An International Research Journal

AJP Vol 27 No 1, 2018

AJP

SSN : 0971 - 3093

Vol 27, No 1, January, 2018

 

Asian Journal of Physics                                                                                                       Vol. 27 No 1, 2018, 01-12


Information Transmission with Quantum Limited Subspace


Francis T S Yu
Department of Electrical Engineering, Pennsylvania State University, University Park, PA 16802,USA

ftypsu@gmail.com

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One important aspect of our universe is that one cannot get something from nothing; there is always a price to pay. In this article we show that every bit of information is limited by a quantum unit.  Since we are communicating within a temporal subspace, this unit can be equivalently described as a quantum limited subspace (QLS), as imposed by the Heisenberg Principle. We show that communication can be exploited within and outside the QLS. The size of a QLS is determined by carrier signal bandwidth; that is narrower the bandwidth the larger the size of the QLS. By manipulating the size of a QLS, more efficient information transmission strategies can be developed.  Examples for inside and outside QLS communication are given. Extension to relativistic communication has also been demonstrated.  We remark that, a new era of communication is anticipated to immerge and it will change our way in communicating, observation and computing, we used to use forever! © Anita Publication. All rights reserved.

Total Refs : 17

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Asian Journal of Physics                                                                                                       Vol. 27 No 1, 2018, 13-21


Growth of KDP crystal by automatic temperature controlled seed rotation method

 

Vikrama, N Vijayana, Ravindraa, Soniaa, Mahaka, and Apurvab

aCSIR- National Physical laboratory, New Delhi-110 012, India

bJamia Millia Islamia, New Delhi-110 025, India

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In the recent past, nonlinear optical (NLO) materials are getting attention because of their excellent applications in the area of fiber optics communication and optical signal processing. The NLO crystals can be  grown by different methods at a desired temperature. A variety of methods of crystallization from solutions can be classified in accordance with the conditions under which they are used. In this article, we describe the fabrication of a bidirectional seed rotation apparatus to grow bulk size single crystals. We have designed the automation circuit which will detect and control the temperature during seed rotation process. The aim of the present work is to grow the single crystal of KDP by seed rotation method. In order to study the properties of the crystal, the grown crystal is subjected to various studies. The PXRD study indicated that the grown crystal has good crystallinity and single phase nature. From the photoluminiscence spectrum it was found that the emission maximum occurs at 405 nm. © Anita Publications. All rights reserved..

Keywords: NLO Materials, Seed rotation controller, Photoluminescence, Micro hardness. Etching study

Growth of KDP crystal by automatic temperature controlled seed rotation method.pdf
Vikram, N Vijayan, Ravindra, Sonia, Mahak and Apurva

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Asian Journal of Physics                                                                                                       Vol. 27 No 1, 2018, 23-34


Theoretical investigations on NLO crystal 1-[4-(methylsulfanyl) phenyl]-3-(4-nitrophenyl) prop-2-en-1-one


Mahesh Pal, Singh Yadav1 and Anuj Kumar2*

1Department of Physics, A.P.M.(P.G.) Degree college, Ujhani (Budaun), 243639,UP, India.

2Department of Physics, C.C.S. University, Meerut, 250005, UP, India.

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In order to broaden the understanding of nonlinear behavior of a chalcone derivative nonlinear optical crystal 1-[4-(methylsulfanyl) phenyl]-3-(4-nitrophenyl) prop-2-en-1-one (4MPNP), we have made theoretical investigations on structure, natural bond orbital (NBO), nonlinear response and other properties of this molecule. The theoretical interpretation of nonlinear behaviour is made by calculating ground state and dispersion tensor components of hyperpolarizabilities using density functional theory (DFT) and HF methods employing 6-31G(d,p) basis set and Becke’s three-parameters hybrid functional (B3LYP). The effect of electron donor and acceptor groups on charge conjugation across the backbone is evaluated using NBO analysis and it is correlated with nonlinear behavior of the molecule. Other properties like Molecular electrostatic potential, Mulliken atomic charge distribution over the molecule and thermodynamical parameters are calculated and explained for understanding structure property relation. © Anita Publications. All rights reserved.

Keywords: Nonlinear optical crystal, DFT, NBO,Hyperpolarizabilities

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