Physics Commons^™

D-Dimensional Bose Gases And The Lambert W Function, Sree Ram Valluri, J Tanguay, M Gil, D J. Jeffrey

Physics and Astronomy Publications

The applications of the Lambert W function (also known as the W function) to D-dimensional Bose gases are presented. We introduce two sets of families of logarithmic transcendental equations that occur frequently in thermodynamics and statistical mechanics and present their solution in terms of the W function. The low temperature T behavior of free ideal Bose gases is considered in three and four dimensions. It is shown that near condensation in four dimensions, the chemical potential μ and pressure P can be expressed in terms of T through the W function. The low T behavior of one- and two-dimensional ideal …

Metastable Anions Of Dinitrobenzene: Resonances For Electron Attachment And Kinetic Energy Release, A. Mauracher, S. Denifl, A. Edtbauer, M. Hager, M. Probst, Olof E. Echt, T. D. Maerk, P. Scheier, T. A. Field, K. Graupner

Physics & Astronomy

Attachment of free, low-energy electrons to dinitrobenzene (DNB) in the gas phase leads to DNB as well as several fragment anions. DNB, (DNB-H), (DNB-NO), (DNB-2NO), and (DNB-NO(2)) are found to undergo metastable (unimolecular) dissociation. A rich pattern of resonances in the yield of these metastable reactions versus electron energy is observed; some resonances are highly isomer-specific. Most metastable reactions are accompanied by large average kinetic energy releases (KER) that range from 0.5 to 1.32 eV, typical of complex rearrangement reactions, but (1,3-DNB-H)(-) features a resonance with a KER of only 0.06 eV for loss of NO. (1,3-DNB-NO)(-) offers a rare …

Parity Violation In The N + 3he → 3h + P Reaction: Resonance Approach, Vladimir Gudkov

Faculty Publications

The method based on microscopic theory of nuclear reactions has been applied for the analysis of parityviolatingeffects in few-body systems. Different parity-violating and parity-conserving asymmetries and theirdependence on neutron energy have been estimated for the n + 3He → 3H + p reaction. The estimated effectsare in a good agreement with available exact calculations.

Time Dilation In Relativistic Two-Particle Interactions, B T. Shields, Rainer Grobe, E V. Stefanovich, M R. Ware, Qichang Su, M C. Morris

Faculty publications – Physics

We study the orbits of two interacting particles described by a fully relativistic classical mechanical Hamiltonian. We use two sets of initial conditions. In the first set (dynamics 1) the system's center of mass is at rest. In the second set (dynamics 2) the center of mass evolves with velocity V. If dynamics 1 is observed from a reference frame moving with velocity-V, the principle of relativity requires that all observables must be identical to those of dynamics 2 seen from the laboratory frame. Our numerical simulations demonstrate that kinematic Lorentz space-time transformations fail to transform particle observables between the …

Pre-Service Physics Teachers And Physics Education Research, David Rosengrant

Faculty and Research Publications

Training pre-service teachers requires, among other things, content knowledge, pedagogical skills and pedagogical content knowledge. Teacher preparation programs have little, if any spare time to add more courses/activities to their program. However, I argue in this paper that we, as educators, must enhance the amount of physics education research in our pre-service physics teacher training programs. In this study, I analyze the results of two different types of exposure to physics education research (PER) from two different groups of pre-service physics teachers in our masters of arts and teaching program. The preliminary results show, for example that the PER helped …

Two-Loop Soft Anomalous Dimensions For Single Top Quark Associated Production With A W- Or H-, Nikolaos Kidonakis

Faculty and Research Publications

I present results for the two-loop soft anomalous dimensions for associated production of a single top quark with a W boson or a charged Higgs boson. The calculation uses expressions for the massive cusp anomalous dimension, which are presented in different forms, and it allows soft-gluon resummation at next-to-next-to-leading-logarithm (NNLL) accuracy. From the NNLL resummed cross section I derive approximate NNLO cross sections for bg→tW- and bg→tH- at LHC energies of 7, 10, and 14 TeV.

