11 research outputs found
Entanglement Sharing in the Two-Atom Tavis-Cummings Model
Individual members of an ensemble of identical systems coupled to a common
probe can become entangled with one another, even when they do not interact
directly. We investigate how this type of multipartite entanglement is
generated in the context of a system consisting of two two-level atoms
resonantly coupled to a single mode of the electromagnetic field. The dynamical
evolution is studied in terms of the entanglements in the different bipartite
partitions of the system, as quantified by the I-tangle. We also propose a
generalization of the so-called residual tangle that quantifies the inherent
three-body correlations in our tripartite system. This enables us to completely
characterize the phenomenon of entanglement sharing in the case of the two-atom
Tavis-Cummings model, a system of both theoretical and experimental interest.Comment: 11 pages, 4 figures, submitted to PRA, v3 contains corrections to
small error
A New Strategy of Quantum-State Estimation for Achieving the Cramer-Rao Bound
We experimentally analyzed the statistical errors in quantum-state estimation
and examined whether their lower bound, which is derived from the Cramer-Rao
inequality, can be truly attained or not. In the experiments, polarization
states of bi-photons produced via spontaneous parametric down-conversion were
estimated employing tomographic measurements. Using a new estimation strategy
based on Akaike's information criterion, we demonstrated that the errors
actually approach the lower bound, while they fail to approach it using the
conventional estimation strategy.Comment: 4 pages, 2 figure
Local asymptotic normality for finite dimensional quantum systems
We extend our previous results on local asymptotic normality (LAN) for
qubits, to quantum systems of arbitrary finite dimension . LAN means that
the quantum statistical model consisting of identically prepared
-dimensional systems with joint state converges as
to a statistical model consisting of classical and quantum
Gaussian variables with fixed and known covariance matrix, and unknown means
related to the parameters of the density matrix . Remarkably, the limit
model splits into a product of a classical Gaussian with mean equal to the
diagonal parameters, and independent harmonic oscillators prepared in thermal
equilibrium states displaced by an amount proportional to the off-diagonal
elements.
As in the qubits case, LAN is the main ingredient in devising a general two
step adaptive procedure for the optimal estimation of completely unknown
-dimensional quantum states. This measurement strategy shall be described in
a forthcoming paper.Comment: 64 page
Composition and Potential Health Benefits of Pomegranate: A Review
Background: Pomegranate (Punica granatum L.) fruits are widely consumed and used as preventive and therapeutic agents since ancient times. Pomegranate is a rich source of a variety of phytochemicals, which are responsible for its strong antioxidative and anti-inflammatory potential. Objective: The aim of this review is to provide an up-to-date overview of the current knowledge of chemical structure and potential health benefits of pomegranate. Methods: A comprehensive search of available literature. Results: The review of the literature confirms that juice and extracts obtained from different parts of this plant, including fruit peel, seeds, and leaves exert health benefits in both in vitro and in vivo studies. The antidiabetic, antihypertensive, antimicrobial and anti-tumour effects of pomegranate fruit are of particular scientific and clinical interest. Conclusion: Further investigations are required to clarify the mechanism of action of the bioactive ingredients and to reveal full potential of pomegranate as both preventive and therapeutic agent