18,678 research outputs found
Quantum-to-Classical Reduction of Quantum Master Equations
A general method of quantum-to-classical reduction of quantum dynamics is
described. The key aspect of our method is the similarity transformation of the
Liouvillian, which provides a new perspective. In conventional studies of
quantum energy transport, the rotating wave approximation has been frequently
regarded as an inappropriate approach because it causes the energy flow through
the system to vanish. Our formulation elucidates as to why this unphysical
result occurs and provides a solution for the problem. That is, not only the
density matrix but also the physical quantity is to be transformed. Moreover,
we show that quantum dynamics can be "exactly" replaced with classical
equations for the calculation of the transport efficiency.Comment: 13 pages, 2 figures; To appear in Prog. Theor. Exp. Phy
Endogenous Women's Autonomy and the Use of Reproductive Health Services: Empirical Evidence from Tajikistan
Though gender equity is widely considered to be a key to improving maternal health in developing countries, little empirical evidence has been presented to support this claim. This paper investigates whether or not and how female autonomy within the household affects women's use of reproductive health care in Tajikistan, where the situation of maternal health and gender equity is worse compared with neighbouring countries. Estimation is performed using bivariate probit models in which woman's use of health services and the level of female autonomy are recursively and simultaneously determined. Empirical results reveal that female autonomy measured by women's decision-making on child wellbeing and on economic affairs within the household increases the probability of receiving both antenatal and delivery care. Policymakers need to address women's empowerment in the household in addition to implementing direct health interventions towards improvement of maternal health.Female autonomy; Antenatal care; Delivery care; Reproductive health services; Tajikistan; Bivariate probit model
Model-independent determination of the compositeness of near-threshold quasibound states
We study the compositeness of near-threshold states to clarify the internal
structure of exotic hadron candidates. Within the framework of effective field
theory, we extend the Weinberg's weak-binding relation to include the nearby
CDD (Castillejo-Dalitz-Dyson) pole contribution with the help of the Pade
approximant. Finally, using the extended relation, we conclude that the CDD
pole contribution to the Lambda(1405) baryon in the Kbar N amplitude is
negligible.Comment: 5 pages, Proceedings of the 14th International Conference on
Meson-Nucleon Physics and the Structure of the Nucleon (MENU2016), July
25-30, 2016, Kyoto, Japa
Generalized weak-binding relations of compositeness in effective field theory
We study the compositeness of near-threshold states to investigate the
internal structure of exotic hadron candidates. Within the framework of
effective field theory, Weinberg's weak-binding relation is extended to more
general cases by easing several preconditions. First, by evaluating the
contribution from the decay channel, we obtain the generalized relation for
unstable quasibound states. Next, we generalize the relation to include the
nearby CDD (Castillejo-Dalitz-Dyson) pole contribution with the help of the
Pade approximant. The validity of the estimation with the generalized
weak-binding relations is examined by numerical calculations. The method to
systematically evaluate the error in the weak-binding relation is presented.
Finally, by applying the extended relation to Lambda(1405), f0(980) and
a0(980), we discuss their internal structure, in comparison with other
approaches.Comment: 46 pages, 12 figures, published versio
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