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UTRGV Optics Lab Participates in STEM Conference at Lamar

This year Lamar University (Beaumont, Texas, and is a member of the Texas State University System) held its 7th Annual STEM Conference on November 2, 2019. The Organizing Committee of the conference invited Dr. Malik Rakhmanov, Associate Professor in the department of Physics and Astronomy, and his research group to participate in the meeting. The 7th STEM Conference featured nearly 50 presentations in which students from Texas and the neighboring state of Louisiana presented highlights of their research. Dr. Rakhmanov and his group prepared several presentations for this conference. Anton Gribovskiy, a PhD candidate in the UTRGV-UT Arlington cooperative Physics PhD program, presented a poster titled "Spectroscopy with Nonlinear Si Integrated Microring Resonators,” Artemiy Bogdanovskiy, also a PhD student in the same program, presented a poster “Experimental Setup to Model Gravitational Wave Detection”. Satzhan Sitmukhambetov gave a talk “Basics of Quantum Computing.” Also from UTRGV attending the meeting was Amit Aich (2nd year MSIS: Science & Technology student). The UTRGV Group actively participated in all sessions of the conference, engaged in the discussions and interacted with the local students and faculty. Lamar commemorated all UTRGV presenters with diplomas and generously supported their visit. In addition, Anton Gribovskiy won the third place among all poster presenters taking home a financial award.

UTRGV gets $375k for gravitational waves research

The NSF grant will support the university’s Laser Interferometer Gravitational Wave-Observatory (LIGO) instrumentation and data analysis, and provide funding for new gravitational wave detection techniques and experimental innovations to enhance the probability of discovering new gravitational waves sources.

More details at The Monitor

NSF funds UTRGV professor’s TOROS telescope project to track cosmic gravitational wave events

The National Science Foundation has awarded UTRGV’s Center for Gravitational Wave Astronomy (CGWA) $516,000 for the second phase of construction of a telescope dedicated to research on gravitational waves.

More details at: UTRGV Newsroom

Dr. Hyun-chul Lee gets the Regents Outstanding Teaching Award

Dr. Hyun-chul Lee, Lecturer in the Department of Physics and Astronomy has received the 2019 Regents Outstanding Teaching Award. The department congratulates Dr. Lee!

Dr. Hyun Lee

Dr. Volker Quetschke given UTRGV Exceptional Service Award

Dr. Volker Quetschke given UTRGV Exceptional Service Award

Faculty members at The University of Texas Rio Grande Valley were recognized, celebrated, and honored for their exceptional accomplishments during the annual Faculty Excellence Awards Thursday, May 2.

More details at: https://www.utrgv.edu/newsroom/2019/05/02-exceptional-accomplishments-by-faculty-recognized-at-annual-utrgv-awards-program.htm

PhysTEC Fellows

Dr. Liang Zeng Dr. Nicolas Pereyra

Dr. Liang Zeng and Dr. Nicolas Pereyra, Associate Professors in the department, have been selected to be 2019-20 PhysTEC Fellows! The UTRGV team comprising Dr. Zeng and Dr. Pereyra was among five selected from different institutions around the country!

Outstanding International Female Student

Fatemeh Mostafavikhatam, a physics graduate student under the supervision of Dr. Hamidreza Ramezani, received the award for Outstanding International Female Student. Dr. Volker Quetschke, associate professor of physics and astronomy, presented her with a plaque and flowers.

“This award is very motivating for me because after a lot of hard work I put into my research here in the United States … and I found that at the end, my results are recognized by the university and they have this type of meeting to encourage students that their effort is seen and rewarded by the university. So, it’s important to me,” Mostafavikhatam said.

Department faculty members recognized

Physics and Astronomy department faculty members have been recognized at the UTRGV College of Sciences Research Symposium held Friday, March 29, 2019. Dr. Hyun-chul Lee (left) has been awarded the 2018-19 Teaching Excellence Prize, while Dr. Volker Quetschke (right) has received the 2018-19 Service Excellence award. The department congratulates Dr. Lee and Dr. Quetschke for their wonderful accomplishments.

