Unitary-Quantum-Lattice Algorithm For Two-Dimensional Quantum Turbulence, 2011 Old Dominion University
Unitary-Quantum-Lattice Algorithm For Two-Dimensional Quantum Turbulence, Bo Zhang, George Vahala, Linda L. Vahala, Min Soe
Electrical & Computer Engineering Faculty Publications
Quantum vortex structures and energy cascades are examined for two-dimensional quantum turbulence (2D QT) at zero temperature. A special unitary evolution algorithm, the quantum lattice algorithm, is employed to simulate the Bose-Einstein condensate governed by the Gross-Pitaevskii (GP) equation. A parameter regime is uncovered in which, as in 3D QT, there is a short Poincare recurrence time. It is demonstrated that such short recurrence times are destroyed by stronger nonlinear interaction. The similar loss of Poincare recurrence is also seen in the 3D GP equation. Various initial conditions are considered in an attempt to discern if 2D QT exhibits inverse ...
Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, 2011 Old Dominion University
Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, George Vahala, Jeffrey Yepez, Linda L. Vahala, Min Soe, Bo Zhang, Sean Ziegeler
Electrical & Computer Engineering Faculty Publications
The time evolution of the ground state wave function of a zero-temperature Bose-Einstein condensate (BEC) gas is well described by the Hamiltonian Gross-Pitaevskii (GP) equation. Using a set of appropriately interleaved unitary collision-stream operators, a qubit lattice gas algorithm is devised, which on taking moments, recovers the Gross-Pitaevskii (GP) equation under diffusion ordering (time scales as length2). Unexpectedly, there is a class of initial states whose Poincaré recurrence time is extremely short and which, as the grid resolution is increased, scales with diffusion ordering (and not as length3). The spectral results of J. Yepez et al. [Phys. Rev ...
Coherent Photoproduction Of Π+ From 3He, 2011 Old Dominion University
Coherent Photoproduction Of Π+ From 3He, K. P. Adhikari, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, F. Sabatié, L. B. Weinstein, Et Al., The Clas Collaboration
Physics Faculty Publications
We have measured the differential cross section for the 𝛾 3He → π+t reaction. This reaction was studied using the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with the Hall-B bremsstrahlung tagging system in the energy range from 0.50 to 1.55 GeV were incident on a cryogenic liquid 3He target. The differential cross sections for the 𝛾 3He → π+t reaction were measured as a function of photon-beam energy and pion-scattering angle. Theoretical predictions to date cannot explain the large cross sections except at backward angles ...
Experimental Results In Dis, Sidis And Des From Jefferson Lab, 2011 Old Dominion University
Experimental Results In Dis, Sidis And Des From Jefferson Lab, Sebastian E. Kuhn
Physics Faculty Publications
Jefferson Lab’s electron accelerator in its present incarnation, with a maximum beam energy slightly above 6 GeV, has already enabled a large number of experiments expanding our knowledge of nucleon and nuclear structure (especially in Deep Inelastic Scattering—DIS—at moderately high x, and in the resonance region). Several pioneering experiments have yielded first results on Deeply Virtual Compton Scattering (DVCS) and other Deep Exclusive Processes (DES), and the exploration of the rich landscape of transverse momentum‐dependent (TMD) structure functions using Semi‐Inclusive electron scattering (SIDIS) has begun. With the upgrade of CEBAF to 12 GeV now underway ...
Stern-Gerlach Dynamics With Quantum Propagators, 2011 Brigham Young University
Stern-Gerlach Dynamics With Quantum Propagators, Bailey C. Hsu, Manuel Berrondo, Jean F. Van Huele
We study the quantum dynamics of a nonrelativistic neutral particle with spin in inhomogeneous external magnetic fields. We first consider fields with one-dimensional inhomogeneities, both unphysical and physical, and construct the corresponding analytic propagators. We then consider fields with two-dimensional inhomogeneities and develop an appropriate numerical propagation method. We propagate initial states exhibiting different degrees of space localization and various initial spin configurations, including both pure and mixed spin states. We study the evolution of their spin densities and identify characteristic features of spin density dynamics, such as the spatial separation of spin components, and spin localization or accumulation. We ...