Space-Time Properties Of A Boson-Dressed Fermion For The Yukawa Model, R E. Wagner, M R. Ware, Q Su, Rainer Grobe

Faculty publications – Physics

We analyze the interaction of fermions and bosons through a one-dimensional Yukawa model. We numerically compute the energy eigenstates that represent a physical fermion, which is a superposition of bare fermionic and bosonic eigenstates of the uncoupled Hamiltonian. It turns out that even fast bare fermions require only low-momentum dressing bosons, which attach themselves to the fast fermion through quantum correlations. We compare the space-time evolution of a physical fermion with that of its bare counterpart and show the importance of using dressed observables. The time evolution of the center of mass as well as the wave packet's spatial width …

Faddeev-Type Equations For Three-Body Symmetry Violating Scattering Amplitudes, Vladimir Gudkov, Young-Ho Song

Faculty Publications

The equations which relate three-body and two-body symmetry violating scattering amplitudes are derivedin the first order of symmetry violating interactions. They can be used to obtain three-body symmetry violatingscattering amplitudes from two-body symmetry violating scattering amplitudes calculated in low energy effectivefield theory.

Time-Resolved Compton Scattering For A Model Fermion-Boson System, R E. Wagner, Rainer Grobe, Q Su

Faculty publications – Physics

We study the scattering of a boson with a fermion with full spatial and temporal resolution based on the one-dimensional Yukawa Hamiltonian. In quantum field theory this interaction is described by the annihilation and creation of bosons with intermediate virtual particle states. We show that this process can be modeled in the center-of-mass frame by a scattering potential, permitting us to interpret the absorption and re-emission processes in quantum mechanical terms of a characteristic force. This Compton force between the fermion and boson is repulsive for large distances and attractive for shorter spacings. We also examine the periodic dynamics of …

Exponential Enhancement Of Field-Induced Pair Creation From The Bosonic Vacuum, R E. Wagner, M R. Ware, Q Su, Rainer Grobe

Faculty publications – Physics

Using numerical solutions to quantum field theory, the creation of boson-antiboson pairs from the vacuum under a very strong localized external electric field is explored. The simulations reveal that the initial linear increase of the number of particles turns into an exponential growth. This self-amplification can be understood as the result of the interaction of the previously generated particles with the creation process. While the number of particles keeps increasing, the spatial shape of the (normalized) charge density of the created particles reaches a universal form that can be related to the bound states of the supercritical potential well. We …

Design Of Electronics For A High-Energy Photon Tagger For The Gluex Experiment, Mitchell "Woody" Underwood

Honors Scholar Theses

In quantum chromodynamics (QCD), quarks and antiquarks are held together inside hadrons by the nuclear strong force, which is mediated by exchange particles known as gluons. The simplest type of hadron, the meson, consists of a single quark and a single antiquark bound by a gluonic field. The flux-tube model of QCD says that this gluonic field forms a tube of color-electric field lines between the quark and the antiquark which can under the right conditions be made to vibrate. Such mesons with excited glue are called hybrid mesons.

GlueX is a high-energy nuclear physics experiment which will study hybrid …

Annotated Bibliography Of Ethical Issues In Physics: Collaboration, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

The rules of collaboration, implicit and explicit, vary from one field to another in physics. This variation has not been studied much, although many general articles on collaboration exist.

Annotated Bibliography Of Ethical Issues In Physics: Research Misconduct, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

Sometimes physicists cross the line in blatant, highly publicized ways, but lines are also crossed in much quieter ways.

Annotated Bibliography Of Ethical Issues In Physics: Data Management, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

From acquiring and documenting data, to storing it and analyzing it, there are numerous procedures we employ to maintain the integrity of the data.

