lamb shift offers physical evidence for the zero-point energy.
Nobel laureate Willis Lamb showed a departure from theory of the actual
frequencies of light emitted from the electron of an excited hydrogen atom.
The naive calculation assumes that the atom is located in a void, but in fact
it isn't. If the effects of the electromagnetic zero-point energy on the
electron are taken into account, then there is a good match between theory
In 1948, Casimir, a Dutch physicist, predicted an effect that arises because
of the fact that zero-point energy exists. The Casimir effect is considered
to be the best demonstration of the zero-point energy. A metal slab is a
boundary condition for electromagnetic wave propagation, including zero-point-
energy electromagnetic waves. However, if a second slab is placed close to
it, i.e., within a millionth of a meter, "empty" space pushes them together.
All the zero-point modes can bounce off the plates and impart momentum to
them. The effect of the pair of metal plates is to exclude modes from
between them. Therefore, the radiation pressure tending to push the plates
apart is overcome by much greater radiation pressure on the outside pushing
them together. This is no small effect, approaching a million newtons
per square meter at small spacings. This phenomenon is observed in certain
applications such as the scanning electron microscope where the emission tip
for electrons is brought very close to the surface of a crystal.
In a fluorescent lamp, the atoms are put into excited states by means of an
electrical discharge. Originally it was thought that spontaneous emission of
electromagnetic radiation was simply a property of atoms, but later it was
realized that this so-called spontaneous emission is really not so
spontaneous. It is actually stimulated by the background fluctuations that
are continually agitating the atoms. If those vacuum modes that are causing
the atom to emit spontaneously are missing, then the atom will stay in its
excited state. It has been observed that the spontaneous emission time for
an atom in a specially constructed cavity can be much greater than for one in
free space, up to a factor of 42. Similarly, in a properly constructed
cavity one can reduce the spontaneous emission time by a factor of 500 and
speed atomic transitions. Spontaneous emission occurs only because the
background, the vacuum, is always fluctuating. Vision, which depends upon
spontaneous emission, is possible only because the background vacuum
fluctuations are jiggling the atoms all the time. If someone could "pull the
plug" on vacuum fluctuations, we would not see anything.
Vacuum fluctuations also play a role in atomic stability. Consider the
simplest atom, atomic hydrogen, a stable atom. A critical question has been,
why doesn't the electron radiate its energy away and the atom collapse? The
electrons in atomic ground states are in agitated states of motion, but not
many have thought about why they don't radiate their energy away. As in the
case with the Lamb shift, those working with atomic models usually do not
take into account the fact that the atom is not in a void but amidst quantum
fluctuations, with the opportunity to absorb energy from this background.
There is one orbit for which the absorption just matches the emission, and
that is the stable ground state orbit. Because of the presence of the zero-
point fluctuations, the electron will continuously move around in response to
them. The amount of energy radiated by an electron is equal to that which it
absorbs when in the ground state. Thus, the atom is actually in a continuous
interactive mode with the vacuum fluctuations continually being absorbed and
re-emitted. Consequently atomic structure is actually sustained by
background fluctuations. Again, if one could "pull the plug" on the
vacuum, all atoms would collapse. Vacuum fluctuations thus underlie some of
the rules of quantum theory.
Another area associated with vacuum fluctuations is gravity. Gravitational
theory is still under development, whether we are talking about classical
theory or general relativity. It is generally recognized that if we have a
certain amount of mass it will warp space, and if we have warped space,
particles will follow certain orbits. However, gravity is still at a
descriptive level and needs further development. Attempts are being made to
derive Einstein's equations from a more fundamental level. Consider, for
example, Newton's law of gravity. Questions remain as to the particular
value of the coupling constant G, where gravitational mass comes from, and
why masses always attract each other. Why is the law of gravitation an
inverse square law? Why can't gravity be shielded like electromagnetic
fields? A fundamental theory of gravity should address these questions.
