Ab initio many-body calculation of the 7Be(p,gamma)8B radiative capture

We apply the ab initio no-core shell model/resonating group method (NCSM/RGM) approach to calculate the cross section of the 7Be(p,gamma)8B radiative capture. This reaction is important for understanding the solar neutrino flux. Starting from a selected similarity-transformed chiral nucleon-nucleon interaction that accurately describes two-nucleon data, we performed parameter-free many-body calculations that simultaneously predict both the normalization and the shape of the S-factor. We study the dependence on the number of 7Be eigenstates included in the coupled-channel equations and on the size of the harmonic oscillator basis used for the expansion of the eigenstates and of the localized parts of the integration kernels. Our S-factor result at zero energy is on the lower side of, but consistent with, the latest evaluation.Comment: 4 pages, 5 figure

The 4^4He total photo-absorption cross section with two- plus three-nucleon interactions from chiral effective field theory

The total photo-absorption cross section of $^4$He is evaluated microscopically using two- (NN) and three-nucleon (NNN) interactions based upon chiral effective field theory ($\chi$EFT). The calculation is performed using the Lorentz integral transform method along with the {\em ab initio} no-core shell model approach. An important feature of the present study is the consistency of the NN and NNN interactions and also, through the Siegert theorem, of the two- and three-body current operators. This is due to the application of the $\chi$EFT framework. The inclusion of the NNN interaction produces a suppression of the low-energy peak and enhancement of the high-energy tail of the cross section. We compare to calculations obtained using other interactions and to representative experiments. The rather confused experimental situation in the giant resonance region prevents discrimination among different interaction models.Comment: 6 pages, 4 figure

Novel NN interaction and the spectroscopy of light nuclei

Nucleon-nucleon (NN) phase shifts and the spectroscopy of $A \le 6$ nuclei are successfully described by an inverse scattering potential that is separable with oscillator form factors.Comment: 4 pages, 1 figure, 13 table

Boson-fermion mapping and dynamical supersymmetry in fermion models

We show that a dynamical supersymmetry can appear in a purely fermionic system. This ``supersymmetry without bosons" is constructed by application of a recently introduced boson-fermion Dyson mapping from a fermion space to a space comprised of collective bosons and ideal fermions. In some algebraic fermion models of nuclear structure, particular Hamiltonians may lead to collective spectra of even and odd nuclei that can be unified using the dynamical supersymmetry concept with Pauli correlations exactly taken into account.Comment: 20 pages. Revtex. One PostScript figure available on request from P

Similarity Renormalization Group Evolution of Many-Body Forces in a One-Dimensional Model

A one-dimensional system of bosons with short-range repulsion and mid-range attraction is used as a laboratory to explore the evolution of many-body forces by the Similarity Renormalization Group (SRG). The free-space SRG is implemented for few-body systems in a symmetrized harmonic oscillator basis using a recursive construction analogous to no-core shell model implementations. This approach, which can be directly generalized to three-dimensional nuclei, is fully unitary up to induced A-body forces when applied with an A-particle basis (e.g., A-body bound-state energies are exactly preserved). The oscillator matrix elements for a given A can then be used in larger systems. Errors from omitted induced many-body forces show a hierarchy of decreasing contribution to binding energies. An analysis of individual contributions to the growth of many-body forces demonstrates such a hierarchy and provides an understanding of its origins.Comment: 23 pages, 11 figures, Changed section on analysis of three-body runnin

No-core shell model in an effective-field-theory framework

We present a new approach to the construction of effective interactions suitable for many-body calculations by means of the no-core shell model (NCSM). We consider an effective field theory (EFT) with only nucleon fields directly in the NCSM model spaces. In leading order, we obtain the strengths of the three contact terms from the condition that in each model space the experimental ground-state energies of 2H, 3H and 4He be exactly reproduced. The first (0^+;0) excited state of 4He and the ground state of 6Li are then obtained by means of NCSM calculations in several spaces and frequencies. After we remove the harmonic-oscillator frequency dependence, we predict for 4He an energy level for the first (0^+;0) excited state in remarkable agreement with the experimental value. The corresponding 6Li binding energy is about 70% of the experimental value, consistent with the expansion parameter of the EFT.Comment: 4 pages, 3 figures, revtex

Inflation Targeting as a Stabilization Tool: Its Design and Performance in the Czech Republic

The article focuses on the development and performance of inflation targeting in the Czech Republic. It is shown that the particulars of the Czech inflation-targeting regime developed from a rather specific setting toward a framework based on international best practices. Its performance is evaluated using three methods. The results suggest that even though inflation targets have been missed more often than met, the practice of inflation targeting has significantly contributed to the stabilization of the Czech economy.inflation targeting; measuring performance of monetary policy

Labor-Market Performance and Macroeconomic Policy: Time-Varying NAIRU in the Czech Republic (in English)

During the second half of the 1990s, the Czech economy experienced a sharp increase in the unemployment rate. The authors attempt to determine whether this was caused by structural changes, worsening labor-market performance, or by the changing business-cycle position. This has direct implications for both monetary and fiscal policy. The authors use NAIRU (non-accelerating inflation rate of unemployment) estimates using time-varying NAIRU. The estimates indicate that the NAIRU increased between 1996 and 2002 by approximately 1.5 percent. Estimated increases in the NAIRU can be associated with the worsening of labor-market efficiency.forward-looking expectations, maximum-likelihood methods, non-accelerating inflation rate of unemployment, time-varying NAIRU

Ab initio optical potentials and nucleon scattering on medium mass nuclei

We show the first results for the elastic scattering of neutrons off oxygen and calcium isotopes obtained from ab initio optical potentials. The potential is derived using self consistent Green's function theory (SCGF) with the saturating chiral interaction NNLO$_{\textrm{sat}}$. Our calculations are compared to available scattering data and show that it is possible to reproduce low energy scattering observables in medium mass nuclei from first principles.Comment: 6 pages, 4 figures, Zakopane conference on nuclear physic