Studies of the nucler equation of state using numerical calculations of nuclear drop collisions

A numerical calculation for the full thermal dynamics of colliding nuclei was developed. Preliminary results are reported for the thermal fluid dynamics in such processes as Coulomb scattering, fusion, fusion-fission, bulk oscillations, compression with heating, and collisions of heated nuclei

Gauge Invariance in Chern-Simons Systems

We show explicitly that the question of gauge invariance of the effective potential in standard scalar electrodynamics remains unchanged despite the introduction of the Chern-Simons term. The result does not depend on the presence of the Maxwell term in the Chern-Simons territory.Comment: 10 pages, Plain Tex, DF/UFPB-14/9

The Peierls substitution in an engineered lattice potential

Artificial gauge fields open new possibilities to realize quantum many-body systems with ultracold atoms, by engineering Hamiltonians usually associated with electronic systems. In the presence of a periodic potential, artificial gauge fields may bring ultracold atoms closer to the quantum Hall regime. Here, we describe a one-dimensional lattice derived purely from effective Zeeman-shifts resulting from a combination of Raman coupling and radiofrequency magnetic fields. In this lattice, the tunneling matrix element is generally complex. We control both the amplitude and the phase of this tunneling parameter, experimentally realizing the Peierls substitution for ultracold neutral atoms.Comment: 6 pages, 5 figure

Wavelength-selectable laser emission from a multistripe array grating integrated cavity laser

We report laser operation of a multistripe array grating integrated cavity (MAGIC) laser in which the wavelength of the emission from a single output stripe is chosen by selectively injection pumping a second stripe. We demonstrate a device that lases in the 1.5 µm fiber band at 15 wavelengths, evenly spaced by ~2 nm. The single-output/wavelength-selectable operation, together with the accurate predefinition of the lasing wavelengths, makes the MAGIC laser a very attractive candidate for use in multiwavelength networks

Monolithic InP-Based Grating Spectrometer for Wavelength-Division Multiplexed Systems at 1.5 μm

A monolithic InP-based grating spectrometer for use in wavelength-division multiplexed systems at 1.5 μm is reported. The spectrometer uses a single etched reflective focusing diffraction grating and resolves >50 channels at 1 nm spacing with a ~0.3nm channel width and at least 19dB channel isolation. Operation is essentially of the state of the input polarisation

Numerical study of solitary wave attenuation in a fragmented ice sheet

A numerical model for direct phase-resolved simulation of nonlinear ocean waves propagating through fragmented sea ice is proposed. In view are applications to wave propagation and attenuation across the marginal ice zone. This model solves the full equations for nonlinear potential flow coupled with a nonlinear thin-plate formulation for the ice cover. A key new contribution is to modeling fragmented sea ice, which is accomplished by allowing the coefficient of flexural rigidity to vary spatially so that distributions of ice floes can be directly specified in the physical domain. Two-dimensional simulations are performed to examine the attenuation of solitary waves by scattering through an irregular array of ice floes. Two different measures based on the wave profile are used to quantify its attenuation over time for various floe configurations. Slow (near linear) or fast (exponential-like) decay is observed depending on such parameters as incident wave height, ice concentration and ice fragmentation