Entangled state preparation via dissipation-assisted adiabatic passages

The main obstacle for coherent control of open quantum systems is decoherence due to different dissipation channels and the inability to precisely control experimental parameters. To overcome these problems we propose to use dissipation-assisted adiabatic passages. These are relatively fast processes where the presence of spontaneous decay rates corrects for errors due to non-adiabaticity while the system remains in a decoherence-free state and behaves as predicted for an adiabatic passage. As a concrete example we present a scheme to entangle atoms by moving them in and out of an optical cavity.Comment: 11 pages, 7 figures, minor changes, accepted for publication in Phys. Rev.

Demonstrating the Principles of Aperture Synthesis with Table- Top Laboratory Exercises

Many undergraduate radio astronomy courses are unable to give a detailed treatment of aperture synthesis due to time constraints and limited math backgrounds of students. We have taken a laboratory-based approach to teaching radio interferometry using a set of college-level, table-top exercises. These are performed with the Very Small Radio Telescope (VSRT), an interferometer developed at the Haystack Observatory using satellite TV electronics as detectors and compact fluorescent light bulbs as microwave signal sources. The hands-on experience provided by the VSRT in these labs allows students to gain a conceptual understanding of radio interferometry and aperture synthesis without the rigorous mathematical background traditionally required. The data are quickly and easily processed using a user-friendly data analysis Java package, VSRTI_Plotter.jar. This software can also be used in the absence of the equipment as an interactive computer activity to demonstrate an interferometer’s responses to assorted surface brightness distributions. The students also gain some familiarity with Fourier transforms and an appreciation for the Fourier relations in interferometry using another Java package, the Tool for Interactive Fourier Transforms (TIFT). We have successfully used these tools in multiple offerings of our radio astronomy course at Union Colleg

3D2PM – 3D Deformable Part Models

Abstract. As objects are inherently 3-dimensional, they have been mod-eled in 3D in the early days of computer vision. Due to the ambiguities arising from mapping 2D features to 3D models, 2D feature-based models are the predominant paradigm in object recognition today. While such models have shown competitive bounding box (BB) detection perfor-mance, they are clearly limited in their capability of fine-grained reason-ing in 3D or continuous viewpoint estimation as required for advanced tasks such as 3D scene understanding. This work extends the deformable part model [1] to a 3D object model. It consists of multiple parts mod-eled in 3D and a continuous appearance model. As a result, the model generalizes beyond BB oriented object detection and can be jointly op-timized in a discriminative fashion for object detection and viewpoint estimation. Our 3D Deformable Part Model (3D2PM) leverages on CAD data of the object class, as a 3D geometry proxy.

Circuit Mechanisms Underlying Motor Memory Formation in the Cerebellum

SummaryThe cerebellum stores associative motor memories essential for properly timed movement; however, the mechanisms by which these memories form and are acted upon remain unclear. To determine how cerebellar activity relates to movement and motor learning, we used optogenetics to manipulate spontaneously firing Purkinje neurons (PNs) in mouse simplex lobe. Using high-speed videography and motion tracking, we found that altering PN activity produced rapid forelimb movement. PN inhibition drove movements time-locked to stimulus onset, whereas PN excitation drove delayed movements time-locked to stimulus offset. Pairing either PN inhibition or excitation with sensory stimuli triggered the formation of robust, associative motor memories; however, PN excitation led to learned movements whose timing more closely matched training intervals. These findings implicate inhibition of PNs as a teaching signal, consistent with a model whereby learning leads first to reductions in PN firing that subsequently instruct circuit changes in the cerebellar nucleus