965 research outputs found

    Exposing the Hocus Pocus of Trusts

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    Part II makes the conceptual case for viewing the trust as an elective cost-externalization device. Part III offers the spendthrift trust as the archetypal model for purposes of our analysis, briefly describes the spendthrift trust, and explores its consequences to outsiders to the trust deal. Part IV offers some reasons why the elective externalities of trusts persist. Part V first examines and rejects a couple of approaches to minimizing the externalized costs of trusts that rely on the “bundle of sticks” approach to property interests. It then moves beyond the bundle of sticks approach, settling on a solution based on priority rules borrowed from legal accidents theory. The conclusion follows in Part VI

    Spin Coherence and 14^{14}N ESEEM Effects of Nitrogen-Vacancy Centers in Diamond with X-band Pulsed ESR

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    Pulsed ESR experiments are reported for ensembles of negatively-charged nitrogen-vacancy centers (NV^-) in diamonds at X-band magnetic fields (280-400 mT) and low temperatures (2-70 K). The NV^- centers in synthetic type IIb diamonds (nitrogen impurity concentration <1<1~ppm) are prepared with bulk concentrations of 210132\cdot 10^{13} cm3^{-3} to 410144\cdot 10^{14} cm3^{-3} by high-energy electron irradiation and subsequent annealing. We find that a proper post-radiation anneal (1000^\circC for 60 mins) is critically important to repair the radiation damage and to recover long electron spin coherence times for NV^-s. After the annealing, spin coherence times of T2=0.74_2 = 0.74~ms at 5~K are achieved, being only limited by 13^{13}C nuclear spectral diffusion in natural abundance diamonds. At X-band magnetic fields, strong electron spin echo envelope modulation (ESEEM) is observed originating from the central 14^{14}N nucleus. The ESEEM spectral analysis allows for accurate determination of the 14^{14}N nuclear hypefine and quadrupole tensors. In addition, the ESEEM effects from two proximal 13^{13}C sites (second-nearest neighbor and fourth-nearest neighbor) are resolved and the respective 13^{13}C hyperfine coupling constants are extracted.Comment: 10 pages, 5 figure

    Local formation of nitrogen-vacancy centers in diamond by swift heavy ions

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    We exposed nitrogen-implanted diamonds to beams of swift uranium and gold ions (~1 GeV) and find that these irradiations lead directly to the formation of nitrogen vacancy (NV) centers, without thermal annealing. We compare the photoluminescence intensities of swift heavy ion activated NV- centers to those formed by irradiation with low-energy electrons and by thermal annealing. NV- yields from irradiations with swift heavy ions are 0.1 of yields from low energy electrons and 0.02 of yields from thermal annealing. We discuss possible mechanisms of NV-center formation by swift heavy ions such as electronic excitations and thermal spikes. While forming NV centers with low efficiency, swift heavy ions enable the formation of three dimensional NV- assemblies over relatively large distances of tens of micrometers. Further, our results show that NV-center formation is a local probe of (partial) lattice damage relaxation induced by electronic excitations from swift heavy ions in diamond.Comment: to be published in Journal of Applied Physic

    Preferred foliation effects in Quantum General Relativity

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    We investigate the infrared (IR) effects of Lorentz violating terms in the gravitational sector using functional renormalization group methods similar to Reuter and collaborators. The model we consider consists of pure quantum gravity coupled to a preferred foliation, described effectively via a scalar field with non-standard dynamics. We find that vanishing Lorentz violation is a UV attractive fixed-point of this model in the local potential approximation. Since larger truncations may lead to differing results, we study as a first example effects of additional matter fields on the RG running of the Lorentz violating term and provide a general argument why they are small.Comment: 12 pages, no figures, compatible with published versio

    Detection of low energy single ion impacts in micron scale transistors at room temperature

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    We report the detection of single ion impacts through monitoring of changes in the source-drain currents of field effect transistors (FET) at room temperature. Implant apertures are formed in the interlayer dielectrics and gate electrodes of planar, micro-scale FETs by electron beam assisted etching. FET currents increase due to the generation of positively charged defects in gate oxides when ions (121Sb12+, 14+, Xe6+; 50 to 70 keV) impinge into channel regions. Implant damage is repaired by rapid thermal annealing, enabling iterative cycles of device doping and electrical characterization for development of single atom devices and studies of dopant fluctuation effects

    Processing Issues in Top-Down Approaches to Quantum Computer Development in Silicon

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    We describe critical processing issues in our development of single atom devices for solid-state quantum information processing. Integration of single 31P atoms with control gates and single electron transistor (SET) readout structures is addressed in a silicon-based approach. Results on electrical activation of low energy (15 keV) P implants in silicon show a strong dose effect on the electrical activation fractions. We identify dopant segregation to the SiO2/Si interface during rapid thermal annealing as a dopant loss channel and discuss measures of minimizing it. Silicon nanowire SET pairs with nanowire width of 10 to 20 nm are formed by electron beam lithography in SOI. We present first results from Coulomb blockade experiments and discuss issues of control gate integration for sub-40nm gate pitch levels

    Absolute calibration of GafChromic film for very high flux laser driven ion beams.

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    We report on the calibration of GafChromic HD-v2 radiochromic film in the extremely high dose regime up to 100 kGy together with very high dose rates up to 7 × 1011 Gy/s. The absolute calibration was done with nanosecond ion bunches at the Neutralized Drift Compression Experiment II particle accelerator at Lawrence Berkeley National Laboratory (LBNL) and covers a broad dose dynamic range over three orders of magnitude. We then applied the resulting calibration curve to calibrate a laser driven ion experiment performed on the BELLA petawatt laser facility at LBNL. Here, we reconstructed the spatial and energy resolved distributions of the laser-accelerated proton beams. The resulting proton distribution is in fair agreement with the spectrum that was measured with a Thomson spectrometer in combination with a microchannel plate detector
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