16,097 research outputs found
Optimal conclusive discrimination of two states can be achieved locally
This paper constructs a LOCC protocol that achieves the global optimality in
conclusive discrimination of any two states with arbitrary a priori
probability. This can be interpreted that there is no ``non-locality'' in the
conclusive discrimination of two multipartite states.Comment: 9 pages, RevTeX, no figure. Comments, criticisms and suggestions are
welcom
A Joint Analysis of the KOSPI 200 Option and ODAX Option Markets Dynamics
As a function of strike and time to maturity the implied volatility estimation is a challenging task in nancial econometrics. Dynamic Semiparametric Factor Models (DSFM) are a model class that allows for the estimation of the implied volatility surface (IVS) in a dynamic context, employing semiparametric factor functions and time-varying loadings. Because nancial asset volatilities move over time, across assets and over markets, this paper analyses volatility interaction between German and Korean stock markets. As proxy for the volatility, factor loadings series derived from a DSFM application on option prices are employed. We examine volatility transmission between the markets under the vector autoregressive (VAR) model framework. Our results show that a shock in the volatility of one market may not translate directly into greater uncertainty in another market and it is unlikely that portfolio investors can benet from diversication among these markets due to cointegration.implied volatility surface, dynamic semiparametric factor model, VAR, cointegration
Systemic Weather Risk and Crop Insurance: The Case of China
The supply of affordable crop insurance is hampered by the existence of systemic weather risk which results in large risk premiums. In this article, we assess the systemic nature of weather risk for 17 agricultural production regions in China and explore the possibility of spatial diversification of this risk. We simulate the buffer load of hypothetical temperature-based insurance and investigate the relation between the size of the buffer load and the size of the trading area of the insurance. The analysis makes use of a hierarchical Archimedean copula approach (HAC) which allows flexible modeling of the joint loss distribution and reveals the dependence structure of losses in different insured regions. Our results show a significant decrease of the required risk loading when the insured area expands. Nevertheless, a considerable part of undiversifiable risk remains with the insurer. We find that the spatial diversification effect depends on the type of the weather index and the strike level of the insurance. Our findings are relevant for insurers and insurance regulators as they shed light on the viability of private crop insurance in China.crop insurance, systemic weather risk, hierarchical Archimedean copulas
Coupling the valley degree of freedom to antiferromagnetic order
Conventional electronics are based invariably on the intrinsic degrees of
freedom of an electron, namely, its charge and spin. The exploration of novel
electronic degrees of freedom has important implications in both basic quantum
physics and advanced information technology. Valley as a new electronic degree
of freedom has received considerable attention in recent years. In this paper,
we develop the theory of spin and valley physics of an antiferromagnetic
honeycomb lattice. We show that by coupling the valley degree of freedom to
antiferromagnetic order, there is an emergent electronic degree of freedom
characterized by the product of spin and valley indices, which leads to
spin-valley dependent optical selection rule and Berry curvature-induced
topological quantum transport. These properties will enable optical
polarization in the spin-valley space, and electrical detection/manipulation
through the induced spin, valley and charge fluxes. The domain walls of an
antiferromagnetic honeycomb lattice harbors valley-protected edge states that
support spin-dependent transport. Finally, we employ first principles
calculations to show that the proposed optoelectronic properties can be
realized in antiferromagnetic manganese chalcogenophosphates (MnPX_3, X = S,
Se) in monolayer form.Comment: 6 pages, 5 figure
Nanoparticle enhanced evaporation of liquids: A case study of silicone oil and water
Evaporation is a fundamental physical phenomenon, of which many challenging
questions remain unanswered. Enhanced evaporation of liquids in some occasions
is of enormous practical significance. Here we report the enhanced evaporation
of the nearly permanently stable silicone oil by dispersing with nanopariticles
including CaTiO3, anatase and rutile TiO2. The results can inspire the research
of atomistic mechanism for nanoparticle enhanced evaporation and exploration of
evaporation control techniques for treatment of oil pollution and restoration
of dirty water
Products of Generalized Stochastic Sarymsakov Matrices
In the set of stochastic, indecomposable, aperiodic (SIA) matrices, the class
of stochastic Sarymsakov matrices is the largest known subset (i) that is
closed under matrix multiplication and (ii) the infinitely long left-product of
the elements from a compact subset converges to a rank-one matrix. In this
paper, we show that a larger subset with these two properties can be derived by
generalizing the standard definition for Sarymsakov matrices. The
generalization is achieved either by introducing an "SIA index", whose value is
one for Sarymsakov matrices, and then looking at those stochastic matrices with
larger SIA indices, or by considering matrices that are not even SIA. Besides
constructing a larger set, we give sufficient conditions for generalized
Sarymsakov matrices so that their products converge to rank-one matrices. The
new insight gained through studying generalized Sarymsakov matrices and their
products has led to a new understanding of the existing results on consensus
algorithms and will be helpful for the design of network coordination
algorithms
- …