Exact results for spin dynamics and fractionization in the Kitaev Model

We present certain exact analytical results for dynamical spin correlation functions in the Kitaev Model. It is the first result of its kind in non-trivial quantum spin models. The result is also novel: in spite of presence of gapless propagating Majorana fermion excitations, dynamical two spin correlation functions are identically zero beyond nearest neighbor separation, showing existence of a gapless but short range spin liquid. An unusual, \emph{all energy scale fractionization}of a spin -flip quanta, into two infinitely massive $\pi$-fluxes and a dynamical Majorana fermion, is shown to occur. As the Kitaev Model exemplifies topological quantum computation, our result presents new insights into qubit dynamics and generation of topological excitations.Comment: 4 pages, 2 figures. Typose corrected, figure made better, clarifying statements and references adde

Linear Response for Granular Fluids

The linear response of an isolated, homogeneous granular fluid to small spatial perturbations is studied by methods of non-equilibrium statistical mechanics. The long wavelength linear hydrodynamic equations are obtained, with formally exact expressions for the susceptibilities and transport coefficients. The latter are given in equivalent Einstein-Helfand and Green-Kubo forms. The context of these results and their contrast with corresponding results for normal fluids are discussed.Comment: Submitted to PR

The Heckscher-Ohlin Model and the Network Structure of International Trade

This paper estimates for 28 product groups a characteristic parameter that reflects the topological structure of its trading network. Using these estimates, it then describes how the structure of international trade has evolved during the 1980-2000 period. Thereafter, it demonstrates the importance of networks in international trade by explicitly accounting for their scaling properties when testing the prediction of the Heckscher-Ohlin model that factor endowment differentials determine bilateral trade flows. The results suggest that differences in factor endowments increase bilateral trade in goods that are traded in "dispersed" networks. For goods that are traded in "concentrated" networks, factor endowment differentials are less important.Networks, international trade, gravity model

An exploration in visibility: some experiences of Indian women accountants

Many studies have emerged in the accounting field that explore women’s experiences in developed economies. However, little research has been undertaken to investigate the experiences and realities facing practising women accountants in India. The study offers exploratory insights into this area, (against the backdrop of the internationalisation and globalisation of accounting). The study involved seventeen women accounting practitioners from four major commercial cities in Indian: Mumbai, Chennai, Bangalore and Hyderabad. The results indicate that several practitioners experienced difficulties in certain areas of practice, whereas others reported that they did not experience any barriers to advancement. A discussion concerning limitations and areas for further research are presented in the conclusion

Changes in the Cropping Pattern, Crop Concentration, Agricultural Efficiency in Papanasam Taluk, Thanjavur District, Tamil Nadu, India

Cropping pattern simply means the proportion of area under different crops at a point of time, where us change in cropping pattern refers to the change in proportion of area under different crops at two different points of time.  The cropping pattern of any area is generally controlled by physical, socio economic and technological factors.  There are more than 20 crops with varying hectares are grown in this taluk.  Of these 20 crops only 5 crops based on the properties of land to the total area under cultivation alone has been considered for analysis.  Simple percentage obtained by dividing total area under crops, in to area of different crops. Paddy is the dominant crop in this taluk. During the year 1995-1996 to 2008-2009 the following are the major 5 major crops are taken in to cultivate in the study area. Such as Paddy 82.2%, Sugarcane 6.5%, Oilseeds 4.5%, Pulses 4.1% and Cotton 1.9% to the total cropped area in the taluk

Energy Management system for Hybrid RES with Hybrid Cascaded Multilevel inverter

In this paper, we propose an energy management system with hybrid solar and wind renewable energy system (RES) with Multilevel inverter to give a lossless power to load. This system continuously receives the battery storage and power consumption after it checks the these value with default value if power consumption is exceeds default value means it turn off  the loads. We are assigns the priority to the loads in order to overcome the user inconvenient. To increase PV module output MPPT is used. The existing system uses only boost converter, in our paper boost converter is combined with buck converter used because the PV module can produce high voltage  than DC-bus voltage. Buck converter used to step down purpose. In this  system  on-line configuration check and buck-boost mode transition will be presented. Experimental results measured from three-string MPPTs with EMS the maximum power level of 10 kW are used to verify the analysis and discussion with hybrid cascaded multilevel inverter.DOI:http://dx.doi.org/10.11591/ijece.v4i1.452

Doped carrier formulation and mean-field theory of the tt't''J model

In the generalized-tJ model the effect of the large local Coulomb repulsion is accounted for by restricting the Hilbert space to states with at most one electron per site. In this case the electronic system can be viewed in terms of holes hopping in a lattice of correlated spins, where holes are the carriers doped into the half-filled Mott insulator. To explicitly capture the interplay between the hole dynamics and local spin correlations we derive a new formulation of the generalized-tJ model where doped carrier operators are used instead of the original electron operators. This ``doped carrier'' formulation provides a new starting point to address doped spin systems and we use it to develop a new, fully fermionic, mean-field description of doped Mott insulators This mean-field approach reveals a new mechanism for superconductivity, namely spinon-dopon mixing, and we apply it to the tt't''J model as of interest to high-temperature superconductors. In particular, we use model parameters borrowed from band calculations and from fitting ARPES data to obtain a mean-field phase diagram that reproduces semi-quantitatively that of hole and electron doped cuprates. The mean-field approach hereby presented accounts for the local antiferromagnetic and d-wave superconducting correlations which, we show, provide a rational for the role of t' and t'' in strengthening superconductivity as expected by experiments and other theoretical approaches. As we discuss how t, t' and t'' affect the phase diagram, we also comment on possible scenarios to understand the differences between as-grown and oxygen reduced electron doped samples.Comment: 17 pages, 2 figures. Homepage http://dao.mit.edu/~wen