1,884 research outputs found
Universality in the Gravitational Stretching of Clocks, Waves and Quantum States
There are discernible and fundamental differences between clocks, waves and
physical states in classical physics. These fundamental concepts find a common
expression in the context of quantum physics in gravitational fields; matter
and light waves, quantum states and oscillator clocks become quantum synonymous
through the Planck-Einstein-de Broglie relations and the equivalence principle.
With this insight, gravitational effects on quantum systems can be simply and
accurately analyzed. Apart from providing a transparent framework for
conceptual and quantitative thinking on matter waves and quantum states in a
gravitational field, we address and resolve with clarity the recent
controversial discussions on the important issue of the relation and the
crucial difference between gravimetery using atom interferometers and the
measurement of gravitational time dilation.Comment: Gravity Research Foundation honorable mention, 201
Moving Observers in an Isotropic Universe
We show how the anisotropy resulting from the motion of an observer in an
isotropic universe may be determined by measurements. This provides a means to
identify inertial frames, yielding a simple resolution to the twins paradox of
relativity theory. We propose that isotropy is a requirement for a frame to be
inertial; this makes it possible to relate motion to the large scale structure
of the universe.Comment: 8 pages, 1 figure, with minor typographical correctio
A probabilistic approach to reduce the route establishment overhead in AODV algorithm for manet
Mobile Ad-hoc Networks (MANETS) is a collection of wireless nodes without any
infrastructure support. The nodes in MANET can act as either router or source
and the control of the network is distributed among nodes. The nodes in MANETS
are highly mobile and it maintains dynamic interconnection between those mobile
nodes. MANTEs have been considered as isolated stand-alone network. This can
turn the dream of networking "at any time and at any where" into reality. The
main purpose of this paper is to study the issues in route discovery process in
AODV protocol for MANET. Flooding of route request message imposes major
concern in route establishment. This paper suggests a new approach to reduce
the routing overhead during the route discovery phase. By considering the
previous behaviour of the network, the new protocol reduces the unwanted
searches during route establishment processComment: International Journal of Distributed and Parallel Systems (IJDPS)
Vol.3, No.2, March 201
Correlation functions, Bell's inequalities and the fundamental conservation laws
I derive the correlation function for a general theory of two-valued spin
variables that satisfy the fundamental conservation law of angular momentum.
The unique theory-independent correlation function is identical to the quantum
mechanical correlation function. I prove that any theory of correlations of
such discrete variables satisfying the fundamental conservation law of angular
momentum violates the Bell's inequalities. Taken together with the Bell's
theorem, this result has far reaching implications. No theory satisfying
Einstein locality, reality in the EPR-Bell sense, and the validity of the
conservation law can be constructed. Therefore, all local hidden variable
theories are incompatible with fundamental symmetries and conservation laws.
Bell's inequalities can be obeyed only by violating a conservation law. The
implications for experiments on Bell's inequalities are obvious. The result
provides new insight regarding entanglement, and its measures.Comment: LaTeX, 12pt, 11 pages, 2 figure
Morphological filtering on hypergraphs
The focus of this article is to develop computationally efficient
mathematical morphology operators on hypergraphs. To this aim we consider
lattice structures on hypergraphs on which we build morphological operators. We
develop a pair of dual adjunctions between the vertex set and the hyper edge
set of a hypergraph H, by defining a vertex-hyperedge correspondence. This
allows us to recover the classical notion of a dilation/erosion of a subset of
vertices and to extend it to subhypergraphs of H. Afterward, we propose several
new openings, closings, granulometries and alternate sequential filters acting
(i) on the subsets of the vertex and hyperedge set of H and (ii) on the
subhypergraphs of a hypergraph
An adaptive disturbance rejection control scheme for voltage regulation in DC micro-grids
© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Uncertain generation by renewable sources and load variations have resulted in adding energy storage systems in the grid to maintain grid parameters (voltage, frequency) within prescribed limits. The disturbances being non-deterministic in nature, the voltage regulation control by the storage systems relies mostly on dual loop architecture with an outer voltage and inner current loop. Improvement in controller dynamics can be achieved through feed forward of disturbance profile but at expense of additional sensors and communication in the grid. This work explores the application of an adaptive disturbance rejection control scheme for disturbance estimation (without using additional sensors) employing an extended state and proportional integral observer (PI+ESO). The proposed observer aim to achieve robust disturbance estimation under grid parameter uncertainty. The effectiveness of the proposed scheme over the conventional one will be put forward through H8 and H2 norm analysis of the system. The design and simulation results of the proposed scheme will be presented in this work.Peer ReviewedPostprint (author's final draft