Annotated Bibliography Of Ethical Issues In Physics: Conflict Of Interest, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

Conflicts can occur when we have competing interests arising from our role as scientists, our career objectives, our family interests, or our financial interests.

Annotated Bibliography Of Ethical Issues In Physics: Publication/Authorship, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

Publications are used to both carry on public discourse in science and to measure the quality of research.

Annotated Bibliography Of Ethical Issues In Physics: Peer Review, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

Peer review of journal submissions and grant applications plays an important role in what ideas and which individuals advance in physics.

Annotated Bibliography Of Ethical Issues In Physics: Mentorship, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

The necessarily unequal relationship between faculty and their students and post-docs gives rise to a number of interesting issues.

Annotated Bibliography Of Ethical Issues In Physics: Under-Represented Groups, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

The demographics of the physics profession in this country do not mirror the population at large in a number of ways that should cause us concern.

Annotated Bibliography Of Ethical Issues In Physics: Rcr Education Strategies, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

Here is where to look for ideas on how to approach ethics education in a classroom or seminar setting.

Annotated Bibliography Of Ethical Issues In Physics: Physics And Society Issues, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

No abstract provided.

Annotated Bibliography Of Ethical Issues In Physics: Physicists As Advisors To Society And Leaders, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

During the last century, physicists have provided advice to society at large on critical issues. These references explore both the history of this advice and ethical standards that apply to those giving advice.

Ethical Issues In Physics: Getting Started, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

Over the years, through discussions with colleagues and observations of debates in various forums, I have identified several concerns some have over the usefulness of ethics education in physics. I have classified some of these concerns as myths in that when they are accepted as fact, they lead us in the wrong direction.

Annotated Bibliography Of Ethical Issues In Physics: National Security, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

World War II put physicists in the midst of a number of issues related to national security, raising questions such as, to what extent are physicists responsible for the use of their research?

Annotated Bibliography Of Ethical Issues In Physics: General Topics, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

No abstract provided.

Annotated Bibliography Of Ethical Issues In Physics: Climate Change, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

Physicists can play an important role in advancing the public debate on climate change.

Annotated Bibliography Of Ethical Issues In Physics: Energy Issues, Marshall Thomsen

Ethics in Science and Engineering National Clearinghouse

Many physicists are directly or indirectly involved in issues related to society’s use of energy.

Bosonic Analog Of The Klein Paradox, R E. Wagner, M R. Ware, Q Su, Rainer Grobe

Faculty publications – Physics

The standard Klein paradox describes how an incoming electron scatters off a supercritical electrostatic barrier that is so strong that it can generate electron- positron pairs. This fermionic system has been widely discussed in textbooks to illustrate some of the discrepancies between quantum mechanical and quantum field theoretical descriptions for the pair creation process. We compare the fermionic dynamics with that of the corresponding bosonic system. We point out that the direct counterpart of the Pauli exclusion principle (the central mechanism to resolve the fermionic Klein paradox) is stimulated emission, which leads to the resolution of the analogous bosonic paradox.

Computer-Guided Solutions To Physics Problems Using Prolog, Thomas J. Bensky, Catherine A. Taff

Physics

By posing a continual stream of pertinent questions, a nonmathematical computer program can prod freshman physics students toward an analytical solution to one-dimensional kinematics problems.

A Phenomenographic Study Of Introductory Physics Students: Approaches To Their Learning And Perceptions Of Their Learning Environment In A Physics Problem-Based Learning Environment, Paul Irving

Doctoral

This phenomenographic study describes students’ approaches to learning and their perceptions of the learning environment in an introductory physics course which is taught using a problem-based learning approach. This research builds on previous studies which showed that these students develop a greater conceptual knowledge than their counterparts in a more traditional learning environment while others showed very little development even though they engaged fully with the pedagogy. This study aimed to examine and describe the students’ approaches to learning. The definitions of surface, strategic and deep approaches to learning are not appropriate in this context and could not be applied …