Physics Commons^™

A Solution To The Tension Of Burning On Neutron Stars And Nuclear Physics, Yuri Cavecchi, D. K. Galloway, A. Heger, P. Santillán-Ortega, M. Nava-Callejas, F. M. Vincentelli, Liliana E. Rivera Sandoval, A. Goodwin, Z. Johnston

Physics & Astronomy Faculty Publications

When neutron stars accrete matter from a companion star, this matter forms a disk around them and eventually falls on their surface. Here, the fuel can ignite into bright flashes called Type I bursts. Theoretical calculations based on state-of-the-art nuclear reactions are able to explain many features of the bursts. However, models predict that the bursts should cease at high accretion rates, whereas in many sources they disappear at much lower rates. Moreover, their recurrence times also show strong discrepancies with predictions. Although various solutions have been proposed, none can account for all the observational constraints. Here, we describe a …

Black Hole Spectroscopy And Tests Of General Relativity With Gw250114, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, Raul Alberto Espinosa Perez, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang

Physics & Astronomy Faculty Publications

The binary black hole signal GW250114, the loudest gravitational wave detected to date, offers a unique opportunity to test Einstein’s general relativity (GR) in the high-velocity, strong-gravity regime and probe whether the remnant conforms to the Kerr metric. Upon perturbation, black holes emit a spectrum of damped sinusoids with specific, complex frequencies. Our analysis of the postmerger signal shows that at least two quasinormal modes are required to explain the data, with the most damped remaining statistically significant for about one cycle. We probe the remnant’s Kerr nature by constraining the spectroscopic pattern of the dominant quadrupolar (ℓ =𝑚 =2) …

A Transferable Force Field For Simulating Adsorption In Metal–Organic Frameworks With Open Metal Sites Based On The 12–6–4 Lennard-Jones Potential, Meng Du, Alan Rodriguez, Matthew Z. Lin, Haoyuan Chen

Physics & Astronomy Faculty Publications

Metal–organic frameworks (MOFs) that contain coordinatively unsaturated open metal sites (OMSs) provide strong host–guest interactions, making them promising sorbents for low-concentration gas adsorption applications such as direct air capture and atmospheric water harvesting. However, accurately modeling host–guest interactions involving OMSs remains challenging for classical force fields (FFs) based on the 12–6 Lennard–Jones (LJ) potential, as the polarization effect of the guest molecule induced by the positively charged OMS is not considered. Here, we introduce an FF based on the 12–6–4 LJ potential, which incorporates charge–induced dipole interactions and is parametrized against a diverse set of host–guest potential energy surfaces (PESs) …

Spectroscopic Investigations On Polyvinylidene Fluoride Nanofibers, Parinaz Amaniabdolmalaki, Jui Vitthal Kharade, Alexandro Trevino, Lydia Morales, Karen Lozano, Victoria Padilla, Karen S. Martirosyan, Horacio Vasquez, Mircea Chipara

Physics & Astronomy Faculty Publications

The production of polyvinylidene fluoride nanofibers by force-spinning from polymer solutions was confirmed by electron microscopy. The structural and phase characteristics of the resulting nanofiber mats were examined using Fourier Transform Infrared Spectroscopy in Attenuated Total Reflectance mode, Raman spectroscopy, and X-ray Diffraction. Results from all these techniques consistently indicated that both the powder and the mats of polyvinylidene fluoride predominantly contain the α phase, with a small admixture of the β phase. Within experimental errors, no other phases were noticed both in the powder and in the as-obtained mats. The ratios of the areas of the Raman lines at …

Gpu And Pso Accelerated Low-Latency Fully-Coherent All-Sky Search For Compact Binary Coalescences, Soumya D. Mohanty

Physics & Astronomy Faculty Publications

The fully-coherent all-sky (FCAS) search, which combines data from a gravitational wave detector network into a single likelihood function, is the preferred method prescribed by statistical theory for Gaussian noise. However, so far, its exorbitant computational cost has blocked its use for compact binary coalescence searches. We introduce a solution combining Particle Swarm Optimization with Graphics Processing Unit (GPU) acceleration that is ≈ 50-fold faster than real-time analysis. This transforms the prospect of a low-latency FCAS search on all GW data into a practical reality for the first time. With large-scale simulations enabled by this speedup, we examine the issue …

Efficient Search For Detection Candidates Using A Peak Finder Strategy For All-Sky-All-Frequency Gravitational Wave Radiometer, Arindam Sharma, Deepali Agarwal, Sanjit Mitra

