**Bienvenue sur la page francophone de l'énergie libre!, ou ENERGIE DU VIDE !**

Mise à jour: 01 janvier 2006-
**Bonne****et****Heureuse****Année****2006****à****Tous****!**

Bonne lecture!

**Les
nouvelles du vide - 01 janvier 2006- les
Archives 2004 - Le
Dossier Environnement - L'Engineering
du Vide Quantique: une nouvelle discipline! -
Le début d'une
nouvelle vision holistique? - Le
coin des sceptiques: La
Roue de l'Histoire - Les
conférences -
les articles de synthèse,
etc...**

par Domenico Giulini (+) et Norbert Straumann(++)

"This strongly suggests that there is
something profound that we do not seem to understand at all, certainly not in
quantum field theory (nor, at least so far, in string theory). We are unable to calculate the
vacuum energy density in quantum field theories, such as the Standard Model of particle
physics."

Les extraits ci-dessous sont
particulièrement intéressants (NB: les passages en rouge sont de moi)

pp.55-56: "Vacuum
energy and gravity (...)For
decades nobody else seems to have worried about contributions of
quantum
fluctuations to the cosmological constant,
although physicists learned after Dirac's hole theory
that the vacuum state in quantum field theory is not empty but has
interesting physical properties. As far as we know,
the first one to come back to possible contributions
of the vacuum energy density to the
cosmological constant was Zel'dovich. He
discussed this issue in two papers (Zel'dovich, 1967, 1968) during the
third renaissance period of the A-term, but before the
advent of spontaneously-broken gauge
theories. He pointed out that, even if one
assumes in a completely ad-hoc fashion that the
zero-point contributions to the vacuum energy density are exactly
cancelled by a bare term, there still remain higher-order
effects. In particular, gravitational interactions between
the particles in the vacuum fluctuations are expected on dimensional
grounds to lead to a gravitational self-energy density of order
Gµ6, where µ is some cut-off
scale. Even for µ as low as 1 GeV, this is about 9 orders of
magnitude larger
than the observational bound.This strongly suggests that there is
something profound that we do not seem to understand at all,
certainly not in quantum field theory (nor, at least so far, in string theory). We are unable to calculate the
vacuum
energy density in quantum field theories, such as the Standard Model of particle
physics. But we can attempt to make what appear
to be reasonable order-of-magnitude estimates for the various
contributions. All expectations are in dramatic conflict
with the facts (see, e.g
., Straumann, 2003b). Trying to arrange the cosmological
constant to be zero is unnatural in a technical sense. It
is like enforcing a particle to be massless, by fine-tuning the
parameters of the theory when
there is no symmetry principle implying a vanishing mass. The vacuum
energy
density
is unprotected from large quantum corrections. This problem is
particularly severe in field theories with spontaneous symmetry
breaking. In such models there are
usually several possible vacuum states
with different energy densities. Furthermore, the
energy density is determined by what is called the effective potential,
and this is a dynamical object. Nobody can see any
reason why the vacuum of the Standard Model we ended up as the universe
cooled, has—by the standards of particle physics—an almost vanishing
energy density. Most likely, we shall only find a satisfactory answer
once we have a theory that successfully combines the concepts and laws
of GR with those of quantum theory.

For a number of years now, cosmology has been going through a fruitful and exciting period. Some of the developments are clearly of general interest, well beyond the fields of astrophysics and cosmology. Lack of space prevents us from even indicating the most important issues of current interest. "

For a number of years now, cosmology has been going through a fruitful and exciting period. Some of the developments are clearly of general interest, well beyond the fields of astrophysics and cosmology. Lack of space prevents us from even indicating the most important issues of current interest. "

20 dec 2005 (68 pp)

(+)Institute of Physics , University of Freiburg, Germany,
giulini@physik.uni-freiburg.de

(++)
Institute for Theoretical
Physics, University of Zürich, Switzerland, norbert.straumann@freesurf.ch

http://arxiv.org/PS_cache/physics/pdf/0507/0507107.pdf

***

17 December 2005 , **NewScientist.com**, par Amanda Gefter

Extraits: "Second was the
discovery that the value of the cosmological constant -
the energy of empty space which contributes to the expansion rate of
the universe - seems absurdly improbable, and nothing in fundamental
physics is able to explain why. I remember when Steven Weinberg first
suggested that the cosmological constant might be anthropically
determined - that it has to be this way otherwise we would not be here
to observe it. I was very impressed with the argument, but troubled by
it. Like everybody else, I thought the cosmological constant was
probably zero - meaning that all the quantum fluctuations that make up
the vacuum energy cancel out, and gravity alone affects the expansion
of the universe. It would be much easier to explain if they cancelled
out to zero, rather than to nearly zero. The discovery that there is a
non-zero cosmological constant changed everything. Still, those two
things were not enough to tip the balance for me."

