Coexistence of regular and irregular dynamics in complex networks of pulse-coupled oscillators

For general networks of pulse-coupled oscillators, including regular, random, and more complex networks, we develop an exact stability analysis of synchronous states. As opposed to conventional stability analysis, here stability is determined by a multitude of linear operators. We treat this multioperator problem exactly and show that for inhibitory interactions the synchronous state is stable, independent of the parameters and the network connectivity. In randomly connected networks with strong interactions this synchronous state, displaying regular dynamics, coexists with a balanced state exhibiting irregular dynamics. External signals may switch the network between qualitatively distinct states.     

Coexistence of cluster and shell-model aspects in nuclear systems

We discuss cluster phenomena in light nuclei. As examples of typical cluster structures, we first review cluster structures of ¹²C, ¹⁶O, and ²⁰Ne, and then introduce some topics of cluster phenomena in light neutron-rich nuclei such as Be and C isotopes. A particular attention is paid on coexistence of cluster and shell-model aspects.     

Border between regular and chaotic quantum dynamics

We identify a border between regular and chaotic quantum dynamics. The border is characterized by a power-law decrease in the overlap between a state evolved under chaotic dynamics and the same state evolved under a slightly perturbed dynamics. For example, the overlap decay for the quantum kicked top is well fitted with [1+(q-1)(t/tau)2](1/(1-q)) (with the nonextensive entropic index q and tau depending on perturbation strength) in the region preceding the emergence of quantum interference effects. This region corresponds to the edge of chaos for the classical map from which the quantum chaotic dynamics is derived.     

Theory of phase dynamics in intrinsic Josephson junctions with multigap superconducting layers

We construct a theory of dynamical behavior in intrinsic Josephson junction stacks with multigap superconducting layers. The theory predicts the existence of two kinds of phase modes, one of which is the Josephson-plasma mode and other of which is the Leggett’s mode. We discuss a cooperative phenomena induced by inter-band Josephson coupling in addition to capacitive and inductive couplings between the superconducting layers.     

The complexity of proving chaoticity and the Church-Turing thesis

Proving the chaoticity of some dynamical systems is equivalent to solving the hardest problems in mathematics. Conversely, classical physical systems may "compute the hard or even the incomputable" by measuring observables which correspond to computationally hard or even incomputable problems.     

Chiral dynamics of nuclear saturation

We apply the relativistic chiral Lagrangian to the nuclear equation of state. An effective chiral power expansion scheme, which is constructed to work around nuclear saturation density, is presented. The leading and subleading terms are evaluated and are shown to provide an excellent equation of state. Our saturation mechanism is found to probe in detail the underlying pion dynamics.     

氢分子离子库仑爆炸中核动力学的理论研究

在非Born-Oppenheimer近似条件下, 通过数值求解一维含时薛定谔方程, 理论模拟了氢分子离子处于不同初始核振动态的库仑爆炸核动能释放谱并探究了氢分子离子发生库仑爆炸时的核动力学. 数值结果表明: 初始核振动态的选取在很大程度上影响着氢分子离子发生库仑爆炸时的核动力学,且高低振动态的选取分别对其核动力学的影响呈现出相反的变化趋势.     

Observation of chaotic and regular dynamics in atom-optics billiards

We report on experimental observations of chaotic and regular motion of ultracold atoms confined by a billiard-shaped optical dipole potential induced by a rapidly scanning laser beam. To investigate the dynamics of the atoms confined by such an "atom-optics" billiard we measure the decay of the number of trapped atoms through a hole on the boundary. A fast and purely exponential decay, the clear signature of chaotic motion, is found for a stadium billiard, but not for a circular or an elliptical billiard, in agreement with theory. We also investigated the effects of decoherence, velocity spread, and gravity on regular and chaotic motion.     

Generation and intrinsic dynamics of ring dark solitary waves

 We present experimental results on the evolution of ring dark solitary waves generated by computer-synthesized holograms. The data obtained and the detailed comparative numerical simulations show that this approach ensures reproduction of the correct intensity and phase portrait of the dark wave at the entrance of the nonlinear medium. The transverse dynamics at both even and odd initial conditions is studied and compared with the theory and simulations. Received: 24 June 1996     

New features in collective dynamics of intrinsic Josephson junctions

We discuss the breakpoint phenomenon, which reflects a resonance between Josephson and plasma oscillations in the system of coupled Josephson junctions. The resonance leads to the creation of the longitudinal plasma waves (LPW) at the breakpoint and to the oscillation dependence of the breakpoint current as a function of the dissipation and coupling parameters. A group behavior of the current-voltage characteristics (IVC) of the stacks with different number of junctions is predicted. Particularly, in the materials with dissipation parameter β=0.35 and coupling parameter α=3, we expect four groups of the IVC, which demonstrate a different character of changing of the breakpoint current with the number of junctions in the stack. Using the k-αβ-method, we find the values of the wave numbers k of the LPW and explain this group behavior of the IVC.     

