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Condensed Matter Super-Radiant Phase Transition

  1. Feb 6, 2012 #1
    Is anyone familiar with this or heard of this concept before?

    It started in 1953 by a paper by Dicke published in peer reviewed Physical Review Journal called "Coherence in Spontaneous Radiation Processes" http://prola.aps.org/abstract/PR/v93/i1/p99_1

    Then in 1973 Hepp and Lieb published in peer reviewed papers "K. Hepp, E.H. Lieb, Phys. Rev. A 8 (1973) 2517. and K. Hepp, E.H. Lieb, Ann. Phys. 76 (1973)" concerning these Super-Radiant Phase Transition in condensed matter.

    Or by way of summary:

    "Dicke formulated a model which was later shown to exhibit a super-radiant phase
    transition (by Hepp and Lieb). The notion that such phase transitions should exist in condensed matter systems has been investigated in a series of papers by Preparata and coworkers [4–6] and others [7–9]. Different workers have come to somewhat different conclusions concerning super-radiant phase transitions [10–19]. Some doubt has been expressed [20–24] concerning the physical laboratory reality of super-radiant phase transition.

    The mathematical issues are as follows: (i) It appears, at first glance, that quadratic
    terms (in photon creation and annihilation operators) enter into the model via quadratic
    terms inthe vector potential A. (ii) The quadratic terms in the “corrected Dicke model”
    appear to destroy the super-radiant phase transition.

    Then many works show that if the dipole–field interactionis treated in a gauge invariant manner [25–27] then the interaction is strictly linear in the electric field E. Thus, quadratic terms are absent for purely electric dipole–photon interactions [28]. These considerations render likely the physical reality of condensed matter super-radiant phase transitions."

    (from http://arxiv.org/abs/cond-mat/0007374)

    What do you make of this? Preparata and others have shown many experimental results.

    http://arxiv.org/abs/cond-mat/9801248
    http://arxiv.org/abs/quant-ph/9804006

    Has anyone encountered the concepts mentioned in this message before? Can you please comment especially experts in Condensed Matter (and even the not so experts). If confirmed. The implications would be significant. Latest paper concerning the original peer reviewed concept or ideas was just last January 31, 2012 for example in http://arxiv.org/pdf/1108.2987.pdf
     
  2. jcsd
  3. Feb 8, 2012 #2

    Cthugha

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    Superradiant phenomena in solid state systems do exist, see e.g. "Superradiance of quantum dots" by M. Scheibner et al., Nature Physics 3, 106 - 110 (2007).

    However, that mostly means that you have an ensemble of emitters, but cannot picture them as individual emitters anymore because they couple to a common electromagnetic field and these effects become prominent. It is sometimes very vaguely described as lasing without cavity. However, I fail to see any connection to the two publications you cite near the end of your post (not the last one, the two before).

    The no-go theorem given in ref. 20 inside the publication you cited is valid for equilibrium situations. Ways around that have been shown in "Dicke quantum phase transition with a superfluid gas in an optical cavity" by Baumann et al. (Nature 464, 1301–1306 (29 April 2010)). A thorough theoretical discussion is given in "Collective Dynamics of Bose-Einstein Condensates in Optical Cavities" by Jonathan Keeling et al. (Phys. Rev. Lett. 105, 043001 (2010)) who is by the way one of the best explaining theoreticians I ever had the pleasure of talking to.
     
  4. Feb 8, 2012 #3
    This is how the two papers before the last is related to it all. In the same paper where you cited ref. 20, see ref. 30 which is about "G. Preparata, “QED Coherence in Matter”, World Scientific,
    Singapore (1995)." and in amazon it says:

    https://www.amazon.com/Qed-Coherenc...2491/ref=sr_1_1?ie=UTF8&qid=1328702127&sr=8-1

    Descriptions: "The dominant view of condensed matter physics has traditionally been that of an "electro-static MECCANO" (or erector set). This work represents a systematic attempt to consider the full quantum electrodynamical interaction, thus enriching the possible dynamical mechanisms that operate in the construction of the variety of condensed matter systems, including life itself. A new paradigm is emerging, replacing the "electrostatic MECCANO" with an "electrodynamic NETWORK," which builds condensed matter through the long range (as opposed to the "short range" nature of the usual electrostatic forces) electrodynamical interaction; this interaction creates "coherent configurations" of the elementary systems (atoms and molecules), which oscillate in phase with a coherent macroscopic (and classical) electromagnetic field that through the strong interaction with matter, remains trapped inside it."

    Hence in the last two papers before the last one. Preparata was showing the results or rationale for it. What do you make of it? The Preparata book was cited in many new papers like the one where you cited ref 20. on the "no-go".
     
  5. Feb 8, 2012 #4

    Cthugha

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    You need very specific tailored systems under very well defined conditions to see any effects of superradiance or superluminescence in solid state systems. BECs or such fine-tailored systems are not routinely found in everyday life and in almost all systems these "long range" effects can be safely neglected.

    By the way, your claim "The Preparata book was cited in many new papers" should be taken with care. At least 80 % of the citations come from crackpot journals about homeopathy, articles about cold fusion, articles about coherence in the brain or other biological tissue and other nonsensic stuff. I do not claim that the book is complete rubbish, but it contains overly speculative elements which invited lots of crackpots to use it as a basis in arguing for their crackpot ideas, so one should be quite careful reading that book. Also Preparata was pretty open for obvious crackpottery in his late days.
     
  6. Feb 8, 2012 #5
    Thanks. He and Del Giudice has written a paper at Physical Review Letters which is heavily cited by many crank groups.

    http://prl.aps.org/abstract/PRL/v61/i9/p1085_1

    "Water as a Free Electric Dipole Laser"

    "Abstract: We show that the usually neglected interaction between the electric dipole of the water molecule and the quantized electromagnetic radiation field can be treated in the context of a recent quantum field theoretical formulation of collective dynamics. We find the emergence of collective modes and the appearance of permanent electric polarization around any electrically polarized impurity."

    Has this been disputed already? How did the mistakes occur? Also papers published in Physical Review Letters are supposed to be peer-reviewed, isn't it?
     
  7. Feb 8, 2012 #6

    Cthugha

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    Hmm, I did not study that paper, but in general there are several possibilities to become a standard crackpot quote. Maybe a paper is quoted completely out of context (which may be the case here, but the same guys were also involved in the cold fusion fiasco, which seems suspicious) or people draw conclusions which are not stated in the paper.

    Also peer review is good for identifying whether the present data allows for drawing the conclusions presented in a paper, but is not designed to identify fraud (e.g. manipulated data). Finally, peer review also has a certain chance to simply fail. Also, some possible theories may be rendered wrong over the course of time.
     
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