Entanglement induced Sub-Planck structures

We study Wigner function of a system describing entanglement of two cat-states. Quantum interferece arising due to entanglement is shown to produce sub-Planck structures in the phase-space plots of the Wigner function. Origin of these structures in our case depends on entanglement unlike those in Zurek \cite{Zurek}. It is argued that the entangled cat-states are better suited for carrying out precision measurements.Comment: 6 pages 2 figures (revised version include more quantitative discussion

A Novel Technique for Harmonics Estimation in Smart Urban Utility Grid with Solar Photovoltaic

Revolution in the field of electrical energy system is happening worldwide and existing grids are transforming into smart grids. The vision of smart grid demands a cutting edge technology for integrating the different renewable energy sources. Integration of renewable such as solar photovoltaic (PV) pose various challenges in the system, one such challenge is harmonics generation. Harmonics are generated by the associated power electronics based interfacing devices. Moreover the load connected to the distribution system is nonlinear and harmonic is rich in nature. Therefore, a lot of harmonics is injected into the system either from the source or from the load ends and affects the performance of power system. Harmonic distortions create excessive power loss and abnormal temperature rise, results the overheating of transformer, overheating of neutral conductor and malfunction of protective devices, which endangers the stability and reliability of the system. The smart distribution grid must absorb such concerns through critical technological solutions. In this paper, harmonics are analyzed for a solar PV integrated smart urban utility distribution feeder. In order to obtain the exact nature of harmonics and its contribution, a fast decoupled harmonic load flow algorithm is formulated and implemented on the designed smart utility grid. Results show that a lot of voltage/current harmonics are injected at various buses, lines and transformers by the solar PV and associated interfacing devices which even violates the harmonic limit of IEEE standards 519-1992. The authors feel that in order to achieve the smart distribution grid objectives of clean power supply to the customers, there is a serious necessity to study the issues related to harmonic generation, and further to develop control strategies to mitigate them. Keywords: Harmonics (THD), fast decoupled load flow, grid integration, solar PV, smart distribution system