2014 Fall Graduate Colloquium Series: Caleb Smith/Blake Birmingham

DateOctober 24, 2014Time3:35 - 5:00 pm
LocationBaylor Sciences Building, Room E.125
Description
Caleb Smith

The Physical Realization of the Dirac Monopole

A recent paper offers the preliminary results of observing the magnetic monopole (Dirac monopole) in the laboratory. The theoretical understanding of magnetic monopoles was first derived in a paper by Dirac in 1931. In his paper, Dirac used the newly formulated theory of quantum mechanics to demonstrate that the existence of magnetic monopoles would imply the discreteness of electric charge. The search for magnetic monopoles in nature has been fervent and fruitless since Diracs historic paper. This resent paper describes the controlled creation of a synthetic magnetic monopole in a Bose-Einstein condensate (BEC). The laboratory results are compared visually and quantitatively with simulations and verify the manifestation of the magnetic field corresponding to a magnetic monopole. The creation and manipulation of synthetic magnetic monopoles offers a new and stimulating area of experimental physics investigation and discovery.

Blake Birmingham

Nanometer-Scale Resolution Chemical Analysis of Carbon Nanotubes by Tip-Enhanced Raman Spectroscopy

Raman spectroscopy can be used to study the chemical properties of nearly any material but is spatially limited by source-laser spot size and wavelength. The combination of Raman spectroscopy with Scanning Tunneling Microscopy (STM) provides subnanometer spatial resolution of surface morphology. There is also a local electronic enhancement of Raman signal intensity by the STM tip allowing for nanometer-scale Raman mapping of surfaces. This talk will introduce the enhancement mechanism of Tip-Enhanced Raman Spectroscopy (TERS) and present the results of a paper which provides a 1.7nm resolution chemical analysis of carbon nanotubes on a gold substrate via STM-TERS.

Source paper: Chen, C., Hayazawa, N. & Kawata, S. A 1.7 nm resolution chemical analysis of carbon nanotubes by tip-enhanced Raman imaging in the ambient. Nature Communications 5, Article 3312 (2014).

For more information, please contact: Dr. Ken Park 254-710-2282

PublisherDepartment of Physics
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