http://www.newscientist.com/channel/fundamentals/mg18825305.800.html

***

par **B.G. Sidharth
**International Institute for Applicable Mathematics & Information
Sciences, Hyderabad (India) & Udine (Italy)

B.M. Birla Science Centre, Adarsh Nagar, Hyderabad - 500 063 (India)

Résumé: After many fruitless decades of trying to unify electromagnetism and gravitation, it is now being realized that this can be done only in discrete spacetime, as indeed the author had demonstrated. In this context, a unified description of gravitation and electromagnetism is provided within the framework of a gauge like formulation. "These latest theories discard the differentiable spacetime of earlier approaches and rely on a lattice like approach to spacetime, wherein there is a minimum fundamental interval which replaces the point space time of earlier theories. Indeed as Hooft has remarked, “It is some what puzzling to the present author why the lattice structure of space and time had escaped attention from other investigators up till now....”

http://www.ensmp.fr/aflb/AFLB-302/aflb302m301.htm

***

Alexander Burinskii

Résumé: The Kerr-Newman solution has
g=2 as that of the Dirac
electron and is considered as a model of spinning particle in general
relativity. The Kerr geometry changes cardinally our representations on
the role of gravity in the particle physics. We show that the Kerr
gravitational field has a stringy local action and a topological
peculiarity which are extended up to the Compton distances, and also a
strong non-local action playing the key role in the
mass-renormalization and regularization of singularities. The
Kerr-Newman gravity determines the structure of spinning particle in
the form of a relativistically rotating disk, a highly oblate bag of
the Compton radius. Interior of this bag consists of an AdS or dS
``false vacuum'', depending on the correlation of the mass density and
charge. In the same time, the local action of gravitational field may
be considered as negligible for regularized particle.

Extraits: "The used in QED mass renormalization is
universally recognized due to an incredible exactness of its
predictions. Although its origin lies in the classical theory of a
pointlike electron, there are serious problems with physical
interpretation and mathematical correctness of this procedure.(...) We
show that the mass renormalization and regularization of the
singularities in the Kerr- Newman source are realized by gravitational
field in a very natural manner.(...) We show that the Kerr
gravity displays
in the Compton the strong local field having a stringy structure, a
nontrivial topological peculiarity and has a strong non-local action
playing the key role in the mass- renormalization.(...) Some of the
terms may be divergent, but the total result will not be changed, since
divergences will always be compensated by contribution from
gravitational term. It shows that, due to the strong non-local action,
gravity has to be very essential for elementary particles, on the
distances which are very far from the considered usually Planck scale."

"Regularization of the zero-point radiation

(...)Twofoldedness of the Kerr geometry confirms this point of view,
since the out-going radiation on the “positive” out-sheet of the metric
is compensated by an in-going radiation on the “negative” in-sheet, see
Fig. 1. So, physically, there is no reason for the lost of mass by
radiation. It shows, that the term F31 = γ 1 ˜r has to be identified
with the vacuum zero-point field. In this case the electromagnetic
excitations on the Kerr background may be interpreted as a resonance of
the zero-point fluctuations on the (superconducting) source of the Kerr
spinning particle [13, 9]."

http://arxiv.org/abs/hep-th/0512095

**F.W. Hehl, Yu.N. Obukhov, G.F. Rubilar , M. Blagojevic**

15 pages, 1 figure - Journal-ref: Phys.Lett. A347 (2005) 14-24

Résumé: It has been observed since the time of Cartan, Kottler, and van
Dantzig, that since the spacetime metric only enters into Maxwell's
equations for electromagnetism by way of the Hodge star operator, and,
more to the point, the metric structure of spacetime seems to follow
from the propagation of electromagnetic waves, that perhaps one should
regard the spacetime metric as a corollary to the electromagnetic
structure of spacetime, and formulate the laws of electromagnetism in a
metric-free fashion.

http://www.physcomments.org/node/301

par **G.E. Volovik**

Low Temperature Laboratory, Helsinki
University of Technology, P.O.Box 2200, FIN-02015 HUT, Finland

