An Isochronicity-Tunable Achromat Module

This note provides closed form expressions (in the thin lens approximation) for the quadrupole strengths required to tune the R56 parameter of the isochronous module based on three identical dipoles [2] and lists the eight sets of possible ranges for the three lengths of the drift spaces separating the magnetic components. Thus it permits the design of an insertion satisfying precise geometric constraints as in the future CLIC test facility CTF3 and which is able to compress or stretch longitudinally the beam according to the settings of the quadrupoles. An application to a CTF3 transfer line is also shown

Effect of matrix parameters on mesoporous matrix based quantum computation

We present a solid state implementation of quantum computation, which improves previously proposed optically driven schemes. Our proposal is based on vertical arrays of quantum dots embedded in a mesoporous material which can be fabricated with present technology. We study the feasibility of performing quantum computation with different mesoporous matrices. We analyse which matrix materials ensure that each individual stack of quantum dots can be considered isolated from the rest of the ensemble-a key requirement of our scheme. This requirement is satisfied for all matrix materials for feasible structure parameters and GaN/AlN based quantum dots. We also show that one dimensional ensembles substantially improve performances, even of CdSe/CdS based quantum dots

Feasibility of approximating spatial and local entanglement in long-range interacting systems using the extended Hubbard model

We investigate the extended Hubbard model as an approximation to the local and spatial entanglement of a one-dimensional chain of nanostructures where the particles interact via a long range interaction represented by a `soft' Coulomb potential. In the process we design a protocol to calculate the particle-particle spatial entanglement for the Hubbard model and show that, in striking contrast with the loss of spatial degrees of freedom, the predictions are reasonably accurate. We also compare results for the local entanglement with previous results found using a contact interaction (PRA, 81 (2010) 052321) and show that while the extended Hubbard model recovers a better agreement with the entanglement of a long-range interacting system, there remain realistic parameter regions where it fails to predict the quantitative and qualitative behaviour of the entanglement in the nanostructure system.Comment: 6 pages, 5 figures and 1 table; added results with correlated hopping term; accepted by EP

Anomalously Low Spending of Municipalities and Citizen Dissatisfaction: An Analysis of Recreation Supply

Local authorities deliver services that seek to contribute to the socio-economic development of countries, and increasingly, these services fulfil the non-basic needs of citizens, including cultural and tourism initiatives. This article studies the impact of local public expenditure for non-basic service delivery on the cultural and socio-economic satisfaction of the population, with a specific case study of a conurbation where spending for recreation is anomalously low. It is found that citizens respond positively only to substantial expenditure but are dissatisfied if such expenditure is small and does not reach a minimum-level threshold

Preliminary design of the CLIC drive-beam transfer line

In the drive-beam generation complex of CLIC there is an important beam transfer line between the drive-beam accelerator and the drive- beam decelerators, where the 30 GHz RF power is generated in the decelerator structures In the drive-beam generation complex of CLIC there is an important beam transfer line between the drive-beam accelerator and the drive-beam decelerators, where the 30 GHz RF power is generated in the decelerator structures. The design proposed for this transport system is based on building blocks or beam optics subsystems, which have been individually studied in detail and can be combined in order to cover specific functions. One function consists of bending the beams wherever required by the geometrical layout, so as to preserve the bunch length and keep the bending arc compact and compatible with acceptable synchrotron radiation. Other functions are to adjust the path length of each drive beam for synchronism with the main-linac beam and to compress or stretch the bunch according to the needs. Furthermore, there are vertical and horizontal beam translations, isochronous or acting as a compressor, and b-function transformers for matching the optics. All these functions are necessary in the drive-beam transfer that precedes injection into the decelerators

Experimental insertions made of two symmetric triplets

The reported study is based on the analytical treatment developed for an experimental collider insertion made of two symmetric triplets,the inner triplet located near the interaction point (IP) and th e outer triplet preceding a regular lattice. These two triplets are assumed to be symmetric in their geometry and quadrupole strengths, but not in their Twiss parameters. The method is applied to an i nsertion of the type of an experimental LHC insertion. The drift between the IP and the first quadrupole is fixed and the inner triplet is constrained to achieve a beta-crossing with equal and opposit e slopes (alpha-values) in the two planes. The outer triplet acts then as a FODO transformer from beta-crossing to beta-crossing in order to match the lattice. The analysis provides in a given paramet er interval all the existing solutions for the distance between triplets and the total insertion length, as functions of one gradient and the quadrupole separation in the inner triplet. The variation of the quadrupole strengths when the beta-functions increase at the IP (detuning) is studied and the extension from thin lens to thick lens illustrated