Application of the nonunitary model operator approach to the16O nucleus

The nonunitary model operator approach, which has been previously described, is applied to the¹⁶O nucleus. Approximate expressions are given for the ground-state energy of this nucleus, by using both variational methods with the separation condition, developed in our previous work. Simple hardand softcore potentials are employed in the computations and the results obtained with the two methods are discussed.     

Microscopic calculation of a model 16O nucleus

We present variational calculations for a hypothetical system of 16 nucleons interacting via the Malfliet-Tjon potential and compare our results with the Green-function Monte Carlo (GFMC) data of Helmbrecht et al.For a system of 16 bosons, we find that the (approximate) ground-state energy of our optimized hypernetted-chain calculation agrees with the GFMC data within 1%. For fermions, we find that the optimized Fermi hypernetted chain calculation leads to a ground state energy between the GFMC data and the variational Monte Carlo result with non-optimized correlations; the one-body density predicted by the FHNC theory agrees well with the one predicted by the GFMC calculation.     

Approximate solution of the problem of,nonsteady-state heat transfer in the active element of a laser

The mathematical formulation of the problem of nonsteady-state heat transfer in active laser crystals is considered. The variation method is used to obtain an approximate solution of the problem. The solution relates the basic laser characteristics (the dimensions and thermophysical characteristics of the crystal and the frequency and energy of the pumping pulses) in a form convenient for engineering computations.     

A translationally invariant RPA-calculation for16O on the basis of an algebraic solution of the many-body oscillator problem

The solution of the many-body oscillator problem is used as a basis for a RPA-calculation of¹⁶O. The calculation is performed in a LS-coupling scheme with an interaction containing central, spin-orbit and tensor forces. The main differences with conventional RPA-calculations occur for the transition probabilities.     

输电线非线性振动问题的同伦映射近似解

研究了一类输电线非线性振动的动力学模.利用同伦映射方法,得到了该模型的任意次精度的近似解. 关键词： 输电线 非线性振动 同伦映射 近似解     

The 5v 3 bands of 18O enriched ozone: line positions of 16O16O18O, 16O18O16O, 16O18O18O and 18O16O18O

The four 5v ₃ bands of ¹⁸O enriched ozone have been observed and analysed for the first time. Two species (¹⁶O¹⁸O¹⁶O and ¹⁸O¹⁶O¹⁸O) belong to the C_2v symmetry group and two other (¹⁸O¹⁸O¹⁶O and ¹⁶O¹⁶O¹⁸O) to the C_s symmetry group. They have been recorded at a resolution of 0.008 cm^?1 with a pathlength of 32.16 m. Despite the very weak absorptions observed, almost 250 energy levels have been derived for each of the 4 species, with J ? 35 and K _a ? 13, and suitable sets of Hamiltonian parameters have been determined. For 3 species it has been necessary to account for the resonance between the (005) and (311) states to correctly reproduce the spectra observed. These resonances, anharmonic for C_2v, and hybrid (both anhar-monic and Coriolis) for C_s symmetry confirm the accidentally extremely strong coupling between the (005) and (311) states for ¹⁶O₃, due in that case to the very close distance between unperturbed energy levels. This work also confirms the excellent prediction of band centres of these four species derived from the recently determined isotopically invariant molecular potential function.     

Multipole expansion of non-local coupling potentials for cluster transfer and application to 16O(16O, 12C)20Ne

When the transfer of clusters and the symmetrization (antisymmetrization) of scattering wave functions is described by cluster models within the coupled-channel formalism, non-local coupling potentials arise. We suggest a procedure to calculate these potentials by a multipole expansion of all potentials and wave functions which depend on sums of vectors. The expansion coefficients are found by least-squares fit. The method is applied to the ¹⁶O(¹⁶O, ¹²C)²⁰Ne reaction, which is treated in the cluster model with two inert ¹²C- and α-clusters as constituents.     

Small-phase solution to the phase-retrieval problem

A solution to the phase-retrieval problem when the unknown phase is small is presented. The solution specifies the even and odd parts of the unknown phase in two separate equations. The odd part requires a single intensity measurement, and the even part requires two measurements. Phase diversity is used for the second measurement, and computer simulations are given.     

Sinh-Gordon方程的同伦近似解

本文利用同伦分析方法得到了Sinh-Gordon方程的近似解.在所得到的解中包含一个辅助参数,可以有效地控制级数解的收敛范围和收敛速度. 关键词： 同伦分析方法 Sinh-Gordon方程 近似解     

A solution to the non-Abelian duality problem

Dualities uniquely excel at resolving non-perturbative aspects of complex phase diagrams of interacting, Landau or topologically ordered, systems. However, traditional duality transformations fail for systems like the Heisenberg model and non-Abelian gauge theories. The bond-algebraic theory of quantum and classical dualities provides a solution to this long-standing conundrum, the so-called non-Abelian duality problem, by embedding traditional dualities into a more general transformation scheme that always preserves locality in any number of dimensions. Remarkably, it turns out to be unimportant whether a model?s group of symmetries is Abelian or non-Abelian. The capability of the bond-algebraic approach to handle finite and infinite systems with arbitrary boundary conditions has recently led to the discovery of holographic symmetries  , relating topological order, edge states, and generalized order parameters. We discuss the interplay between these distinguished boundary symmetries and our solution to the non-Abelian duality problem. To illustrate our technique we present, among others, novel dualities for the SU(2)$\mathit{SU}(2)$ principal chiral field and both U(1)$U(1)$ and SU(2)$\mathit{SU}(2)$ generalizations of the planar quantum compass model of orbital ordering.     

M theory solution to the hierarchy problem

An old idea for explaining the hierarchy is strong gauge dynamics. We show that such dynamics also stabilizes the moduli in M theory compactifications on manifolds of G2 holonomy without fluxes. This gives stable vacua with softly broken supersymmetry, grand unification, and a distinctive spectrum of TeV and sub-TeV sparticle masses.     

Choreographic solution to the general-relativistic three-body problem

We reexamine the three-body problem in the framework of general relativity. The Newtonian N-body problem admits choreographic solutions, where a solution is called choreographic if every massive particle moves periodically in a single closed orbit. One is a stable figure-eight orbit for a three-body system, which was found first by Moore (1993) and rediscovered with its existence proof by Chenciner and Montgomery (2000). In general relativity, however, the periastron shift prohibits a binary system from orbiting in a single closed curve. Therefore, it is unclear whether general-relativistic effects admit choreography such as the figure eight. We examine general-relativistic corrections to initial conditions so that an orbit for a three-body system can be choreographic and a figure eight. This illustration suggests that the general-relativistic N-body problem also may admit a certain class of choreographic solutions.     

Exact solution of a meiman problem with an application to the pionic contribution to the muon magnetic moment

An exact solution is obtained tp the follpwing problem: given a form factor F(t) analytic in the cut t plane, to find a lower bpund to a weighted ontegral over |F(t)|² over the cut in the presence of space-like data and also time-like data on both the modulus and the phase of F(t). The solution is used to obtain a lower bound on the pionic contribution to the muon magnetic moment (a_μ(ππ)). We obtain a_μ(ππ) ≥ 41.8 × 10^?9.     

The inhomogeneous slab,a rigorous solution to the propagation problem

A rigorous solution based on an integral equation to investigate the propagation in an inhomogeneous slab of arbitratry index profile is given.