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Full-Text Articles in Quantum Physics

Triplet Superconductors From The Viewpoint Of Basic Elements For Quantum Computers, Armen M. Gulian, Kent S. Wood Jul 2003

Triplet Superconductors From The Viewpoint Of Basic Elements For Quantum Computers, Armen M. Gulian, Kent S. Wood

Mathematics, Physics, and Computer Science Faculty Articles and Research

We discuss possibilities of utilizing superconductors with Cooper condensates in triplet pairing states (where the spin of condensate pairs is S=1) for practical realization of quantum computers. Superconductors with triplet pairing condensates have features that are unique and cannot be found in the usual (singlet pairing, S=0) superconductors. The symmetry of the order parameter in some triplet superconductors (e.g., ruthenates) corresponds to doubly-degenerate chiral states. These states can serve as qubit base states for quantum computing.


Quantum Mechanical Calculations Of Monoxides Of Silicon Carbide Molecules, John W. Roberts Jr. Mar 2003

Quantum Mechanical Calculations Of Monoxides Of Silicon Carbide Molecules, John W. Roberts Jr.

Theses and Dissertations

Modern semiconductor devices are principally made using the element silicon. In recent years, silicon carbide (SiC), with its wide band-gap, high thermal conductivity, and radiation resistance, has shown prospects as a semiconductor material for use in high temperature and radiation environments such as jet engines and satellites. A limiting factor in the performance of many SiC semiconductor components is the presence of lattice defects formed at oxide dielectric junctions during processing. Recent theoretical work has used small quantum mechanical systems embedded in larger molecular mechanics structures to attempt to better understand SiC surfaces and bulk materials and their oxidation. This …


Hydrogenic Spin Quantum Computing In Silicon: A Digital Approach, A. J. Skinner, M. E. Davenport, B. E. Kane Feb 2003

Hydrogenic Spin Quantum Computing In Silicon: A Digital Approach, A. J. Skinner, M. E. Davenport, B. E. Kane

Dartmouth Scholarship

We suggest an architecture for quantum computing with spin-pair encoded qubits in silicon. Electron-nuclear spin-pairs are controlled by a dc magnetic field and electrode-switched on and off hyperfine interaction. This digital processing is insensitive to tuning errors and easy to model. Electron shuttling between donors enables multiqubit logic. These hydrogenic spin qubits are transferable to nuclear spin-pairs, which have long coherence times, and electron spin-pairs, which are ideally suited for measurement and initialization. The architecture is scalable to a highly parallel operation.


Study Of Nanoidentation And Tip Geometry In Gaas (100) At Ultra-Low-Loads For The Patterning Of Quantum Dots, Robin Prince Jan 2003

Study Of Nanoidentation And Tip Geometry In Gaas (100) At Ultra-Low-Loads For The Patterning Of Quantum Dots, Robin Prince

Inquiry: The University of Arkansas Undergraduate Research Journal

In this study, nanoindentations were produced and characterized for the future patterning of quantum dots. Nanoindentation was performed on a Si-doped (n-type) Vertical Gradient Freeze (VGF) GaAs (100) wafer with a 700 nm GaAs (100) layer grown by molecular beam epitaxy (MBE). Nanoindentation was performed with a Berkovich diamond tip, a cube corner diamond tip, and a 600 conical diamond tip. Nanoindentation of GaAs has been studied in the past, but not at extremely low loads. Previous research has been done on high load (50-200 mN) and low load (200-8000 mN) nanoindentation. The applied load in this study ranges from …


Multiphoton Interaction In A System Of Two Quantum Dots, Brian Sawyer Jan 2003

Multiphoton Interaction In A System Of Two Quantum Dots, Brian Sawyer

Inquiry: The University of Arkansas Undergraduate Research Journal

As the size and proximity of components on modern computer chips approaches quantum mechanical limits, various novel solutions have been proposed to ensure further increases in processing speed and reliability. Of these, small semiconductor devices called quantum dots may constitute the logic gates of future quantum computers - processors taking advantage of phenomena such as entanglement and quantum teleportation to enable ultra-fast computation speeds. Quantum dots behave much like designer atoms in that their absorption/emission energies can be adjusted lo desired values. A quantum mechanical model of semiconductor quantum dots having equal size and interacting with a single-mode electric field …


Optimal Entanglement Generation From Quantum Operations, Matthew S. Leifer, L. Henderson, N. Linden Jan 2003

Optimal Entanglement Generation From Quantum Operations, Matthew S. Leifer, L. Henderson, N. Linden

Mathematics, Physics, and Computer Science Faculty Articles and Research

We consider how much entanglement can be produced by a nonlocal two-qubit unitary operation, UAB—the entangling capacity of UAB. For a single application of UAB , with no ancillas, we find the entangling capacity and show that it generally helps to act with UAB on an entangled state. Allowing ancillas, we present numerical results from which we can conclude, quite generally, that allowing initial entanglement typically increases the optimal capacity in this case as well. Next, we show that allowing collective processing does not increase the entangling capacity if initial entanglement is allowed.


