For linear combinations of quantum product averages in an arbitrary bipartite state, we derive new quantum Bell-form and CHSH-form inequalities with the right-hand sides expressed in terms of a bipartite state. This allows us to specify bipartite state properties sufficient for the validity of a classical CHSH-form inequality and the perfect correlation form of the original Bell inequality for any bounded quantum observables. We also introduce a new general condition on a bipartite state and quantum...

We show that an effect tribe of fuzzy sets $𝒯\subseteq {[0,1]}^X$ with the property that every $f\in 𝒯$ is ${ℬ}_0\left(𝒯\right)$-measurable, where ${ℬ}_0\left(𝒯\right)$ is the family of subsets of $X$ whose characteristic functions are central elements in $𝒯$, is a tribe. Moreover, a monotone $\sigma$-complete effect algebra with RDP with a Loomis-Sikorski representation $(X,𝒯,h)$, where the tribe $𝒯$ has the property that every $f\in 𝒯$ is ${ℬ}_0\left(𝒯\right)$-measurable, is a $\sigma$-MV-algebra.

This work is devoted to generalizing the Lebesgue decomposition and the Radon-Nikodym theorem to Gleason measures. For that purpose we introduce a notion of integral for operators with respect to a Gleason measure. Finally, we give an example showing that the Gleason theorem does not hold in non-separable Hilbert spaces.

In this paper we present an entropic description of quantum state obtained by interaction of one mode of quantized electromagnetic field with two two-level atoms inside a cavity, known as Tavis-Cumming model. Wehrl entropy has been calculated analytically and investigated as a function of the average value of the photon number operator. Husimi's Q function has been calculated and compared with the behaviour of the field entropy.