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Seminars and Colloquiums
for the week of September 4, 2017


Xia Chen, UTK, Tuesday
Tadele Mengesha, UTK, Wednesday
Logan Higginbotham, UTK, Wednesday
Hamza Ruzayqat, UTK, Wednesday
Sergey Gavrilets, Distinguished Professor, EEB/Math, Thursday

3:00 pm – 3:30 pm
Tuesday & Wednesday
Room: Ayres 401
Hosted By: Tricia Phillips

Tuesday, September 5

TITLE: Organizational Meeting
TIME: 2:10p – 3:25p
ROOM: 113

Wednesday, September 6

TITLE: A fractional Hardy-type inequality over the half space with an application
SPEAKER: Tadele Mengesha, UTK
TIME: 2:10p – 3:10p
ROOM: 113
In this talk, I will discuss a new fractional Hardy-type inequality for vector fields that is based on a modified fractional semi-norm.  A priori, the modified semi-norm is not known to be equivalent to the standard fractional semi-norm and in fact gives a smaller norm, in general. As such, the new inequality improves the classical fractional Hardy’s inequality for vector fields. We will use the result, with the help of Fourier transform, to prove the equivalence of two spaces of functions (of interest) defined over the half space.

TITLE: Group Actions on Large Scale Spaces II
SPEAKER: Logan Higginbotham, UTK
TIME: 3:35pm – 4:25pm
ROOM: Ayres 404/5
We will prove the following theorem: 
Let X be a discrete bounded geometry metric space and let $\mathcal{X}$ be the large scale structure induced by the metric on X. Let G be an amenable group that acts on X by coarse equivalences. If $(X,\mathcal{X})$ has property A, then $(X,\mathcal{X}_G)$ has property A, where $\mathcal{X}_G$ is obtained from $X$ by trivializing the action of $G$.

TITLE: A Rejection Scheme for Off-Lattice Kinetic Monte Carlo Simulations
SPEAKER: Hamza Ruzayqat, UTK
TIME: 3:35pm – 4:35pm
ROOM: Ayres 113
While most Kinetic Monte Carlo (KMC) simulations are lattice based, many important technological applications involve multi-component systems where lattice mismatch leads to elastic strain and crystal defects, neither of which can be accurately modeled with a lattice based approach. Off-lattice Kinetic Monte Carlo (OLKMC) is aimed at overcoming these limitations. Fully general off-lattice simulations make use of either an empirical potential or an even more costly density functional theory calculation, seeking to exhaustively calculate the transition path to all the neighboring states within the multi-particle $\mathbb{R}^{3N}$ configuration space. Thus, a fully implemented off-lattice simulation is an enormously complex task when compared to lattice based simulations, where rates can be precomputed and stored. So much so that KMC simulation loses much of its utility and applications of these methods are often limited to systems with only a few hundred atoms, simulated for much shorter times, and at much greater computational cost. The principal aim of this talk is to discuss a rejection-based Monte Carlo procedure that used local environment information to create rate estimates. These estimates can be computed in a relatively inexpensive way and allow one to select a candidate move without computing detailed rates for the entire system. This new algorithm leads to faster simulations (e.g. For a 50 particles cluster it is at least 10 times faster) with almost the same accuracy as of the full OLKMC.

Thursday, September 7

SPEAKER: Sergey Gavrilets, Distinguished Professor, EEB/Math
TIME: 3:40 pm – 4:35, Arrive at 3:15 for pizza
ROOM: Ayres 405


If you are interested in giving or arranging a talk for one of our seminars or colloquiums, please review our calendar.

If you have questions, or a date you would like to confirm, please contact colloquium AT math DOT utk DOT edu

Past notices:



last updated: May 2018

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