The renormalization of single-particle states in nuclear field theory

The single-particle states are renormalized by taking into account the emission and subsequent absorption of a phonon to all orders of perturbation theory. The Ward identity provides a useful normalization condition to the new dressed excitations. Other orthonormalization properties are interpreted in terms of anticommutation and energy weighted sum rules. A two-level model with a monopole phonon is treated in detail as an example.     

Dynamical models in economics: The case of inflation

We discuss a fully dynamical microeconomic model where inflation appears as the response of an unstable system to stochastic noise and/or time discretisation of the dynamics. In the model economic agents fix prices and production volumes following simple, robust, suboptimal rules. A global parameter (named viability) measures the degree of stability of the system: for sufficiently small values the system flares into inflationary episodes that may become self-sustained and permanent. Our analysis shows that models relying on agents taking decisions on the basis of goods availability will leave undetermined the global level of future activity. Thus the Monetary Mass constraint reappears in this simplistic contex. © 1997 John Wiley & Sons, Inc.     

News & views: New Scientific Opportunities at the European Synchrotron Radiation Facility

Approximately 400 participants learned about the latest scientific capabilities at the Stanford Synchrotron Radiation Lightsource (SSRL) and Linac Coherent Light Source (LCLS) during the 2013 Users' Meeting at the SLAC National Accelerator Laboratory, October 1–4, 2013. The Users' Meeting included more than a dozen workshops as well as scientific awards, poster presentations, and talks on the latest scientific trends, challenges, and opportunities.     

Self-similar collapse of a circular cavity of a power-law liquid

Using the lubrication approximation we investigate the self-similar axisymmetric flow of a power-law liquid towards a central circular cavity. It is shown that this problem has a self-similar solution of the second kind. The self-similarity exponent is found by solving a non-linear eigenvalue problem arising from the requirement that the integral curve that represents the solution must join the appropriate singular points in the phase plane of the governing equation. The eigenvalues for different values of the rheological index are computed. Numerical integration of the equations allows us to determine the shape of the solution in terms of the physical variables. We make a detailed analysis of the influence of the rheology on the properties of the solutions.     

The (d, 6Li) reaction in the f-p shell at Ed = 27.25 MeV

The differential cross sections for the reactions ⁵⁶Fe(d, ⁶Li)⁵²Cr and ⁵⁸Ni(d, ⁶Li)⁵⁴Fe leading to the ground 0⁺ and the first 2⁺ excited states are measured at 27.25 MeV. A DWBA analisis of these data and those previously obtained for three Zn isotopes at the same energy is performed. The calculation of the microscopic form factors is carried out within the frame-work of different approximations.     

The dehydration of CuSr2(HCOO)6 · 8H2O: A crystallographic study

The isothermal dehydration of CuSr₂(HCOO)₆ · 8H₂O single crystals as well as powdered material has been followed by several techniques, mainly X-ray diffraction and optical microscopy. Evidence was found of a two-stage process, with an early appearance of an amorphous state (attributed to internal dissolution) and further recrystallization of the stable phases. One of these (CuSr(HCOO)₄, monoclinic, P_c, Z = 2, a = 7.345(10) Å, b = 8.692(15) Å, c = 6.702(10)Å, β = 97.25(5)°) has not been reported so far in the literature. When dehydration takes place near room temperature, the remaining product (Sr(HCOO)₂) bears a topotactic relationship to the parent matrix ((hk0)//(hk0)′; 〈0k0〉//〈0k0〉′). A striking metric match between both (hk0) sections, as well as the absence of any common structural motive, suggest an inner epitactic growth as the most probable mechanism for the transformation.     

Non local effects induced by the particle-vibration coupling

Dynamical corrections to the single particle potential are (perturbatively) evaluated. The corrections tom ^*/m resulting from the coupling of independent (effective) fermions to collective vibrations (low energy modes) are analyzed within the NFT formalism. The results for the²⁰⁸Pb are discussed.