In 1968 the famous Soviet physicist, Andrei Sakharov, made the then
outrageous proposal that perhaps gravity was not a fundamental force, but
rather was due to unbalanced zero-point fluctuation forces which arise in
the vacuum in the presence of matter. Unfortunately he did not develop this
idea further. I decided to examine it since I was doing vacuum fluctuation
Basically gravitational attraction between two bodies is primarily an
attraction between the nucleons--protons, and neutrons, i.e., the heavy part
of matter. We now know by modern theory that neutrons and protons are
composed of quarks, charged particles that reside within them. The quarks
themselves are moved around by the zero-point background fluctuations.
Furthermore, since they are charged, as they are so jiggled, they emit
radiation fields which other quarks also see. So an individual quark sees
both the bare background zero-point fluctuation fields as well as fields
associated with nearby fluctuating quarks. It is well known that if you have
fluctuating charged particles, there is a certain interaction potential, the
van der Waals forces, responsible for much of chemical binding. Following
the Sakharov model, it occurred to me to take a look at the leading term of
this potential to see whether that might not account for gravity as he
suggested. The average force is found to be proportional to the square of
the mass, for two identical particles, and inversely proportional to the
square of the distance between them. The value of the proportionality
constant turns out to be G, where G is related to the cut-off frequency of
the background zero-point fluctuations. This is an already unified
gravitational theory. This description of the gravitational force tells us
why the gravitational constant is so weak; it depends inversely on the square
of the cutoff frequency, which is very high. It also tells us why gravity is
only attractive, because van der Waals forces in general are only attractive.
The reason gravity cannot be shielded is that high frequency zero-point
fluctuation quantum noise in general cannot be shielded. Hence, the
application of zero-point fluctuations actually provides a deeper
understanding of gravity.
These are essentially theoretical concerns, but there are also potential
applications. There is a phenomenon associated with the Casimir effect that
leads to the condensation of charge. Ordinarily, electrically charged
particles of the same sign repel each other. To understand why the Casimir
effect predicts charge condensation under certain conditions, consider the
two metal plates in a vacuum which are attracted together by an inverse
fourth law Casimir force. If two metal plates, both strongly charged, are
put somewhat near each other, the electrical repulsion force would make them
fly apart. However, at very small distances this inverse fourth law
attractive force can overcome that repulsion force, no matter how much charge
is on the plates. Casimir believed that this same attractive force might
also be involved in holding the electron together. However, the
applicability of this goes beyond the elementary particle level; it could be
applied for clustering larger amounts of charge in macroscopic phenomena.
Under certain conditions when Casimir forces might overcome Coulomb
repulsion, laboratory phenomena would reveal the sudden condensation of
charge, a Casimir pinch effect, as it were.
Condensed charge technology, pioneered in the corporate domain, may be
explained in this way. Much laboratory evidence has already been collected
on this condensed charge phenomenon. Present-day electronic devices have
limitations due to difficulties in forcing charge carriers up to very high
densities. However, with charge condensation phenomena these limitations
are overcome. Charge condensation occurs in micro-discharges, similar to
static electrical discharges, and involves kilovolt pulses of a billionth of
a second and amps of current. Upon further examination, charge, rather than
repelling, is seen to form into charge clusters. The parameters under which
that occurs matches very closely with what the Casimir charge condensation
effect predicts. Typical environments in which this occurs are certain field
emission conditions, i.e., a metal tip in a strong electric field such that
electrons are drawn out of the metal and cluster together. Theory predicts
the possibility of charge clustering. If one blasts high-density electron
currents having millions of volts of energy at a titanium foil target, the
result is not Coulomb repulsion of the current elements with consequent
diffusion of the elecrons. Instead, all the charge arrives at discrete
points and the areas in between are undamaged. Such vacuum witness-plate
marks are also observed in welding where instead of million volt beams there
are 10 to 50 volt differences between electrodes spaced very closely
together, and the voltage is raised until they spark. Again, one observes
hot spots where most of the current comes out at very discrete sites, of the
order of a million amps per square cm. It is considered anomalous. As the
technology is improving, the current densities are still increasing which are
harder to explain without a model like charge condensation.
