4,801 research outputs found
Numerical Modelling of Satellite Downlink Signals in a Finslerian-Perturbed Schwarzschild Spacetime
The work presented in this paper aims to contribute to the problem of testing
Finsler gravity theories by means of experiments and observations in the solar
system. Within a class of spherically symmetric static Finsler spacetimes we
consider a satellite with an on-board atomic clock, orbiting in the
Finslerian-perturbed gravitational field of the earth, whose time signal is
transmitted to a ground station, where its receive time and frequency are
measured with respect to another atomic clock. This configuration is realized
by the Galileo 5 and 6 satellites that have gone astray and are now on
non-circular orbits. Our method consists in the numerical integration of the
satellite's orbit, followed by an iterative procedure which provides the
numerically integrated signals, i.e., null geodesics, from the satellite to the
ground station. One of our main findings is that for orbits that are
considerably more eccentric than the Galileo 5 and 6 satellite orbits,
Finslerian effects can be separated from effects of perturbations of the
Schwarzschild spacetime within the Lorentzian geometry. We also discuss the
separation from effects of non-gravitational perturbations. This leads us to
the conclusion that observations of this kind combined with appropriate
numerical modelling can provide suitable tests of Finslerian modifications of
general relativity
Pattern recognition receptors in antifungal immunity
We thank the Wellcome Trust for funding this study.Peer reviewedPublisher PD
Measuring the Influence of Commodity Fund Trading on Soybean Price Discovery
The increase in commodity fund trading in the agricultural commodity futures markets has raised concern that this trading is degrading the price discovery performance of these markets. We used the Beveridge-Nelson Decomposition procedure to estimate the price discovery performance of the soybean futures and spot markets. We found that the price discovery performance of the soybean futures market has improved along with the increased commodity fund trading. Our results indicated that a portion of the price discovered in the soybean futures market is passed to the spot market.price discovery, commodity funds, cointegration, Beveridge-Nelson decomposition,
Crito
An LTS Workshop production, Plato\u27s conversation between Crito and Socrates probes responses to injustice. September, 1973.
The LTS Workshop is a special project of the John Carroll University Speech Department to encourage original and creative work in the theatre arts.https://collected.jcu.edu/plays/1062/thumbnail.jp
Measurement, Decoherence and Master Equations
In the first part of this thesis we concern ourselves with the problem of generating
pseudo-random circuits. These are a series of quantum gates chosen at
random, with the overall effect of implementing unitary operations with statistical
properties close to that of unitaries drawn at random with respect to the
Haar measure. Such circuits have a growing number of applications in quantum-information
processing, but all known algorithms require an external input of
classical randomness. We suggest a scheme to implement random circuits in a
weighted graph state. The input state is entangled with the weighted graph state
and a random circuit is implemented by performing local measurements in one
fixed basis only. A central idea in the analysis of this proposal is the average
bipartite entanglement generated by the repeated application of such circuits on
a large number of randomly chosen input product states. For a truly random circuit,
this should agree with that obtained by applying unitaries at random chosen
uniformly with respect to the Haar measure, values which can be calculated using
Pages Conjecture.
Part II is largely concerned with continuous variables (CV) systems. In particular,
we are interested in two descriptions. That of the class of Gaussian
states, and that of systems which can be adequately described through the use
of Markovian master equations. In the case of the latter, there are a number of
approaches one may take in order to derive a suitable equation, all of which require
some sort of approximation. These approximations can be made based on a
mixture of mathematical and physical grounds. However, unfortunately it is not
always clear how justified we are in making a particular choice, especially when
the test system we wish to describe includes its own internal interactions. In an
attempt to clarify this situation, we derive Markovian master equations for single
and interacting harmonic systems under different scenarios, including strong
internal coupling. By comparing the dynamics resulting from the corresponding
master equations with numerical simulations of the global systems evolution, we
assess the robustness of the assumptions usually made in the process of deriving
the reduced Markovian dynamics. This serves to clarify the general properties of
other open quantum system scenarios subject to treatment within a Markovian
approximation.
Finally, we extend the notions of the smooth min- and smooth max-entropies
to the continuous variable setting. Specifically, we have provided expressions to
evaluate these measures on arbitrary Gaussian states. These expressions rely
only on the symplectic eigenvalues of the corresponding covariance matrix. As
an application, we have considered their use as a suitable measure for detecting
thermalisation
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