Descripción

Más veloz que la luz por Jean-Pierre Petit por Godelieve Van Overmeire

 

 

Dr.  Jean – Pierre   Petit

 

MÁS         VELOZ   QUE     LA    LUZ

 

Subject: Re: FTL Travel NOT a theory

From: cluster_user@yale.edu (Cluster User)

Date: Mon, 04 May 1998 19:31:44 GMT

 

 

“Faster than the speed of light ?.     Current research will provide the basis for further expanding man’s understanding of the universe.”

 

 

 

By Peter Symonds

 

 

 

 

 

MODERN physics rests on two basic pillars‑‑the general theory of

relativity as elaborated by Albert Einstein and quantum mechanics

as developed by a line of brilliant physicists, including Neils

Bohr, Werner Heisenberg, Louis De Broglie, Max Planck and Erwin

Schrodinger.  Both theories have provided remarkable and often

startling insights into the nature of matter and its laws.

Relativity deals with fast objects traveling with velocities

approaching that of light and provides a theory of gravitational

forces. Quantum mechanics emerged from investigations into the

realm of subatomic particles.

 

Relativity and quantum mechanics have been applied to

investigations into a range of phenomena‑‑ from the intricacies

of the atom to the evolution of the universe itself‑‑and have

been confirmed by a host of experimental observations.

Yet scientists have long noted certain limits to, and conflicts

between, these two theories. The noted theoretical physicist

Stephen Hawking states in his book A Brief History of Time:

«Unfortunately … these two theories are known to be

inconsistent with each other‑‑they cannot both be correct. »

 

A unified theory providing a description of all four fundamental

physical forces‑‑electromagnetic, gravity and the weak and strong

nuclear forces‑‑has so far evaded the efforts of theoretical

physicists.

 

A series of extraordinary experiments conducted by teams of

physicists in the US and Europe over the last five years has once

again highlighted the lack of a unified theory. For the first

time, physicists have measured photons‑‑particles of

electromagnetic radiation‑‑traveling faster than the speed of

light.

 

One of the consequences of Einstein’s special theory of

relativity is that nothing can travel at superluminal velocities,

that is, faster than the speed of light. Any particle with a mass

would require an infinite amount of energy to accelerate to the

speed of light. Only light itself or other forms of

electromagnetic waves can travel at such a velocity.

 

Yet through one of the quirks of quantum mechanics, physicists

have predicted and now measured photons of light and microwaveÔ     ø*          p‑à+à+@ @    Ô

radiation moving at superluminal speeds. Thus we are confronted

with the riddle of light traveling faster than the speed of

light!

Exploring the «tunnel effect»

 

At the core of quantum mechanics, and of its many apparent

paradoxes, is the uncertainty principle, first elaborated by

Werner Heisenberg in 1927. According to this principle, no

observer, regardless of the subtlety of his methods, can

determine precisely both the speed and the momentum of a particle

at one point in time.

 

Quantum mechanics does not predict outcomes with certainty, but

calculates the probabilities of different eventualities.

 

The observation of everyday events‑‑the motion of a car or the

firing of a gun‑‑remain virtually unaffected by the limits

imposed by the Heisenberg uncertainty principle. But at the

subatomic level, it has some extraordinary consequences. Matter

itself takes on a dual character, able to act in differing

circumstances both as waves and as particles.

 

The possibility of particles traveling faster than the speed of

light depends upon an outcome of quantum mechanics known as the

tunnel effect. If one bounces a tennis ball against a brick

wall, one expects the ball to bounce back, not reappear on the

other side of the wall‑‑no matter how many times one throws the

ball.

 

However, in the case of particles such as electrons fired at a

subatomic barrier, quantum mechanics predicts that not all will

be reflected. Some electrons will literally pass through the

«wall» and appear on the other side. Not only is the tunnel

effect experimentally observable, but it forms the basis for an

electronic device known as the tunnel diode.

 

In 1955, the American physicist Eugene Wigner and his student L.

Eisenbud at Princeton University analyzed the phenomenon of

quantum tunneling and concluded that under certain circumstances

particles could pass through a barrier at faster than the speed

of light.

 

This conclusion has been the subject of continuing debate among

theoretical physicists because of the difficulties it raises. But

up until recently scientists’ ability to test the various

predictions has been limited by the technology available.

 

Light travels in a vacuum at a velocity close to 300,000

kilometers a second. To measure particles moving at a speed

faster than light over extremely small distances requires a

capacity to determine time more accurately than the most

sensitive atomic clocks.

 

Steven Chu and Stephen Wong at AT&T Bell Labs in the US first

measured superluminal speeds for light pulses traveling throughÔ     ø*          p‑à+à+@ @    Ô

an absorbing material 10 years ago, but their results

were largely ignored.

 

In 1991, an Italian team of scientists at the National Institute

for Research into Electromagnetic Waves examined a phenomenon

closely related to quantum tunneling. Under certain conditions,

microwaves can be transmitted through a «forbidden zone» of a

wave guide, contrary to the

prediction of classical physics that they will be reflected.

