Sep. 3
The equation of state of neutron-rich nuclear matter and its impacts on astrophysics and cosmology
Dr. Bao-An Li, TAMUC-Physics
Abstract
Nuclear reactions, especially those induced by radioactive beams, provide a unique opportunity to probe the EOS (Equation of State) of neutron-rich nuclear matter in terrestrial laboratories [1]. The isospin-dependent part of the EOS, i.e., the density dependence of the nuclear symmetry energy, has been rather poorly known especially at supra-saturation densities. However, it is very important for nuclear structure, nuclear reactions and many phenomena/processes in astrophysics and cosmology. In this talk, some recent progress in constraining the EOS of neutron-rich nuclear matter especially at supra-saturation densities will be discussed [2]. In addition, some impacts of the partially constrained EOS on properties of neutron stars [3,4,5] will also be discussed. References:
[1] B.A. Li, L.W. Chen and C.M. Ko, Physics Reports 464, 113 (2008).
[2] Z.G. Xiao, B.A. Li, L.W. Chen, G.C. Yong and M. Zhang, Phys. Rev. Lett. 102, 062502 (2009).
[3] P.G. Krastev, B.A. Li and A. Worley, The Astrophysical Journal 676, 1170 (2008).
[4] A. Worley, P. G. Krastev and B.A. Li, The Astrophysical Journal 685, 390 (2008).
[5] J. Xu, L.W. Chen, B.A. Li and H. R. Ma, The Astrophysical Journal 697, 1549 (2009).
Sep. 10
Nuclear Modifications of Parton Distributions and Their Signatures in High Energy Deuteron-Gold Collisions
Dr. Adeola Adeluyi, TAMUC-Physics
Dr. Adeola Adeluyi received in 2009 his PhD from Kent State University, Ohio where he worked on ultra-relativistic nucleus-nucleus collisions. He also received a Diploma of The International Center for Theoretical Physics (DICTP) in High Energy Physics in 2001 from the Abdus Salam ICTP, Trieste, Italy, and a research Master of Science (MSc) in Nuclear Physics from the Obafemi Awolowo University, Nigeria, in 2000. He joined the Department of Physics and Astronomy at Texas A&M University-Commerce as a postdoctoral associate on Sept. 1, 2009.
Abstract
The basic constituent of matter familiar to most people is the atom, which consists of electrons moving around a charged central core, the nucleus. The nucleus, in turn, consists of protons and neutrons, collectively referred to as nucleons. The current view is that nucleons are made up of quarks and gluons. In a fast moving (high energy) nucleon, the quarks and gluons are collectively termed partons, and their momentum-fraction distributions in the nucleon are called Parton Distribution Functions (PDFs). A most remarkable fact is that the parton distributions in a nucleus are significantly different from that of a free nucleon, a condition referred to as nuclear modifications of parton distributions. These modifications play an important role in correctly understanding and interpreting experimental results in high-energy nucleus-nucleus collisions. In this talk I will discuss the characteristics of these nuclear modifications and how they affect experimental results in deuteron-gold collisions.
Sep. 17
Embodiment in Complex Systems: Perceiving and Enacting Actions in Virtual Environments
Dr. Shulan Lu, Department of Psychology, TAMU-Commerce
Dr. Shulan Lu graduated from University of Memphis with a Ph.D. in cognitive science and is currently an assistant professor of psychology at Texas A&M University-Commerce. Under Shulan’s direction, research at cognitive science lab takes an interdisciplinary approach, where we use a range of behavioral experimentation methods including eye tracking and computational methods including neural network models. Furthermore, we collaborate with colleagues in artificial intelligence building intelligent systems that are grounded in these basic research questions, and collaborate with colleagues in cognitive and clinical neuroscience in investigating how people with individual differences differ in real time event processing. More information about Dr. Lu and her research can be found at
http://shulanlu.com/
Abstract
Classic cognitive science on higher level cognition investigated sensors and effectors in relative isolation. In contrast, embodied cognitive science takes the stance that the body, and the environment which it inhabits, are tightly coupled with the mind, and together they form a complex system for perception and action. There are significant differences in perceptual and motor feedback between the real versus virtual environments. In this talk, we will look at two questions: (a) whether there are tangible differences in how people perceive and enact actions in real versus virtual environments; (b) what conditions might promote perceiving and enacting actions in real versus virtual environments.
Sep. 24
Characterization of Silicon Carbide Nanowires Obtained from Carbon Blacks
Dr. T. Waldek Zerda, Department of Physics & Astronomy, Texas Christian University
Prof. T. Waldek Zerda obtained his Ph.D. degree in physics in 1978 from the Silesian University, Poland. Since 1987 he has been a professor of physics at TCU and since 2005 the chairman of the department. His research interests include studies on sol-gel process, structure of porous sol-gel glass, dynamics of molecular systems inside the pores, structure of carbon blacks, reinforcing properties of carbon black filler in tires, high pressure studies, nanostructures, and Raman imaging techniques. Recently he has focused his interests on investigation of the structure of superhard diamond based composites and silicon carbide nanowires.
