1,029 research outputs found
Thermalized non-equilibrated matter and high temperature superconducting state in quantum many-body systems
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(,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
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+D 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
We discuss the effect of slow phase relaxation and the spin off-diagonal
-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
intermediate complex, Schr\"odinger cat states and
quantum-classical transition are studied for Mg+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
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
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
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
Mortality of hospital or community-acquired Legionnairesâ disease (LD): a prospective study
Periodic Orbits and Escapes in Dynamical Systems
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
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
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 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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