Abstract:
The phenomenon of emergent physics in condensed-matter many-body
systems has
become the paradigm of modern physics, and can probably also be applied
to
high-energy physics and cosmology. This encouraging fact comes from the
universal properties of the ground state (the analog of the quantum
vacuum) in
fermionic many-body systems, described in terms of the momentum-space
topology.
In one of the two generic universality classes of fermionic quantum
vacua the
gauge fields, chiral fermions, Lorentz invariance, gravity,
relativistic spin,
and other features of the Standard Model gradually emerge at low
energy. The
condensed-matter experience provides us with some criteria for
selecting the
proper theories in particle physics and gravity, and even suggests
specific
solutions to different fundamental problems. In particular, it provides
us with
a plausible mechanism for the solution of the cosmological constant
problem,
which I will discuss in some detail.

http://arxiv.org/abs/cond-mat/0507454

Guang-jiong Ni

Department of Physics, Fudan
University, Shanghai, 200433, China

Department of Physics, Portland State
University, Portland, OR97207, U.S.A.

Email : pdx01018@pdx.edu

Abstract:
In order to clarify why the zero-point energy associated with the
vacuum
fluctuations cannot be a candidate for the dark energy in the universe,
a
comparison with the Casimir effect is analyzed in some detail. A
principle of
epistemology is stressed that it is meaningless to talk about an
absolute
(isolated) thing. A relative thing can only be observed when it is
changing
with respect to other things. Then a new conjecture of antigravity
--the
repulsive force between matter and antimatter derived from the modified
Einstein field equation in general relativity-- is proposed. this is
due to the
particle-antiparticle symmetry based on a new understanding about the
essence
of special relativity. Its possible consequences in the theory of
cosmology are
discussed briefly, including a new explanation for the accelerating
universe
and gamma-ray-bursts.

http://arxiv.org/abs/physics/0506017

**Michael Levin and Xiao-Gang Wen**

Department of Physics, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139

(Dated: May, 2005)

We give an example of a purely
bosonic model – a rotor model on the 3D cubic lattice – whose low
energy excitations behave like massless U(1) gauge bosons and massless
Dirac fermions. This model can be viewed as a "quantum ether ": a
medium that gives rise to both photons and electrons. It illustrates a
general mechanism for the emergence of gauge bosons and fermions known
as " stringnet condensation." Other, more complex, string-net condensed
models can have excitations that behave like gluons, quarks and other
particles in the standard model. This suggests that photons, electrons
and other elementary particles may have a unified origin:
string-net condensation in our vacuum.

http://132.236.180.11/abs/hep-th/0507118

RADIO - De récentes interviews d'Edgar Günzig sont rediffusées par la RTBF les 18, 24, 25 et 31 décembre, 1er janvier. Sujet: LE VIDE

NB: Les émissions du samedi sont réécoutables durant une
semaine via le site de Memo.

La dernière émission est écoutable via le lien: http://www.rtbf.be/media/radio/alademande/prem_curieux_1700/DI_play.m3u

***********************

- Les auteurs de science-fiction ne
sont pas tous des hommes de science, loin de là, et la
crédibilité scientifique des scénarii ne
constitue pas l’élément essentiel d’un bon roman de
SF. Certains auteurs mettent néanmoins un point d’honneur à
valider les hypothèses originales formant la trame de leurs
récits au regard de la science, de préférence
celle de pointe.

Par exemple, l’utilisation du vide comme source d’énergie a été développée par Arthur C. Clarke dans ses romans « The Songs of Distant Earth » ainsi que dans « 3001 : the Final Odyssey ». Après s’être informé des dernières recherches et consulté les experts en la matière, cet auteur - l’un des plus célèbres du XXe siècle- s’est passionné pour les applications technologiques fantastiques qui pourraient découler de la manipulation du vide. De formation scientifique, il a été à plusieurs reprises à l’origine de concepts en avance sur leur temps. Citons entre autre l’orbite géostationnaire – les communications téléphoniques via satellite - HAL l’ordinateur psychologue - l'ascenseur spatial, etc.

Gageons que le recours au vide et à ses mystères n'en est qu'à ses début.**Quelques références:**

« Les chroniques de Mac Andrew », du physicien Charles Sheffield

“Vacuum States”, de Geoffrey A. Landis, Asimov's Science Fiction, July 1988

“Ripples in the Dirac Sea”, Asimov's Science Fiction, Oct. 1988.

“River of Gods”, de Ian McDonald, Simon & Schuster, 2004 (583 pages)

*******************

Contact:
ADAM&EVQ**©
M. Hermans - T. Dang Vu, 1997-2006**

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