Quantum harmonic oscillator state synthesis and analysis

Experiments are described in which a single, harmonically bound, beryllium ion in a Paul trap is put into Fock, thermal, coherent, squeezed, and Schroedinger cat states. Experimental determinations of the density matrix and the Wigner function are described. A simple calculation of the decoherence of a superposition of coherent states due to an external electric field is given.Comment: 13 pages, LaTeX2e, special style file spie.sty included, 11 eps figures included using epsfig, graphicx, subfigure, floatflt macros. To appear in Proc. Conf. on Atom Optics, San Jose, CA, Feb. 1997, edited by M. G. Prentiss and W. D. Phillips, SPIE Proc. # 299

Strong-driving-assisted multipartite entanglement in cavity QED

We propose a method of generating multipartite entanglement by considering the interaction of a system of N two-level atoms in a cavity of high quality factor with a strong classical driving field. It is shown that, with a judicious choice of the cavity detuning and the applied coherent field detuning, vacuum Rabi coupling produces a large number of important multipartite entangled states. It is even possible to produce entangled states involving different cavity modes. Tuning of parameters also permits us to switch from Jaynes-Cummings to anti-Jaynes-Cummings like interaction.Comment: Last version with minor changes and added references. Accepted for publication in Phys. Rev. Letter

Simplified quantum logic with trapped ions

We describe a simplified scheme for quantum logic with a collection of laser-cooled trapped atomic ions. Building on the scheme of Cirac and Zoller, we show how the fundamental controlled-NOT gate between a collective mode of ion motion and the internal states of a single ion can be reduced to a single laser pulse, and the need for a third auxiliary internal electronic state can be eliminated.Comment: 8 pages, PostScript, submitted to Physical Review A, Rapid Communication

Book Reviews

The Law Practice of Alexander Hamilton By Julius Goebel, Ed. and Associate Editors New York and London: Columbia University Press, 1964. Pp. XXV, 898. reviewer: Elliot E. Cheatham ============================== Lawyers in Politics: A Study in Professional Convergence By Heinz Eulau and John D. Sprague Indianapolis: Bobbs-Merrill,1964. Pp. 164. $1.95. reviewer: Joseph B. Board, Jr. =============================== Occupational Disability and Public Policy Edited by Earl F. Cheit and Margaret S. Gordon. New York: John Wiley and Sons,Inc., 1963. Pp. xii, 446. reviewer: Monroe Berkowit

Preparing encoded states in an oscillator

Recently a scheme has been proposed for constructing quantum error-correcting codes that embed a finite-dimensional code space in the infinite-dimensional Hilbert space of a system described by continuous quantum variables. One of the difficult steps in this scheme is the preparation of the encoded states. We show how these states can be generated by coupling a continuous quantum variable to a single qubit. An ion trap quantum computer provides a natural setting for a continuous system coupled to a qubit. We discuss how encoded states may be generated in an ion trap.Comment: 5 pages, 4 figures, RevTe

Cooling the Collective Motion of Trapped Ions to Initialize a Quantum Register

We report preparation in the ground state of collective modes of motion of two trapped 9Be+ ions. This is a crucial step towards realizing quantum logic gates which can entangle the ions' internal electronic states. We find that heating of the modes of relative ion motion is substantially suppressed relative to that of the center-of-mass modes, suggesting the importance of these modes in future experiments.Comment: 5 pages, including 3 figures. RevTeX. PDF and PostScript available at http://www.bldrdoc.gov/timefreq/ion/qucomp/papers.htm . final (published) version. Eq. 1 and Table 1 slightly different from original submissio

Implementing the Quantum Random Walk

Recently, several groups have investigated quantum analogues of random walk algorithms, both on a line and on a circle. It has been found that the quantum versions have markedly different features to the classical versions. Namely, the variance on the line, and the mixing time on the circle increase quadratically faster in the quantum versions as compared to the classical versions. Here, we propose a scheme to implement the quantum random walk on a line and on a circle in an ion trap quantum computer. With current ion trap technology, the number of steps that could be experimentally implemented will be relatively small. However, we show how the enhanced features of these walks could be observed experimentally. In the limit of strong decoherence, the quantum random walk tends to the classical random walk. By measuring the degree to which the walk remains `quantum', this algorithm could serve as an important benchmarking protocol for ion trap quantum computers

Generation of long-living entanglement using cold trapped ions with pair cat states

With the reliance in the processing of quantum information on a cold trapped ion, we analyze the entanglement entropy in the ion-field interaction with pair cat states. We investigate a long-living entanglement allowing the instantaneous position of the center-of-mass motion of the ion to be explicitly time dependent. An analytic solution for the system operators is obtained. We show that different nonclassical effects arise in the dynamics of the population inversion, depending on the initial states of the vibrational motion. We study in detail the entanglement degree and demonstrate how the input pair cat state is required for initiating the long living entanglement. This long living entanglement is damp out with an increase in the number difference $q$. Owing to the properties of entanglement measures, the results are checked using another entanglement measure (high order linear entropy).Comment: 15 pages, 7 figures, Sub. Appl. Phys. B: Laser and Optic

Protean and Boundaryless Career Attitudes: Do Teacher Candidates Have These?

Since the late 20th century, the Protean (Hall, 1996) and Boundaryless (Arthur, 1994) career concepts have been posited as explanations for employment transformations in corporate structures. While previous research (Briscoe, Hall, & Fratschy DeMuth, 2006) provides evidence of these constucts with business students, research has lacked in evaluating the Protean and Boundaryless Career Attitudes Scale (PBCAS) with other professions. The purpose of this study was to investigate the factor structure of the PBCAS with 350 undergraduate teacher candidates and to test the new model with a second sample (n = 194). The results showed moderate support for the validity of the PBCAS with teacher candidates. The data produced a five-factor model similar to the factor structure reported by de Bruin and Buchner (2010). These results support previous findings and indicate the need for further research with the instrument