Prof. Mohanty has published a new book "Swarm intelligence methods for statistical regression"

Prof. Mohanty has published a new book "Swarm intelligence methods for statistical regression" (Chapman and Hall/CRC press). The book expands on lectures delivered by Prof. Mohanty at the "BigDat2017" winter school on big data, Bari, Italy, and explains how to tackle the optimization challenges often encountered in

statistical analysis of big data using a relatively new breed of nature-inspired methods. One particular swarm intelligence method, called particle swarm optimization (PSO), was first used in gravitational wave data analysis by Prof. Mohanty and collaborators and has helped solve some outstanding challenges in this area. The book discusses the application of PSO to both parametric and non-parametric regression problems in general, not confined to gravitational waves alone. Further information is available at the publisher's website.

LIGO and Virgo Announce Four New Gravitational-Wave Detections

On Saturday, December 1, scientists attending the Gravitational Wave Physics and Astronomy Workshop in College Park, Maryland, presented new results from the National Science Foundation's LIGO (Laser Interferometer Gravitational-Wave Observatory) and the European-based VIRGO gravitational-wave detector regarding their searches for coalescing cosmic objects, such as pairs of black holes and pairs of neutron stars. The LIGO and Virgo collaborations have now confidently detected gravitational waves from a total of 10 stellarmass binary black hole mergers and one merger of neutron stars, which are the dense, spherical remains of stellar explosions. Six of the black hole merger events had been reported before, while four are newly announced. See CGWA press release.

4th NANOSMAT-USA 2018 conference at South Padre Island, TX, USA

(click on image for larger view)
The 4th NANOSMAT-USA 2018 conference will be held at Isla Grand Beach Resort South Padre Island, TX, USA during October 29th to November 1st 2018. NANOSMAT is widely recognized as a premier conference focused on traditional topics in “NANO” such as Nanoscience, Nano-Engineering and Nanotechnology as well as emerging new research directions such as Nanobiology, Nanomedicine and economical aspects of NANO. The conference will be sponsored by UTRGV. For more information, see http://www.nanosmat-usa.com/default.asp. The abstract submission deadline is 15 August, 2018. For registration details, see http://www.nanosmat-usa.com/registration.asp.

Prof. Myoung-Hwan Kim receives 2018 Outstanding Young Researcher Award from AKPA

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Prof. Myoung-Hwan Kim received the 2018 Outstanding Young Researcher Award from the Association of Korean Physicists in America (AKPA) for his contribution to modern material research including low-dimensional, topological, and correlated systems with terahertz and infrared lasers. Prof. Kim has more than 10 years of experience in far/mid/near infrared Hall measurements for various types of materials including topological insulators, graphene mono- and multilayers, itinerant ferromagnets, superconductors, semiconductors, and insulators. The infrared Hall angle measurement is one of the most powerful way to disclose Fermi surface information, which are comparable with the results acquired from angular-resolved photoemission spectroscopy (ARPES) and de Haas-van Alphen oscillations. In addition, Prof. Kim has recently developed a new tool to measure polarimetric spectrum at underexplored mid/far infrared. Using this tool, Prof. Kim will observe a frequency evolution of quasi-particle scattering in a time-reversal symmetry broken system. This research will benefit the understanding of more complex spin-orbit coupled system. The award ceremony took place at the Korean Physical Society-AKPA Symposium at the Los Angeles Convention Center during the American Physical Society March meeting. Prof. Kim gave an award presentation on his research.
(For more details visit akpa.org)

Prof. HyeongJun Kim receives UT System Rising STARs award.

Prof. HyeongJun Kim received the prestigious UT System Rising STARs award. The award will go towards establishing research on single-molecule biophysics of genome organization at UTRGV. Dr. Kim will join our department from Harvard Medical School in spring 2018. Dr. Kim has been trained as a single-molecule biophysicist. Traditionally, biologists observed multiple (tens or even thousands of) molecules simultaneously and obtained "averaged" (ensemble) information. However, the advent of single-molecule biophysics techniques enabled scientists to observe "individual" biological molecules such as DNA or proteins one-by-one, getting very detailed information that cannot be obtained by traditional methods. Dr. Kim's research as a graduate student at the University of Illinois at Urbana-Champaign (UIUC) and postdoctoral fellow at Harvard Medical School focused on both single-molecule technology development and its application to answering biological questions. At UTRGV, Dr. Kim plans to carry out research on underlying working mechanisms of various DNA-associated proteins by utilizing his single-molecule biophysics expertise.

