Intermediate structure and doorway states in nuclear reactions

Feshbach, Herman; Kerman, A.K.; Lemmer, R. H.

doi:10.1016/0003-4916(67)90235-7

Cited by 407 publications

(98 citation statements)

References 27 publications

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“…It should be mentioned that similar Fourier spectra have also been observed in many different seisms. On the other hand, a similar phenomenon has been observed in many instances in nuclear experiments [19].…”

Section: Copyright C Epla 2011supporting

confidence: 82%

Novel doorways and resonances in large-scale classical systems

Franco-Villafañe¹,

Flores²,

Mateos³

et al. 2011

EPL

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We show how the concept of doorway states carries beyond its typical applications and usual concepts. The scale on which it may occur is increased to large classical wave systems. Specifically we analyze the seismic response of sedimentary basins covered by water-logged clays, a rather common situation for urban sites. A model is introduced in which the doorway state is a plane wave propagating in the interface between the sediments and the clay. This wave is produced by the coupling of a Rayleigh and an evanescent SP -wave. This in turn leads to a strong resonant response in the soft clays near the surface of the basin. Our model calculations are compared with measurements during Mexico City earthquakes, showing quite good agreement. This not only provides a transparent explanation of catastrophic resonant seismic response in certain basins but at the same time constitutes up to this date the largest-scale example of the doorway state mechanism in wave scattering. Furthermore the doorway state itself has interesting and rather unusual characteristics.

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Section: Copyright C Epla 2011supporting

confidence: 82%

Novel doorways and resonances in large-scale classical systems

Franco-Villafañe¹,

Flores²,

Mateos³

et al. 2011

EPL

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“…Thanks to the availability of short, femtosecond laser pulses both the control of reactions by coherent light ( [16], [84]- [94]) and the probing of phases in a wave packet are now experimental possibilities ( [19], [95] - [97]). With short duration excitations the initial form of the wave packet is a real "doorway state" ( [98]- [100]) and this develops phases for each of its component amplitudes as the wave-packet evolves. It has recently been shown that the phases of these components are signposts of a time arrow ([101]- [102]) and of the irreversibility; both of these are inherent in the quantum mechanical process of preparation and evolution [34].…”

Section: Introduction and Preview Of The Chaptermentioning

confidence: 99%

Complex States of Simple Molecular Systems

Englman¹,

Yahalom²

2002

Advances in Chemical Physics

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A review is given of phase properties in molecular wave functions, composed of a number of (and, at least, two) electronic states that become degenerate at some nearby values of the nuclear configuration. Apart from discussing phases and interference in classical (non-quantal) systems, including light-waves, the review looks at the constructability of complex wave functions from observable quantities ("the phase problem"), at the controversy regarding quantum mechanical phase-operators, at the modes of observability of phase and at the role of phases in some non-demolition measurements. Advances in experimental and (especially) theoretical aspects of Aharonov-Bohm and topological (Berry) phases are described, including those involving two-electron and relativistic systems. Several works in the phase control and revivals of molecular wave-packets are cited as developments and applications of complex-function theory. Further topics that this review touches on are: coherent states, semiclassical approximations and the Maslov index. The interrelation between time and the complex state is noted in the contexts of time delays in scattering, of time-reversal invariance and of the existence of a molecular time-arrow.When the stationary Born-Oppenheimer description for nearly degenerate state is regarded as "embedded" in a broader dynamic formulation, namely through solution of the time dependent Schrödinger equation, the wave function becomes necessarily complex. The analytic behavior of this function in the complex time-plane can be exploited to gain information about the connection between phases and moduli of the componentamplitudes. One form of this connection are a pair of reciprocal (Kramers-Kronig type) relations in the complex time-domain. These show that certain phase changes in a component amplitude (such as, e.g., lead to a non-zero Berry-phase) require changes in the amplitude-moduli, too, and imply degeneracies of the electronic state.The subject of conical degeneracy, or intersection, of adjacent potential surface is extended to nonlinear nuclear-electronic coupling, which can then result in multiple conical degeneracies on a nuclear coordinate plane. We treat cases of double and fourfold intersections, the latter under trigonal symmetry, and employ an analytic-graphical phase tracing method to obtain the resulting Berry phases as the system circles around some or all of the degeneracy points. These phases can take up values that are all integral multiples of π, with integers that vary with the physical situation (or with the model postulated for it).A further type of invariance, with respect to gauge transformation, is also tied to the complex form of the wave function. For a many-component state this leads to a consideration of tensorial (Yang-Mills type) fields F for molecular systems. It is shown that it is the truncation of the Born-Oppenheimer electron-nuclear superposition that generates the molecular Yang-Mills fields.The equations of motion for the nuclear degrees of freedom are derived from a Lagr...

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“…We apply this approach to particles, especially here to neutral scalar mesons. The formal ansatz is as follows (see [18])…”

Section: The Qq (Qq)mentioning

confidence: 99%

Structure of scalar mesons and the Higgs sector of strong interaction

Schumacher

2011

J. Phys. G: Nucl. Part. Phys.

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The scalar mesons σ(600), κ(800), f 0 (980) and a 0 (980) together with the pseudo Goldstone bosons π, K and η may be considered as the Higgs sector of strong interaction. After a long time of uncertainty about the internal structure of the scalar mesons there now seems to be consistency which is in line with the major parts of experimental observations. Great progress has been made by introducing the unified model of Close and Törnqvist. This model states that scalar mesons below 1 GeV may be understood as q 2q2 in S-wave with some qq in P -wave in the center, further out they rearrange as (qq)2 and finally as meson-meson states. The P -wave component inherent in the structure of the neutral scalar mesons can be understood as a doorway state for the formation of the scalar meson via two-photon fusion, whereas in nucleon Compton scattering these P-wave components serve as intermediate states. The masses of the scalar mesons are predicted in terms of spontaneous and explicit symmetry breaking.

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Intermediate structure and doorway states in nuclear reactions

Cited by 407 publications

References 27 publications

Novel doorways and resonances in large-scale classical systems

Novel doorways and resonances in large-scale classical systems

Complex States of Simple Molecular Systems

Structure of scalar mesons and the Higgs sector of strong interaction

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