1,029 research outputs found

    Thermalized non-equilibrated matter and high temperature superconducting state in quantum many-body systems

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    A characteristic feature of thermalized non-equilibrated matter is that, in spite of energy relaxation--equilibration, a phase memory of the way the many-body system was excited remains. As an example, we analyze data on a strong forward peaking of thermal proton yield in the Bi(Îł\gamma,p) photonuclear reaction. New analysis shows that the phase relaxation in highly-excited heavy nuclei can be 8 orders of magnitude or even much longer than the energy relaxation. We argue that thermalized non-equilibrated matter resembles a high temperature superconducting state in quantum many-body systems. We briefly present results on the time-dependent correlation function of the many-particle density fluctuations for such a superconducting state. It should be of interest to experimentally search for manifestations of thermalized non-equilibrated matter in many-body mesoscopic systems and nanostructures.Comment: 12 pages, 1 eps figure. To be published in Radiation Effects and Defects in Solid

    Quantum-classical transition for an analog of double-slit experiment in complex collisions: Dynamical decoherence in quantum many-body systems

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    We study coherent superpositions of clockwise and anti-clockwise rotating intermediate complexes with overlapping resonances formed in bimolecular chemical reactions. Disintegration of such complexes represents an analog of famous double-slit experiment. The time for disappearance of the interference fringes is estimated from heuristic arguments related to fingerprints of chaotic dynamics of a classical counterpart of the coherently rotating complex. Validity of this estimate is confirmed numerically for the H+D2_2 chemical reaction. Thus we demonstrate the quantum--classical transition in temporal behavior of highly excited quantum many-body systems in the absence of external noise and coupling to an environment.Comment: 5 pages, 2 ps color figures. Accepted for publication in Phys. Rev.

    Slow cross-symmetry phase relaxation in complex collisions

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    We discuss the effect of slow phase relaxation and the spin off-diagonal SS-matrix correlations on the cross section energy oscillations and the time evolution of the highly excited intermediate systems formed in complex collisions. Such deformed intermediate complexes with strongly overlapping resonances can be formed in heavy ion collisions, bimolecular chemical reactions and atomic cluster collisions. The effects of quasiperiodic energy dependence of the cross sections, coherent rotation of the hyperdeformed ≃(3:1)\simeq (3:1) intermediate complex, Schr\"odinger cat states and quantum-classical transition are studied for 24^{24}Mg+28^{28}Si heavy ion scattering.Comment: 10 pages including 2 color ps figures. To be published in Physics of Atomic Nuclei (Yadernaya fizika

    Effect of phase relaxation on quantum superpositions in complex collisions

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    We study the effect of phase relaxation on coherent superpositions of rotating clockwise and anticlockwise wave packets in the regime of strongly overlapping resonances of the intermediate complex. Such highly excited deformed complexes may be created in binary collisions of heavy ions, molecules and atomic clusters. It is shown that phase relaxation leads to a reduction of the interference fringes, thus mimicking the effect of decoherence. This reduction is crucial for the determination of the phase--relaxation width from the data on the excitation function oscillations in heavy--ion collisions and bimolecular chemical reactions. The difference between the effects of phase relaxation and decoherence is discussed.Comment: Extended revised version; 9 pages and 3 colour ps figure

    Time-resolved broadband analysis of slow-light propagation and superluminal transmission of electromagnetic waves in three-dimensional photonic crystals

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    A time-resolved analysis of the amplitude and phase of THz pulses propagating through three-dimensional photonic crystals is presented. Single-cycle pulses of THz radiation allow measurements over a wide frequency range, spanning more than an octave below, at and above the bandgap of strongly dispersive photonic crystals. Transmission data provide evidence for slow group velocities at the photonic band edges and for superluminal transmission at frequencies in the gap. Our experimental results are in good agreement with finite-difference-time-domain simulations.Comment: 7 pages, 11 figure

