Set Of Spin Observables Research Articles

Entropic measurement uncertainty relations for all the infinite components of a spin vector

The information-theoretic formulation of quantum measurement uncertainty relations (MURs), based on the notion of relative entropy between measurement probabilities, is extended to the set of all the spin components for a generic spin s. For an approximate measurement of a spin vector, which gives approximate joint measurements of the spin components, we define the device information loss as the maximum loss of information per observable occurring in approximating the ideal incompatible components with the joint measurement at hand. By optimizing on the measuring device, we define the notion of minimum information loss. By using these notions, we show how to give a significant formulation of state independent MURs in the case of infinitely many target observables. The same construction works as well for finitely many observables, and we study the related MURs for two and three orthogonal spin components. The minimum information loss plays also the role of measure of incompatibility and in this respect it allows us to compare quantitatively the incompatibility of various sets of spin observables, with different number of involved components and different values of s.

Constancy of maximal nonlocal probability in Hardy's nonlocality test for bipartite quantum systems

We give the generic form of the entangled states of a system of two spin-1 (and two spin-) particles and the appropriate set of spin observables that together exhibit maximum nonlocality under Hardy's nonlocality test. We show the maximum nonlocality to be 0.090 17 just as in the case of two spin- particles. We conjecture that this result holds good for a system of two spin-j particles for all values of j.

Quasi-Bound3He −ηState and Spin-Observables of the Reactionpd→3Heη

A formalism for total set of spin observables of the reaction pd → 3 Heη derived in a model independent way is presented and a possibility to perform a complete polarization experiment is investigated. Separation of s- and p-wave amplitudes of this reaction in the threshold region allows one to determine a position of the quasibound pole in the 3 He − η system. It is shown that in order to get such a separation one should measure spin-transfer coefficients in addition to analyzing powers and spin-correlations. Specific observables, given by products of one s- and one p-wave amplitudes, are found. Measurement of these observables will provide new independent information on the 3 He − η pole position and this allows one to determine whether the 3 He − η state is quasi-bound or anti-bound.

Spin observables in elastic proton scattering from polarized 3He.

We have measured the absolute cross section {sigma}({theta}) and complete sets of spin observables {ital A}{sub 00{ital i}{ital j}} in {sup 3}He({ital p},{ital p}) elastic scattering at energies of 200 and 500 MeV. The observables depend on linear combinations of six complex scattering amplitudes for the {ital p}-{sup 3}He system and provide a severe test of current reaction models. The in-scattering plane observables ({ital A}{sub 00{ital m}{ital m}}, {ital A}{sub 00{ital l}{ital l}}, {ital A}{sub 00{ital l}{ital m}}, and {ital A}{sub 00{ital m}{ital l}}) are all in quantitative disagreement with fully microscopic nonrelativistic optical model calculations and nonrelativistic distorted wave Born approximation calculations.