Events Calendar View

CSP Lunch Seminar
Feb 1, 2022
Numerical Integration with WangLandau Sampling
Guest: Prof. David Landau, Center for Simulational Physics, University of Georgia
Tuesday, February 1, 2022 12:45 pm  1:45 pm
Location: Zoom Meeting 
Departmental Colloquium
Feb 3, 2022
SelfOrganization of Lifelike Behaviors

CSP Lunch Seminar
Feb 8, 2022
Simulating Entanglement Purification and Chaos on IBM Quantum Computer

Departmental Colloquium
Feb 10, 2022
Joint Theoretical and Experimental Efforts to Create New Atomic Data for Astrophysics
Almost everything we know about the Universe has been discovered through the light that reaches us from the stars, galaxies, nebulae, and other astrophysical objects. The use of spectroscopy to analyze this light has yielded information about size, temperature, composition and dynamics of a wide array of astrophysical objects from comets to planetary nebulae. No field of science places higher demands on the quantity and accuracy of atomic data than astrophysics. This data is produced by Herculean efforts of both theorists and experimentalist, but both are often needed to overcome the shortcomings of the other. This talk will discuss the aspects of some new, collaborative, joint theoretical and experimental projects to produce new atomic data that is improved for analysis and modeling of data from the increasing observational capacity of our most advanced ground and spacebased telescopes.

Departmental Colloquium
Feb 17, 2022
Nearfield microscopy for nanoscale materials characterization
Semiconducting nanostructures have been proposed as material platforms for a wide variety of photonic, electronic, and photovoltaic elements. In order to realize these applications, careful design and characterization of electronic properties such as dopant concentration, activation, and distribution are needed. I will discuss the use of nearfield optical microscopy as a nondestructive method for chemical, structural, and electronic imaging in nanomaterials, focusing on a specific application, the study of axiallydoped silicon nanowires (SiNWs). We can detect local changes in the electricallyactive doping concentration from the freecarrier absorption in both n type and ptype doped SiNWs. The < 20 nm spatial resolution allows us to directly measure dopant transition abruptness and charge carrier properties in the vicinity of interfaces in single and multijunction SiNWs, both in the infrared and the microwave spectral regimes. However, the tip is perturbative in terms of both the electromagnetic wave (frequencyresolved) and electrostatic (charge carrier redistribution) interactions, and this affects the measured results, an important consideration in nanostructured materials especially. Our results demonstrate the utility of nearfield spectroscopy in probing local properties of nanomaterials, but emphasize the littleunderstood convolutional role of the tip in many forms of scanning probe microscopy.

Departmental/CSP Colloquium
Feb 24, 2022
The interplay between memory and potentials of mean force
The Langevin equation is widely used to model coarsegrained dynamics of soft and biological materials. However, it is not obvious for which systems and which processes the Langevin equation predicts a good approximation to the true dynamics. In this talk we will give an introduction to projection operator formalisms as a tool to systematically coarsegrain dynamics. We will show under which approximations the Langevin equation can be obtained from the dynamics of the underlying microscopic system and in which cases it makes sense to introduce a potential of mean force. We demonstrate the implications of our derivation for the structure of memory terms and for generalized fluctuationdissipation relations. We show, in particular, that the widely used, simple structure which contains a potential of mean force, a memory term which is linear in the observable, and a fluctuating force which is related to the memory term by a fluctuationdissipation relation, is neither exact nor can it, in general, be derived as a controlled approximation to the exact dynamics.
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