Physics Commons^™

Black Holes, Wormholes, And Extra Dimensions, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

No abstract provided.

New Numerical Code For Black Hole Initial Data, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

There are no exact solutions of Einstein Equations that describes a bound system radiating gravitational waves. One needs to resort to numerical simulations, or analytical approximation methods. Current methods to constrained initial data exhibit junk radiation and ambiguities about constrained and free data. It was mathematically proved that given the correct initial data, Einstein equation will yield the expected solution.

Undergraduate Research In Gravitational Waves Astronomy At Marshall University, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

This is a presentation of undergraduate student research into gravitational waves at Marshall University.

Dawn Of Gravitational Wave Astronomy, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

This presentation chronicles the discovery of gravity waves.

Learning To Teach And Teaching To Learn, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

New studies show that students do better in science classes that are taught interactively. We compare two different pedagogical approaches in teaching introductory physics: the lecture-based method, the active learning laboratories. We present the data on student performance on exams, homework, lab activities and tests, from 126 students taking the 200-level introductory physics courses at Marshall University, in Huntington, WV. We discuss the efficiency of each method in fostering the success of students in the introductory physics courses. We find that subtle differentiations can be implicitly detected in students’ exam grades, homework, participation, and choice of major.

Carbide-Derived Carbon By Electrochemical Etching Of Vanadium Carbides, Luis G.B. Camargo, Benjamin G. Palazzo, Greg Taylor, Zach A. Norris, Yash K. Patel, Jeffrey D. Hettinger, Lei Yu

Jeffrey Hettinger

Carbide-derived Carbon (CDC) has been demonstrated to be an excellent electrode material for electrochemical devices including supercapacitors due to its chemical and electrochemical stability, large specific surface area and controllable pore size and morphology. Currently, CDC is prepared from metal carbides by chlorination in a chlorine gas atmosphere at temperatures of 350°C or higher. In this paper, conversion using electrochemical methods is reported, which can be achieved by oxidizing vanadium carbides (VC or V2C) in aqueous solutions at room temperature and a mild electrode potential to prepare CDC thin film as electrode materials for “on-chip” supercapacitiors. It was found that …

Behavior Of Na+-Polystyrene Sulfonate At The Interface With Single-Walled Carbon Nanotubes (Swnts) And Its Implication To Swnt Suspension Stability, Tabbetha A. Dobbins, Richard Chevious, Yuri Lvov

Tabbetha A. Dobbins

The assembly of sodium polystyrene sulfonate (Na+-PSS) at the surface of single-walled carbon nanotubes (SWNTs) in pH 3 aqueous solution is described. Rather than forming linear or sheet-like chain morphologies over SWNT surfaces, Na+-PSS adopts a spherically collapsed conformation believed to be the result of cation (either Na+ or H+) condensation onto the ionized polymer chain. It is well reported that cations (and also anions) adsorb preferentially onto single-walled and multi-walled carbon nanotube surfaces leading to an increased ion concentration in the near surface regions relative to the bulk solution. This work provides experimental evidence for preferentially absorbed cation condensation …

Study Of Morphological Changes In Mgh2 Destabilized Libh4 Systems Using Computed X-Ray Microtomography, Tabbetha A. Dobbins, Shathabish Narasegowda, Leslie G. Butler

Tabbetha A. Dobbins

The objective of this study was to apply three-dimensional x-ray microtomographic imaging to understanding morphologies in the diphasic destabilized hydride system: MgH2 and LiBH4. Each of the single phase hydrides as well as two-phase mixtures at LiBH4:MgH2 ratios of 1:3, 1:1, and 2:1 were prepared by high energy ball milling for 5 minutes (with and without 4 mol % TiCl3 catalyst additions). Samples were imaged using computed microtomography in order to (i) establish measurement conditions leading to maximum absorption contrast between the two phases and (ii) determine interfacial volume. The optimal energy for measurement was determined to be 15 keV …

Hypervolatiles In A Jupiter-Family Comet: Observations Of 45p/Honda–Mrkos–Pajdušáková Using Ishell At The Nasa-Irtf, Michael A. Disanti, Boncho P. Bonev, Neil Dello Russo, Ronald J. Vervack, Erika L. Gibb, Nathan X. Roth, Adam J. Mckay, Hideyo Kawakita, Lori M. Feaga, Harold A. Weaver

Erika Gibb

Evolution And Rationale For United States Department Of Defense Electromagnetic Pulse Protection Standard, George H. Baker Iii

