Discussion:
Hydrogène métallique
(trop ancien pour répondre)
François Guillet
2017-01-30 17:26:41 UTC
Permalink
Raw Message
Il a été obtenu :
https://phys.org/news/2017-01-metallic-hydrogen-theory-reality.html

J'y lis que l'hydrogène métallique pourrait être supraconducteur à
température ambiante. Ce serait révolutionnaire et même pas un test de
supraconductivité de leur échantillon ?!
Quand on fait de l'hydrogène métallique, c'est le premier truc à voir,
mais qu'est-ce qu'ils fichent à publier quand ils devraient être au
labo à bosser ?!
r***@pla.net.invalid
2017-01-30 17:55:29 UTC
Permalink
Raw Message
Post by François Guillet
https://phys.org/news/2017-01-metallic-hydrogen-theory-reality.html
j'ai lu ailleurs (Nature...) qu'il y avait de gros doutes.
--
Fabrice
Sylvain
2017-01-30 19:55:39 UTC
Permalink
Raw Message
Post by François Guillet
https://phys.org/news/2017-01-metallic-hydrogen-theory-reality.html
J'y lis que l'hydrogène métallique pourrait être supraconducteur à
température ambiante. Ce serait révolutionnaire et même pas un test de
supraconductivité de leur échantillon ?!
Quand on fait de l'hydrogène métallique, c'est le premier truc à voir, mais
qu'est-ce qu'ils fichent à publier quand ils devraient être au labo à
bosser ?!
Tu es abonné au même truc que moi !!!

A mon avis même si c'est supraconducteur je n'en vois pas trop l'intérêt vu
la difficulté a maintenir de l'hydrogéne métallique a température ambiante.
C'est beaucoup plus simple de prendre un supraconducteur classique et de la
refroidir
François Guillet
2017-01-31 10:03:44 UTC
Permalink
Raw Message
Sylvain a présenté l'énoncé suivant :
...
Post by Sylvain
A mon avis même si c'est supraconducteur je n'en vois pas trop l'intérêt vu
la difficulté a maintenir de l'hydrogéne métallique a température ambiante.
...

Au contraire, et c'est pour ça que j'ai passé l'info ici : il n'est pas
question de température mais de pression, et ils disent justement que
même après libération de la pression, l'hydrogène reste dans sa forme
métallique.
jc_lavau
2017-01-30 21:09:57 UTC
Permalink
Raw Message
Post by François Guillet
https://phys.org/news/2017-01-metallic-hydrogen-theory-reality.html
J'y lis que l'hydrogène métallique pourrait être supraconducteur à
température ambiante. Ce serait révolutionnaire et même pas un test de
supraconductivité de leur échantillon ?!
Quand on fait de l'hydrogène métallique, c'est le premier truc à voir,
mais qu'est-ce qu'ils fichent à publier quand ils devraient être au labo
à bosser ?!
Poisson d'avril !
--
http://jacques.lavau.deonto-ethique.eu/Physique/Microphysique_contee.pdf
http://jacques.lavau.deonto-ethique.eu/Physique/4e_couverture.pdf
http://deontologic.org/quantic
Lucas Levrel
2017-02-17 10:33:14 UTC
Permalink
Raw Message
Post by François Guillet
https://phys.org/news/2017-01-metallic-hydrogen-theory-reality.html
------------------------------------------------------------------------------
\\
arXiv:1702.04246
Date: Mon, 13 Feb 2017 16:37:39 GMT (355kb)
Title: Comment on Observation of the Wigner-Huntington transition to metallic
hydrogen
Authors: Alexander F. Goncharov and Viktor V. Struzhkin (Geophysical
Laboratory, Carnegie Institution of Washington, DC)
Categories: cond-mat.mtrl-sci
Comments: 3 pages, 1 figure
\\
A recent paper of Dias and Silvera (DS) reports on production of metallic
hydrogen in a diamond anvil cell at 495 GPa at 5.5 and 83 K. The results are
implied to have a great impact on energy and rocketry. Here we argue that the
presented (very scarce) results are contradictory with the presented
experimental description making their claims unsupported experimentally.
Moreover, the proposed implications are highly speculative making this paper
very confusing for a broad audience. Elucidating the claims and the related
implications is important for building a coherent picture that is currently
emerging as the results of theoretical calculations at various levels and
experimental investigations employing static and dynamic compression
techniques. There is no doubt that hydrogen metallizes at high pressures. But
this does not make all claims about reaching this state immediately valid.
Scientific community would like to learn at what conditions hydrogen
metallizes, what is the nature of the conducting state and its properties (e.g.
superconductivity). Here we argue that the presented data do not provide any
reliable information on this.
\\ ( https://arxiv.org/abs/1702.04246 , 355kb)
------------------------------------------------------------------------------
--
LL
Ἕν οἶδα ὅτι οὐδὲν οἶδα (Σωκράτης)
François Guillet
2017-02-19 17:40:06 UTC
Permalink
Raw Message
Post by François Guillet
https://phys.org/news/2017-01-metallic-hydrogen-theory-reality.html
------------------------------------------------------------------------------
\\
arXiv:1702.04246
Date: Mon, 13 Feb 2017 16:37:39 GMT (355kb)
Title: Comment on Observation of the Wigner-Huntington transition to metallic
hydrogen
Authors: Alexander F. Goncharov and Viktor V. Struzhkin (Geophysical
Laboratory, Carnegie Institution of Washington, DC)
Categories: cond-mat.mtrl-sci
Comments: 3 pages, 1 figure
\\
A recent paper of Dias and Silvera (DS) reports on production of metallic
hydrogen in a diamond anvil cell at 495 GPa at 5.5 and 83 K. The results are
implied to have a great impact on energy and rocketry. Here we argue that the
presented (very scarce) results are contradictory with the presented
experimental description making their claims unsupported experimentally.
Moreover, the proposed implications are highly speculative making this paper
very confusing for a broad audience. Elucidating the claims and the related
implications is important for building a coherent picture that is currently
emerging as the results of theoretical calculations at various levels and
experimental investigations employing static and dynamic compression
techniques. There is no doubt that hydrogen metallizes at high pressures. But
this does not make all claims about reaching this state immediately valid.
Scientific community would like to learn at what conditions hydrogen
metallizes, what is the nature of the conducting state and its properties (e.g.
superconductivity). Here we argue that the presented data do not provide any
reliable information on this.
\\ ( https://arxiv.org/abs/1702.04246 , 355kb)
------------------------------------------------------------------------------
C'est quasiment une accusation de fraude !
Lucas Levrel
2017-02-20 10:34:15 UTC
Permalink
Raw Message
Post by François Guillet
Post by François Guillet
https://phys.org/news/2017-01-metallic-hydrogen-theory-reality.html
------------------------------------------------------------------------------
\\
\\ ( https://arxiv.org/abs/1702.04246 , 355kb)
------------------------------------------------------------------------------
C'est quasiment une accusation de fraude !
Et ça continue !

