The Solar Shield project is a collaborative effort between the Electric Power Research Institute (EPRI) and NASA. It was launched to utilize state-of-the-art space physics models in experimental space weather forecasting. More specifically, Solar Shield is using an extensive pool of coupled space physics models hosted at the Community Coordinated Modeling Center (CCMC) at NASA/GSFC. The models propagate information obtained from solar observations to the interplanetary medium, from the interplanetary medium to the Earth’s magnetosphere and ionosphere and eventually all the way down to the surface of the Earth. Here is where geomagnetically induced currents (GIC) flowing in high-voltage power transmission systems are calculated. The two-level forecasting system provides both 2-3 day lead-time and 30-60 minute lead-time forecasts, and it is already capable of generating predictions of GIC flow at few individual nodes of the North American power transmission system.

An important special aspect of the project is the participation of the end-user, i.e. power transmission industry, in the development of the forecast products. The goal is to define a system, which, when integrated into EPRI’s SUNBURST decision support tool, will help power transmission system operators to make decisions about possible mitigation actions during “poor” space weather conditions. Industry participation will also enable quantification of the economic value of the generated GIC forecasting system. The result of the economic analysis can be used to indicate if there is a business case for transitioning the experiment into operations.

Location: Physics Bldg., Room 401
Coffee: 3:15 p.m.

Vincenzo successfully defended his thesis proposal on October 3, 2008.

TITLE:
Gauss Sums Factorization with liquid crystals and optical interference.

ABSTRACT:
The factorization of a large number N is a quite complicated problem, that has a great impact on the computing field and, in particular, in public-key encryption. A more recent approach to factorization, proposed by Schleich, exploits the periodic properties of the Gauss sums. We propose a different implementation of Gauss sums factorization, using liquid crystals and optical interferometry. This scheme allows us to find the factors of any large number N in only one run, exploiting the spectrum of the incoming light. This apparatus is also able, in principle, to reproduce generalized exponential sums of order p. This allows, at the same time, a reduction of the number of resources to the order of 4pp N and to get a better suppression of the so called ghost factors. A future development of this work will consist of a quantum approach to factorization, exploiting the periodicity of the Gauss sums with the use of intanglement. In fact the quantum entanglement has a key role in reducing the number of resources to an order polynomial in logN, which is not achievable classically.

Supercooled cloud water is in a metastable thermodynamic state and, therefore, the associated phase transition (to ice) must be irreversible. Has this irreversibility been considered? Does it matter to atmospheric scientists? I'll argue No and Yes, respectively.

We used measured temperature-dependent heat capacities of supercooled water and ice to calculate the ice-(metastable) water entropy difference and to estimate a lower bound on the amount of latent heat, liberated by the freezing droplets. The calculation is compared with tabulated values of the latent heat of fusion with surprising results. Based on a novel physical picture of the freezing process, we suggest a simple estimate for the effective latent heat, suitable for heat budget calculations of glaciating clouds. In addition, we arrive at a quadratic dependence on supercooling for the irreversible contribution to heat exchange during the freezing process. Implications for optical properties of the "hurriedly made ice" will also be discussed.

Location: Physics Bldg., Room 401
Coffee: 3:15 p.m.

When the state of a quantum system cannot be separated into the states of its constituents, we say the system is entangled. In some cases, the presence of entanglement means that measurements on different parts of a system have correlations stronger than can be explained by any purely classical theory. Einstein derisively called this effect “spooky action at a distance,” but now we know that entanglement is a hallmark of quantum mechanics. In this talk, I will investigate entanglement in particle systems. Different types of entanglement can occur in such systems, and dynamical processes can change the amount of entanglement.

In particular, I will look at how entanglement is generated between particles by scattering, the fundamental experimental paradigm for particle physics.

Location: Physics Bldg., Room 401
Coffee: 3:15 p.m.

This seminar has been cancelled! There will be no seminar on Oct. 22, 2008.

The Balloon-borne Experiment with a Superconducting Spectrometer (BESS) program is searching for antimatter in the galactic cosmic radiation by precisely measuring the elemental and isotopic composition of the light cosmic ray component. The experiment is a highly successful US-Japanese collaboration and over the past 15 years, the BESS payload has had eight low geomagnetic cutoff, northern latitude flights and two long duration balloon flights from Antarctica. The most recent flight of the BESS-Polar experiment was a long-duration Antarctica flight, which occurred between December 2007 and January 2008. This flight yielded 24.5 days of observation time at a time of low solar activity (solar minimum). We will review the BESS program and report the results of the antiproton and proton spectra measured in the BESS-Polar I flight, the search for cosmic antinuclei, and the status of the BESS-Polar II analysis.

Location: Physics Bldg., Room 401
Coffee: 3:15 p.m.

Mike successfully defended his masters thesis on October 30, 2008.

TITLE:
Improved Technologies for a Single Photon Source

ABSTRACT:
One of the key requirements for an optical approach to quantum computing is a reliable source of single photons. The efforts of this research have been directed towards improving both the heralding efficiency and heralding rates of a high performance fiber-coupled single photon source based on an ultrafast pulsed beam-like Type-II parametric down conversion (PDC) source. Entangled photons generated from PDC are inherently broadband (many frequencies) and exit the nonlinear crystal at varying angles (different directions). This makes coupling the photons into single-mode fibers, a desirable feature for quantum computing, difficult. In response to these difficulties we have explored applying multi-layered thin film broadband anti-reflection coatings onto the ends of single-mode fibers using the technique of RF Planar Magnetron Sputtering in an effort to increase the coupling efficiency of the beam-like down converted photons. In addition, we have explored theoretically the broadband nature of novel phase matching geometries to increase heralding rates and minimize photon losses. With the ability to tailor coupling fibers to various down conversion sources we hope to increase both the heralding efficiency and heralding rate to levels needed for a broad range of future experiments.