Physics & Astronomy Faculty Publications

The first all-sky-all-frequency (ASAF) radiometer search was conducted using data from the first three observing runs of the Advanced LIGO and Advanced Virgo detectors. The significance of this search lies in its fast and unmodeled approach, leveraging a cross-correlation technique to identify common signals across the detector network. As a result, this method serves as an excellent alternative to search for unknown or poorly modeled continuous wave sources and narrow band components of the gravitational wave (GW) background. For continuous wave sources whose waveform can be modeled, this method can serve as the first stage of a hierarchical scheme by …

Gauge-Invariant Gravitational Wave Polarization In Metric F(R) Gravity With Cosmological Implications, Ramesh Radhakrishnan, David Mcnutt, Delaram Mirfendereski, Alejandro Pinero, Eric Davis, William Julius, Gerald Cleaver

Physics & Astronomy Faculty Publications

We develop a fully gauge-invariant analysis of gravitational-wave polarizations in metric 𝑓⁡(𝑅) gravity with a particular focus on the modified Starobinsky model 𝑓⁡(𝑅) =𝑅 +𝛼⁢𝑅2 −2⁢Λ, whose constant-curvature solution 𝑅𝑑 =4⁢Λ provides a natural de Sitter background for both early- and late-time cosmology. Linearizing the field equations around this background, we derive the Klein–Gordon equation for the curvature perturbation 𝛿⁢𝑅 and show that the scalar propagating mode acquires a mass 𝑚2𝜓 =1/(6⁢𝛼), highlighting how the same scalar degree of freedom governs inflationary dynamics at high curvature and the propagation of gravitational waves in the current accelerating Universe. Using the scalar–vector–tensor …

Accurate Prediction Of Geometrical Parameters Of An Ultra-Broadband Metamaterial Absorber Using Machine Learning, Md. Rezwan Ahmed, Oishi Jyoti, Pritu Parna Sarkar, Mohammod Abdul Motin, Md. Selim Habib, Md. Samiul Habib

Electrical and Computer Engineering Faculty Publications

In this paper, we systematically demonstrate the design and analysis of a new type of ultra-broadband tunable metamaterial perfect absorber (MPA) comprising a top vanadium dioxide (VO2) based patterned resonating patch, a continuous metallic film at the bottom, and an intermediate dielectric substrate having a thickness of only 0.18 at the center working frequency. The simulation results reveal that the absorber achieves a bandwidth of 7.26 THz, ranging from 5.40 THz to 12.66 THz, with more than 90% absorptance and an average absorption of 98.21% under normal incidence of the incoming THz wave. Furthermore, absorptance exceeding 99% is achieved between …

Design And Evaluation Of Gamified Kahoot Modules For Improving Engagement And Conceptual Understanding Of Introductory Physics Students, Yaritza Villarreal

Theses and Dissertations

This study investigates the effectiveness of gamified learning modules in enhancing the engagement and conceptual understanding of introductory physics students. The first phase of this study focused on the design and development of gamified learning modules for selected topics in introductory physics. The modules were developed by integrating principles of Backward Design, following an escape-room theme with interactive scenarios, and incorporating classic game elements (e.g., points and leaderboards).

The second phase examined the effectiveness of the gamified Kahoot modules using a pretest-posttest control-group design. Sixty-eight (68) students were equally randomly assigned to the control and experimental groups. The experimental group …

Adsorption-Photodegradation Performance Of Silver Titanate For Methylene Blue Removal: Kinetics, Thermodynamics And Isotherm Studies, Nawrin Rahman Shefa, Most. Afroza Khatun, Ahmed Hasnain Jalal, M. Jasim Uddin, Md. Wasikur Rahman

Physics & Astronomy Faculty Publications

Silver titanate (AgTO) was synthesized via an ion-exchange reaction between sodium titanate and silver nitrate. This study investigates the efficiency of AgTO in the combined adsorption-photodegradation process for removing Methylene Blue (MB). The synthesized material was characterized using FTIR, XRD, SEM, and EDX techniques. Batch adsorption experiments were conducted to assess the effects of AgTO dosage (0.1–1.0 g/L), initial MB concentration (5–20 mg/L), pH (3–11), and temperature (313–333 K). The highest MB removal efficiency (90 %) was achieved at 313 K, pH 3, and an initial MB concentration of 5 mg/L. The photocatalytic performance of AgTO was further evaluated under …

Thermodynamic Feasibility Of Nanoenergetic Systems Based On Metal Oxynitrides, Manoj Chhetri, Mkhitar A. Hobosyan, Maxim Zyskin, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