George H Baker

The United States (US) Department of Defense (DoD) Electromagnetic Pulse (EMP) protection standard offers a solid basis for protecting commercial communication, data, and control facilities. Because of the standard’s shielded barrier and test requirements, it is not surprising that there is a strong temptation within industry and government to dismiss the MIL-STD 188-125 approach in favor of less rigorous protection methods. It is important to understand that US DoD EMP protection standard for fixed facilities, MIL-STD-188-125, reflects an evolution by trial and error that spanned a period of decades beginning with the acquisition of the Minuteman Missile System in the …

Proposal For A Dod Combined Battlefield Electromagnetic Environmental Effects (E3) Initiative, George H. Baker Iii

George H Baker

The presentation emphasizes the growing importance of electromagnetic survivability and compatibility. Operation Desert Storm demonstrated the clear military advantage provided by sophisticated electronic weapon and communication systems. In addition, the offensive tactic of taking out the enemy's eyes and ears during the air war paid off, giving our military decisive air superiority. The lessons for the future are clear. High-tech electronics now so dominates the battlefield that the outcome of future conflicts could well be decided by electronics attrition rather than human casualties. Our Desert Storm experience thus accentuates the importance of guaranteeing that our electronic systems will not be …

First Direct Constraints On Fierz Interference In Free-Neutron Β Decay, Kevin P. Hickerson, Xiaohui Sun, Yelena Bagdasarova, David Bravo-Berguño, Leah J. Broussard, Peter Brown, Richard Carr, Scott Currie, Xinjian Ding, Bradley W. Filippone, Alejandro García, Peter Geltenbort, J. Todd Hoagland, A. T. Holley, Ran Hong, Takeyasu M. Ito, Andreas Knecht, Chao-Yu Liu, Jiang-Lai Liu, Mark Makela, Russell R. Mammei, J. W. Martin, Dan Melconian, Michael P. Mendenhall, Spencer D. Moore, Christopher L. Morris, Robert W. Pattie, A. Pérez Galván, Ruediger Picker, Margaret L. Pitt, Bradley R. Plaster, John C. Ramsey, Roger H. Rios, A. Saunders, Susan J. Seestrom, Eduard I. Sharapov, Walter E. Sondheim, Erdinch Tatar, R. Bruce Vogelaar, Brittney Vorndick, Christopher Wrede, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

Testimony Of Dr. George H. Baker, Senior Advisor To The Congressional Emp Commission, George H. Baker Iii

George H Baker

This is the script of testimony before the Federal Energy Regulatory Commission. It offers a vision for a future in which our electric power systems will be able to operate through or quickly recover from catastrophic failure due to electromagnetic pulse (EMP), cyber, and physical attacks. The scope of the term ‘EMP’ used in this testimony includes both naturally occurring solar storms and the more energetic man-made EMP hazards. The vision has been discussed with members of the electric power industry, and prominent EMP/cyber/physical protection advocates who find it to be supportable and actionable. The nature of EMP, cyber, and …

Applying A Resources Framework To Analysis Of The Force And Motion Conceptual Evaluation, Trevor I. Smith, Michael C. Wittmann

Trevor I. Smith

We suggest one redefinition of common clusters of questions used to analyze student responses on the Force and Motion Conceptual Evaluation. Our goal is to propose a methodology that moves beyond an analysis of student learning defined by correct responses, either on the overall test or on clusters of questions defined solely by content. We use the resources framework theory of learning to define clusters within this experimental test that was designed without the resources framework in mind. We take special note of the contextual and representational dependence of questions with seemingly similar physics content. We analyze clusters in ways …

Student Understanding Of Taylor Series Expansions In Statistical Mechanics, Trevor I. Smith, John R. Thompson, Donald B. Mountcastle

Trevor I. Smith

One goal of physics instruction is to have students learn to make physical meaning of specific mathematical expressions, concepts, and procedures in different physical settings. As part of research investigating student learning in statistical physics, we are developing curriculum materials that guide students through a derivation of the Boltzmann factor using a Taylor series expansion of entropy. Using results from written surveys, classroom observations, and both individual think-aloud and teaching interviews, we present evidence that many students can recognize and interpret series expansions, but they often lack fluency in creating and using a Taylor series appropriately, despite previous exposures in …

Comparing Three Methods For Teaching Newton’S Third Law, Trevor I. Smith, Michael C. Wittmann

Trevor I. Smith

Although guided-inquiry methods for teaching introductory physics have been individually shown to be more effective at improving conceptual understanding than traditional lecture-style instruction, researchers in physics education have not studied differences among reform-based curricula in much detail. Several researchers have developed University of Washington–style tutorial materials, but the different curricula have not been compared against each other. Our study examines three tutorials designed to improve student understanding of Newton’s third law: the University of Washington’s Tutorials in Introductory Physics (TIP), the University of Maryland’s Activity-Based Tutorials (ABT), and the Open Source Tutorials (OST) also developed at the University of Maryland. …

Non-Hermitian Engineering Of Single Mode Two Dimensional Laser Arrays, M. H. Teimourpour, Li Ge, Demetrios N. Christodoulides, Ramy El-Ganainy

Ramy El-Ganainy

A new scheme for building two dimensional laser arrays that operate in the single supermode regime is proposed. This is done by introducing an optical coupling between the laser array and lossy pseudo-isospectral chains of photonic resonators. The spectrum of this discrete reservoir is tailored to suppress all the supermodes of the main array except the fundamental one. This spectral engineering is facilitated by employing the Householder transformation in conjunction with discrete supersymmetry. The proposed scheme is general and can in principle be used in different platforms such as VCSEL arrays and photonic crystal laser arrays.

