1,747 research outputs found
The Impact of Provider Choice on Workers' Compensation Costs and Outcomes
We study how provider choice in workers' compensation cases affects costs and outcomes. When employees choose the provider, costs are higher and return-to-work outcomes are worse, while physical recovery is the same although satisfaction with medical care is higher. The higher costs and worse return-to-work outcomes associated with employee choice arise largely when employees selected a new provider, rather than a provider with whom the worker had a pre-existing relationship. The findings lend some support to recent policy changes limiting workers' ability to choose a provider with whom they do not have a prior relationship.
Largest separable balls around the maximally mixed bipartite quantum state
For finite-dimensional bipartite quantum systems, we find the exact size of
the largest balls, in spectral norms for , of
separable (unentangled) matrices around the identity matrix. This implies a
simple and intutively meaningful geometrical sufficient condition for
separability of bipartite density matrices: that their purity \tr \rho^2 not
be too large. Theoretical and experimental applications of these results
include algorithmic problems such as computing whether or not a state is
entangled, and practical ones such as obtaining information about the existence
or nature of entanglement in states reached by NMR quantum computation
implementations or other experimental situations.Comment: 7 pages, LaTeX. Motivation and verbal description of results and
their implications expanded and improved; one more proof included. This
version differs from the PRA version by the omission of some erroneous
sentences outside the theorems and proofs, which will be noted in an erratum
notice in PRA (and by minor notational differences
A two-qubit Bell inequality for which POVM measurements are relevant
A bipartite Bell inequality is derived which is maximally violated on the
two-qubit state space if measurements describable by positive operator valued
measure (POVM) elements are allowed rather than restricting the possible
measurements to projective ones. In particular, the presented Bell inequality
requires POVMs in order to be maximally violated by a maximally entangled
two-qubit state. This answers a question raised by N. Gisin.Comment: 7 pages, 1 figur
Minimal optimal generalized quantum measurements
Optimal and finite positive operator valued measurements on a finite number
of identically prepared systems have been presented recently. With physical
realization in mind we propose here optimal and minimal generalized quantum
measurements for two-level systems.
We explicitly construct them up to N=7 and verify that they are minimal up to
N=5. We finally propose an expression which gives the size of the minimal
optimal measurements for arbitrary .Comment: 9 pages, Late
Minimum-error discrimination between three mirror-symmetric states
We present the optimal measurement strategy for distinguishing between three
quantum states exhibiting a mirror symmetry. The three states live in a
two-dimensional Hilbert space, and are thus overcomplete. By mirror symmetry we
understand that the transformation {|+> -> |+>, |-> -> -|->} leaves the set of
states invariant. The obtained measurement strategy minimizes the error
probability. An experimental realization for polarized photons, realizable with
current technology, is suggested.Comment: 4 pages, 2 figure
Gallium Oxide and Dioxide: Investigation of the Ground and Low-Lying Electronic States via Anion Photoelectron Spectroscopy
The GaO and GaO2 molecules were investigated using negative ion photoelectron spectroscopy. All the photoelectron spectra showed vibrationally resolved progressions. With the aid of electronic structure calculations and Franck-Condon spectral simulations, different molecular parameters and energetics of GaO-/GaO and GaO2-/GaO2 were determined, including the electron affinity of GaO, the vibrational frequency of GaO-, and the term energy, spin-orbit splitting, and vibrational frequency for the first excited A 2PiOmega state of GaO. The GaO2- photoelectron spectra comprised three bands assigned as transitions from the linear X 1Sigma(g)+ ground state of GaO2- to three linear neutral states: the A 2Pi(g), B 2Pi(u), and C 2Sigma(u) + states. The symmetric stretch frequencies of the anion and three neutral states as well as the spin-orbit splitting of the neutral 2Pi states were determined. Electronic structure calculations found the neutral lowest energy linear structure to be only 63 meV higher than the neutral bent geometry
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Disentangling conical intersection and coherent molecular dynamics in methyl bromide with attosecond transient absorption spectroscopy
Attosecond probing of core-level electronic transitions provides a sensitive tool for studying valence molecular dynamics with atomic, state, and charge specificity. In this report, we employ attosecond transient absorption spectroscopy to follow the valence dynamics of strong-field initiated processes in methyl bromide. By probing the 3d core-to-valence transition, we resolve the strong field excitation and ensuing fragmentation of the neutral σ* excited states of methyl bromide. The results provide a clear signature of the non-adiabatic passage of the excited state wavepacket through a conical intersection. We additionally observe competing, strong field initiated processes arising in both the ground state and ionized molecule corresponding to vibrational and spin-orbit motion, respectively. The demonstrated ability to resolve simultaneous dynamics with few-femtosecond resolution presents a clear path forward in the implementation of attosecond XUV spectroscopy as a general tool for probing competing and complex molecular phenomena with unmatched temporal resolution
Minimum Wages and Poverty with Income-Sharing
Textbook analysis tells us that in a competitive labor market, the introduction of a minimum wage in terms of poverty rather than in terms of unemployment. This paper makes three contributions to the basic theory of the minimum wage. First, we analyze the effects of a higher minimum wage in terms of poverty rather than in terms of unemployment. Second, we extend the standard textbook model to allow for income-sharing between employed and unemployed persons in society. Third, we extend the basic model to deal with income sharing within families. We find that there are situations in which a higher minimum wage raises poverty, others where it reduces poverty, and yet others in which poverty is unchanged. We characterize precisely how the poverty effect depends on four parameters: the degree of poverty aversion, the elasticity of labor demand, the ratio of the minimum wage to the poverty line, and the extent of income-sharing. Thus, shifting the perspective from unemployment to poverty leads to a considerable enrichment of the theory of the minimum wage
Universal Algorithm for Optimal Estimation of Quantum States from Finite Ensembles
We present a universal algorithm for the optimal quantum state estimation of
an arbitrary finite dimensional system. The algorithm specifies a physically
realizable positive operator valued measurement (POVM) on a finite number of
identically prepared systems. We illustrate the general formalism by applying
it to different scenarios of the state estimation of N independent and
identically prepared two-level systems (qubits).Comment: 4 pages, RevTeX, minor modifications to the tex
Optimal generalized quantum measurements for arbitrary spin systems
Positive operator valued measurements on a finite number of N identically
prepared systems of arbitrary spin J are discussed. Pure states are
characterized in terms of Bloch-like vectors restricted by a SU(2 J+1)
covariant constraint. This representation allows for a simple description of
the equations to be fulfilled by optimal measurements. We explicitly find the
minimal POVM for the N=2 case, a rigorous bound for N=3 and set up the analysis
for arbitrary N.Comment: LateX, 12 page
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