A comprehensive computational study was conducted to identify and evaluate nano-energetic systems utilizing aluminum (Al) as the fuel and a range of metal oxynitrides as oxidizers. The primary objective was to determine combinations that yield highly exothermic reactions, specifically those that maximize gas generation, adiabatic combustion temperature, and energy release. These parameters are critical for optimizing the performance of energetic materials in applications such as controlled energy delivery, propulsion, and pyrotechnics. By systematically analyzing thermodynamic properties including the heat of formation, enthalpy of reaction, Gibbs free energy, and equilibrium reaction products across a range of Al/oxynitride stoichiometries, the study aimed …

Likelihoods For Stochastic Gravitational Wave Background Data Analysis, Gabriele Franciolini, Mauro Pieroni, Angelo Ricciardone, Joseph D. Romano

Physics & Astronomy Faculty Publications

We present a systematic study of likelihood functions used for stochastic gravitational wave background (SGWB) searches. By dividing the data into many short segments, one customarily takes advantage of the central limit theorem to justify a Gaussian cross-correlation likelihood. We show, with a hierarchy of ever more realistic examples—beginning with a single frequency bin and one detector, and then moving to two and three detectors with white and colored signal and noise—that approximating the exact Whittle likelihood by various Gaussian alternatives can induce systematic biases in the estimation of the SGWB parameters. We derive several approximations for the full likelihood …

Gw241011 And Gw241110: Exploring Binary Formation And Fundamental Physics With Asymmetric, High-Spin Black Hole Coalescences, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, R. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang

Physics & Astronomy Faculty Publications

We report the observation of gravitational waves from two binary black hole coalescences during the fourth observing run of the LIGO–Virgo–KAGRA detector network, GW241011 and GW241110. The sources of these two signals are characterized by rapid and precisely measured primary spins, nonnegligible spin–orbit misalignment, and unequal mass ratios between their constituent black holes. These properties are characteristic of binaries in which the more massive object was itself formed from a previous binary black hole merger and suggest that the sources of GW241011 and GW241110 may have formed in dense stellar environments in which repeated mergers can take place. As the …

The Role Of Atmospheric Turbulence On Cloud Droplet Distribution And Droplet Impaction On An Airfoil, Arash Shad, Hashnayne Ahmed, ‪Nadim Zgheib, S. Balachandar, S. A. Sherif

Mechanical Engineering Faculty Publications

We conduct turbulence-informed Euler–Lagrange simulations of droplet-laden flow to examine the effects of atmospheric turbulence on droplet impingement characteristics on a NACA 0012 airfoil. We implement statistical overloading, whereby we inject millions of droplets, ranging in diameter from 1 to 160 microns, upstream of the airfoil at an average streamwise velocity of 120 m/s. Within a fraction of a second, these droplets would have either impinged on the airfoil or continued downstream. While the incoming air flow is maintained uniform, droplet injection is informed by ambient turbulence, affecting both the droplet velocity distribution as well as the size-dependent preferential concentration …

Constraining Deviations From The Kerr Metric Via A Bumpy Parametrization And Particle Swarm Optimization In Extreme Mass-Ratio Inspirals, Xiaobo Zou, Xingyu Zhong, Wen-Biao Han, Soumya D. Mohanty

Physics & Astronomy Faculty Publications

The measurement of deviations in the Kerr metric using gravitational-wave observations will provide a clear signal of new physics. Previous studies have developed multiple parametrizations (e.g., “bumpy” spacetime) to characterize such deviations in extreme mass-ratio inspirals (EMRIs). These approaches often rely on the Fisher information matrix (FIM) formalism to quantify the constraining power of future space-borne gravitational-wave detectors, such as LISA and Tianqin. For instance, using the analytical kludge waveform model under varying source configurations, such methods have achieved constraint sensitivity levels ranging from 10−4 to 10−2 on the dimensionless bumpy parameter 𝛿⁢˜𝑄 for LISA. In this paper, we advance …

Gw231123: A Binary Black Hole Merger With Total Mass 190–265 M⊙, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, R. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang

Physics & Astronomy Faculty Publications

On 2023 November 23 the two LIGO observatories both detected GW231123, a gravitational-wave signal consistent with the merger of two black holes with masses and (90\% credible intervals), at luminosity distance 0.7-4.1 Gpc and redshift of , and a network signal-to-noise ratio of 20.7. Both black holes exhibit high spins, and respectively. A massive black hole remnant is supported by an independent ringdown analysis. Some properties of GW231123 are subject to large systematic uncertainties, as indicated by differences in inferred parameters between signal models. The primary black hole lies within or above the theorized mass gap where black holes between …