At the Institute for Advanced Studies we have generators designed to
investigate this phenomenon. If one raises the voltage between two metal
plates separated by a dielectric material until a spark discharge runs across
it, under certain conditions one observes a small lightning stroke that is
very rigidly confined. If one slowly applies low voltages, one sees more
diffuse manifestations, but if one applies a high voltage very rapidly,
instantaneous arcing is observed. Witness plates struck by these arc
discharges show evidence for individual small craters with spaces between
them. This phenomenon appears to be fundamental. Upon examining a propeller
that was struck by lightning, we found it covered by the same small
Applications of this technology are presently being negotiated with various
corporations and are in various stages of development.
For example, it turns out that the highly condensed charge can propagate
through a small device such as a hypodermic needle and create x-rays when it
impacts on a metal. It turns out that the amount of energy involved in
these tiny clusters is enormous. Rather than having a large x-ray machine
that kills a patient on its way to treating a tumor, the whole x-ray
generator inside of a hypodermic needle penetrates the skin, goes to the
tumor site, and then irradiates the tumor directly with lower voltage x-rays.
We gave a medical x-ray company the blueprints for one of these devices, and
they now have a hand-held device using condensed charge technology which is
as effective as a large x-ray machine. Also, unlike many new electronic
technologies such as semiconductors which are very expensive, this phenomenon
is quite simple and economical.
One can also use condensed charge technology to generate radio frequencies
for use in radar devices. A prototype is being developed for an aerospace
corporation for testing. Another development is a TV set that is a flat
panel display. Such a TV set would work by means of a whole series of
channels down which the charge clusters travel, emitting their electrons,
which then pass through control plates to produce the appropriate colors and
intensities. This concept of flat panel display technology is well
understood, but has not yet become available because there have not
heretofore been intense enough electron sources that could be used as power
By understanding the role that quantum fluctuations play in condensing
charge, we see that many new applications are possible, several of which have
been patented. One remaining important question is whether there is any
way to actually obtain energy from the zero-point fluctuations. A decade ago
that would have been thought of as very controversial. Many have expressed
doubts or considerations that this would violate the laws of physics.
However, a method for extracting electrical energy from the vacuum by
cohesion of charged conductors is presently in the literature. How can that
possibly work? Consider the simple case of two metal plates in outer space.
As they begin to move together, they eliminate more of the modes in between.
The zero-point energy that starts dropping out of those modes is converted to
kinetic energy as the plates move together. They get closer, and when the
plates hit, they create heat. In the Casimir effect we thus already have the
conversion of vacuum energy to actual measurable useful energy. There is no
violation of energy conservation.
R.L. Forward, at Hughes Research Laboratories, proposed a similar device
involving a spring form which would be compressed together by the vacuum
forces. The spring is under stress with charge distributed over its
volume with an associated electric field around it, and the vacuum pushes it
together via the Casimir force. As this occurs, the fields around the device
increase which can be used as useful energy, e.g., to drive current through a
battery. This output represents one cycle of the device, but one needs to do
work on it for the next cycle. If the devices are cheap and disposable, then
we could use them sequentially and discard them. However, if it takes more
energy to make those devices, then it is impractical to discard them. On the
other hand, condensed charge technology may offer another possibility.
Electronic charge is brought close together in some form of plasma, and then
the Casimir pinch effect condenses it even more. There are stores of energy
in that condensed charge, which can be liberated by a number of techniques.
Various laboratories have reported anomalous energy gains associated with
such charge condensation phenomena. However, these are very rare and very
hard to reproduce, so at this point they remain anomalies. Only a decade ago
research of this type was unthinkable, but today more is known about quantum
fluctuations of vacuum, and people are seriously looking at this kind of
When one utilizes solar energy, it is not free in the sense of violating
physics, but it is free in the sense that you pay only a small price for it.
