Partial Fourier-Mukai transform for integrable systems with applications to Hitchin fibration

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The Effective Fragment Molecular Orbital Method for Fragments Connected by Covalent Bonds

We extend the effective fragment molecular orbital method (EFMO) into treating fragments connected by covalent bonds. The accuracy of EFMO is compared to FMO and conventional ab initio electronic structure methods for polypeptides including proteins. Errors in energy for RHF and MP2 are within 2 kcal/mol for neutral polypeptides and 6 kcal/mol for charged polypeptides similar to FMO but obtained two to five times faster. For proteins, the errors are also within a few kcal/mol of the FMO results. We developed both the RHF and MP2 gradient for EFMO. Compared to ab initio, the EFMO optimized structures had an RMSD of 0.40 and 0.44 {\AA} for RHF and MP2, respectively.Comment: Revised manuscrip

alpha particle momentum distributions from 12C decaying resonances

The computed $\alpha$ particle momentum distributions from the decay of low-lying $^{12}$C resonances are shown. The wave function of the decaying fragments is computed by means of the complex scaled hyperspherical adiabatic expansion method. The large-distance part of the wave functions is crucial and has to be accurately calculated. We discuss energy distributions, angular distributions and Dalitz plots for the $4^+$, $1^+$ and $4^-$ states of $^{12}$C.Comment: 6 pages, 4 figures. Proceedings of the SOTANCP2008 conference held in Strasbourg in May 200

Three-Body Halos in Two Dimensions

A method to study weakly bound three-body quantum systems in two dimensions is formulated in coordinate space for short-range potentials. Occurrences of spatially extended structures (halos) are investigated. Borromean systems are shown to exist in two dimensions for a certain class of potentials. An extensive numerical investigation shows that a weakly bound two-body state gives rise to two weakly bound three-body states, a reminiscence of the Efimov effect in three dimensions. The properties of these two states in the weak binding limit turn out to be universal. PACS number(s): 03.65.Ge, 21.45.+v, 31.15.Ja, 02.60NmComment: 9 pages, 2 postscript figures, LaTeX, epsf.st

Condensates and correlated boson systems

We study two-body correlations in a many-boson system with a hyperspherical approach, where we can use arbitrary scattering length and include two-body bound states. As a special application we look on Bose-Einstein condensation and calculate the stability criterium in a comparison with the experimental criterium and the theoretical criterium from the Gross-Pitaevskii equation.Comment: 6 pages, 4 figures. Contribution to Workshop on Critical Stability III in Trento. Submitted to Few-Body System

Three-body bremsstrahlung and the rotational character of the 12C-spectrum

The electric quadrupole transitions between $0^+$, $2^+$, and $4^+$ states in $^{12}$C are investigated in a $3\alpha$ model. The three-body wave functions are obtained by means of the hyperspherical adiabatic expansion method, and the continuum is discretized by imposing a box boundary condition. Corresponding expressions for the continuum three-body ($3\alpha$) bremsstrahlung and photon dissociation cross sections are derived and computed for two different $\alpha-\alpha$ potentials. The available experimental energy dependence is reproduced and a series of other cross sections are predicted. The transition strengths are defined and derived from the cross sections, and compared to schematic rotational model predictions. The computed properties of the $^{12}$C resonances suggest that the two lowest bands are made, respectively, by the states $\{0^+_1, 2^+_1, 4^+_2\}$ and $\{0^+_2, 2^+_2, 4^+_1\}$. The transitions between the states in the first band are consistent with the rotational pattern corresponding to three alphas in an equal sided triangular structure. For the second band, the transitions are also consistent with a rotational pattern, but with the three alphas in an aligned distribution.Comment: To be published in Phys. Rev.

The Continuum Structure of the Borromean Halo Nucleus 11Li

We solve the Faddeev equations for 11Li (n+n+9Li) using hyperspherical coordinates and analytical expressions for distances much larger than the effective ranges of the interactions. The lowest resonances are found at 0.65 MeV (1/2+, 3/2+, 5/2+) and 0.89 MeV (3/2+, 3/2-) with widths of about 0.35 MeV. A number of higher-lying broader resonances are also obtained and related to the Efimov effect. The dipole strength function and the Coulomb dissociation cross section are also calculated. PACS numbers: 21.45.+v, 11.80.Jy, 21.60.GxComment: 10 pages, LaTeX, 3 postscript figures, psfig.st