The Perfect Host: Jwst Cepheid Observations In A Background-Free Type Ia Supernova Host Confirm No Bias In Hubble-Constant Measurements, Adam G. Riess, Siyang Li, Gagandeep S. Anand, Wenlong Yuan, Louise Breuval, Stefano Casertano, Lucas M. Macri, Dan Scolnic, Yukei S. Murakami, Alexei V. Filippenko

Physics & Astronomy Faculty Publications

Cycle 1 JWST observations of Cepheids in Type Ia supernova (SN Ia) hosts resolved their red-giant-dominated near-infrared backgrounds, sharply reducing crowding and showing that photometric bias in lower-resolution Hubble Space Telescope (HST) data does not account for the Hubble tension. We present cycle 2 JWST observations of >100 Cepheids in NGC 3447, a unique system that pushes this test to the limit by transitioning from low to no background contamination. NGC 3447, an SN Ia host at D ≈ 25 Mpc, is an interacting pair comprising (i) a spiral with mixed stellar populations, typical of H0 calibrators, and (ii) a …

Tess Light Curves And Period Changes In Low-Mass Eclipsing Binary Bb Persei, Marek Wolf, Petr Zasche, Miloslav Zejda, Martin Mašek, Andrej Mudray, Hana Kučáková, Waldemar Ogłoza, Jaroslav Merc, Jan Kára, Vojtěch Dienstbier

Physics & Astronomy Faculty Publications

We present a detailed analysis of the low-mass detached eclipsing binary system BB Persei, which contains two K-type stars in a circular orbit with a short period of 0.4856 d. We used light curves from the Transiting Exoplanet Survey Satellite (Tess), which observed BB Per in five sectors, to determine its photometric properties and a precise orbital ephemeris. The solution of the Tess light curve in Phoebe results in a detached configuration, where the temperature of the primary component was fixed to T 1 = 5 300 K according to Lamost, which gives us T 2 = 5 050 ± …

Six New Doubly Eclipsing Quadruples In A 2+2 Architecture, Petr Zasche, Hana Kučáková, Jan Kára, Jaroslav Merc, Z. Henzl, Martin Mašek, L. Červinka, Vojtěch Dienstbier

Physics & Astronomy Faculty Publications

The study presents a confirmation of six quadruples with two sets of eclipses that have the 2+2 architecture. These so-called doubly eclipsing systems still present a quite rare group of stars. We collected all available photometric data and carried out a detailed analysis of them. In addition to the precise TESS photometry used to model the light curves for both inner eclipsing binaries, photometric survey data were also used, and more than 100 nights of our own dedicated observations were carried out. These were mainly used for the detection of the long-term evolution of orbital periods. Thanks to these data, …

Solutions For Linear Fractional Differential Equations With Multiple Constraints Using Fractional B-Poly Bases, Md. Habibur Rahman, Muhammad I. Bhatti, Nicholas Dimakis

Physics & Astronomy Faculty Publications

This study presents an innovative numerical method for solving linear fractional differential equations (LFDEs) using modified Bernstein polynomial bases. The proposed approach effectively addresses the challenges posed by the nonlocal nature of fractional derivatives, providing a robust framework for handling multiple initial and boundary value constraints. By integrating the LFDEs and approximating the solutions with modified fractional-order Bernstein polynomials, we derive operational matrices to solve the resulting system numerically. The method’s accuracy is validated through several examples, showing excellent agreement between numerical and exact solutions. Comparative analysis with existing data further confirms the reliability of the approach, with absolute errors …

Click-Ready Gold Nanoparticles From Aqueous Mechanochemistry: 2-Propynylamine As A Reducing Agent And Surface Ligand, Amber L. Garcia, Brian S. Mitchell, Amanda Reusch, Mark J. Fink, Juan P. Hinestroza, Yelin Ko, Julie P. Vanegas

Physics & Astronomy Faculty Publications

We report a rapid aqueous method for synthesizing monodisperse gold nanoparticles (AuNPs), employing 2-propynylamine as both an intrinsic reducing agent and a surface-stabilizing ligand. This self-mediated process—achieved in a single step—yields spherical AuNPs with an average diameter of 4.0 ± 1.0 nm and a well-defined localized surface plasmon resonance band centered at 520 nm. Acting as a bifunctional molecule, 2-propynylamine simultaneously reduces HAuCl4·3H2O to elemental gold and passivates the nanoparticle surface through coordination via the amine group, while preserving a terminal alkyne (–C≡CH) functionality. This reactive moiety remains exposed and chemically accessible, enabling post-synthetic modification through Cu(I)-catalyzed azide–alkyne cycloaddition. Control …

