Continuum Singularities of a Mean Field Theory of Collisions

Consider a complex energy $z$ for a $N$-particle Hamiltonian $H$ and let $\chi$ be any wave packet accounting for any channel flux. The time independent mean field (TIMF) approximation of the inhomogeneous, linear equation $(z-H)|\Psi>=|\chi>$ consists in replacing $\Psi$ by a product or Slater determinant $\phi$ of single particle states $\phi_i.$ This results, under the Schwinger variational principle, into self consistent TIMF equations $(\eta_i-h_i)|\phi_i>=|\chi_i>$ in single particle space. The method is a generalization of the Hartree-Fock (HF) replacement of the $N$-body homogeneous linear equation $(E-H)|\Psi>=0$ by single particle HF diagonalizations $(e_i-h_i)|\phi_i>=0.$ We show how, despite strong nonlinearities in this mean field method, threshold singularities of the {\it inhomogeneous} TIMF equations are linked to solutions of the {\it homogeneous} HF equations.Comment: 21 pages, 14 figure

Photonic bandgap plasmonic waveguides

A novel type of a plasmonic waveguide has been proposed featuring an "open" design that is easy to manufacture, simple to excite and that offers a convenient access to a plasmonic mode. Optical properties of photonic bandgap (PBG) plasmonic waveguides are investigated experimentally by leakage radiation microscopy and numerically using the finite element method confirming photonic bandgap guidance in a broad spectral range. Propagation and localization characteristics of a PBG plasmonic waveguide have been discussed as a function of the wavelength of operation, waveguide core size and the number of ridges in the periodic reflector for fundamental and higher order plasmonic modes of the waveguide

Los “Chicago Boys”: A Powerful Exchange of People and Ideas between Chile and Chicago

On September 11th, 1973, Chile broke with its strong democratic history when the military bombed the presidential palace and Augusto Ugarte Pinochet began his 17-year dictatorship. On the day of the coup, a team of Chicago-educated Chilean economists presented a document they had been asked to draft by the Chilean Navy. It called for the abolition of the statist economy that characterized Chile at that time and the implementation of a free-market model. The free-market model that emerged under the dictatorship brought Chile to its position as one of the strongest economies in Latin America and its fundamentals are still in place in present-day Chile. The model is glorified by some and criticized by others because of the authoritarian atmosphere in which it was introduced. But the forced exit of Pinochet in 1990 and return to democracy provides an example to other Latin American countries that a free-market can only be sustained alongside a democratic regime. Drawing from personal interviews, archival material, and historical documents, I examine how and why an exchange between Chilean Universities and the University of Chicago began in the mid-1950s and how these ideas have carried through to reshape Chile’s economy. I focus on the context in which the exchange emerged and how the Chicago Boys’ policies infiltrated Chile. Ultimately, the longevity of the free-market policies demonstrates that they have been effective in bringing Chile to its superior economic position in Latin America today

Shell structure in neutron-rich Ca and Ni nuclei under semi-realistic mean fields

Shell structure in the neutron-rich Ca and Ni nuclei is investigated by the spherical Hartree-Fock calculations with the semi-realistic $NN$ interactions. Specific ingredients of the effective interaction, particularly the tensor force, often play a key role in the $Z$ dependence of the neutron shell structure. Such examples are found in N=32 and N=40; N=32 becomes magic or submagic in $^{52}$Ca while its magicity is broken in $^{60}$Ni, and N=40 is submagic (though not magic) in $^{68}$Ni but not in $^{60}$Ca. Comments are given on the doubly magic nature of $^{78}$Ni. We point out that the loose binding can lead to a submagic number N=58 in $^{86}$Ni, assisted by the weak pair coupling.Comment: 14 pages including 5 figures, to appear in Physical Review C (Rapid Communication

Mixing effectiveness in the Apollo oxygen tanks of spin-up and rotation-reversal maneuvers

Two-dimensional simulations of stratified flows in the Apollo oxygen tanks have been used to estimate the mixing effectiveness of spin-up and rotation-reversal maneuvers. Calculations have been made for square and circular cylindrical tank geometries. Differences arising from heater position on the tank wall or near the center of the tank have been investigated. In the event of a prolonged period without normal maneuvers, the potential pressure decay (drop in pressure that would result from adiabatic mixing) can be suppressed by more than a factor of two through the use of spin-up and rotation-reversal maneuvers. Changes in rotation rate of order three revolutions per hour or greater are sufficient for this purpose

How I Love A Pretty Face

https://digitalcommons.library.umaine.edu/mmb-vp/5627/thumbnail.jp

The Loving Cup

https://digitalcommons.library.umaine.edu/mmb-vp/3650/thumbnail.jp

Two Little Love Bees

VERSEWe’ll seek a haven of flowers and trees,Where we’ll sip honey just like the bees;There in the sunshine as time passes by,We’ll live on kisses sweet, just you and I.Two little love bees buzzing in a bower,Feasting on the sweetness of the fairest flower,There we will build a cosy honeycomb,And settle in our home, sweet home.Two little love beesTwo little love bees buzzing in a bower,Feasting on the sweetness of the fairest flower,There we will build a cosy honeycomb,And settle in our home, sweet home.Under a sky of blue we’ll live all day,Deep in the woodland where lovers stray;Where fragrant violets perfume the air,And the red roses bloom everywhere.Two little love bees buzzing in a bower,Feasting on the sweetness of the fairest flower,There we will build a cosy honeycomb,And settle in our home, sweet home.Two little love beesTwo little love bees buzzing in a bower,Feasting on the sweetness of the fairest flower,buzzing in a bower,Feasting on the sweetness of the fairest flower,There we will build a cosy honeycomb,And settle in our home, sweet home.There we will build a cosy honeycomb,And settle in our home, sweet home