Conjugated Quantum Dots Inhibit The Amyloid Β (1–42) Fibrillation Process, 2010 University of Miami
Conjugated Quantum Dots Inhibit The Amyloid Β (1–42) Fibrillation Process, Garima Thakur, Miodrag Micic, Yuehai Yang, Wenzhi Li, Dania Movia, Silvia Giordani, Hongzhou Zhou, Roger M. Levlanc
Department of Physics
Nanoparticles have enormous potential in diagnostic and therapeutic studies. We have demonstrated that the amyloid beta mixed with and conjugated to dihydrolipoic acid- (DHLA) capped CdSe/ZnS quantum dots (QDs) of size approximately 2.5 nm can be used to reduce the fibrillation process. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used as tools for analysis of fibrillation. There is a significant change in morphology of fibrils when amyloid β (1–42) (Aβ (1–42)) is mixed or conjugated to the QDs. The length and the width of the fibrils vary under modified conditions. Thioflavin T (ThT ...
Scattering Matrix Elements For The Nonadiabatic Collision B (2PJₐ) + H2 (1Σ+G, Ν, Ј) ↔ B (2PJ’ₐ) + H2 (1Σ+G, Ν’, J’)., 2010 Air Force Institute of Technology
Scattering Matrix Elements For The Nonadiabatic Collision B (2PJₐ) + H2 (1Σ+G, Ν, Ј) ↔ B (2PJ’ₐ) + H2 (1Σ+G, Ν’, J’)., Luke A. Barger
Theses and Dissertations
Scattering matrix elements are calculated for the nonadiabatic inelastic collision B (2Pjₐ) + H2 (1Σ+g, ν, ј) ↔ B (2Pj’ₐ) + H2 (1Σ+g, ν’, j’). This calculation utilizes the effective potential energy surfaces for this collision generated by Garvin along with a correction to the asymptotic H2 potential. Wavepackets are propagated on these surfaces using a split-operator propagator. This propagation yields correlation functions between reactant and product Møller states which are used to calculate the scattering matrix elements with the channel packet method. These scattering matrix elements represent probability amplitudes ...
Information-Preserving Structures: A General Framework For Quantum Zero-Error Information, 2010 Perimeter Institute for Theoretical Physics
Information-Preserving Structures: A General Framework For Quantum Zero-Error Information, Robin Blume-Kohout, Hui Khoon Ng, David Poulin, Lorenza Viola
Quantum systems carry information. Quantum theory supports at least two distinct kinds of information (classical and quantum), and a variety of different ways to encode and preserve information in physical systems. A system’s ability to carry information is constrained and defined by the noise in its dynamics. This paper introduces an operational framework, using information-preserving structures, to classify all the kinds of information that can be perfectly (i.e., with zero error) preserved by quantum dynamics. We prove that every perfectly preserved code has the same structure as a matrix algebra, and that preserved information can always be corrected ...
Changing Mutual Perception Of Television News Viewers And Program Makers In India- A Case Study Of Cnn-Ibn And Its Unique Initiative Of Citizen Journalism, Ratnesh Dwivedi Mr
The Indian television system is one of the most extensive systems in the world. Terrestrial broadcasting, which has been the sole preserve of the government, provides television coverage to over 90% of India's 900 million people. By the end of 1996 nearly 50 million households had television sets. International satellite broadcasting, introduced in 1991, has swept across the country because of the rapid proliferation of small scale cable systems. By the end of 1996, Indians could view dozens of foreign and local channels and the competition for audiences and advertising revenues was one of the hottest in the world ...
