Bulletin of the American Physical Society
2006 8th Annual APS Northwest Section Meeting
Friday–Saturday, May 19–20, 2006; Tacoma, Washington
Session G2: Atomic, Molecular, and Optical Physics |
Hide Abstracts |
Chair: Shannon Mayer, University of Portland Room: Macintyre 303 |
Saturday, May 20, 2006 2:00PM - 2:36PM |
G2.00001: Quantum Hydrodynamics in Bose-Einstein Condensates Invited Speaker: Bose-Einstein condensates (BECs) provide us with unique means to study intriguing nonlinear behaviors in a quantum system. For example, when a BEC is set into rotation, vortices can form and arrange themselves in lattices. The observed vortex lattices provide evidence for the existence of a macroscopic wavefunction governing the dynamics. In the group of Eric Cornell at JILA, University of Colorado, we have recently extended our studies of quantum hydrodynamics by creating shock waves in rotating and non-rotating condensates. In these experiments quantum shock waves have been observed directly. Quantum shock waves differ from classical shocks because the Gross-Pitaevskii equation that describes the BEC dynamics admits no dissipation. Instead, quantum shock waves are governed by dispersive effects leading to new dynamical features. In this talk, I will highlight some of our recent experiments in the field of nonlinear BEC dynamics. In addition, I will report on the progress of a new BEC machine that is currently being constructed in my laboratory at WSU, Pullman. [Preview Abstract] |
Saturday, May 20, 2006 2:36PM - 3:00PM |
G2.00002: Implementing Hardy's Test of Local Realism M. Beck, M.D. Olmstead, J.A. Carlson We have performed a test of local realism using entangled photons produced by spontaneous parametric downconversion. This experimental test is based on an idea originally proposed by Hardy for a test of local realism without inequalities [1], although our experiment actually measures an inequality (as any experiment must). We find a more-than-70 standard deviation violation of the predictions of local realism. The experimental effort required for this test is essentially the same as that required for a test of a Bell inequality. However, this test is based on concepts that are easier to understand and more compelling than those behind the original Bell inequality. Furthermore, we have implemented this experiment in an undergraduate teaching laboratory. \newline \newline [1] L. Hardy, Phys. Rev. Lett. \textbf{71}, 1665 (1993). [Preview Abstract] |
Saturday, May 20, 2006 3:00PM - 3:20PM |
G2.00003: BREAK
|
Saturday, May 20, 2006 3:20PM - 3:56PM |
G2.00004: Paired Photons with Controllable Waveforms Invited Speaker: The major theme of this talk is the incorporation of electromagnetically induced transparency (EIT) with nonlinear optics in atoms to achieve efficient processes at low-light levels, particularly the generation and manipulation of correlated photon pairs. Entangled photons are an ideal tool for quantum information processing; they are now routinely used in experiments on quantum measurement, quantum teleportation, and quantum information processing. Principle limitations of existing sources of paired photons are two-fold. First, the wide bandwidth of paired photons encumbers resonant interactions with atoms, which is the most promising avenue for photon storage and quantum repeaters as well as for entanglement of atomic ensembles. Second, conventional paired photons' coherence length is prohibitively short for long-distance quantum communication. An experiment requiring the transmission of a simultaneous pair of photons over many kilometers necessitates a length difference of the transmitting fibers {\it less than} the coherence length of the spontaneous parametric source ($\sim 30~\mu$m for traditional paired photons created in a BBO crystal). Electromagnetically induced transparency in cold atomic ensembles enables the creation of paired photons which decisively overcome these limitations. This talk will describe experiments and theory showing the generation of counterpropagating paired photons with waveforms that are controllable by using EIT to vary the optical group velocity. Typical waveform lengths are tens of nanoseconds. [Preview Abstract] |
Saturday, May 20, 2006 3:56PM - 4:20PM |
G2.00005: An Overview of HP's Research Towards Optical Quantum Information Processing Ray Beausoleil Quantum Information Science is an emerging discipline with the potential to revolutionize computation and communication, but with an extremely high barrier to realizing practical results. After describing a framework for performing optical quantum information processing [1], we will outline a set of key scientific and engineering challenges which must be met before a quantum information technology industry can materialize. As a first step toward developing scalable systems, we will describe experiments showing coherent population trapping in nitrogen- vacancy centers in diamond under optical excitation at zero magnetic field. [2] In addition, we will describe experiments demonstrating fabrication of massive photonic crystals using nanoimprint lithography, and the construction of an all-fiber self-calibrating random number generator based on polarization-entangled photons that generates high-quality cryptographic random numbers and is immune to back-door attacks. \newline \newline [1] W.\ J.\ Munro, et al., J. Opt. B: Quant.\ Semiclass.\ Opt.\ \textbf{7}, S135--S140 (2005). \newline [2] C.\ Santori et. al., arXiv:cond-mat/0602573 (2006). [Preview Abstract] |
Saturday, May 20, 2006 4:20PM - 4:56PM |
G2.00006: Large Cross-Phase Modulation between Slow Co-propagating Weak Pulses in $^{87}$Rb Invited Speaker: Cross-phase modulation (XPM) is a nonlinear optical effect in which the index of refraction $n$ of one laser field depends on the intensity $I_2$ of a second laser field, $n = n_0 + \chi_{\mbox{{\tiny XPM}}} I_2$. Generating a large XPM coefficient $\chi_{\mbox{{\tiny XPM}}}$ for weak laser fields is tremendously important, e.g.~for optical quantum information processing and for all-optical switches in classical communication. Several proposals based on electromagnetically induced transparency (EIT) have been brought forward, but so far large XPM remains an experimental challenge. One problem is to achieve equal slow group velocities (double EIT) for two signal light pulses to maximize their interaction time. \\ We present an optical pumping scheme that combines the best features of previous proposals and adds some new techniques, thereby optimizing $\chi_{\mbox{{\tiny XPM}}}$. A feasible procedure to prepare the atomic initial state is proposed such that double EIT with a single atomic species can be achieved, and a specific implementation of the scheme for $^{87}$Rb is presented that only uses a single pump laser and a homogeneous magnetic field of moderate (150 G) strength. The efficiency of the scheme is studied using different theoretical methods, including third-order perturbation theory in the weak signal fields for an atomic five-level model, and a numerical simulation of the master equation that includes the full hyperfine level structure for the spectroscopic D1 line of $^{87}$Rb. Furthermore, we study the nonlinear evolution of the two weak signal pulses and present a new upper bound on the maximal XPM phase shift achievable for two Gaussian single-photon pulses. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700