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Research

Gravitational waves, as Einstein predicted

UTRGV Center for Gravitational Waves "The Amazing Discovery"

(Feb. 2016) For the first time, scientists have observed ripples in the fabric of spacetime called gravitational waves, arriving at the earth from a cataclysmic event in the distant universe. This confirms a major prediction of Albert Einstein's 1915 general theory of relativity, and opens an unprecedented new window onto the cosmos.

Press links

Publications

Faculty and students are engaged in fundamental research in relativistic astrophysics, gravitational wave astronomy, biophysics, nanoscience, and optics.

UT Rio Grande Valley Department of Physics Publications 2011-Present

Recent Research Highlights

Eigenstates Transition without Undergoing an Adiabatic Process. The current transition of technological advancements from classical to quantum systems makes the quantum adiabatic theorem an important matter beyond a conceptual curiosity. We introduce a class of non-Hermitian Hamiltonians that offers a dynamical approach to a shortcut to adiabaticity (DASA). In particular, in our proposed

2 \times 2

Hamiltonians, one eigenvalue is absolutely real and the other one is complex. This specific form of eigenvalues helps us to exponentially decay the population in an undesired eigenfunction or amplify the population in the desired state while keeping the probability amplitude in the other eigenfunction conserved. This provides us with a powerful method to have a diabatic process with the same outcome as its corresponding adiabatic process. In contrast to standard shortcuts to adiabaticity, our Hamiltonians have a much simpler form with a lower thermodynamic cost. Furthermore, we show that DASA can be extended to higher dimensions using the parameters associated with our

2 \times 2

Hamiltonians. Our proposed Hamiltonians not only have application in DASA but also can be used for tunable mode selection and filtering in acoustics, electronics, and optics.

Photons are bosons, namely, indistinguishable particles. This means that in principle we cannot independently select two similar photons traveling in opposite directions and trap one of them. In a letter accepted for publication in Phys. Rev. Lett. (H. Ramezani, P. K. Jha, Y. Wang, and X. Zhang, Nonreciprocal localization of photons, accepted to Phys. Rev. Lett.) H. Ramezani et al. have shown that indeed one can break this limitation and trap photons traveling in one direction in spatiotemporally modulated photonic lattices. Photons with exactly the same properties coming from the opposite direction can freely pass through the photonic lattice. Ramezani's proposal opens new avenues to design new devices like isolators, circulators, sensors, limiters, and even lasers.

LIGO and Virgo make first detection of gravitational waves produced by colliding neutron stars. For the first time, scientists have directly detected gravitational waves - ripples in space and time - in addition to light from the spectacular collision of two neutron stars. This marks the first time that a cosmic event has been viewed in both gravitational waves and light. The discovery was made using the U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO); the Europe-based Virgo detector; and some 60 ground- and space- based telescopes. Among these 60, the TOROS (Transient Optical Robotic Observatory of the South), an international collaboration with more than 50 scientists, and lead by CGWA faculty and students, operated two telescopes: one in Co. Tololo, Chile and the other one in Bosque Alegre, Argentina. Top image: pseudo-color image of a small subsection of the FoV of the T80S telescope, centered on the transient near galaxy NGC4993. Bottom: 3 times zoom in with the galaxy subtracted. See CGWA press release.

The LIGO Scientific Collaboration and the Virgo collaboration report the first joint detection of gravitational waves with both the LIGO and Virgo detectors. This is the fourth announced detection of a binary black hole system and the first significant gravitational-wave signal recorded by the Virgo detector, and highlights the scientific potential of a three-detector network of gravitational-wave detectors. The three-detector observation was made on August 14, 2017 at 10:30:43 UTC. The two Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors, located in Livingston, Louisiana, and Hanford, Washington, and funded by the National Science Foundation (NSF), and the Virgo detector, located near Pisa, Italy, detected a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes. Image: Skymap showing the localization area of the event over the constellations in the sky (top) and the time series and frequency maps (bottom). A paper about the event, known as GW170814, has been accepted for publication in the journal Physical Review Letters. See CGWA press release.