Casimir Potential Of A Compact Object Enclosed By A Spherical Cavity, 2010 University of Pennsylvania
Casimir Potential Of A Compact Object Enclosed By A Spherical Cavity, Saad Zaheer, Sahand Jamal Rahi, Thorsten Emig, Robert L. Jaffe
Department of Physics Papers
We study the electromagnetic Casimir interaction of a compact object contained inside a closed cavity of another compact object. We express the interaction energy in terms of the objects’ scattering matrices and translation matrices that relate the coordinate systems appropriate to each object. When the enclosing object is an otherwise empty metallic spherical shell, much larger than the internal object, and the two are sufficiently separated, the Casimir force can be expressed in terms of the static electric and magnetic multipole polarizabilities of the internal object, which is analogous to the Casimir-Polder result. Although it is not a simple power ...
Community Radio:History,Growth,Challenges And Current Status Of It With Special Reference To India, Ratnesh Dwivedi Mr
Community radio is a type of radio service that caters to the interests of a certain area, broadcasting content that is popular to a local audience but which may often be overlooked by commercial or mass-media broadcasters. Modern-day community radio stations often serve their listeners by offering a variety of content that is not necessarily provided by the larger commercial radio stations. Community radio outlets may carry news and information programming geared toward the local area, particularly immigrant or minority groups that are poorly served by other major media outlets. Philosophically two distinct approaches to community radio can be discerned ...
The Trilinear Hamiltonian: A Zero-Dimensional Model Of Hawking Radiation From A Quantized Source, 2010 Dartmouth College
The Trilinear Hamiltonian: A Zero-Dimensional Model Of Hawking Radiation From A Quantized Source, Paul D. Nation, Miles P. Blencowe
We investigate a quantum parametric amplifier with dynamical pump mode, viewed as a zero-dimensional model of Hawking radiation from an evaporating black hole. We derive the conditions under which the spectrum of particles generated from vacuum fluctuations deviates from the thermal spectrum predicted for the conventional parametric amplifier. We find that significant deviations arise when the pump mode (black hole) has emitted nearly half of its initial energy into the signal (Hawking radiation) and idler (in-falling particle) modes. As a model of black hole dynamics, this finding lends support to the view that late-time Hawking radiation contains information about the ...
History Of Communication And Its Application In Multicultaral,Multilingual Social System In India Across Ages, Ratnesh Dwivedi Mr
The history of communication dates back to the earliest signs of cavemen.Communication can range from very subtle processes of exchange, to full conversations and mass communication. Human communication was revolutionized with speech perhaps 200,000 years ago, Symbols were developed about 30,000 years ago and writing about 7,000. On a much shorter scale, there have been major developments in the field of telecommunication in the past few centuries.
Magnetic Structure And Magnetoelectric Coupling In Bulk And Thin Film Fevo4, 2010 University of Pennsylvania
Magnetic Structure And Magnetoelectric Coupling In Bulk And Thin Film Fevo4, Ambesh V. Dixit, Gavin J. Lawes, A. Brooks Harris
Department of Physics Papers
We have investigated the magnetoelectric and magnetodielectric response in FeVO4, which exhibits a change in magnetic structure coincident with ferroelectric ordering at TN2≈15 K. Using symmetry considerations, we construct a model for the possible magnetoelectric coupling in this system and present a discussion of the allowed spin structures in FeVO4. Based on this model, in which the spontaneous polarization is caused by a trilinear spin-phonon interaction, we experimentally explore the magnetoelectric coupling in FeVO4 thin films through measurements of the electric field-induced shift of the multiferroic phase transition temperature, which exhibits an increase of 0 ...
Exotic Smoothness In Four Dimensions And Euclidean Quantum Gravity, Christopher L. Duston
Physics Faculty Publications
In this paper we calculate the effect of the inclusion of exotic smooth structures on typical observables in Euclidean quantum gravity. We do this in the semiclassical regime for several gravitational free-field actions and find that the results are similar, independent of the particular action that is chosen. These are the first results of their kind in dimension four, which we extend to include one-loop contributions as well. We find these topological features can have physically significant results without the need for additional exotic physics.
