327 research outputs found
Micro Smart Grid Technology for Rural Indian model
Today world is step-in 21st century. But still in major part of India cannot get 24 X 7 eclectic power supply. Electrical power has become a prime necessity for any country for economic development. And power shortage is a dominant problem, being faced by the most of the countries today. On the top of this, the conventional fuel sources for power generation i.e. coal & oil deposits are fast getting depleted. The Obvious way out, is to shift focus to renewable sources of energy and in country like India our village population & remote location load always suffer by power cut or grid failure although they have enough potential to generate own power but due to lake of technology they can’t get 24 x 7 power supply to provide some solution of this problem we try to develop smart grid Indian version. Although more invention has to be carried out still in the use of non-conventional energy sources for power generation to reach to most economic point, but every little effort in this direction may provide a solution to power shortage problems. Hence the same topic was selected as a part of the curriculum. The goal of the paper is to construct a micro smart grid which is capable of producing enough electrical power by using local removable energy electrical power sources like wind, bio-gas, solar, current running hydro plan for the places like remote places like villages? In this paper, we propose a decentralized framework named Micro Smart GRID to tackle grid resource management a simulation study of operation and control of local generation & co-ordination with state grid in case of normal operation or power islands in Micro Smart Grid environment
Dynamics of rotating Bose-Einstein condensates probed by Bragg scattering
Gaseous Bose-Einstein condensates (BECs) have become an important test bed
for studying the dynamics of quantized vortices. In this work we use two-photon
Doppler sensitive Bragg scattering to study the rotation of sodium BECs. We
analyze the microscopic flow field and present laboratory measurements of the
coarse-grained velocity profile. Unlike time-of-flight imaging, Bragg
scattering is sensitive to the direction of rotation and therefore to the phase
of the condensate. In addition, we have non-destructively probed the vortex
flow field using a sequence of two Bragg pulses.Comment: 13 pages, 5 figures. Invited paper submitted to a special issue on
"Nonlinear Waves" of the (Elsevier) journal 'Math. Comput. Simul.', for
participants in the 4th IMACS International Conference on Nonlinear Evolution
Equations and Wave Phenomena (2005). Visit our website at
http://www.physics.gatech.edu/chandra for additional informatio
Efficient quantum key distribution scheme with nonmaximally entangled states
We propose an efficient quantum key distribution scheme based on
entanglement. The sender chooses pairs of photons in one of the two equivalent
nonmaximally entangled states randomly, and sends a sequence of photons from
each pair to the receiver. They choose from the various bases independently but
with substantially different probabilities, thus reducing the fraction of
discarded data, and a significant gain in efficiency is achieved. We then show
that such a refined data analysis guarantees the security of our scheme against
a biased eavesdropping strategy.Comment: 5 Pages, No Figur
Linear optical implementation of a single mode quantum filter and generation of multi-photon polarization entangled state
We propose a scheme to implement a single-mode quantum filter, which
selectively eliminates the one-photon state in a quantum state
. The vacuum state and the two photon state are
transmitted without any change. This scheme requires single-photon sources,
linear optical elements and photon detectors. Furthermore we demonstrate, how
this filter can be used to realize a two-qubit projective measurement and to
generate multi-photon polarization entangled states.Comment: revision submitted to PR
Tomographic Quantum Cryptography
We present a protocol for quantum cryptography in which the data obtained for
mismatched bases are used in full for the purpose of quantum state tomography.
Eavesdropping on the quantum channel is seriously impeded by requiring that the
outcome of the tomography is consistent with unbiased noise in the channel. We
study the incoherent eavesdropping attacks that are still permissible and
establish under which conditions a secure cryptographic key can be generated.
The whole analysis is carried out for channels that transmit quantum systems of
any finite dimension.Comment: REVTeX4, 9 pages, 3 figures, 1 tabl
Quantum Distribution of Gaussian Keys with Squeezed States
A continuous key distribution scheme is proposed that relies on a pair of
canonically conjugate quantum variables. It allows two remote parties to share
a secret Gaussian key by encoding it into one of the two quadrature components
of a single-mode electromagnetic field. The resulting quantum cryptographic
information vs disturbance tradeoff is investigated for an individual attack
based on the optimal continuous cloning machine. It is shown that the
information gained by the eavesdropper then simply equals the information lost
by the receiver.Comment: 5 pages, RevTe
Quantum and Classical Noise in Practical Quantum Cryptography Systems based on polarization-entangled photons
Quantum-cryptography key distribution (QCKD) experiments have been recently
reported using polarization-entangled photons. However, in any practical
realization, quantum systems suffer from either unwanted or induced
interactions with the environment and the quantum measurement system, showing
up as quantum and, ultimately, statistical noise. In this paper, we investigate
how ideal polarization entanglement in spontaneous parametric downconversion
(SPDC) suffers quantum noise in its practical implementation as a secure
quantum system, yielding errors in the transmitted bit sequence. Because all
SPDC-based QCKD schemes rely on the measurement of coincidence to assert the
bit transmission between the two parties, we bundle up the overall quantum and
statistical noise in an exhaustive model to calculate the accidental
coincidences. This model predicts the quantum-bit error rate and the sifted key
and allows comparisons between different security criteria of the hitherto
proposed QCKD protocols, resulting in an objective assessment of performances
and advantages of different systems.Comment: Rev Tex Style, 2 columns, 7 figures, (a modified version will appear
on PRA
Maximizing the entanglement of two mixed qubits
Two-qubit states occupy a large and relatively unexplored Hilbert space. Such
states can be succinctly characterized by their degree of entanglement and
purity. In this letter we investigate entangled mixed states and present a
class of states that have the maximum amount of entanglement for a given linear
entropy.Comment: 4 pages, 3 figure
Reducing the communication complexity with quantum entanglement
We propose a probabilistic two-party communication complexity scenario with a
prior nonmaximally entangled state, which results in less communication than
that is required with only classical random correlations. A simple all-optical
implementation of this protocol is presented and demonstrates our conclusion.Comment: 4 Pages, 2 Figure
Solid-state laser system for laser cooling of Sodium
We demonstrate a frequency-stabilized, all-solid laser source at 589 nm with
up to 800 mW output power. The laser relies on sum-frequency generation from
two laser sources at 1064 nm and 1319 nm through a PPKTP crystal in a
doubly-resonant cavity. We obtain conversion efficiency as high as 2 W/W^2
after optimization of the cavity parameters. The output wavelength is tunable
over 60 GHz, which is sufficient to lock on the Sodium D2 line. The robustness,
beam quality, spectral narrowness and tunability of our source make it an
alternative to dye lasers for atomic physics experiments with Sodium atoms
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