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[escepticos] Mas noticias con enjundia... La observacion afecta a la realidad...
Jeje... XDD Siento que este en ingles... ¿Algun comentario? XDD
Quantum Theory Demonstrated: Observation Affects Reality
REHOVOT, Israel, February 26, 1998--One of the most bizarre premises of
quantum theory, which has long fascinated philosophers and physicists alike,
states that by the very act of watching, the observer affects the observed
In a study reported in the February 26 issue of Nature (Vol. 391, pp.
871-874), researchers at the Weizmann Institute of Science have now
conducted a highly controlled experiment demonstrating how a beam of
electrons is affected by the act of being observed. The experiment revealed
that the greater the amount of "watching," the greater the observer's influence
on what actually takes place.
The research team headed by Prof. Mordehai Heiblum, included Ph.D.
student Eyal Buks, Dr. Ralph Schuster, Dr. Diana Mahalu and Dr. Vladimir
Umansky. The scientists, members of the Condensed Matter Physics
Department, work at the Institute's Joseph H. and Belle R. Braun Center for
When a quantum "observer" is watching Quantum mechanics states that
particles can also behave as waves. This can be true for electrons at the
submicron level, i.e., at distances measuring less than one micron, or one
thousandth of a millimeter. When behaving as waves, they can simultaneously
pass through several openings in a barrier and then meet again at the other
side of the barrier. This "meeting" is known as interference.
Strange as it may sound, interference can only occur when no one is watching.
Once an observer begins to watch the particles going through the openings,
the picture changes dramatically: if a particle can be seen going through one
opening, then it's clear it didn't go through another. In other words, when
under observation, electrons are being "forced" to behave like particles and
not like waves. Thus the mere act of observation affects the experimental
To demonstrate this, Weizmann Institute researchers built a tiny device
measuring less than one micron in size, which had a barrier with two openings.
They then sent a current of electrons towards the barrier. The "observer" in
this experiment wasn't human. Institute scientists used for this purpose a tiny
but sophisticated electronic detector that can spot passing electrons. The
quantum "observer's" capacity to detect electrons could be altered by
changing its electrical conductivity, or the strength of the current passing
Apart from "observing," or detecting, the electrons, the detector had no effect
on the current. Yet the scientists found that the very presence of the
detector-"observer" near one of the openings caused changes in the
interference pattern of the electron waves passing through the openings of the
barrier. In fact, this effect was dependent on the "amount" of the observation:
when the "observer's" capacity to detect electrons increased, in other words,
when the level of the observation went up, the interference weakened; in
contrast, when its capacity to detect electrons was reduced, in other words,
when the observation slackened, the interference increased.
Thus, by controlling the properties of the quantum observer the scientists
managed to control the extent of its influence on the electrons' behavior. The
theoretical basis for this phenomenon was developed several years ago by a
number of physicists, including Dr. Adi Stern and Prof. Yoseph Imry of the
Weizmann Institute of Science, together with Prof. Yakir Aharonov of Tel
Aviv University. The new experimental work was initiated following
discussions with Weizmann Institute's Prof. Shmuel Gurvitz, and its results
have already attracted the interest of theoretical physicists around the world
and are being studied, among others, by Prof. Yehoshua Levinson of the
The experiment's finding that observation tends to kill interference may be
used in tomorrow's technology to ensure the secrecy of information transfer.
This can be accomplished if information is encoded in such a way that the
interference of multiple electron paths is needed to decipher it. "The presence
of an eavesdropper, who is an observer, although an unwanted one, would kill
the interference," says Prof. Heiblum. "This would let the recipient know that
the message has been intercepted."
On a broader scale, the Weizmann Institute experiment is an important
contribution to the scientific community's efforts aimed at developing quantum
electronic machines, which may become a reality in the next century. This
radically new type of electronic equipment may exploit both the particle and
wave nature of electrons at the same time and a greater understanding of the
interplay between these two characteristics are needed for the development of
this equipment. Such future technology may, for example, open the way to the
development of new computers whose capacity will vastly exceed that of
today's most advanced machines.
This research was funded in part by the Minerva Foundation, Munich,
Germany. Prof. Imry holds the Max Planck Chair of Quantum Physics and
heads the Albert Einstein Minerva Center for Theoretical Physics.
The Weizmann Institute of Science, in Rehovot, Israel, is one of the world's
foremost centers of scientific research and graduate study. Its 2,400 scientists,
students, technicians, and engineers pursue basic research in the quest for
knowledge and the enhancement of the human condition. New ways of
fighting disease and hunger, protecting the environment, and harnessing
alternative sources of energy are high priorities.
EDUARDO ZOTES SARMIENTO
SDAC Sociedad para el Desarrollo de la Actitud Cientifica
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