Intermode Dephasing In A Superconducting Stripline Resonator, 2010 Technion-Israel Institute of Technology
Intermode Dephasing In A Superconducting Stripline Resonator, Oren Suchoi, Baleegh Abdo, Eran Segev, Oleg Shtempluck, M. P. Blencowe, Eyal Buks
We study a superconducting stripline resonator (SSR) made of niobium, which is integrated with a superconducting interference device (SQUID). The large nonlinear inductance of the SQUID gives rise to a strong Kerr nonlinearity in the response of the SSR, which in turn results in strong coupling between different modes of the SSR. We experimentally demonstrate that such intermode coupling gives rise to dephasing of microwave photons. The dephasing rate depends periodically on the external magnetic flux applied to the SQUID, where the largest rate is obtained at half integer values (in units of the flux quantum). To account for our ...
Results From Electrostatic Calibrations For Measuring The Casimir Force In The Cylinder-Plane Geometry, Q. Wei, D. A. R. Dalvit, F. C. Lombardo, F. D. Mazzitelli, R. Onofrio
We report on measurements performed on an apparatus aimed to study the Casimir force in the cylinder-plane configuration. The electrostatic calibrations evidence anomalous behaviors in the dependence of the electrostatic force and the minimizing potential upon distance. We discuss analogies and differences of these anomalies with respect to those already observed in the sphere-plane configuration. At the smallest explored distances we observe frequency shifts of non-Coulombian nature preventing the measurement of the Casimir force in the same range. We also report on measurements performed in the parallel-plane configuration, showing that the dependence on distance of the minimizing potential, if present ...
Modeling Bound States In The Continuum For Multiple Electrons In A Quantum Dot Pair, 2010 Butler University
Modeling Bound States In The Continuum For Multiple Electrons In A Quantum Dot Pair, Thomas Ian Tuegel
Undergraduate Honors Thesis Collection
The bound eigenstates of an electron inside a pair of quantum dots embedded on an infinite quantum wire are examined using the method of particular solutions. The eigenstates of a two-electron system in the same structure are examined perturbatively using wavefunction expansions for the one-electron eigenstates. The stability of the two-electron eigenstates is evaluated and compared with other theoretical results. It is found that stable bound states in the continuum exist for two electrons confined to this geometry.
Charge And Spin Ordering In The Mixed-Valence Compound Lufe2O4, 2010 University of Pennsylvania
Charge And Spin Ordering In The Mixed-Valence Compound Lufe2O4, A. Brooks Harris, Taner Yildirim
Department of Physics Papers
Landau theory and symmetry considerations lead us to propose an explanation for several seemingly paradoxical behaviors of charge ordering (CO) and spin ordering (SO) in the mixed valence compound LuFe2O4. Both SO and CO are highly frustrated. We analyze a lattice gas model of CO within mean-field theory and determine the magnitude of several of the phenomenological interactions. We show that the assumption of a continuous phase transitions at which CO or SO develops implies that both CO and SO are incommensurate. To explain how ferroelectric fluctuations in the charge-disordered phase can be consistent with an antiferroelectric ...
Theoretical And Computational Study Of Time Dependent Scattering On A 2d Surface, 2010 University of Nevada Las Vegas
Theoretical And Computational Study Of Time Dependent Scattering On A 2d Surface, Michael Sohn
UNLV Theses, Dissertations, Professional Papers, and Capstones
The quantum mechanical treatment of the elastic scattring of atoms from a crystal surface provides valuable information, such as surface properties and gas-surface interaction potentials. However, since it is based on the stationary state solution, it does not provide the details of the scattering process in the neighborhood of the surface, especially when atoms are physically adsorbed. In this thesis, the time evolution of the scattering process is treated in 2D with a model potential, V(x, z) = -|g|δ(z) + λδ(z)cos(2πx/a), using the Gaussian wave packet approach. The focus is on the case where the ...