Initial wave packets and the various power-law decreases of scattered wave packets at long times
The long time behavior of scattered wave packets from a
finite-range potential is investigated, by assuming to be
initially located outside the potential. It is then shown that can
asymptotically decrease in the various power laws at long time, according to
its initial characteristics at small momentum. As an application, we consider
the square-barrier potential system and demonstrate that exhibits
the asymptotic behavior , while another behavior like can
also appear for another .Comment: 5 pages, 1 figur
Transition region of TEC enhancement phenomena during geomagnetically disturbed periods at mid-latitudes
Large-scale TEC perturbations/enhancements observed during the day sectors of major storm periods, 12-13&nbsp;February 2000, 23&nbsp;September 1999, 29&nbsp;October 2003, and 21&nbsp;November 2003, were studied using a high resolution GPS network over Japan. TEC enhancements described in the present study have large magnitudes (&ge;25&times;10<sup>16</sup> electrons/m<sup>2</sup>) compared to the quiet-time values and long periods (&ge;120 min). The sequential manner of development and the propagation of these perturbations show that they are initiated at the northern region and propagate towards the southern region of Japan, with velocities &gt;350 m/s. On 12&nbsp;February 2000, remarkably high values of TEC and background content are observed at the southern region, compared to the north, because of the poleward expansion of the equatorial anomaly crest, which is characterized by strong latitudinal gradients near 35&deg; N (26&deg; N geomagnetically). When the TEC enhancements, initiating at the north, propagate through the region 39-34&deg; N (30-25&deg; N geomagnetically), they undergo transitions characterized by a severe decrease in amplitude of TEC enhancements. This may be due to their interaction with the higher background content of the expanded anomaly crest. However, at the low-latitude region, below 34&deg; N, an increase in TEC is manifested as an enhanced ionization pattern (EIP). This could be due to the prompt penetration of the eastward electric field, which is evident from high values of the southward Interplanetary Magnetic Field component (IMF <i>B<sub>z</sub></i>) and AE index. The TEC perturbations observed on the other storm days also exhibit similar transitions, characterized by a decreasing magnitude of the perturbation component, at the region around 39-34&deg; N. In addition to this, on the other storm days, at the low-latitude region, below 34&deg; N, an increase in TEC (EIP feature) also indicates the repeatability of the above scenario. It is found that, the latitude and time at which the decrease in magnitude of the perturbation component/amplitude of the TEC enhancement are matching with the latitude and time of the appearance of the high background content. In the present study, on 12&nbsp;February 2000, the F-layer height increases at Wakkanai and Kokubunji, by exhibiting a typical dispersion feature of LSTID, or passage of an equatorward surge, which is matching with the time of occurrence of the propagating TEC perturbation component. Similarly, on 29&nbsp;October 2003, the increase in F-layer heights by more than 150km at Wakkanai and 90 km at Kokubunji around 18:00&nbsp;JST, indicates the role of the equatorward neutral wind. On that day, TEC perturbation observed at the northern region, after 18:30&nbsp;JST, which propagates towards south, could be caused mainly by the equatorward neutral wind, leading to an F-layer height increase. These observations imply the role of the equatorward neutral wind, which increases the F-layer height, by lifting the ionization to the regions of lower loss during daytime, when production is still taking place, which, in turn, increases the TEC values. <P style="line-height: 20px;"> Large-scale traveling ionospheric disturbances (LSTIDs) are considered as ionospheric manifestations of the passage of Atmospheric Gravity Waves (AGWs) that are generated at the high latitude by energy input from the magnetosphere to the low-latitude ionosphere. This study shows that large-scale TEC perturbations observed here are produced at the northern region due to the combined effects of the equatorward neutral wind, the subsequent F-layer height increase, and LSTIDs. When these perturbation components propagate through the region, 39-34&deg; N, they undergo transitions characterised by a decrease in magnitude. Also, at the low-latitude region, below 34&deg; N, an increase in the TEC exhibits EIP feature, due to the prompt penetration of the eastward electric field
Entropic uncertainty relation for power-law wave packets
For the power-law quantum wave packet in configuration space, the variance of
the position observable may be divergent. Accordingly, the information-entropic
formulation of the uncertainty principle becomes more appropriate than the
Heisenberg-type formulation, since it involves only the finite quantities. It
is found that the total amount of entropic uncertainty converges to its lower
bound in the limit of a large value of the exponent.Comment: 10 pages, 3 figure
Knowledge, risk perceptions and attitudes of nurses towards HIV in a tertiary care hospital in Mangalore, India
- …