Non-Hermitian Engineering Of Synthetic Saturable Absorbers For Applications In Photonics, M. H. Teimourpour, A. Rahman, K. Srinivasan, Ramy El-Ganainy

Ramy El-Ganainy

We explore a type of synthetic saturable absorber based on quantum-inspired photonic arrays. We demonstrate that the interplay between optical Kerr nonlinearity, interference effects, and non-Hermiticity through radiation loss leads to a nonlinear optical filtering response with two distinct regimes of small and large optical transmissions. More interestingly, we show that the boundary between these two regimes can be very sharp. The threshold optical intensity that marks this abrupt “phase transition” and its steepness can be engineered by varying the number of the guiding elements. The practical feasibility of these structures as well as their potential applications in laser systems …

Supersymetric Laser Arrays, Ramy El-Ganainy, Li Ge, M. Khajavikhan, Demetrios N. Christodoulides

Ramy El-Ganainy

We introduce the concept of supersymmetric laser arrays that consist of a main optical lattice and its superpartner structure, and we investigate the onset of their lasing oscillations. Due to the coupling of the two constituent lattices, their degenerate optical modes form doublets, while the extra mode associated with unbroken supersymmetry forms a singlet state. Singlet lasing can be achieved for a wide range of design parameters, either by introducing stronger loss in the partner lattice or by pumping only the main array. Our findings suggest the possibility of building single-mode, high-power laser arrays and are also important for understanding …

Topological Tight-Binding Models From Nontrivial Square Roots, J. Arkinstall, M. H. Teimourpour, L. Feng, Ramy El-Ganainy, H. Schomerus

Ramy El-Ganainy

We describe a versatile mechanism that provides tight-binding models with an enriched, topologically nontrivial band structure. The mechanism is algebraic in nature, and leads to tight-binding models that can be interpreted as a nontrivial square root of a parent lattice Hamiltonian—in analogy to the passage from a Klein-Gordon equation to a Dirac equation. In the tight-binding setting, the square-root operation admits to induce spectral symmetries at the expense of broken crystal symmetries. As we illustrate in detail for a simple one-dimensional example, the emergent and inherited spectral symmetries equip the energy gaps with independent topological quantum numbers that control the …

Fractal Holography: A Geometric Re-Interpretation Of Cosmological Large Scale Structure, Jonas R. Mureika

Jonas Mureika

The fractal dimension of large-scale galaxy clustering has been demonstrated to be roughly D_F∼2 from a wide range of redshift surveys. If correct, this statistic is of interest for two main reasons: fractal scaling is an implicit representation of information content, and also the value itself is a geometric signature of area. It is proposed that the fractal distribution of galaxies may thus be interpreted as a signature of holography (``fractal holography''), providing more support for current theories of holographic cosmologies. Implications for entropy bounds are addressed. In particular, because of spatial scale invariance in the matter distribution, …

Differentiating Unparticles From Extra Dimensions Via Mini Black Hole Thermodynamics, Jonas R. Mureika

Jonas Mureika

A thermodynamics-based method is presented for differentiating mini black hole creation mechanisms in high energy parton collisions, including scenarios with large compactified extra dimensions and unparticle-enhanced gravity with real scaling dimension dU. Tensor unparticle interactions are shown to mimic the physics of (2dU−2) noninteger extra spatial dimensions. This yields unique model-dependent production rates, Hawking temperature profiles, and decay multiplicities for black holes of mass MBH∼1–15  TeV that may be created at the LHC and other future colliders.