Efficient Parallel Processing Of Second-Generation Tdi Data For Galactic Binaries In Space-Based Gravitational Wave Missions, Xue-Hao Zhang, Soumya D. Mohanty, S. R. Valluri, Shao-Dong Zhao, Qun-Ying Xie, Yu-Xiao Liu

Physics & Astronomy Faculty Publications

Space-based gravitational wave missions such as LISA, Taiji, and Tianqin rely on the time-delay interferometry (TDI) technique to observe low-frequency signals such as Galactic binaries (GBs), massive black-hole binaries, and extreme-mass-ratio inspirals. Among these sources, resolving the large population of GBs poses a central challenge for data analysis. In this work, we present GBSIEVER-C, a pipeline implemented in C and parallelized using OpenMP (Open Multi-Processing), along with a range of additional algorithmic optimizations, including a fast implementation of second-generation TDI response modeling. It builds upon the previous MATLAB-based pipeline that demonstrated competitive performance on LISA Data Challenge (LDC) data. To …

Gw250114: Testing Hawking’S Area Law And The Kerr Nature Of Black Holes, A. G. Abac, I. Abouelfettouh, F. Acernese, Teviet Creighton, Mario C. Diaz, R. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, M. Ramos Arevalo, Wenhui Wang

Physics & Astronomy Faculty Publications

The gravitational-wave signal GW250114 was observed by the two LIGO detectors with a network matched-filter signal-to-noise ratio of 80. The signal was emitted by the coalescence of two black holes with near-equal masses m_{1}=33.6_{-0.8}^{+1.2}M_{⊙} and m_{2}=32.2_{-1.3}^{+0.8}M_{⊙}, and small spins χ_{1,2}≤0.26 (90% credibility) and negligible eccentricity e≤0.03. Postmerger data excluding the peak region are consistent with the dominant quadrupolar (ℓ=|m|=2) mode of a Kerr black hole and its first overtone. We constrain the modes' frequencies to ±30% of the Kerr spectrum, providing a test of the remnant's Kerr nature. We also examine Hawking's area law, also known as the second law …

Performance Analysis Of Flapping-Foil Energy Harvesters Under Shear-Flow Conditions, Maqusud Alam, Bubryur Kim, Shehnaz Akhtar, Sujeen Song, Zengshun Chen, Jinwoo An

Civil Engineering Faculty Publications

Flapping-foil energy harvesters represent a promising technology for extracting energy from fluid flows, although their performance under shear-flow conditions is poorly understood. To address this research gap, we investigated the impact of power-law shear flow on the performance of flapping-foil energy harvesters. We conducted numerical simulations at different Reynolds numbers (Re = 1000, 50 000, and 500 000) under uniform-flow and shear-flow conditions. Based on the results, shear flow minimally affected the power outputs at Re = 1000 and 50 000, where viscous forces dominate the flow dynamics. However, at Re = 500 000, shear flow significantly reduced the …

Classifying Compact Radio Emission In Nearby Galaxies: A 10 Ghz Study Of Active Galactic Nuclei, Supernovae, Anomalous Microwave Emission, And Star-Forming Regions, Kristen C. Dage, Eric W. Koch, Evangelia Tremou, Kwangmin Oh, Susmita Sett, Cosima Eibensteiner, Sean T. Linden, Angiraben D. Mahida, Eric J. Murphy, Liliana E. Rivera Sandoval

Physics & Astronomy Faculty Publications

We present 115 compact radio point sources in three galaxies, NGC 5474, NGC 4631, and M51, taken in the most extended (A-)configuration of the Karl G. Jansky Very Large Array at 10 GHz. Several of these compact radio point sources have diffuse counterparts identified in previous multiband studies of resolved radio continuum emission. We find compact counterparts to eight star forming regions, four anomalous microwave emission candidates, and one supernova remnant (SN 2011dh). Nine of the compact radio sources match X-ray counterparts, the majority of which are background galaxies. These AGN are all within the D25 (isophotal diameter) of the …

Probing The Effect Of Peg-Dna Interactions And Buffer Viscosity On Tethered Dna In Shear Flow, Fatema Tuz Zohra, Huda Al-Zuhairi, Jefferson Reinoza, Hyeongjun Kim, Andreas Hanke