Abstract
SiC nanowires were obtained by a reaction between vapor silicon and carbon black powder in vacuum at 1200oC. Their structures and properties were studied using X-ray diffraction, high resolution transmission microscopy, FTIR, and Raman scattering techniques. Diameters of sintered nanowires depend on carbon black grade and its history of thermal treatment. SiC nanowires of diameter as small as 10 nm were obtained from graphitized furnace carbon blacks. Chemical composition of nanowires was similar for all samples, but concentration of structural defects varied and depended on carbon black surface properties and surface morphology. Stacking faults and twins dislocations were observed in all specimens.
Oct. 1
ATLAS, CERN and The Large Hadron Collider: Where the Physics of Elementary Particles and Astronomy Collide (and a few protons too!)
Prof. Joseph M. Izen Department of Physics, The University of Texas at Dallas
Prof. Izen received his Ph.D. in Physics (1982) and A.M. in Physics (1978) from Harvard University. He received a B.S. in Physics and Math (1977) from The Cooper Union.
Dr. Izen is currently a Professor of Physics and Principal Investigator for UTD's elementary particle research group. Dr. Izen and his group work on the commissioning and operations of the pixel subdetector, shared inner detector systems of the Atlas experiment at CERN's Large Hadron Collider near Geneva, Switzerland. They are preparing to analyze data from the first LHC collisions late this fall. Izen also studies the physics of bottom and charm quarks with the BaBar experiment at SLAC. In the past, Izen has collaborated on the Cleo, Tasso, Aleph, Mark III, SLD, SDC, and BES experiments, serving as US BES Spokesperson from 1996 to 1997.
Abstract
Thousands of elementary particle physicists are traveling to scenic Switzerland to spend an awful lot of time in a big hole in the ground. Do these physicists have anything common with the astronomers who go to mountain tops, only to work all night and sleep all day? Could it be something more than needing to get a life? This Fall, the ATLAS experiment at CERN's Large Hadron Collider (LHC) will recreate the conditions that existed just after the Big Bang. We hope to solve some of the biggest mysteries that puzzle both particle physicists and astronomers. I will describe some of the physics motivating the LHC and the ATLAS experiment at CERN, and I'll describe what it is like to work "down in the pit" on the ATLAS Pixel detector.
Oct. 15
Bioinformatics: GUIDED SEQUENCE ALIGNMENT
Dr. Abdullah N. Arslan, Department of Computer Science and Information Systems, TAMU-Commerce
Dr. Abdullah N. Arslan is an Assistant Professor at the Department of Computer Science and Information Systems at Texas A&M University – Commerce. He received his PhD degree in Computer Science from University of California, Santa Barbara in 2002. His previous degrees were a BS degree in Computer Engineering from the Middle East Technical University in Turkey and an MS degree in Computer Science from University of North Texas. Before joining Texas A&M University – Commerce, he worked as an Assistant Professor in the Department of Computer Science at the University of Vermont. Dr. Arslan’s main research interests are in computational biology and bioinformatics, and in general, he is interested in a wide array of search and optimization problems.
Abstract
Sequence alignment is a very important tool in computational biology. Life’s code is stored in DNA. Species have many similar regions in their DNA’s indicating common genetic code. Similarities in protein sequences indicate potential common functions. Although we only recently have started acquiring complete genomic data for species, sequence databases have been and are expected to be growing very rapidly. Sequence alignments help us turn this data into knowledge. With the help of sequence alignment, we find common genes in different species, detect in genes alterations that may cause diseases such as cancer, and find protein families that have common functions. Ordinarily, the sequence alignment is a problem of aligning symbols of given sequences in a way to optimize the resulting similarity score. This is based on scores that have been derived from alignments verified by biologists over years. Expectation has been that these scores perform well for alignments of all sequences. However, it has been shown that this is not always true. The ordinary definition of sequence alignment does not always reveal biologically accurate similarities. To overcome this, there have been attempts that redefined sequence similarity. These redefinitions yield interesting optimization problems with various objectives and constraints. In this talk, I summarize some of these attempts. My emphasis will be on the definitions that my collaborators and I have introduced. We have proposed algorithms for the resulting sequence alignment problems under these definitions. The techniques that we use in these algorithms include fractional programming and (hybrid) dynamic programming combined with automata simulation. A small part of my presentation can also be viewed as a tutorial to the fractional programming technique. At the end of my talk, very briefly, I will list some of my other research on sequence alignment problems, and on some other topics such as approximate search in dictionaries and databases, string similarity in high dimensions, and phylogeny.
