1,336 research outputs found
A New Relation between post and pre-optimal measurement states
When an optimal measurement is made on a qubit and what we call an Unbiased
Mixture of the resulting ensembles is taken, then the post measurement density
matrix is shown to be related to the pre-measurement density matrix through a
simple and linear relation. It is shown that such a relation holds only when
the measurements are made in Mutually Unbiased Bases- MUB. For Spin-1/2 it is
also shown explicitly that non-orthogonal measurements fail to give such a
linear relation no matter how the ensembles are mixed. The result has been
proved to be true for arbitrary quantum mechanical systems of finite
dimensional Hilbert spaces. The result is true irrespective of whether the
initial state is pure or mixed.Comment: 4 pages in REVTE
A Stepwise Planned Approach to the Solution of Hilbert's Sixth Problem. III : Measurements and von Neumann Projection/Collapse Rule
Supmech, the universal mechanics developed in the previous two papers,
accommodates both quantum and classical mechanics as subdisciplines (a brief
outline is included for completeness); this feature facilitates, in a supmech
based treatment of quantum measurements, an unambiguous treatment of the
apparatus as a quantum system approximated well by a classical one. Taking
explicitly into consideration the fact that observations on the apparatus are
made when it has `settled down after the measurement interaction' and are
restricted to macroscopically distinguishable pointer readings, the unwanted
superpositions of (system + apparatus) states are shown to be suppressed; this
provides a genuinely physics based justification for the (traditionally
\emph{postulated}) von Neumann projection/collapse rule. The decoherence
mechanism brought into play by the stated observational constraints is free
from the objections against the traditional decoherence program.Comment: 29 pages; one section and two references added; results unchange
Testing the Rule with Exclusive Semi-Leptonic Kaon Decays
We consider the possibility of violations of the selection rule at an appreciable level in {\it exclusive} semi-leptonic decays of
Kaons. At -Factories, intense Kaon beams will be available and will probe
among others, the semi-leptonic decays and in addition
to and could provide novel testing grounds for the
rule. In particular, the branching ratio of is non-negligible
and could be used to probe new phenomena associated with the violation of this
selection rule. Furthermore, we modify certain di-lepton event rate ratios and
asymmetries and time asymmetries that have been constructed by Dass and Sarma
for di-lepton events from Beon decays to test the at the
, to the Kaon system at the . We find that the large
width of the relative to that of plays an important role in
enhancing some of the time asymmetries.Comment: 10 pages, Plain Latex, To be run twice
The effects of aqueous ginger extract on aluminium chloride (AlCl3) induced alteration in lipid profile of male wister rats
Background: This study was aimed at investigating the effects of aluminium chloride (AlCl3) in altering the serum lipid profiles and ways to reduce its effect using two different doses of ginger extract 500mg/kg and 1000mg/kg body weight in male wister rats.Methods: The rats were randomly divided into 4 groups consisting of 5 animals in each group. Groups II, III and IV received AlCl3 100mg/kg bodyweight single dose, Groups III and IV receiving an additional daily oral single dose of ginger plant extract through a stomach tube. All animals were fasted before the treatment. All rats were weighed before the start of the experiment and at the end of the experiment. The blood was collected firstly at the beginning of the experiment, then on the 45th day. The collected blood was left to clot then centrifuged at 3500 rpm for 5 min. The serum was separated and stored at - 80°C for later analyses.Results: This study shows that a single dose of 100mg/kg aluminium chloride causes a rise in total body weight, TC (total cholesterol), LDL (low density lipoproteins) and TG (triglycerides) levels in the rat, and aqueous Zingiber officinal (ginger) extract reduces this rise in TC, LDL and TG levels in the rats.Conclusions: Ginger was effective in lowering serum cholesterol levels levels in the ginger treated rats to almost normal value. These results indicate that treatment with aqueous extract of ginger may be effective in lowering lipid levels in AlCl3 induced hyperlipidemia in rats
Implementing standardised rhodes index to measure the efficacy of ginger extract (Zingiber officinale) in pregnancy induced nausea and vomiting