Ep → Ep Π⁰ Reaction Studied In The Δ(1232) Mass Region Using Polarization Asymmetries, M. Bektasoglu, L. Ciciani, K.V. Dharmawardane, G. E. Dodge, T.A. Forest, C.E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration Jan 2003

Ep → Ep Π⁰ Reaction Studied In The Δ(1232) Mass Region Using Polarization Asymmetries, M. Bektasoglu, L. Ciciani, K.V. Dharmawardane, G. E. Dodge, T.A. Forest, C.E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration

Physics Faculty Publications

Measurements of the angular distributions of target and double-spin asymmetries for the Δ+(1232) in the exclusive channel p(e,e'p)π0 obtained at the Jefferson Lab in the Q2 range from 0.5 to 1.5 GeV2/c2 are presented. Results of the asymmetries are compared with the unitary isobar model [D. Drechsel , Nucl. Phys. A645, 145 (1999)], dynamical models [T. Sato and T. S. Lee, Phys. Rev. C 54, 2660 (1996); S. S. Kamalov , Phys. Lett. B 27, 522 (2001)], and the effective Lagrangian theory [R. M. Davidson , Phys. Rev. …


Kinematically Complete Measurement Of The Proton Structure Function F₂ In The Resonance Region And Evaluation Of Its Moments, M. Bektasoglu, L. Ciciani, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, F. Sabatié, S. Stepanyan, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration Jan 2003

Kinematically Complete Measurement Of The Proton Structure Function F₂ In The Resonance Region And Evaluation Of Its Moments, M. Bektasoglu, L. Ciciani, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, F. Sabatié, S. Stepanyan, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

We measured the inclusive electron-proton cross section in the nucleon resonance region (W <2.5 GeV) at momentum transfers Q2 below 4.5 (GeV/c)2 with the CLAS detector. The large acceptance of CLAS allowed the measurement of the cross section in a large, contiguous two-dimensional range of Q2 and x, making it possible to perform an integration of the data at fixed Q2 over the significant x interval. From these data we extracted the structure function F2 and, by including other world data, we studied the Q2 evolution of its moments, Mn(Q2), in order to estimate higher twist …


Measurement Of Ep → E ' P Π⁺Π⁻ And Baryon Resonance Analysis, M. Bektasoglu, L. Ciciani, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, L. M. Qin, F. Sabatié, S. Stepanyan, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration Jan 2003

Measurement Of Ep → E ' P Π⁺Π⁻ And Baryon Resonance Analysis, M. Bektasoglu, L. Ciciani, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, L. M. Qin, F. Sabatié, S. Stepanyan, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

The cross section for the reaction ep→ e'pπ+π- was measured in the resonance region for 1.4 2 < 1.5 GeV2/c2using the CLAS detector at Jefferson Laboratory. The data show resonant structures not visible in previous experiments. The comparison of our data to a phenomenological prediction using available information on N* and Δ states shows an evident discrepancy. A better description of the data is obtained either by a sizable change of the properties of the P13(1720) resonance or by introducing a new baryon state, not reported in published analyses.


Measurement Of Inclusive Spin Structure Functions Of The Deuteron, J. Yun, S. E. Kuhn, G. E. Dodge, T. A. Forest, M. Bektasoglu, L. Ciciani, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, L. M. Qin, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration Jan 2003

Measurement Of Inclusive Spin Structure Functions Of The Deuteron, J. Yun, S. E. Kuhn, G. E. Dodge, T. A. Forest, M. Bektasoglu, L. Ciciani, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, L. M. Qin, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration

Physics Faculty Publications

We report the results of a new measurement of spin structure functions of the deuteron in the region of moderate momentum transfer [Q2 = 0.27-1.3 (GeV/c)2] and final hadronic state mass in the nucleon resonance region (W=1.08-2.0 GeV). We scattered a 2.5 GeV polarized continuous electron beam at Jefferson Lab off a dynamically polarized cryogenic solid state target (15ND3) and detected the scattered electrons with the CEBAF large acceptance spectrometer. From our data, we extract the longitudinal double spin asymmetry A∥ and the spin structure function g1d. Our data are …


Renormalization-Group Studies Of Three Model Systems Far From Equilibrium, Ivan T. Georgiev Jan 2003

Renormalization-Group Studies Of Three Model Systems Far From Equilibrium, Ivan T. Georgiev

Electronic Theses and Dissertations

This thesis describes the development of analytical and computational techniques for systems far from equilibrium and their application to three model systems. Each of the model systems reaches a non-equilibrium steady state and exhibits one or more phase transitions. We first introduce a new position-space renormalization-group approach and illustrate its application using the one-dimensional fully asymmetric exclusion process. We have constructed a recursion relation for the relevant dynamic parameters for this model and have reproduced all of the important critical features of the model, including the exact positions of the critical point and the first and second order phase boundaries. …


First Measurement Of Transferred Polarization In The Exclusive E P → E'K+ →Λ, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, J. Yun Jan 2003

First Measurement Of Transferred Polarization In The Exclusive →E P → E'K+ →Λ, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, J. Yun

Physics Faculty Publications

The first measurements of the transferred polarization for the exclusive ep → e'K+ Λ over right arrow reaction have been performed at Jefferson Laboratory using the CLAS spectrometer. A 2.567 GeV beam was used to measure the hyperon polarization over Q2 from 0.3 to 1.5 (GeV/c)2, W from 1.6 to 2.15 GeV, and over the full K+ center-of-mass angular range. Comparison with predictions of hadrodynamic models indicates strong sensitivity to the underlying resonance contributions. A nonrelativistic quark-model interpretation of our data suggests that the s -s quark pair is produced with spins predominantly …