Negative Shannon Information Hides Networks

Shannon information was defined for characterizing the uncertainty information of classical probabilistic distributions. As an uncertainty measure it is generally believed to be positive. This holds for any information quantity from two random variables because of the polymatroidal axioms. However, it is unknown why there is negative information for more than two random variables on finite dimensional spaces. We first show the negative tripartite Shannon mutual information implies specific Bayesian network representations of its joint distribution. We then show that the negative Shannon information is obtained from general tripartite Bayesian networks with quantum realizations. This provides a device-independent witness of negative Shannon information. We finally extend the result for general networks. The present result shows new insights in the network compatibility from non-Shannon information inequalities.Comment: 6+11 pages, 7 figure

Genuine Multipartite Nonlocality for All Isolated Many-body Systems

Understanding the nonlocality of many-body systems offers valuable insights into the behaviors of these systems and may have practical applications in quantum simulation and quantum computing. Gisin's Theorem establishes the equivalence of three types of quantum correlations: Bell nonlocality, EPR-steering, and entanglement for isolated systems. No similar result exists with regard to genuine multipartite correlations. We answer this open problem by proposing a new network-inflation method. Our approach demonstrates that genuine multipartite nonlocality, genuine multipartite EPR-steering, and genuine multipartite entanglement are equivalent for any isolated many-body system. This is achieved through an extended Bell test on an inflated network consisting of multiple copies of the given sources. The device-independent method is also robust against noise.Comment: Main results, 5 pages, 2 figures, comments welcom

Genuinely Multipartite Entanglement vias Quantum Communication

Multipartite entanglement is of important resources for quantum communication and quantum computation. Our goal in this paper is to characterize general multipartite entanglement according to quantum biseparable channels. We firstly prove a no-go result for fully genuinely multipartite entanglement on finite-dimensional spaces with the biseparable channel model. We further propose a semi-device-independent entanglement model depending on the connection ability in quantum circuit. This implies a complete hierarchy of genuinely multipartite entanglements. It also provides a completely different multipartite nonlocality from quantum network entanglements. These results show new insights for multipartite entanglement, quantum network, and measurement-based quantum computation.Comment: 4+5 pages, 7 figures. Comments welecome

Revisit to Non-decoupling MSSM

Dipole operator $\bar{s}\sigma_{\mu\nu}F^{\mu\nu}b$ requires the helicity flip in the involving quark states thus the breaking of chiral $U(3)_{Q}\times U(3)_{d}$. On the other hand, the $b$-quark mass generation is also a consequence of chiral $U(3)_{Q}\times U(3)_{d}$ symmetry breaking. Therefore, in many models, there might be strong correlation between the $b\to s\gamma$ and $b$ quark Yukawa coupling. We use non-decoupling MSSM model to illustrate this feature. The light Higgs boson may evade the direct search experiments at LEPII or Tevatron while the 125 GeV Higgs-like boson is identified as the heavy Higgs boson in the spectrum. A light charged Higgs is close to the heavy Higgs boson which is of 125 GeV and its contribution to $b\to s \gamma$ requires large supersymmetric correction with large PQ and $R$ symmetry breaking. The large supersymmetric contribution at the same time significantly modifies the $b$ quark Yukawa co upling. With combined flavor constraints $B\to X_{s}\gamma$ and $B_{s}\to \mu^{+}\mu^{-}$ and direct constraints on Higgs properties, we find best fit scenarios with light stop of $\cal O$(500 GeV), negative $A_{t}$ around -750 GeV and large $\mu$-term of 2-3 TeV. In addition, reduction in $b\bar{b}$ partial width may also result in large enhancement of $\tau\tau$ decay branching fraction. Large parameter region in the survival space under all bounds may be further constrained by $H\to \tau\tau$ if no excess of $\tau\tau$ is confirmed at LHC. We only identify a small parameter region with significant $H\to hh$ decay that is consistent with all bounds and reduced $\tau\tau$ decay branching fraction.Comment: 18pages, 6 figure