589 research outputs found

    Simulating Quantum Magnetism with Correlated Non-Neutral Ion Plasmas

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    By employing forces that depend on the internal electronic state (or spin) of an atomic ion, the Coulomb potential energy of a strongly coupled array of ions can be modified in a spin-dependent way to mimic effective quantum spin Hamiltonians. Both ferromagnetic and antiferromagnetic interactions can be implemented. We use simple models to explain how the effective spin interactions are engineered with trapped-ion crystals. We summarize the type of effective spin interactions that can be readily generated, and discuss an experimental implementation using single-plane ion crystals in a Penning trap.Comment: 10 pages, 5 figures, to be published in the Proceedings of 10th International Workshop on Non-Neutral Plasma

    Corrugated Silicon Platelet Feed Horn Array for CMB Polarimetry at 150 GHz

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    Next generation cosmic microwave background (CMB) polarization anisotropy measurements will feature focal plane arrays with more than 600 millimeter-wave detectors. We make use of high-resolution photolithography and wafer-scale etch tools to build planar arrays of corrugated platelet feeds in silicon with highly symmetric beams, low cross-polarization and low side lobes. A compact Au-plated corrugated Si feed designed for 150 GHz operation exhibited performance equivalent to that of electroformed feeds: ~-0.2 dB insertion loss, <-20 dB return loss from 120 GHz to 170 GHz, <-25 dB side lobes and <-23 dB cross-polarization. We are currently fabricating a 50 mm diameter array with 84 horns consisting of 33 Si platelets as a prototype for the SPTpol and ACTpol telescopes. Our fabrication facilities permit arrays up to 150 mm in diameter.Comment: 12 pages; SPIE proceedings for Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (Conference 7741, June 2010, San Diego, CA, USA

    Sampler – open-source data acquisition module for quantum physics

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    The Sinara hardware platform is a modular, open-source measurement and control system dedicated to quantum applications that require hard real-time performance. The hardware is controlled and managed by the ARTIQ, open-source software that provides nanosecond timing resolution and sub-microsecond latency. The Sampler is a general-purpose precision ADC sampling unit with programmable gain and configurable interface. It is used in numerous applications like laser frequency and intensity servo. This paper presents the Sampler module construction and obtained characteristics

    Spectroscopy and Thermometry of Drumhead Modes in a Mesoscopic Trapped-Ion Crystal using Entanglement

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    We demonstrate spectroscopy and thermometry of individual motional modes in a mesoscopic 2D ion array using entanglement-induced decoherence as a method of transduction. Our system is a \sim400 μ\mum-diameter planar crystal of several hundred 9^9Be+^+ ions exhibiting complex drumhead modes in the confining potential of a Penning trap. Exploiting precise control over the 9^9Be+^+ valence electron spins, we apply a homogeneous spin-dependent optical dipole force to excite arbitrary transverse modes with an effective wavelength approaching the interparticle spacing (\sim20 \nolinebreakμ\mum). Center-of-mass displacements below 1 nm are detected via entanglement of spin and motional degrees of freedom.Comment: 12 pages, 7 figures (includes Supplementary Material

    Processing and Characterization of PETI Composites Fabricated by High Temperature VARTM

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    The use of composites as primary structures on aerospace vehicles has increased dramatically over the past decade. As these advanced structures increase in size and complexity, their production costs have grown significantly. A major contributor to these manufacturing costs is the requirement of elevated processing pressures, during the thermal cure, to create fully consolidated composites. For certain composite parts, high temperature vacuum assisted resin transfer molding (HT-VARTM) can offer reduced fabrication costs compared to conventional autoclave techniques. The process has been successfully used with phenylethynyl terminated imide (PETI) resins developed by NASA LaRC. In the current study, two PETI resins, LARC(TradeMark) PETI-330 and LARC(TradeMark) PETI-8 have been used to make test specimens using HT-VARTM. Based on previous work at NASA LaRC, larger panels with a quasi-isotropic lay-up were fabricated. The resultant composite specimens exhibited void contents <3% by volume depending on the type of carbon fabric preform used. Mechanical properties of the panels were determined at both room and elevated temperatures. These included open-hole compressive (OHC) and short beam shear (SBS) properties. Limited process modeling efforts were carried out including infusion times, composite panel size limitations and fabric permeability characterization. Work has also been carried out to develop new PETI based resins specifically geared towards HT-VARTM. The results of this work are presented herein