共查询到20条相似文献,搜索用时 31 毫秒
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The real compact supergroup is analysed from different perspectives and its representation theory is studied. We prove it is the only (up to isomorphism) supergroup, which is a real form of with reduced Lie group , and a link with SUSY structures on is established. We describe a large family of complex semisimple representations of and we show that any -representation whose weights are all nonzero is a direct sum of members of our family. We also compute the matrix elements of the members of this family and we give a proof of the Peter–Weyl theorem for . 相似文献
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Michael Page James La Fontaine Xu Chen Chunnong Zhao Li Ju David Blair Huang-wei Pan Shiuh Chao 《Physics letters. A》2018,382(33):2174-2180
Broadband enhancement of the sensitivity of gravitational wave detectors can be achieved by the use of negative dispersion filters to create white light signal recycling cavities. This filter should have mechanical frequency of 300 kHz or higher and K, in order to achieve appreciable sensitivity enhancement in the range of 1–2 kHz. This paper investigates the possibility of using optical dilution of GaAs/AlGaAs-coated Si and GaAs “cat-flap” micro-resonators to achieve such performance. We analyse the loss contributions to such resonators, particularly thermoelastic loss, suspension loss and acceleration loss. Sufficient reduction of thermoelastic loss is possible when operating near the zero thermal expansion point with temperature control of ~1 K for both materials. Acceleration loss and suspension losses can be minimised in the frequency range , allowing Q-factors in the range , but these are reduced at the target 400 kHz frequency. Results are subject to assumptions regarding material losses. Fabrication techniques for creating GaAs and SiNx suspended silicon cat-flap resonators are presented. 相似文献
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The paper reports the results of numerical studies on the laser-driven acceleration of super-heavy ions by a multi-PW laser pulse of ultra-relativistic intensity attainable with the Extreme Light Infrastructure lasers currently being built in Europe. Using a multi-dimensional (2D3V) particle-in-cell code, it is shown that multi-GeV super-heavy (thorium) ion beams with an intensity of , fluence and time duration can be produced from a sub-μm thorium target irradiated by a 150-J, 20-fs laser pulse with an intensity of . Such ion beams are impossible to obtain presently with the use of conventional RF-driven accelerators, so they can open the door to new areas of research in both nuclear and high energy-density physics. 相似文献
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《Comptes Rendus Physique》2014,15(4):300-308
The shape and composition of the primary spectrum as well as the large-scale anisotropy in the arrival direction of cosmic rays are key elements to understand the origin, acceleration and propagation of the Galactic radiation. Besides the well-known knee and ankle features, the measured energy spectrum exhibits also a less pronounced but still clear deviation from a single power law between the knee and the ankle, with a spectral hardening at and a steepening at . The average mass composition gets heavier after the knee till , where a bending of the heavy component is observed. An indication of a hardening of the light component just above has been measured as well. First indications of anisotropy of the arrival direction in the southern hemisphere have been reported at . 相似文献
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In terms of quantum Fisher information, we discuss the dynamics of quantity of the Ising model. The inequality detects the class of entangled states which are useful for sub-shot-noise sensitivity. All the exact dynamics of the expectations of collective spin operators are derived. The minimum in the plane perpendicular to the mean spin direction is analytically given. We find that does not depend on the system size when . Except for the periodic points, the evolution states are always entangled and useful for the sub-shot-noise phase estimation. 相似文献
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Zhao-Yi Zeng Cui-E Hu Ling-Cang Cai Xiang-Rong Chen Fu-Qian Jing 《Solid State Communications》2009,149(47-48):2164-2168
We have performed detailed first-principles calculations to investigate the structural and lattice dynamical properties of NiTi alloy. The calculated static structures consist well with the experimental data and other theoretical results. With quasi harmonic approximation, the phase boundary between B19′ and BCO phases can be described as a five order polynomial . The change of vibrational entropy is /atom at the transition temperature 100 K under zero pressure. 相似文献
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《Radiation measurements》2007,42(4-5):644-647
The tetragonal : persistent luminescence materials were prepared by a solid state reaction. The UV excited and persistent luminescence was observed in the green region centred at 535 nm. Both luminescence phenomena are due to the same ion occupying the single site in the host lattice. The codoping usually reduced the persistent luminescence of :, which differs from the : and : materials. Only the ion enhanced slightly the persistent luminescence. With the aid of synchrotron radiation, the band gap energy of : was found to be about 7 eV that is very similar to those of the : materials. Thermoluminescence results suggested that the ions might act as electron traps, but only the TL peaks created by and can be found in the temperature range accessible. Lattice defects (e.g. oxygen vacancies) are also important, since the same main thermoluminescence peak was observed at about with and without codoping. 相似文献
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《Journal of Geometry and Physics》2006,56(11):2231-2236
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-monopoles are solutions to gauge theoretical equations on noncompact -manifolds of holonomy. We shall study this equation on the Bryant–Salamon manifolds. We construct examples of -monopoles on two of these manifolds, namely the total space of the bundle of anti-self-dual two forms over the and . These are the first nontrivial examples of -monopoles.Associated with each monopole there is a parameter , known as the mass of the monopole. We prove that under a symmetry assumption, for each given there is a unique monopole with mass . We also find explicit irreducible -instantons on and on .The third Bryant–Salamon -metric lives on the spinor bundle over the -sphere. In this case we produce a vanishing theorem for monopoles. 相似文献
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Negative thermal expansion materials can experience significant stresses when they are used in composites. Under ambient conditions Zr2(WO4)(PO4)2 displays anisotropic negative thermal expansion (NTE) (, , , at 0 GPa). The effect of hydrostatic pressure on its thermal expansion characteristics was investigated by neutron diffraction between 300 and 60 K at pressures up to 0.3 GPa. No phase transitions were observed in the pressure and temperature range examined. The material was found to have a bulk modulus, B0, of 61.3(8) GPa at ambient temperature, and unlike some other NTE materials, pressure had no detectable effect on thermal expansion (, , , at 0.3 GPa). 相似文献