Tasting nuclear pasta made with classical molecular dynamics simulations

Recently the AMS-02 reported the precise measurements of the energy spectra of medium-mass compositions (Neon, Magnesium, Silicon) of primary cosmic rays, which reveal different properties from those of light compositions (Helium, Carbon, Oxygen). Here we propose a nearby source scenario, together with the background source contribution, to explain the newly measured spectra of cosmic ray Ne, Mg, Si, and particularly their differences from that of He, C, O. Their differences at high energies can be naturally accounted for by the element abundance of the nearby source. Specifically, the abundance ratio of the nearby source to the background of the Ne, Mg, Si elements is lower by a factor of ~ 1.7 than that of the He, C, O elements. Such a difference could be due to the abundance difference of the stellar evolution of the progenitor star or the acceleration process/environment, of the nearby source. This scenario can simultaneously explain the high-energy spectral softening features of cosmic ray spectra revealed recently by CREAM/NUCLEON/DAMPE, as well as the energy-dependent behaviors of the large-scale anisotropies. It is predicted that the dipole anisotropy amplitudes below PeV energies of the Ne, Mg, Si group are smaller than that of the He, C, O group, which can be tested with future measurements.

     

Vorticity in nuclear fluid dynamics

We consider a model for gloun jet fragmentation based on QCD in which the fast hadrons in the jet are produced by the sequential reaction gluon $\text{→}\text{q}\text{q}\text{?}\text{q}\text{→}$ hadrons. The resulting jet shows an oblate transverse momentum structure, with a major axis preferential oriented normally to the direction of linear polarization of the gluon. We discuss jet-jet oblateness angular correlations in decays of heavy QQ? pseudoscalar and vector systems.     

One-body dissipation and nuclear dynamics

We discuss recent developments in the “one-body” dissipation theory described in B?ocki et al. [Ann. Phys. (N.Y.)113 (1978), 330]. The principal new result is the derivation of the functional form of the dissipation expression (the Rayleigh Dissipation Function) for a finite idealized nucleus with a diffuse surface, in the form of an expansion in powers of the dimensionless ratio of the surface diffuseness to the size, R, of the system. The leading term in such an expansion is a surface contribution, of relative order R², in the form of the “Wall Formula” of B?ocki et al. The next is a curvature correction of order R. At the next level (R⁰) there are two higher order curvature corrections and a correction for the presence of gradients in the normal velocity field specifying the motion of the surface. For simple models of the nuclear surface profile we work out analytically the coefficients in the curvature and velocity-gradient correction terms. We compare the one-body dissipation theory formulated in this way with recent linear-response and Time-Dependent Hartree-Fock treatments of the nuclear problem. The principal theme that emerges from this study is the close analogy between the problem of the nuclear macroscopic dissipation function and the problem of the nuclear macroscopic potential energy.     

The breaking of intrinsic reflection symmetry in nuclear ground states

Negative-parity excited states of doubly even nuclei have earlier been attributed to vibrational excitations. This paper shows that an interpretation starting from a reflection asymmetric intrinsic state is more appropriate for certain nuclei in the radium region. Theoretical evidence for stable octupole deformation comes from a deformed shell-model calculation in which we use a single-particle potential with a realistic radial shape and a finite-range interaction for the surface energy. The octupole effect systematically improves the agreement between theoretical and experimental masses. The low-lying O⁺ excitations observed in experiment are compatible with the calculated collective octupole potentials. The possibility of obtaining further evidence from the spectroscopy of odd-mass nuclei is considered in an exactly solvable model, which shows that the smaller energy splitting observed in odd-A parity doublets mainly reflects single-particle fragmentation of the collective mode. The systematics of theoretical shell structure and experimental spectroscopy suggests the presence of other regions of octupole collectivity near the limits of stability.     

Extension of Belyaev-Zelevinski method for rotation as intrinsic nuclear excitation

The method of Belyaev-Zelevinski is extended and it is extended and it is shown how more complicated forms of the rotational energy can be obtained in lowest order.     

Pion scattering and nuclear dynamics

A phenomenological optical-model analysis of pion elastic scattering and single- and doublecharge-exchange scattering to isobaric-analog states is reviewed. Interpretation of the opticalmodel parameters is briefly discussed, and several applications and extensions are considered. The applications include the study of various nuclear properties, including neutron deformation and surface-fluctuation contributions to the density. One promising extension for the near future would be to develop a microscopic approach based on powerful momentum-space methods brought to existence over the last decade. In this, the lowest-order optical potential as well as specific higher-order pieces would be worked out in terms of microscopic pion-nucleon and delta-nucleon interactions that can be determined within modern meson-theoretical frameworks. A second extension, of a more phenomenological nature, would use coupled-channel methods and shell-model wave functions to study dynamical nuclear correlations in pion double charge exchange.Invited talk to the symposium 'Mesons and Light Nuclei IV, Bechyn, Czechoslovakia, September 5–10, 1988.The author would like to express his appreciation to Dr. Mach and the organizers for their the hospitality at the Conference.     

The angular momentum distribution of the deformed intrinsic nuclear state

In a Hartree-Fock or Hartree-Foek-Bogoliubov calculation of a deformed intrinsic state, one obtains a distribution of angular momentum states. Using an analogy from statistical mechanics, we obtain an expression for this distribution. The concept of an average temperature for the intrinsic state is introduced, which is directly related to the rotational energy content of the intrinsic state. The relationship of this temperature to microscopic particle-hole calculations is clarified. Assuming a rotational spectrum for the ground-state band of an axially symmetric doubly even nucleus, it is demonstrated that the deduced distribution of the angular momentum states gives rise to an overlap function of the intrinsic wave function which falls off, for small angles of rotation, as a Gaussian. Finally, the Yoccoz formula for the moment of inertia is derived using classical statistical mechanics, and semiclassical corrections to it are obtained.