Background: Although nausea and vomiting are natural signs of pregnancy affecting about half the pregnant women during their first trimester of pregnancy, it is unpleasant and difficult symptom to deal with. Considering the fact that medication during pregnancy is not advised, we decided to study the efficacy of a natural product to control nausea and vomiting during early pregnancy. Our study was directed to estimate the efficacy of ginger extract (Zingiber officinale) in pregnancy induced nausea and vomiting.Methods: A total of 30 women with pregnancy of 4-16 weeks, suffering from nausea and vomiting were included in this study (n=30). Subjects were given ginger extract 250mg, to be taken 3 times a day half an hour before food for 1 week. Severity of vomiting was assessed by Rhodes Index of Nausea and Vomiting by the patients. Baseline scores were compared with the score at the end of 7 day. The findings were analysed statistically.Results: Effect with the ginger extract in pregnancy induced nausea and vomiting was assessed at the end of treatment (day 7) and compared with the baseline values. Four patients reported symptoms of heartburn. Otherwise, there were no other reports of any adverse effects. The results showed significance (p <0.005).Conclusions: Ginger extract (Zingiber officinale) helps in reducing severity and frequency of pregnancy induced nausea and vomiting. Therefore, we conclude that ginger extract can be used for mild to moderate nausea and vomiting induced by pregnancy during first trimester
A radical approach to promote multiferroic coupling in double perovskites
Double perovskites provide a unique opportunity to induce and control
multiferroic behaviors in oxide systems. The appealing possibility to design
materials with a strong coupling between the magnetization and the polarization
fields may be achieved in this family since these magnetic insulators can
present structural self-ordering in the appropriate growth conditions. We have
studied the functional properties of La2CoMnO6 and Bi2CoMnO6 epitaxial thin
films grown by pulsed laser deposition. Cation-ordered La2CoMnO6 films display
a magnetic Curie temperature of 250 K while cation-disordered Bi2CoMnO6 films
present ferromagnetism up to ~ 800 K. Such high transition temperature for
magnetic ordering can be further tuned by varying the strain in the films
indicating an important contribution from the structural characteristics of the
materials. Our approach might be generalized for other oxide systems. At this
end, our results are compared with other multiferroic systems. The roles of
various cations, their arrangements and structural effects are further
discussed.Comment: 12 pages, 5 fig
String-like behaviour of 4d SU(3) Yang-Mills flux tubes
We present here results on the fine structure of the static q\bar q potential
in d=4 SU(3) Yang-Mills theory. The potential is obtained from Polyakov loop
correlators having separations between 0.3 and 1.2 fermi. Measurements were
carried out on lattices of spatial extents of about 4 and 5.4 fermi. The
temporal extent was 5.4 fermi in both cases. The results are analyzed in terms
of the force between a q\bar q pair as well as in terms of a scaled second
derivative of the potential. The data is accurate enough to distinguish between
different effective string models and it seems to favour the expression for
ground state energy of a Nambu-Goto string.Comment: 9 pages in LaTeX with 2 figures and 2 tables in JHEP style. Replaced
to match with shortened published versio
The confining string beyond the free-string approximation in the gauge dual of percolation
We simulate five different systems belonging to the universality class of the
gauge dual of three-dimensional random percolation to study the underlying
effective string theory at finite temperature. All the data for the finite
temperature string tension, when expressed by means of adimensional variables,
are nicely described by a unique scaling function. We calculate the first few
terms of the string tension up to order and compare to different
theoretical predictions. We obtain unambiguous evidence that the coefficients
of and terms coincide with those of the Nambu-Goto string, as
expected, while the term strongly differs and is characteristic of the
universality class of this specific gauge theory.Comment: 13 pages, 3 figure
Effects of Possible Transitions in Neutral Meson Decays}
We explore the possibility that the existing data on like-sign dileptons at
the resonance consist of events arising from mixing and also from transitions. The
consequences of these nonstandard transitions for certain time-asymmetries
which are likely to be measured at the factories are studied.Comment: {\LARGE \bf 10 pages, no figures, process using latex, TIFR/TH/93-5
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