------------------------------------------------------------------------------
\\
arXiv:1702.05125
Date: Thu, 16 Feb 2017 19:34:08 GMT (1014kb)

Title: Comments on the claimed observation of the Wigner-Huntington
Transition to Metallic Hydrogen
Authors: M.I. Eremets, A. P. Drozdov
Categories: cond-mat.mtrl-sci cond-mat.other
\\
In their recent work Dias and Silvera (Science 2017) claim to have
observed the Wigner-Huntington transition of hydrogen to a metallic state
(MH) at a pressure of 495 GPa at low temperatures. The evidence for this
transition is based on a high electron carrier density deduced from a
Drude free electron model fitted to the reflectivity of the sample. Based
on our analysis of the reflectivity data we find no convincing evidence
for metallic hydrogen in their published data. The pressure determination
is also ambiguous - it should be ~630 GPa according to the presented Raman
spectrum. For comparison, we present our own data on the observation of
highly reflecting hydrogen at pressures of 350-400 GPa. The appearance of
metallic reflectivity is accompanied with a finite electrical conductivity
of the sample. We argue that the actual pressure in the experiment of Dias
and Silvera is likely below 400 GPa. In this case the observed enhanced
reflectivity would be related to the phase transformation to conductive
state published in arXiv:1601.04479.
\\ ( https://arxiv.org/abs/1702.05125 , 1014kb)
Lucas Levrel
2017-02-24 13:28:26 UTC
Permalink
Raw Message
Post by Lucas Levrel
Post by François Guillet
Post by François Guillet
https://phys.org/news/2017-01-metallic-hydrogen-theory-reality.html
------------------------------------------------------------------------------
\\ ( https://arxiv.org/abs/1702.04246 , 355kb)
------------------------------------------------------------------------------
C'est quasiment une accusation de fraude !
Et ça continue !
------------------------------------------------------------------------------
\\ ( https://arxiv.org/abs/1702.05125 , 1014kb)
------------------------------------------------------------------------------
Jamais 2 sans 3 :

------------------------------------------------------------------------------
\\
arXiv:1702.07192 (*cross-listing*)
Date: Thu, 23 Feb 2017 12:33:22 GMT (320kb)

Title: Comment on: Observation of the Wigner-Huntington transition to
metallic hydrogen
Authors: Paul Loubeyre, Florent Occelli, Paul Dumas
Categories: cond-mat.other cond-mat.mtrl-sci
Comments: 6 pages, 3 figures
\\
In a recently published article [1], Ranga P. Dias & Isaac F. Silvera
have reported the visual evidence of metallic hydrogen concomitantly with
its characterization at a pressure of 495 GPa and low temperatures. We
have expressed serious doubts of such a conclusion when interviewed to
comment on this publication [2,3]. In the following comment, we would like
to detail the reasons, based on experimental evidences obtained by us and
by other groups worldwide that sustain our skepticism. We have identified
two main flaws in this paper, as discussed in details below: the pressure
is largely overestimated; the origin of the sample reflectivity and the
analysis of the reflectance can be seriously questioned.
\\ ( https://arxiv.org/abs/1702.07192 , 320kb)

Loading...