    Towards a common thread in Complexity: an accuracy-based approach

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    The complexity of a system, in general, makes it difficult to determine some or almost all matrix elements of its operators. The lack of accuracy acts as a source of randomness for the matrix elements which are also subjected to an external potential due to existing system conditions. The fluctuation of accuracy due to varying system-conditions leads to a diffusion of the matrix elements. We show that, for the single well potentials, the diffusion can be described by a common mathematical formulation where system information enters through a single parameter. This further leads to a characterization of physical properties by an infinite range of single parametric universality classes

    Periodic Orbits and Escapes in Dynamical Systems

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    We study the periodic orbits and the escapes in two different dynamical systems, namely (1) a classical system of two coupled oscillators, and (2) the Manko-Novikov metric (1992) which is a perturbation of the Kerr metric (a general relativistic system). We find their simple periodic orbits, their characteristics and their stability. Then we find their ordered and chaotic domains. As the energy goes beyond the escape energy, most chaotic orbits escape. In the first case we consider escapes to infinity, while in the second case we emphasize escapes to the central "bumpy" black hole. When the energy reaches its escape value a particular family of periodic orbits reaches an infinite period and then the family disappears (the orbit escapes). As this family approaches termination it undergoes an infinity of equal period and double period bifurcations at transitions from stability to instability and vice versa. The bifurcating families continue to exist beyond the escape energy. We study the forms of the phase space for various energies, and the statistics of the chaotic and escaping orbits. The proportion of these orbits increases abruptly as the energy goes beyond the escape energy.Comment: 28 pages, 23 figures, accepted in "Celestial Mechanics and Dynamical Astronomy

    Opportunities, Constraints and Perceptions of Rural Communities Regarding Their Potential to Contribute to Forest Landscape Transitions Under REDD+: Case Studies from Mexico

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    In Mexico, REDD+ is being presented as a win-win policy enabling forest communities to benefit financially and diversify their income sources while preserving and increasing their forest carbon stocks through more sustainable management. Under the national programme, it is expected that forest communities will have opportunities to tailor their own approaches. However, to date there is little understanding about what opportunities and constraints exist in reality for forest communities to contribute to REDD+, and even less about how their members perceive these opportunities. We assess potential and constraints at community level and investigate perceptions about opportunities in REDD+ and strategies that communities are currently envisaging for participation, in seven communities in the Ayuquila River Basin and around the Chamela-Cuixmala Biosphere Reserve in Jalisco, and in the area surrounding the Monarch Butterfly Reserve in Michoacan. We find that there is more opportunity for reduced degradation and forest enhancement than for reduced deforestation, in all the communities; that it may be difficult to establish additionality for REDD+ activities in some communities; that the amount of forest resource per community may greatly affect the potential to participate; that the presence of people with no land rights may complicate the distribution of benefits; that communities expect REDD+ in general to follow the Payment for Environmental Services model, and that lack of information about what activities may count as REDD+ activities and what level of financial rewards may be expected mean that communities cannot at present adequately appraise whether REDD+ will be worth their while or no

    Macroscopic quantum superpositions in highly-excited strongly-interacting many-body systems

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    We demonstrate a break-down in the macroscopic (classical-like) dynamics of wave-packets in complex microscopic and mesoscopic collisions. This break-down manifests itself in coherent superpositions of the rotating clockwise and anticlockwise wave-packets in the regime of strongly overlapping many-body resonances of the highly-excited intermediate complex. These superpositions involve ∌104\sim 10^4 many-body configurations so that their internal interactive complexity dramatically exceeds all of those previously discussed and experimentally realized. The interference fringes persist over a time-interval much longer than the energy relaxation-redistribution time due to the anomalously slow phase randomization (dephasing). Experimental verification of the effect is proposed.Comment: Title changed, few changes in the abstract and in the main body of the paper, and changes in the font size in the figure. Uses revTex4, 4 pages, 1 ps figur
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