Symmetries and Triplet Dispersion in a Modified Shastry-Sutherland Model for SrCu_2(BO_3)_2

We investigate the one-triplet dispersion in a modified Shastry-Sutherland Model for SrCu_2(BO_3)_2 by means of a series expansion about the limit of strong dimerization. Our perturbative method is based on a continuous unitary transformation that maps the original Hamiltonian to an effective, energy quanta conserving block diagonal Hamiltonian H_{eff}. The dispersion splits into two branches which are nearly degenerated. We analyse the symmetries of the model and show that space group operations are necessary to explain the degeneracy of the dispersion at k=0 and at the border of the magnetic Brillouin zone. Moreover, we investigate the behaviour of the dispersion for small |k| and compare our results to INS data.Comment: 9 pages, 8 figures accepted by J. Phys.: Condens. Matte

Unitary transformations for testing Bell inequalities

It is shown that optical experimental tests of Bell inequality violations can be described by SU(1,1) transformations of the vacuum state, followed by photon coincidence detections. The set of all possible tests are described by various SU(1,1) subgroups of Sp(8,$\Bbb R$). In addition to establishing a common formalism for physically distinct Bell inequality tests, the similarities and differences of post--selected tests of Bell inequality violations are also made clear. A consequence of this analysis is that Bell inequality tests are performed on a very general version of SU(1,1) coherent states, and the theoretical violation of the Bell inequality by coincidence detection is calculated and discussed. This group theoretical approach to Bell states is relevant to Bell state measurements, which are performed, for example, in quantum teleportation.Comment: 3 figure

Persepsi Masyarakat Desa Sahan Terhadap Satuan Polhut Reaksi Cepat (Sporc) (Perception of Community Sahan Village Towards Satuan Polhut Reaksi Cepat (Sporc))

Disturbance to protected areas Nyiut Mountain Nature Reserve from the village who lives close to the nature reserve, one of which is the village Sahan. People who want to meet the necessities of life to have to deal with SPORC Brigade Bekantan officers, so this study aims to determine the perception of community sahan village towards Satuan Polhut Reaksi Cepat (SPORC) activities in Nyiut Mountain Nature Reserve and to determine the relationship between the level of age, knowledge and cosmopolitan village with perception of community sahan village towards Satuan Polhut Reaksi Cepat (SPORC) activities in Nyiut Mountain Nature Reserve. The method used was a survey method with interview-assisted questionnaire. Determination of the number of respondents using Slovin formula and its determination by purposive sampling. Data analysis using Chi Square formula. Perception of community sahan village towards Satuan Polhut Reaksi Cepat (SPORC) activities in Nyiut Mountain Nature Reserve tend to be different. Data analysis showed 50.70% of the respondents are neutral, it is because they basically support the SPORC Brigade Bekantan activities that preserve Nyiut Mountain Nature Reserve but people also complained about the lack of SPORC Brigade Bekantan to dissemination and outreach to the community Sahan Village. Independent variables that have a real relationship / significant with the perception of community sahan village towards Satuan Polhut Reaksi Cepat (SPORC) activities in Nyiut Mountain Nature Reserve is the level of knowledge, whereas that does not have a real relationship / significant is the age level and the level of cosmopolitan society. Keywords: Perception, Sahan Village, SPORC Brigade Bekanta

Study Of Productivity And Costs On The Implementation Method Of Foundation Work Using Precast Concrete Pile As A Substitute To The Use Of Wooden Pile Foundations In Low Rise Building (Housing)

The soil condition in Pontianak City is mostly soft soil and peat soil which causes the low bearing capacity of the soil. Various efforts have been made to increase the bearing capacity of the soil, such as the use of wooden pile (kayu cerucuk). With the limited availability of wooden pile, the use of precast piles is an alternative in increasing the bearing capacity of the soil on the foundations of buildings/housings in Pontianak City. The purpose of this study is to compare the productivity and costs of using a wooden pile foundation measuring 12/15 cm with a length of 9-12 M against the use of a square precast concrete pile foundation measuring 15x15 cm2 with a segment length of 3-4 M at a depth of 12-20 M and a size of 12-20 M. 20x20 cm2 with a segment length of 6 M at a depth of 12-18 M in low-rise buildings in Pontianak City. From the results of the study, it is known that the productivity and average cost of piling per M' in a 2-storey shophouse building with an alternative foundation using 12/15 cm cerucuk piles is 22.3 seconds/m' at a cost of Rp. 17,306.24, precast piles square 15 x 15 cm2 of 111.5 seconds/m' at a cost of Rp. 144,274,439 and precast square piles of 20 x 20 cm2 of 125.7 seconds/m' at a cost of Rp. 291,338,955. In a type 150 house building with an alternative foundation using 12/15 cm wooden piles of 18.05 seconds/m' at a cost of Rp. 17,185.58, precast square piles of 15 x 15 cm2 of 104.67 seconds/m at a cost of Rp. 143,890.04 and 20 x 20 cm2 square precast piles of 94.66 seconds/m' with a cost of Rp. 289,724.234. The cost of foundation work with alternative foundations using precast square piles of 15 x 15 cm2 is the most efficient both from the aspect of driving costs, overall costs and the cost of the unit load carried by the foundatio

On maximal immediate extensions of valued division algebras

We show an extension theorem for strictly contracting bilinear mappings into a spherically complete valued vector space and we apply this result to prove that every maximal valued division algebra having the same characteristic as its residue division algebra is spherically complete

Influence of the Measure on Simplicial Quantum Gravity in Four Dimensions

We investigate the influence of the measure in the path integral for Euclidean quantum gravity in four dimensions within the Regge calculus. The action is bounded without additional terms by fixing the average lattice spacing. We set the length scale by a parameter $\beta$ and consider a scale invariant and a uniform measure. In the low $\beta$ region we observe a phase with negative curvature and a homogeneous distribution of the link lengths independent of the measure. The large $\beta$ region is characterized by inhomogeneous link lengths distributions with spikes and positive curvature depending on the measure.Comment: 12pg

Currency Mismatches in Non-Financial Firms in Chile

Using a new data base that includes the currency composition of assets and liabilities of non-financial firms, this paper examines the effects and determinants of currency mismatches in Chile. In line with previous studies, we find that after a depreciation in real terms, firms with the largest debt in dollars perform no worse than their counterparts indebted in pesos. Nonetheless, once we control properly by differences across firms in the currency composition of their assets, income and use of derivatives, significant balance sheet effects arise.