"Pulsar timing array based search for supermassive black hole binaries in the Square Kilometer Array era", Yan Wang and Soumya D. Mohanty, Phys. Rev. Lett. 118, 151104 (2017). This article was chosen for the cover and as feature article of Physical Review Letters.
There is now strong observational evidence that most massive galaxies, including our own, host black holes - with masses ranging from million to billion solar masses - at their cores. The merger of galaxies containing such black holes should have lead to the formation of binary systems containing supermassive black holes. Gravitational waves emitted by such binaries, which are potentially detectable with the technique of Pulsar timing, would be the clearest signature of their existence. In this paper, we show that the detection of gravitational waves from Supermassive Black Holes Binaries is practically guaranteed when the Square Kilometer Array (SKA) - a next generation radio telescope - starts operation. This will happen through the discovery by SKA of thousands of millisecond pulsars - the most stable clocks in nature - which will boost the sensitivity of the pulsar timing technique by orders of magnitude. Our predictions are derived from a realistic simulation of a SKA-era array of timed pulsars (a "Pulsar Timing Array") and a rigorous, quantitative analysis of the corresponding data. This analysis also allows us to predict the accuracy with which a given binary can be localized on the sky. This enables future studies of joint observational strategies for supermassive black hole binaries using SKA at radio frequencies and the upcoming Large Synoptic Survey Telescope (LSST) in the optical.

Dr. Ahmed Touhami and collaborators have recently published a paper in Nature Biofilms. First author Kristin Kovach is a graduate student at UT Austin, co-advised by Dr. Touhami. The published research shows that over time bacteria can evolve the ability to strengthen their biofilms, making it harder for the host's immune cells to break them up and consume the bacteria. The Pseudomonas aeruginosa bacteria do this trick by secreting more and more of a carbohydrate that links up with proteins to form a tough, super glue-like network between bacteria. In cystic fibrosis (CF), a serious genetic disease that afflicts roughly 30,000 Americans, patients produce thick, dry mucus in their lungs that is hard to cough up and provides an ideal breeding ground for bacterial infections. The researchers are now investigating whether blocking the carbohydrate from binding to a specific protein would prevent the resulting biofilm from becoming tougher. If so, it would be a good target for future therapies, making the biofilm more vulnerable to the host's own immune system. This new perspective has the potential to improve the lives of a lot of people. The published paper was also covered on the Cystic Fibrosis News Today website. The research was funded by the University of Texas at Austin, ExxonMobil and grants from the Human Frontiers Science Program and the National Science Foundation.

After Advanced LIGO's recent direct observation of gravitational waves for the first time it becomes apparent that in order to make the transition from detection to meaningful observation and analysis of gravitational wave events precision calibration of the detectors is required. For the analysis after the detection of the gravitational waves from the mergers of binary black hole systems accurate calibration of the output of these detectors was crucial for the observation of these events and the extraction of parameters of the sources. This article, with co-authors Darkhan Tuyenbayev (UTRGV graduate student) and Dr. Volker Quetschke among other LIGO researcher, was chosen for the cover and as feature article of Review of Scientific Instruments. The article describes the photon calibrator systems that were completely redesigned for Advanced LIGO that meet the calibration requirements of second-generation gravitational wave detectors in the new era of gravitational-wave astronomy. The article describes the design, implementation, and operation of these Advanced LIGO photon calibrators that are currently providing fiducial displacements of the LIGO testmasses on the order of 10^-18m/vHz with accuracy and precision of better than 1%.

M.-H. Kim at UTRGV, N. Yu at Columbia Univ., and S. Zhang at Harvard Univ. designed for the first time functional flat lenses for mid-infrared light with high efficiency and near diffraction-limited focusing. This work was performed in parallel with the first design of functional flat lenses at visible wavelengths by the Capasso group, Harvard Univ. [M. Khorasaninejad et al., Science 352, 1190-1194 (2016)]. These studies show that conventional bulk lenses can be replaced with metasurface lenses by overcoming the low power efficiency problem, and show promise for commercial applications such as camera lenses for smart phones and miniature lenses for health care and diagnosis applications.

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.

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 colored 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 colors, 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/Texas Southmost College 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 shouldn't depend on the size of the gap. According to theory, though, this picture doesn't 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.

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.

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.

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