Comparison of various types of coherence and emergent coherent systems

Squire, Richard H.; March, N. H.; Minnick, Rebecca A.; Turschmann, Richard

doi:10.1002/qua.24423

Cited by 4 publications

(2 citation statements)

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“…when γ ≈ 0. The reasonable mechanism of the reduced relaxation of protein collective motion may be linked to the interaction of macromolecules with their environment, for example with ordered water clusters possessing slow dynamics (Xie, van der Meer and Austin, 2002;Squire et al, 2013). Another mechanism of slow relaxation of the collective modes was suggested to be based on the experimental observation of vibrational wave packets of a long lifetime over 500 picoseconds in bacteriorhodopsin exposed by picosecond far IR sources (Xie, van der Meer and Austin, 2002).…”

Section: Vibrational Dynamics Of α-Helical Protein In a Long Wave Appmentioning

confidence: 99%

Collective excitations in α-helical protein structures interacting with the water environment

Kadantsev

Goltsov

2020

Electromagnetic Biology and Medicine

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Low-frequency vibrational excitations of protein macromolecules in the terahertz frequency region are suggested to contribute to many biological processes such as enzymatic activity, energy/charge transport, protein folding, and others. To explain high effectiveness of energy storage and transport in proteins, two possible mechanisms of the long-lived excitation in proteins were proposed by H. Fröhlich and A.S. Davydov in the form of either vibrational modes or solitary waves, respectively. In this paper, we developed a quantum dynamic model of vibrational excitation in α-helical proteins interacting with their environment formed by water molecules. In the model, we distinguished three coupled subsystems, i.e. (i) a chain of hydrogen-bonded peptide groups (PGs), interacting with (ii) the subsystem of side residuals which in turn interacts with (iii) the environment, surrounding water responsible for dissipation and fluctuation processes in the system. It was shown that under reasonable approximations the equation of motion for phonon variables of the PG chain can be transformed to nonlinear Schrodinger equation for order parameter which admits bifurcation into the solution corresponding to weak damped vibrational modes (Fröhlich-type regime). A bifurcation parameter in the model is derived through the strength of interaction between alpha-helical protein and its environment. As shown, in the bifurcation region, a solution corresponding to Davydov soliton can exist. The suggested mechanism underlying emerging macroscopic dissipative structures in the form of collective vibrational modes is discussed in connection with the recent experimental data on the long-lived collective protein excitations in the terahertz frequency region.

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Section: Vibrational Dynamics Of α-Helical Protein In a Long Wave Appmentioning

confidence: 99%

Collective excitations in α-helical protein structures interacting with the water environment

Kadantsev

Goltsov

2020

Electromagnetic Biology and Medicine

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“…The original Bardeen, Cooper, Schrieffer (BCS) theory (for a recent topical review, see ) begins with a rather weak attraction between phonons and electrons described by the Fröhlich Hamiltonian which leads to an instability of the “normal” electron bonding pattern near the boundary between filled energy levels (Fermi sea) and unfilled levels. The resulting overall energy follows from a competition between the usually dominant Coulomb potential and the weak attraction mentioned.…”

Section: Brief Reviewmentioning

confidence: 99%

Are there really cooper pairs and persistent currents in aromatic molecules?

Squire

March

Rubio

2014

Int J of Quantum Chemistry

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Over twenty years ago one of us suggested the title was affirmative. In 2012 Cooper pairs were identified in several, but not all "aromatic" compounds tested, benzene being one. This manuscript discusses the formation of three time-reversed pairs of states forming pseudobosons (high energy Cooper pairs) in benzene at room temperature. The large stabilization in energy that results is the additive effect of energy gaps of an s wave state and a charge density wave permitting the pseudobosons to exist at room temperature. The overall result of these interactions is three pseudobosons occupying the lowest boson state and the positions of the carbon nuclei are optimum by forming a perfect hexagon. The possibility of a persistent current exists; detection might not be easy. 2 1. Introduction. Over twenty years ago we proposed that the formation of highly correlated electron pairs, possibly a high energy form of Cooper pairs, might explain why certain organic compounds such as benzene have a much more stable ground state than might be expected by eV [1,2]. We were not completely satisfied with our article since the prevalent thought on the upper temperature limit with a phonon mechanism is c T 30K  [3]; today it is speculated to be as high as 170K [4]. Also, our use of perturbation theory seemed inappropriate for such a large energy. Indeed, we were unaware that in the 1950's Feynman tried to deduce a theory of superconductivity by an infinite order perturbation theory summation on the Frohlich  electronphonon interaction; the sum was zero. He did not succeed because the energy gap related to the electron-phonon interaction has an essential singularity which cannot be solved by a power series [5]. The purpose of this manuscript is to propose a more complete theory of benzene and other organics including recent developments which encompass the gist of the original publication [1]. An outline of this manuscript begins with section 2, a brief review of superconductivity followed by new considerations in section 3. Section 4 discusses topological aspects while section 5 contains a summary, conclusions, and possibilities for future work.

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