The condensed charge cycle appears to be similar. A certain amount of energy
is put in to excite a plasma, making a very dense plasma to reach the Casimir
charge condensation point. The source is not the sun but the vacuum zero-
point fluctuations. If one satisfies the conditions that the energy used to
make the plasma is less than what the vacuum put in to make condensed charge
clusters, then one gains. This is quite similar to ordinary fusion. There a
dense plasma is made, which takes a lot of energy, but at a certain point,
the nuclear force then provides more energy than one put in. In the
condensed charge process the Casimir force plays the role of the nuclear
force. Furthermore, in the condensed charge device there is the possibility
of a direct electrical output. The condensed charge cycle zero-point energy
device, if workable, will be pollution free as far as we can tell. Should
this source prove utilizable, the vacuum zero-point fluctuations are
available everywhere, rendering the notion of the central power plant
This would be the most positive possible outcome that could be expected of
vacuum energy physics leading to dramatically new technology. With cautious
optimism, the most appropriate statement concerning this possibility was
perhaps made by a Soviet science historian, Podolny, who said, "It would be
just as presumptuous to deny the ability of useful application as it would be
irresponsible to guarantee such application". Only the future will reveal to
what use humanity will eventually put this remaining fire of the gods, the
quantum fluctuations of empty space.
1. Puthoff, H.E. "Source of Vacuum Electromagnetic Zero-Point Energy",
Physical Review A 40 (9), 4857-4862, (1989).
2. Milonni, P.W., R.J. Cook, et al. "Radiation Pressure from the Vacuum:
Physical Interpretation of the Casimir Force", Physical Review A 38,
3. Puthoff, H.E. "Ground State of Hydrogen as a Zero-Point-Fluctuation
Determined State", Physical. Review. D 35, 3266 (1987).
4. Puthoff, H.E. "Gravity as a Zero-Point-Fluctuation Force", Physical Review
A. 39, 2333 (1989).
5. Casimir, H.B.G. "Introductory Remarks on Quantum Electrodynamics".
Physica 19, 846 (1953).
6. U.S. Patent Nos. 5,018,180; 5,054,046; 5,054,047.
7. Forward, R.L. "Extracting Electrical Energy from the Vacuum by Cohesion of
Charge Foliated Conductors", Physical. Review B 30, 1700, (1984).
8. Puthoff, H.E. "The Energetic Vacuum: Implications for Energy Research".
Speculations in Science and Technology, 13(3), 247 (1990).
This is based on an article in Physical Review A39 (1989), p.2333,
which is simply wrong. The calculation of the averaged interaction
potential in appendix B contains a bad approximation (a polynomial
is approximated by the first two terms in its binomial expansion),
which neglects terms that are of the same order as other terms that
are kept. When the integral (eqn. B5 in this paper) is done carefully,
the "gravitational" effect that Puthoff sees cancels completely; one is
left with an inverse fourth power interaction with an extremely small
coefficient, completely unobservable on the scales for which gravity
I have submitted a Comment to Phys. Rev. addressing this issue,
which will probably be published sooner or later. In the meantime,
two exercises for the interested reader:
First obtain the journal in question. Then
1) Using the fact that 0<= 1 - cos x <= 2, obtain an upper and lower
bound on the integral in equation (B5). Compare these bounds to
Puthoff's result (B7). What is the largest distance for which the
result claimed by this paper is inside these bounds? (Hint ---
2) Evaluate the integral (B5) exactly in terms of the sine integral
Si(x). Using the standard asymptotic expansion of Si, compare the
exact result to the result reported in this paper in the limit that
the distance is large compared to the Planck length. Show that the
difference includes a term that exactly cancels Puthoff's inverse
The basic idea of induced gravity --- gravity as a result of vacuum
fluctuations --- is an interesting one, and some good work has been
done in the area. But I'm afraid this ain't it.