The Society of Physics Students (SPS) is a professional association explicitly designed for students. Membership, through collegiate chapters, is open to anyone interested in physics. The only requirement for membership is that you be interested in physics. Besides physics majors, our members include majors in chemistry, computer science, engineering, geology, mathematics, medicine, and other fields.
Within SPS is housed Sigma Pi Sigma, the national physics honor society, which elects members on the basis of outstanding academic achievement. This unique two-in-one society operates within the American Institute of Physics, an umbrella organization for ten other professional science societies.
Regular Meetings are held on Wednesdays at 12PM in Rusteberg 205.
Professor Martirosyan Receives DOD Grant to Purchase Field Emission Scanning Electron Microscope
(Dec. 2014) Dr. Karen Martirosyan, Associate Professor of Physics was recently awarded DOD grant to install
a cutting-edge commercial multi-functional instrument, a high resolution analytical Field Emission Scanning Electron Microscope
(JSM-7100FA, JEOL). DOD funding for this project is $433,500 for one year. The instrument will support fundamental and
interdisciplinary DOD related research and educational projects in the Rio Grande Valley (RGV) region of South Texas.
Physics Student accepted to winter astronomy workshop
(Dec. 2014) UTB physics student Alejandro Reyes has been accepted for the University of Maryland winter physics and astronomy workshop for undergrads
interested in attending graduate school in astronomy and physics. The workshop will include a weekend excursion to the National Radio
Astronomy Observatory in Greenbank, West Virginia, as well as tours of local facilities such as UMD physics labs, NASA's Goddard Space Flight
Center, and the National Institutes for Standards and Technology (NIST).
Physics Students Winning the Best Presentation Awards at UTPA
(Nov. 2014) Congratulations to our students Ramona Luna and Mkhitar Hobosyan on winning the Best presentation awards
at the 6th Annual PACE Bioethics Conference, which was held at the University of Texas Pan-American on November 4-6th. The
Topic of the PACE (Pan American Collaboration for Ethics in the Professions) conference was “Bioethics & the Future of Medical
Education”. Each winner was awarded a certificate and an iPad as a prize.
Faculty and students are engaged in fundamental research in relativistic astrophysics, gravitational wave astronomy, biophysics, nanoscience, and optics.
Publications by department faculty members:
Fall 2012 - Summer 2013
Fall 2011 - Summer 2012
We describe an alternative approach to the analysis of gravitational-wave backgrounds,
based on the formalism used to characterize the polarization of the cosmic microwave
background. In contrast to standard analyses, this approach makes no assumptions about
the nature of the background and so has the potential to reveal much more about the
physical processes that generated it. An arbitrary background can be decomposed into
modes whose angular dependence on the sky is given by gradients and curls of spherical
harmonics. We derive the pulsar timing overlap reduction functions for the individual
modes, which are given by simple combinations of spherical harmonics evaluated at the
pulsar locations. We show how these can be used to recover the components of an
arbitrary background, giving explicit results for both isotropic and anisotropic
uncorrelated backgrounds. We also find that the response of a pulsar timing array to
curl modes is identically zero, so half of the gravitational-wave sky will never be
observed using pulsar timing, no matter how many pulsars are included in the array.
Fermi-normal (FN) coordinates provide a standardized way to describe the
effects of gravitation from the point of view of an inertial observer. These
coordinates have always been introduced via perturbation expansions and
were usually limited to distances much less than the characteristic length
scale set by the curvature of spacetime. For a plane gravitational wave this
scale is given by its wavelength which defines the domain of validity for
these coordinates known as the long-wavelength regime. The symmetry of this
spacetime, however, allows us to extend FN coordinates far beyond the longwavelength
regime. Here we present an explicit construction for this long-range
FN coordinate system based on the unique solution of the boundary-value
problem for spacelike geodesics.
Nanoenergetic systems also known as metastable intermolecular composites (MIC) have various potential applications as propellants, explosives, and primers. The development of novel MIC systems, their design, synthesis and fabrication procedures are critical for national security and it was recognized as a significant addition to support of changing force structure for advanced weapons platforms. Our research at UTB focuses on developing a framework of principles for design and fabrication of nano-tailored highly energetic systems and nanoenergetic gas generators (NGG) for advanced energetic platforms. This involved a systematic study of physics based knowledge in energy release, shock waves and pressure discharge needed to enhance the performance and functionality of novel high density energetic systems.
Galaxies appear simpler than before by Disney et
al. The image shows a montage of coloured images of a dozen galaxies (huge
whirlpools of stars in space) drawn from our survey of the universe, which is the
subject of the letter. As well as being very beautiful they have considerable scientific
interest too because they show a wider variety of galaxies than it has been possible to
portray before. Hitherto galaxies were found optically, and hence tended to look
rather like one another. These, however, were picked up in a radio survey and imaged
only afterwards. Consequently they exhibit a much wider range of colours, shapes and
surface brightnesses. Intriguingly some of them, although close-by in cosmic terms,
are almost, but not quite, invisible. We believe both astronomers and laymen will find
them fascinating. Copyright belongs to one of the co-authors, Andrew West.
Although predicted by S. Rytov more than sixty years ago the experimental proof that radiative heat transfer can be exponentially improved by reducing the gap between two surfaces of different temperature was only recently demonstrated for macroscopic objects with a geometry that can be compared with theoretical predictions. The scientists from the University of Florida and the University of Texas at Brownsville demonstrated good agreement between theoretical prediction and measurement. When an infinite warm surface is separated from a cooler one by a vacuum gap, the rate of radiative heat transfer between the two shouldnt depend on the size of the gap. According to theory, though, this picture doesnt hold when the surfaces are sufficiently close. In the paper "Near-Field Radiative Heat Transfer between Macroscopic Planar Surfaces" (Phys. Rev. Lett. 107, 014301, 2011), the scientists focused on a straightforward planar geometry. The heat transfer between two parallel square sapphire plates, each about two inches on a side, was measured for separations from a 0.1 mm down to only a few microns. A pronounced increase in heat transfer is seen as the gap between the plates is reduced following the theoretical predictions. In principle, near-field heat transfer could be used to control the temperature of an object without ever contacting it. This is an interesting possibility for cooling the sensitive mirrors in future gravity wave detectors.
Using recent data from the LIGO interferometers, LIGO scientists have been able to constrain the fractional energy density in gravitational waves to < 6.9 x10-6 (at 95% confidence) in a ~100 Hz band around 100 Hz. This number improves on indirect limits on the gravitational wave background obtained from the relative abundance of light elements in the very early universe (Big Bang Nucleosynthesis). The attached figure shows various limits on the gravitational wave background and predictions from three different models (inflation, pre-Big Bang cosmology, and cosmic strings). The indirect limits are from Big Bang Nucleosynthesis and the Cosmic Microwave Background; the direct limits are from the LIGO S4 and S5 science data (see attached paper), and from pulsar timing data. Projected limits from the advanced LIGO detectors, the CMB Planck satellite mission, and the proposed space-based interferometer LISA are also shown.
We study the fluctuation-induced, time-dependent force between two plates confining a correlated fluid which is driven out of equilibrium mechanically by harmonic vibrations of one of the plates. For a purely relaxational dynamics of the fluid we calculate the fluctuation-induced force generated by the vibrating plate on the plate at rest. The time-dependence of this force is characterized by a positive lag time with respect to the driving. We obtain two distinctive contributions to the force, one generated by diffusion of stress in the fluid and another related to resonant dissipation in the cavity. The relation to the dynamic Casimir effect of the electromagnetic field and possible experiments to measure the time-dependent Casimir force are discussed.