Oct. 22
The Search for Planets beyond the Solar System
Prof. Kenneth Janes, Boston University
Dr. Kenneth Janes is a Professor of Astronomy at Boston University. He received a
BA degree from Harvard College in 1963, an MS degree from San Diego State
University in 1968 and a PhD degree from Yale University in 1972. Besides serving as a
faculty member and department chairman at Boston University, Dr. Janes also held visiting
Professor positions at the Institute for Astronomy of the University of Hawaii, Lund Observatory
in Sweden and at the University College of London. His research interests include studies
of the structure and evolution of our galaxy and searches for extra-solar planets. He is the
author or co-author of more than 100 scientific papers. His research is supported by the
NSF and NASA. He has served on a number of national boards and scientific review committees.
More information about Prof. Janes and his research can be found at
http://web.bu.edu/dbin/astronomy/people.php?id=18
Abstract
The first planets outside our solar system were discovered in 1992. Since then, the number of known
extra-solar planets has increased to about 375, with more being discovered almost daily. None of the
extra-solar planet systems discovered so far resembles our own solar system. Nevertheless, while no Earth-like
planets have yet been discovered around other stars, the first extra-solar Earths are likely to be found within
the next 3 years. We are also now beginning to move beyond the pure discovery phase to the characterization
of planet properties, including observations and modeling of planetary atmospheres and interiors. I will review
the current state of the field and describe the XO planet search project in which I have been participating.
Oct. 29
Neutron Star Seismology and the Neutron Star Crust
Dr. Andrew W. Steiner
Joint Institute of Nuclear Astrophysics and Department of Physics and Astronomy
Michigan State University
Dr. Steiner received his Ph. D. in 2002 from the State University of New York at Stony Brook and his B.S. in 1997 from the Carnegie Mellon University. He is the 2004 recipient of the American Physical Society Dissertation Award in Nuclear Physics. He is currently a research associate at the Joint Institute of Nuclear Astrophysics and the Department of Physics and Astronomy at Michigan State University. More information about Dr. Steiner and his research can be found at
http://tharkad.pa.msu.edu/~asteiner/?page_id=8
Abstract
There is a long history of connections between astrophysics and nuclear physics: often nuclear physics provides a critical role in explaining astrophysical phenomena, and occasionally astrophysical observations provide critical input for understanding nuclei and nuclear matter. In this talk, I give a recent example of the latter. I show that the oscillations induced by starquakes on highly-magnetized neutron stars can provide an important constraint on the properties of very neutron-rich nuclei. Furthermore, this constraint does not require a neutron star distance measurement, and thus the associated systematic uncertainties are smaller than many of the astrophysical alternatives. Connections to the nuclear symmetry energy and the neutron skin thickness of lead will also be explored.
Nov. 5
Cold Atom Physics: the magic of macroscopic wavefunctions
Dr. Eddy Timmermans
Center for Nonlinear Studies, Los Alamos National Laboratory
Dr. Eddy Timmermans received his PhD from Rice University in 1995. He was a postdoctoral fellow at the Harvard-Smithsonian Institute for Theoretical Atomic and Molecular Physics, Harvard, 1995-1998, Director’s fellow in 1999 and then then J. Robert Oppenheimer fellow at Los Alamos National Laboratory, 2000-2003. He became a technical Staff Member at the Los Alamos National Laboratory in 2003. Dr. Timmermans has been the Deputy Director of the Los Alamos Center for Nonlinear Studies (CNLS) since 2007. He became a Fellow of the American Physical Society in 2006. His current research focuses on magnetic-like behavior and macroscopic spin quantum tunneling of cold atom gas systems, cold atom quantum phase transitions, finite-range effective interactions and Bose Einstein Condensation-standing wave structures. More information about Dr. Eddy Timmermans and his research can be found at
http://cnls.lanl.gov/External/people/Eddy_Timmermans.php
Abstract
The relevance of macroscopic phase coherence in superfluids and superconductors has been appreciated for almost half a century. To this theme of quantum coherence, cold atom physics adds a novel touch: in the dilute gas Bose-Einstein condensates (BEC's) and fermion superfluids, the correlation length scales are macroscopic (micron-scale) as well. As a consequence, macroscopic tools such as classical magnetic and laser fields can engineer the macroscopic wavefunctions, control the inter-particle interactions and mimic effective hamiltonians that model strongly correlated electron systems. I will describe experimental demonstrations of BEC-wavefunction engineering, ongoing progress towards designer hamiltonians and new theory-proposals for the realization of finite-range interactions and standing wave BEC-patterns.
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Seminars and colloquia in previous semesters