 

While the Italian scientists were unsuccessful, the following

year GUnter Nimtz and his colleagues at the University of Cologne

in Germany reported measuring microwaves passing through the

forbidden zone at speeds greater than that of light.

 

A breakthrough in measurement

 

In 1993, an American team headed by Raymond Chiao at the

University of California in Berkeley provided further

confirmation of superluminal speeds by measuring the tunneling

times of photons of visible light.

 

The experiment required considerable ingenuity, as the time

intervals involved were extremely short‑‑a few femtoseconds (a

femtosecond is a thousandth of a trillionth of a second).

 

Chiao’s team began by establishing an optical «race» for two

photons by shining a laser beam on a special crystal known as a

down‑converter, which absorbs a high energy photon and emits a

pair of photons of lower energy. Each photon of the pair was then

directed along a different path using mirrors and directed into

a device known as a co‑incidence counter, which registers whether

the two photons arrive simultaneously.

 

The difficulty with the co‑incidence counter is that it is only

able to measure to within a billionth of a second, making it far

too inaccurate for the experiment being considered.

 

To overcome the deficiency, the Berkeley scientists utilized a

another quantum property of matter. The two beams of photons were

directed at a half‑silvered mirror. Ordinarily a photon has a

50‑50 chance of passing through or being reflected by the mirror,

and thus there is also a 50‑50 chance that the two photons will

travel along separate paths and will be registered by the

co‑incidence counter.

 

If however, the pair of photons arrive at the mirror within 20

femtoseconds of each other, quantum mechanics predicts that the

pair will travel on the same path and thus will not be detected

by the counter. By fine‑tuning the apparatus, Chiao and his

colleagues were able to achieve the remarkable accuracy of a

quarter of a femtosecond. They demonstrated that when a thin

optical barrier was placed in the path of one of the photons, it

tunneled through the obstacle at a velocity 1.7 times that of

light.

Ô     ø*          p‑à+à+@ @    ÔŒCan signals exceed the speed of light?

 

How such speeds can be achieved without breaching the laws of

physics is not well understood. One way of viewing the problem

is to regard the tunneling particle as «orrowing» energy

to overcome the barrier. This would mean that other particles

would acquire a negative kinetic energy. This notion of negative

kinetic energy makes no sense in classical physics, according to

which an object at rest has no kinetic energy and one which is

moving has a positive kinetic energy.

 

Chiao states that his discovery does not violate Einstein’s laws

of relativity. While individual particles may travel faster than

the speed of light, he maintains that it is not possible to

transmit a message at superluminal speeds.

 

«These experiments do not mean that you can send a signal faster

than light. Only a few photons get through the barrier. Because

tunneling is probabilistic, we’ve no way of knowing which

ones they will be. So it would not be possible to send any useful

information»»  Chiao told the New Scientist magazine.

 

Other scientists dispute Chiao’s conclusions.

 

Several European teams have been experimenting with more intense

photon sources and thicker barriers. Their results indicate that

the tunneling time for a particle becomes «saturated» or reaches

an upper limit. If a particle can «borrow» energy, quantum

mechanics does not permit

it to do so indefinitely.

 

Once the limit is reached, the particle will tunnel through the

barrier in the same time, regardless of whether its thickness is

two meters, two kilometers or 2,000 kilometers‑‑if, of course,

such an experiment could ever be carried out!

 

Last year, New Scientist reported the extraordinary findings of

a German research team headed by Nimtz, who was attending a

conference organized in Snowbird, Utah:

 

«Attending the meeting were some of the leading researchers in

this field of faster‑than‑light quantum phenomena. To an

astonished audience, Nimtz announced that his team in Cologne had

not only measured superluminal speeds for their microwaves, but

had actually sent a signal faster than light. The signal in

question was Mozart’s 40th Symphony….

 

«According to Nimtz, Mozart’s 40th Symphony hopped across 12

centimeters of space at 4.7 times the speed of light. What’s

more, Nimtz actually had a recording to prove it. To his now

bemused audience, he played a tape in which among the background

hiss strains of Mozart could be heard. This was the ‘signal’ that

had traveled faster than light.»

 

A vigorous debate ensued as to whether or not a piece of music

could be considered a signal. According to Einstein, a signalÔ     ø*          p‑à+à+@ @    Ô

traveling faster than light would effectively be traveling back

in time. The ability to send information back in time would

violate the scientific conceptions of cause and effect: the

results of an experiment could be influenced after it had

happened!

 

Few scientists accept Nimtz’s claim that a signal can be

propagated faster than the speed of light. However, the

experiments by Nimtz, Chiao and others point to the limitations

of the existing theories of physics and add a further spur to the

quest for a unified theory embracing quantum mechanics and the

theory of general relativity.

 

 

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INFORMACIÓN   EN   EL ARCHIVO   DE     MADAME  GODELIEVE   VAN OVERMEIRE    ( BRUSELAS  ,  BÉLGICA ).

 

 

Documents  from   the   private   files  of

 

Madame   Godelieve   Van   Overmeire

 

(  Brussels   ,   Belgium  )