8,543 research outputs found
Quantum discord and classical correlation can tighten the uncertainty principle in the presence of quantum memory
Uncertainty relations capture the essence of the inevitable randomness
associated with the outcomes of two incompatible quantum measurements.
Recently, Berta et al. have shown that the lower bound on the uncertainties of
the measurement outcomes depends on the correlations between the observed
system and an observer who possesses a quantum memory. If the system is
maximally entangled with its memory, the outcomes of two incompatible
measurements made on the system can be predicted precisely. Here, we obtain a
new uncertainty relation that tightens the lower bound of Berta et al., by
incorporating an additional term that depends on the quantum discord and the
classical correlations of the joint state of the observed system and the
quantum memory. We discuss several examples of states for which our new lower
bound is tighter than the bound of Berta et al. On the application side, we
discuss the relevance of our new inequality for the security of quantum key
distribution and show that it can be used to provide bounds on the distillable
common randomness and the entanglement of formation of bipartite quantum
states.Comment: v1: Latex, 4 and half pages, one fig; v2: 9 pages including 4-page
appendix; v3: accepted into Physical Review A with minor change
Report of Acoustic Test on PSLV IS.1/2L Structure
The results of acoustic conducted on PSLV IS.1/2L at Acoustic Test Facility are briefly given. It contains test set up,
Instrumentation details and tables of spectral response
Shell Banding Pattern and Chromosomal Studies on the Giant African Snail, Achatina Fulica (Bowdich) (Achatinidae: Gastropoda)
A pioneer report on the shell banding, chirality (shell coiling) and chromosomal studies on populations of the giant African snail, Achatina fulica (Bowdich) (Achatinidae: Gastropoda) occurring in Bengaluru region is detailed in this paper. Shell coiling in A. fulica was found to be dextral and significant variation in banding pattern within and between populations was observed. The chromosome number from well spread diakinesis and metaphase stages of meiosis in ovotestis is found to be n=30 and 2n=60, which is similar to earlier works, also the similarity in different stages is in agreement with the earlier reports
Barrier modification in sub-barrier fusion reactions using Wong formula with Skyrme forces in semiclassical formalism
We obtain the nuclear proximity potential by using semiclassical extended
Thomas Fermi (ETF) approach in Skyrme energy density formalism (SEDF), and use
it in the extended -summed Wong formula under frozen density
approximation. This method has the advantage of allowing the use of different
Skyrme forces, giving different barriers. Thus, for a given reaction, we could
choose a Skyrme force with proper barrier characteristics, not-requiring extra
``barrier lowering" or ``barrier narrowing" for a best fit to data. For the
Ni+Mo reaction, the -summed Wong formula, with effects of
deformations and orientations of nuclei included, fits the fusion-evaporation
cross section data exactly for the force GSkI, requiring additional barrier
modifications for forces SIII and SV. However, the same for other similar
reactions, like Ni+Ni, fits the data best for SIII force.
Hence, the barrier modification effects in -summed Wong expression
depends on the choice of Skyrme force in extended ETF method.Comment: INPC2010, Vancouver, CANAD
Novel optically active lead-free relaxor ferroelectric (Ba0.6Bi0.2Li0.2)TiO3
We discovered a near room temperature lead-free relaxor-ferroelectric
(Ba0.6Bi0.2Li0.2)TiO3 (BBLT) having A-site compositional disordered ABO3
perovskite structure. Microstructure-property relations revealed that the
chemical inhomogeneities and development of local polar nano regions (PNRs) are
responsible for dielectric dispersion as a function of probe frequencies and
temperatures. Rietveld analysis indicates mixed crystal structure with 80%
tetragonal structure (space group P4mm) and 20% orthorhombic structure (space
group Amm2) which is confirmed by the high resolution transmission electron
diffraction pattern. Dielectric constant and tangent loss dispersion with and
without illumination of light obey nonlinear Vogel-Fulture relation. It shows
slim polarization-hysteresis (P-E) loops and excellent displacement
coefficients (d33 ~ 233 pm/V) near room temperature, which gradually diminish
near the maximum dielectric dispersion temperature (Tm). The underlying physics
for light-sensitive dielectric dispersion was probed by X-ray photon
spectroscopy (XPS) which strongly suggests that mixed valence of bismuth ions,
especially Bi5+ ions, are responsible for most of the optically active centers.
Ultraviolet photoemission measurements showed most of the Ti ions are in 4+
states and sit at the centers of the TiO6 octahedra, which along with
asymmetric hybridization between O 2p and Bi 6s orbitals appears to be the main
driving force for net polarization. This BBLT material may open a new path for
environmental friendly lead-free relaxor-ferroelectric research.Comment: 23 pages, 5 figure
Interference due to Coherence Swapping
We propose a method called `coherence swapping' which enables us to create
superposition of a particle in two distinct paths, which is fed with initially
incoherent, independent radiations. This phenomenon is also present for the
charged particles, and can be used to swap the effect of flux line due to
Aharonov-Bohm effect. We propose an optical version of the experimental set-up
to test the coherence swapping. The phenomenon, which is simpler than
entanglement swapping or teleportation, raises some fundamental questions about
true nature of wave-particle duality, and also opens up the possibility of
studying the quantum erasure from a new angle.Comment: Latex file, 10 pages, Two figure
Permeation, antifouling and desalination performance of TiO2 nanotube incorporated PSf/CS blend membranes
Polysulfone (PSf) and chitosan (CS) blend membranes were prepared by incorporating titanium dioxide nanotubes (TiO2NT) in different compositions. The proper blending of PSf and CS in the PSf/CS/TiO2 membranes was confirmed by ATR-IR spectroscopy. The influence of nanotubes on morphology of membranes was investigated by Field Emission Scanning Electron Microscopy (FESEM). The effect of nanotubes on hydrophilicity of the membranes was studied by water swelling and contact angle measurements. The distribution of TiO2NT on the membrane surface was determined by Transmission Electron Microscope (TEM) analysis. The permeation property of PSf/CS/TiO2NT membranes was carried out by measuring the time dependent pure water flux (PWF). Bovine serum albumin (BSA) protein rejection studies were performed to know the antifouling properties. The rheological percolation threshold of PSf/CS/TiO2NT solutions was measured by viscosity studies. The nanotubes incorporated PSf/CS membranes showed enhanced permeation and antifouling properties compared to PSf/CS and nascent PSf ultrafiltration membranes. Membranes prepared well above rheological percolation threshold showed drastic reduction in pore size and acted as nanofiltration (NF) membranes
The Paths to Choreography Extraction
Choreographies are global descriptions of interactions among concurrent
components, most notably used in the settings of verification (e.g., Multiparty
Session Types) and synthesis of correct-by-construction software (Choreographic
Programming). They require a top-down approach: programmers first write
choreographies, and then use them to verify or synthesize their programs.
However, most existing software does not come with choreographies yet, which
prevents their application.
To attack this problem, we propose a novel methodology (called choreography
extraction) that, given a set of programs or protocol specifications,
automatically constructs a choreography that describes their behavior. The key
to our extraction is identifying a set of paths in a graph that represents the
symbolic execution of the programs of interest. Our method improves on previous
work in several directions: we can now deal with programs that are equipped
with a state and internal computation capabilities; time complexity is
dramatically better; we capture programs that are correct but not necessarily
synchronizable, i.e., they work because they exploit asynchronous
communication
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