Mechanical Engineering Faculty Publications

DNA flow-stretching is a widely employed, powerful technique for investigating the mechanisms of DNA-binding proteins involved in compacting and organizing chromosomal DNA. We combine single-molecule DNA flow-stretching experiments with Brownian dynamics simulations to study the effect of the crowding agent polyethylene glycol (PEG) in these experiments. PEG interacts with DNA by an excluded volume effect, resulting in compaction of single, free DNA molecules in PEG solutions. In addition, PEG increases the viscosity of the buffer solution. By stretching surface-tethered bacteriophage lambda DNA in a flow cell and tracking the positions of a quantum dot labeled at the free DNA end …

Development Of A New Ground-Based Instrumentation Technique For Low-Resolution Exoplanet Transmission Spectroscopy, Mary Anne Limbach, Luke M. Schmidt, Ryan J. Oelkers, Darren L. Depoy

Physics & Astronomy Faculty Publications

We present a new instrumentation technique for high-precision, ground-based spectrophotometric measurements ideal for low-resolution (R ∼ 20–60) exoplanet transmission spectroscopy. This technique employs novel thin-film coating technology for wide-band, simultaneous multi-band imaging, enabling high-precision differential photometry through self-referencing and comparison stars. Theoretical calculations and on-sky results show that this method effectively reduces 96% of amplitude scintillation noise and other systematics that typically limit ground-based spectrophotometric precision for bright stars. On-sky results are demonstrated using the custom-built Exoplanet Transmission Spectroscopy Imager (ETSI), deployed at the McDonald Observatory 2.1 m telescope in 2022. For a V = 9.7 mag star, ETSI …

Red Noise Suppression In Pulsar Timing Array Data Using Adaptive Splines, Yi-Qian Qian, Yan Wang, Soumya Mohanty

Physics & Astronomy Faculty Publications

Noise in Pulsar Timing Array (PTA) data is commonly modeled as a mixture of white and red noise components. While the former is related to the receivers, and easily characterized by three parameters (EFAC, EQUAD and ECORR), the latter arises from a mix of hard to model sources and, potentially, a stochastic gravitational wave background (GWB). Since their frequency ranges overlap, GWB search methods must model the non-GWB red noise component in PTA data explicitly, typically as a set of mutually independent Gaussian stationary processes having power-law power spectral densities. However, in searches for continuous wave (CW) signals from resolvable …

Computational Calculations On Zno (0001) And Zno (1010) Surfaces With And Without Pd Adatoms, Amit Aich

Theses and Dissertations

In this research work, first-principles density functional theory (DFT) was used to study O-terminated, Zn-terminated ZnO (0001) surfaces and non-polar ZnO (1010) surfaces. Both clean surfaces and those with Pd or PdO adatoms were examined. Adsorption was considered at O, Zn and hollow sites. After structural relaxation, we analyzed the electronic, optical and adsorption properties. The O-terminated ZnO (0001) surface has a larger band gap of 0.76 eV and p-type conduction. The Zn-terminated surface has a smaller band gap of 0.15 eV and shows n-type behavior. Pd adsorption modifies ZnO’s electronic structure in a site-dependent manner. On O-terminated surfaces, it …

Rabi Oscillations And Entanglement Between Two Atoms Interacting By The Rydberg Blockade And With A Quantized Radiation Field Studied By The Jaynes-Cummings Model, Francisco D. Santillan, Andreas Hanke

Physics & Astronomy Faculty Publications

The interaction between atoms and a quantized radiation field is fundamentally important in quantum optics and quantum information science. Due to their unusual properties, Rydberg atoms are promising building blocks for two-qubit gates and atom-light quantum interfaces, exploiting the Rydberg blockade interaction which prevents two atoms at close distance (< 10μm) from being simultaneously excited to Rydberg states. Recently, this effect was used to engineer quantum processors based on arrays of interacting Rydberg atoms illuminated by Raman lasers. Motivated by these experiments, we extend the Jaynes–Cummings model to study the interaction between two Rydberg atoms interacting by the Rydberg blockade and a quantized radiation field. We consider both number (Fock) states of the field and single-mode quantum coherent states. In particular, we discuss different types of entanglements between various components of the total system consisting of the two Rydberg-interacting atoms and coherent states of the field, and show that the behavior is significantly different compared to a system with non-interacting atoms corresponding to the two-atom Tavis-Cummings model. Our results are relevant in view of atom-light quantum interfaces as components for future long-distance quantum communication.