Vector Unparticle Enhanced Black Holes: Exact Solutions And Thermodynamics, Jonas R. Mureika, Euro Spallucci

Jonas Mureika

Tensor and scalar unparticle couplings to matter have been shown to enhance gravitational interactions and provide corrections to the Schwarzschild metric and associated black hole structure. We derive an exact solution to the Einstein equations for vector unparticles, and conclusively demonstrate that these induce Riessner–Nordström (RN)-like solutions where the role of the “charge” is defined by a composite of unparticle phase space parameters. These black holes admit double-horizon structure, although unlike the RN metric these solutions have a minimum inner horizon value. In the extremal limit, the Hawking temperature is shown to vanish. As with the scalar/tensor case, the (outer) …

Self-Completeness And Spontaneous Dimensional Reduction, Jonas R. Mureika, Piero Nicolini

Jonas Mureika

A viable quantum theory of gravity is one of the biggest challenges physicists are facing. We discuss the confluence of two highly expected features which might be instrumental in the quest of a finite and renormalizable quantum gravity —spontaneous dimensional reduction and self-completeness. The former suggests the spacetime background at the Planck scale may be effectively two-dimensional, while the latter implies a condition of maximal compression of matter by the formation of an event horizon for Planckian scattering. We generalize such a result to an arbitrary number of dimensions, and show that gravity in higher than four dimensions remains self-complete, …

The Effects Of Temperature, Humidity, And Barometric Pressure On Short-Sprint Race Times, Jonas R. Mureika

Jonas Mureika

A numerical model of 100 m and 200 m world class sprinting performances is modified using standard hydrodynamic principles to include effects of air temperature, pressure, and humidity levels on aerodynamic drag. The magnitude of the effects are found to be dependent on wind speed. This implies that differing atmospheric conditions can yield slightly different corrections for the same wind gauge reading. In the absence of wind, temperature is found to induce the largest variation in times (0.01 s per 10◦C increment in the 100 m), while relative humidity contributes the least (under 0.01 s for all realistic conditions for …

Multifractal Structure In Nonrepresentational Art, Jonas R. Mureika, C. C. Dyer, G. C. Cupchik

Jonas Mureika

Multifractal analysis techniques are applied to patterns in several abstract expressionist artworks, painted by various artists. The analysis is carried out on two distinct types of structures: the physical patterns formed by a specific color (“blobs”) and patterns formed by the luminance gradient between adjacent colors (“edges”). It is found that the multifractal analysis method applied to “blobs” cannot distinguish between artists of the same movement, yielding a multifractal spectrum of dimensions between about 1.5 and 1.8. The method can distinguish between different types of images, however, as demonstrated by studying a radically different type of art. The data suggest …

Does Entropic Gravity Bound The Masses Of The Photon And Graviton?, Jonas R. Mureika, R. B. Mann

Jonas Mureika

If the information transfer between test particle and holographic screen in entropic gravity respects both the uncertainty principle and causality, a lower limit on the number of bits in the universe relative to its mass may be derived. Furthermore, these limits indicate particles that putatively travel at the speed of light -- the photon and/or graviton -- have a non-zero mass m≥10−68 kg. This result is found to be in excellent agreement with current experimental mass bounds on the graviton and photon, suggesting that entropic gravity may be the result of a (recent) softly-broken local symmetry. Stronger bounds emerge from …

Self-Completeness And The Generalized Uncertainty Principle, Maximiliano Isi, Jonas Mureika, Piero Nicolini

Jonas Mureika

The generalized uncertainty principle discloses a self-complete characteristic of gravity, namely the possibility of masking any curvature singularity behind an event horizon as a result of matter compression at the Planck scale. In this paper we extend the above reasoning in order to overcome some current limitations to the framework, including the absence of a consistent metric describing such Planck-scale black holes. We implement a minimum-size black hole in terms of the extremal configuration of a neutral non-rotating metric, which we derived by mimicking the effects of the generalized uncertainty principle via a short scale modified version of Einstein gravity. …

Primordial Black Hole Evaporation And Spontaneous Dimensional Reduction, Jonas R. Mureika

Jonas Mureika

Several different approaches to quantum gravity suggest the effective dimension of spacetime reduces from four to two near the Planck scale. In light of such evidence, this Letter re-examines the thermodynamics of primordial black holes (PBHs) in specific lower-dimensional gravitational models. Unlike in four dimensions, (1 + 1)-D black holes radiate with power P ∼ M²_BH, while it is known no (2+1)-D (BTZ) black holes can exist in a non-anti-de Sitter universe. This has important relevance to the PBH population size and distribution, and consequently on cosmological evolution scenarios. The number of PBHs that have evaporated to …

Unparticle-Enhanced Black Holes At The Lhc, Jonas R. Mureika

Jonas Mureika

Based on the idea that tensor unparticles can enhance the gravitational interactions between standard model particles, potential black hole formation in high energy collisions is examined. Modifications to the horizon radius rH are derived, and the corresponding geometric cross-sections of such objects are calculated. It is shown that rH increases dramatically to the electroweak scale for masses MBH∼1–10 TeV, yielding a geometric cross-section σBH=πr2H on the order of ⩽50 pb. This suggests that unparticle physics provides a mechanism for black hole formation in future accelerators, without the requirement of extra spatial dimensions.