12,758 research outputs found

    Photoelectron microscopy and quantum yields of membrane phospholipids

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    2 page

    If at First You Do Not Succeed: Student Behavior When Provided Feedforward With Multiple Trials for Online Summative Assessments

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    Best practices suggest that timely, actionable feedback is provided with the option to apply the feedback. We used a learning management system to deliver assessments with automatic feedback provided at the conclusion of the assessment, allowing for multiple attempts in order to apply the knowledge gained. Questions were pooled so each attempt was unique, the highest score earned was awarded, with no penalty for failure to use multiple attempts. We found that students who did not earn an A on their first attempt were more likely to try again. Those that did tended to score better on their second attempt. This leads us to conclude that assessment design with multiple attempts that incorporates feedforward influences student behavior. Future work will include additional STEM general education courses in a broader study and a survey of student opinions regarding the utility of the feedback and the option for multiple attempts

    Fully quantum mechanical dynamic analysis of single-photon transport in a single-mode waveguide coupled to a traveling-wave resonator

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    We analyze the dynamics of single photon transport in a single-mode waveguide coupled to a micro-optical resonator using a fully quantum mechanical model. We examine the propagation of a single-photon Gaussian packet through the system under various coupling conditions. We review the theory of single photon transport phenomena as applied to the system and we develop a discussion on the numerical technique we used to solve for dynamical behavior of the quantized field. To demonstrate our method and to establish robust single photon results, we study the process of adiabatically lowering or raising the energy of a single photon trapped in an optical resonator under active tuning of the resonator. We show that our fully quantum mechanical approach reproduces the semi-classical result in the appropriate limit and that the adiabatic invariant has the same form in each case. Finally, we explore the trapping of a single photon in a system of dynamically tuned, coupled optical cavities.Comment: 24 pages, 10 figure

    Rapid state purification protocols for a Cooper pair box

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    We propose techniques for implementing two different rapid state purification schemes, within the constraints present in a superconducting charge qubit system. Both schemes use a continuous measurement of charge (z) measurements, and seek to minimize the time required to purify the conditional state. Our methods are designed to make the purification process relatively insensitive to rotations about the x-axis, due to the Josephson tunnelling Hamiltonian. The first proposed method, based on the scheme of Jacobs [Phys. Rev. A 67, 030301(R) (2003)] uses the measurement results to control bias (z) pulses so as to rotate the Bloch vector onto the x-axis of the Bloch sphere. The second proposed method, based on the scheme of Wiseman and Ralph [New J. Phys. 8, 90 (2006)] uses a simple feedback protocol which tightly rotates the Bloch vector about an axis almost parallel with the measurement axis. We compare the performance of these and other techniques by a number of different measures.Comment: 14 pages, 14 figures. v2: Revised version after referee comments. Accepted for publication by Physical Review

    History of the Division of Campus Planning: The Ohio State University

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    Prepared for the Centennial of The Ohio State University

    Scattering in an environment

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    The cross section of elastic electron-proton scattering taking place in an electron gas is calculated within the Closed Time Path method. It is found to be the sum of two terms, one being the expression in the vacuum except that it involves dressing due to the electron gas. The other term is due to the scattering particles-electron gas entanglement. This term dominates the usual one when the exchange energy is in the vicinity of the Fermi energy. Furthermore it makes the trajectories of the colliding particles more consistent and the collision more irreversible, rendering the scattering more classical in this regime.Comment: final version to appear in Phys. Rev.

    The nitrogen-vacancy center in diamond re-visited

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    Symmetry considerations are used in presenting a model of the electronic structure and the associated dynamics of the nitrogen-vacancy center in diamond. The model accounts for the occurrence of optically induced spin polarization, for the change of emission level with spin polarization and for new measurements of transient emission. The rate constants given are in variance to those reported previously.Comment: 12 pages 10 figure
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