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Charles E. Schmidt College of Science


Physics Colloquia    Fall 2014 (usually Fridays 2:00 PM in SE 319)

Titles link to the abstracts.

Aug 29
George Kalantzis, FAU
Sep 19
Paul M. Alsing, AFRL
Oct 10
Robert Alfano, CUNY
Nov 7
Pablo Laguna, Georgia Tech

Colloquium Abstracts

Advances in Biomedical Optics
Robert Alfano, Oct 10
The underlying optical physics behind linear and nonlinear processes involved in optical biopsy will be presented. The recent salient advances in biomedical optics to be discussed are : the key fingerprint biomarker of tryptophan to detect aggressive cancer cells; the two new NIR spectral windows( about 1250 nm and 1660nm ) with less scattering of light in tissues to image deeper into tissue ; the use of the of upper singlet S2 for dyes to increase imaging depth using two photon fluorescence microscope techniques for brain; the use of spatial frequencies spectra to detect structure changes in cancerous tissues vs normal tissues ; and most of all describe the use of compact optical analyzers for cancer detection without removing tissue for biomedicine applications.
Advances in Biomedical Optics
Paul M. Alsing, Sep 19
In this talk, we extend the investigation of Adami and Ver Steeg [Class. Quantum Grav. 31, 075015 (2014)] to treat the process of black hole particle emission as an effective parametric down conversion (PDC) with a depleted (vs. un-depleted) pump. We investigate both the short time (non-depleted pump) and long time (depleted pump) regimes and its impact on the Holevo channel capacity for communicating information from the far past to the far future in the presence of Hawking radiation. The new feature introduced in this paper is the coupling of the emitted modes through the black hole ‘source pump’ which can be depleted. Within our analogous quantum optical model we examine the entanglement between two emitted particle/anti-particle and anti-particle/particle pairs coupled via the black hole (BH) depleted ‘pump.’ We also discuss the ’Page time’ for our model which refers to the conventionally held belief that the information in the BH radiation becomes significant after the black hole has evaporated half its initial state into the outgoing radiation. Lastly, we outline our results on the effect of BH particle production/evaporation on two modes in the exterior region of the BH event horizon that are initially maximally entangled, when one mode falls inward and interacts with the black hole and the other remains forever outside and non- interacting.
Prompt Accretion in Tidal Stellar Disruptions by Massive Black Holes
Pablo Laguna, Nov 7
A bright flare followed at late times by a power-law decay in luminosity are expected to be the generic signatures of a tidal disruption event. They are produced when the stellar debris returns to the vicinity of the massive black hole, self-intersects and eventually forms an accretion disk. In the canonical scenario of a solar-type star disrupted by a million solar mass black hole, the time elapsing between the disruption of the star as it passes periapsis and the formation of the accretion disk could be years. I will present results from a new class of tidal disruption events of solar-type stars in which the flare and disk formation take place promptly after disruption, with the accretion remaining super-Eddington throughout this process. The new class involves ultra-close encounters with intermediate mass black holes. I will discuss how these events could potentially be used as the smoking gun for the identification of intermediate mass black holes.
FAU Campuses: Boca Raton/Davie/Dania Beach/Fort Lauderdale/Jupiter/Treasure Coast/Harbor Branch