Ajay Maurya - Academia.edu (original) (raw)

Papers by Ajay Maurya

Journal of Physics: Conference Series, 2010

Lightning discharges during thunderstorm are the significant natural source of electromagnetic wa... more Lightning discharges during thunderstorm are the significant natural source of electromagnetic waves. They generate electromagnetic pulses, which vary from few Hz to tens of MHz, but the maximum radiated energy is confined in extremely low (ELF: 3-3000Hz) and very low (VLF: 3-30 KHz) frequency band. These pulsed signals with frequency dispersion are known as radio atmospherics or tweeks. These waves

Lightning generated radio atmospheric that propagates over long distances via multiple reflection... more Lightning generated radio atmospheric that propagates over long distances via multiple reflections through the boundaries of the Earth-ionosphere waveguide (EIWG), shows sharp dispersion near the cut-off frequency ˜1.8 kHz of the EIWG. These dispersed atmospherics at lower frequency end are called as `tweek' radio atmospherics. In order to estimate D-region electron densities at the ionospheric reflection heights we have utilized the dispersive property of tweeks observed at low latitude Indian stations Nainital (Geomag. Lat., 20.29° N) and Allahabad (Geomag. Lat., 16.05° N). Direction finding technique has also been applied to determine the source locations of causative lightning discharge of tweeks. In this perspective, the geographic locations is determined by the intersection of two circles that are drawn by taking the travelled / propagation distance by tweek atmospherics from source location to Allahabad (ALD) and Nainital (NTL) stations. These results are in good agreement with World Wide Lightning Location Network (WWLLN) data. The average D-region electron density along the propagation path varied in the range ˜20-35 el/cc at ionospheric reflection heights of 70-90 km. The tweek method has unique advantage of monitoring lower boundary of the D-region over an area of several thousand of km surrounding to the receiving stations.


In this paper, we generalize the secure quantum information exchange (SQIE) protocol, originally ... more In this paper, we generalize the secure quantum information exchange (SQIE) protocol, originally proposed by the authors [J. Phys. B: At. Mol. Opt. Phys. 44 (2011) 115504] for secure exchange of one qubit information with each of Alice and Bob, to the case of secure exchange of quantum information of arbitrary qubits with Alice and Bob. We also discuss security of the original and generalized SQIE protocols with respect to the number of qubits with controller, Charlie.

Journal of Physics B-atomic Molecular and Optical Physics, 2011

In this paper, we present a new idea of two-way quantum communication called 'secure quantum info... more In this paper, we present a new idea of two-way quantum communication called 'secure quantum information exchange' (SQIE). If there are two arbitrary unknown quantum states |ξrangIA and |ηrangIB, initially with Alice and Bob, respectively, then SQIE protocol leads to the simultaneous exchange of these states between Alice and Bob with the aid of the special kind of six-qubit entangled (SSE) state and classical assistance of the third party, Charlie. The term 'secure' signifies the fact that SQIE protocol either faithfully exchanges the unknown quantum states proceeding in a prescribed way or, in case of any irregularity, the process generates no results. For experimental realization of the SQIE protocol, we have suggested an efficient scheme for generating SSE states using the interaction between highly detuned Λ-type three-level atoms and the optical coherent field. By theoretical calculations, we found that SSE states of almost unit fidelity with perfect success rates for appreciable mean photon numbers (Fav >= 0.999 for |α|2 >= 1.5) can be generated by our scheme. Further, we have discussed possible experimental imperfections, such as atomic-radiative time, cavity damping time, atom-cavity interaction time, and the efficiency of discrimination between the coherent field and the vacuum state shows that our SQIE protocol is within the reach of technology presently available.

Optics Communications, 2011

Journal of Physics: Conference Series, 2010

Lightning discharges during thunderstorm are the significant natural source of electromagnetic wa... more Lightning discharges during thunderstorm are the significant natural source of electromagnetic waves. They generate electromagnetic pulses, which vary from few Hz to tens of MHz, but the maximum radiated energy is confined in extremely low (ELF: 3-3000Hz) and very low (VLF: 3-30 KHz) frequency band. These pulsed signals with frequency dispersion are known as radio atmospherics or tweeks. These waves

Lightning generated radio atmospheric that propagates over long distances via multiple reflection... more Lightning generated radio atmospheric that propagates over long distances via multiple reflections through the boundaries of the Earth-ionosphere waveguide (EIWG), shows sharp dispersion near the cut-off frequency ˜1.8 kHz of the EIWG. These dispersed atmospherics at lower frequency end are called as `tweek' radio atmospherics. In order to estimate D-region electron densities at the ionospheric reflection heights we have utilized the dispersive property of tweeks observed at low latitude Indian stations Nainital (Geomag. Lat., 20.29° N) and Allahabad (Geomag. Lat., 16.05° N). Direction finding technique has also been applied to determine the source locations of causative lightning discharge of tweeks. In this perspective, the geographic locations is determined by the intersection of two circles that are drawn by taking the travelled / propagation distance by tweek atmospherics from source location to Allahabad (ALD) and Nainital (NTL) stations. These results are in good agreement with World Wide Lightning Location Network (WWLLN) data. The average D-region electron density along the propagation path varied in the range ˜20-35 el/cc at ionospheric reflection heights of 70-90 km. The tweek method has unique advantage of monitoring lower boundary of the D-region over an area of several thousand of km surrounding to the receiving stations.


In this paper, we generalize the secure quantum information exchange (SQIE) protocol, originally ... more In this paper, we generalize the secure quantum information exchange (SQIE) protocol, originally proposed by the authors [J. Phys. B: At. Mol. Opt. Phys. 44 (2011) 115504] for secure exchange of one qubit information with each of Alice and Bob, to the case of secure exchange of quantum information of arbitrary qubits with Alice and Bob. We also discuss security of the original and generalized SQIE protocols with respect to the number of qubits with controller, Charlie.

Journal of Physics B-atomic Molecular and Optical Physics, 2011

In this paper, we present a new idea of two-way quantum communication called 'secure quantum info... more In this paper, we present a new idea of two-way quantum communication called 'secure quantum information exchange' (SQIE). If there are two arbitrary unknown quantum states |ξrangIA and |ηrangIB, initially with Alice and Bob, respectively, then SQIE protocol leads to the simultaneous exchange of these states between Alice and Bob with the aid of the special kind of six-qubit entangled (SSE) state and classical assistance of the third party, Charlie. The term 'secure' signifies the fact that SQIE protocol either faithfully exchanges the unknown quantum states proceeding in a prescribed way or, in case of any irregularity, the process generates no results. For experimental realization of the SQIE protocol, we have suggested an efficient scheme for generating SSE states using the interaction between highly detuned Λ-type three-level atoms and the optical coherent field. By theoretical calculations, we found that SSE states of almost unit fidelity with perfect success rates for appreciable mean photon numbers (Fav >= 0.999 for |α|2 >= 1.5) can be generated by our scheme. Further, we have discussed possible experimental imperfections, such as atomic-radiative time, cavity damping time, atom-cavity interaction time, and the efficiency of discrimination between the coherent field and the vacuum state shows that our SQIE protocol is within the reach of technology presently available.

Optics Communications, 2011