3,981 research outputs found
Number conserving particle-hole RPA for superfluid nuclei
TheAuthor(s) - .Published by Elsevier B.V. "This is an open access article under the CCBY license (http://creativecommons.org/licenses/by/4.0/).Funded by SCOAP"We present a number conserving particle-hole RPA theory for collective excitations in the transition from normal to superfluid nuclei. The method derives from an RPA theory developed long ago in quantum chemistry using antisymmetric geminal powers, or equivalently number projected HFB states, as reference states. We show within a minimal model of pairing plus monopole interactions that the number conserving particle-hole RPA excitations evolve smoothly across the superfluid phase transition close to the exact results, contrary to particle-hole RPA in the normal phase and quasiparticle RPA in the superfluid phase that require a change of basis at the broken symmetry point. The new formalism can be applied in a straightforward manner to study particle-hole excitations on top of a number projected HFB state.Consejería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucía (Spain) FQM-160 and FQM-370Fondo Europeo de Desarrollo Regional (ERDF), ref. SOMM17/6105/UGRMinisterio de Ciencia, Innovación y Universidades and the ERDF under Projects No. FIS2015-63770-P, FIS2017-88410-P and PGC2018-094180-B-I00CEAFMC and Universidad de Huelva High Performance Computer (HPC@UHU) funded by FEDER/MINECO project UNHU-15CE-284
Number conserving particle-hole RPA for superfluid nuclei
TheAuthor(s) - .Published by Elsevier B.V. "This is an open access article under the CCBY license (http://creativecommons.org/licenses/by/4.0/).Funded by SCOAP"We present a number conserving particle-hole RPA theory for collective excitations in the transition from normal to superfluid nuclei. The method derives from an RPA theory developed long ago in quantum chemistry using antisymmetric geminal powers, or equivalently number projected HFB states, as reference states. We show within a minimal model of pairing plus monopole interactions that the number conserving particle-hole RPA excitations evolve smoothly across the superfluid phase transition close to the exact results, contrary to particle-hole RPA in the normal phase and quasiparticle RPA in the superfluid phase that require a change of basis at the broken symmetry point. The new formalism can be applied in a straightforward manner to study particle-hole excitations on top of a number projected HFB state.Consejería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucía (Spain) FQM-160 and FQM-370Fondo Europeo de Desarrollo Regional (ERDF), ref. SOMM17/6105/UGRMinisterio de Ciencia, Innovación y Universidades and the ERDF under Projects No. FIS2015-63770-P, FIS2017-88410-P and PGC2018-094180-B-I00CEAFMC and Universidad de Huelva High Performance Computer (HPC@UHU) funded by FEDER/MINECO project UNHU-15CE-284
Compatison of S-SI, A-SI and CDTE technologies wording at the same conditions, after the first year of electricity production
Grid connected solar plants are a good opportunity for their use for research as a secondary objective. In countries were feed-in tariffs are still active, it is possible to include in the design of the solar plant elements for its use for research. In the case of the solar plant presented here both objectives are covered. The solar plant of this work is formed by PV modules of three different technologies: Multicrystalline, amorphous and CdTe. In one part of the solar plant, the three technologies are working at the same conditions, not only ambient conditions but also similar voltage and current input to the inverters. Both the commercial and the experimental parts of the solar plant have their own independent inverters with their meters but are finally connected to the same meter to inject. In this work we analyse the results for the first year of operation of the experimental solar plant. Productions of three different technologies in exactly the same conditions are compared and presented. According to the results, all the three technologies have conversion efficiencies dropping when the temperature increases. Amorphous module experiences the lesser reduction, whereas the multicrystalline module suffers the most
Nanoparticles for the tratment of osteoporosis
Osteoporosis is by far the most frequent metabolic disease affecting bone. Current clinical therapeutic treatments are not able to offer long-term solutions. Most of the clinically used antiosteoporotic drugs are administered systemically, which might lead to side effects in non-skeletal tissues. Therefore, to solve these disadvantages, researchers have turned to nanotechnologies and nanomaterials to create innovative and alternative treatments. One of the innovative approaches to enhance osteoporosis therapy and prevent potential adverse effects is the development of bonetargeting drug delivery technologies. It minimizes the systemic toxicity and also improves the pharmacokinetic profile and therapeutic efficacy of chemical drugs. This paper reviews the current
available bone targeting drug delivery systems, focusing on nanoparticles, proposed for osteoporosis treatment. Bone targeting delivery systems is still in its infancy, thus, challenges are ahead of us, including the stability and the toxicity issues. Newly developed biomaterials and technologies with potential for safer and more effective drug delivery, require multidisciplinary collaboration between scientists from many different areas, such as chemistry, biology, engineering, medicine, etc, in order
to facilitate their clinical applications
Success possibilities of grid parity in particular cases in the new spanish regulatory framework
During the last 10 years the Spanish photovoltaic market has experienced one of the most important
increases worldwide. The continuous raise on the price of the electricity in Spain, as in other European countries,
USA and Japan, as well as the decrease of the cost of solar photovoltaic systems along this decade is opening a new
way to reach grid parity point in some particular scenarios. A new Spanish legislation is being performed toward selfconsumption, and it is in this new context where the grid parity in a wide sense could be achieved.
This work will study different cases in Spain, in order to determine whether grid parity would be possible along 2012.
Keywords: grid parity, self-consumption, photovoltaic, net-meterin
Transient behavior of a parametric amplifier with an added fourth-order interaction
8 págs.; 13 figs.; PACS number(s): 42.50.Dv, 42.65.Ky, 42.50.MdThe dynamical properties of an optical parametric amplifier with an added fourth-order (Kerr-effect term) nonlinearity are studied by means of a computer simulation of a semiclassical nonlinear Langevin formulation. The transient statistics above threshold are analyzed in detail, and the relevance of the present results for the production of squeezed light in traveling-wave devices is finally discussed. © 1992 The American Physical Society.Thiiss wwoork was supported in part by Grant No. TIC-90/80 (DGICYT, Spain).Peer Reviewe
Selective area growth and characterization of InGaN nano-disks implemented in GaN nanocolumns with different top morphologies
This work reports on the morphology control of the selective area growth of GaN-based nanostructures on c-plane GaN templates. By decreasing the substrate temperature, the nanostructures morphology changes from pyramidal islands (no vertical m-planes), to GaN nanocolumns with top semipolar r-planes, and further to GaN nanocolumns with top polar c-planes. When growing InGaN nano-disks embedded into the GaN nanocolumns, the different morphologies mentioned lead to different optical properties, due to the semi-polar and polar nature of the r-planes and c-planes involved. These differences are assessed by photoluminescence measurements at low temperature and correlated to the specific nano-disk geometry
Quantum simulation of Anderson and Kondo lattices with superconducting qubits
We introduce a mapping between a variety of superconducting circuits and a
family of Hamiltonians describing localized magnetic impurities interacting
with conduction bands. This includes the Anderson model, the single impurity
one- and two-channel Kondo problem, as well as the 1D Kondo lattice. We compare
the requirements for performing quantum simulations using the proposed circuits
to those of universal quantum computation with superconducting qubits, singling
out the specific challenges that will have to be addressed.Comment: Longer versio
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