The noncommutative Kubo Formula: Applications to Transport in Disordered Topological Insulators with and without Magnetic Fields

The non-commutative theory of charge transport in mesoscopic aperiodic systems under magnetic fields, developed by Bellissard, Shulz-Baldes and collaborators in the 90's, is complemented with a practical numerical implementation. The scheme, which is developed within a $C^*$-algebraic framework, enable efficient evaluations of the non-commutative Kubo formula, with errors that vanish exponentially fast in the thermodynamic limit. Applications to a model of a 2-dimensional Quantum spin-Hall insulator are given. The conductivity tensor is mapped as function of Fermi level, disorder strength and temperature and the phase diagram in the plane of Fermi level and disorder strength is quantitatively derived from the transport simulations. Simulations at finite magnetic field strength are also presented.Comment: 10 figure

Possible Molecular Structure of the Newly Observed Y(4260)

We suggest that the newly observed resonance Y(4260) is a $\chi_{c}-\rho^0$ molecule, which is an isovector. In this picture, we can easily interpret why $Y(4260)\to \pi^+\pi^-J/\psi$ has a larger rate than $Y(4260)\to D\bar D$ which has not been observed, and we also predict existence of the other two components of the isotriplet and another two possible partner states which may be observed in the future experiments. A direct consequence of this structure is that for this molecular structure $Y(4260)\to \pi^+\pi^-J/\psi$ mode is more favorable than $Y(4260)\to K\bar KJ/\psi$ which may have a larger fraction if other proposed structures prevail.Comment: 5 pages, 2 figures. Some descriptions changed, more references added and typos corrected. Published version in PR

'To trust or not to trust': The impact of social media influencers on the reputation of corporate brands in crisis

Corporates often partner with social media influencers to bolster brand image after crises. Although existing evidence suggests that influencers have a largely positive effect on brands, yet there is paucity of research on the role of influencers in corporate crisis communications. Across two studies, we examine the impact of influencers on consumers’ perception of corporate brand in crisis. Drawing on persuasion knowledge theory, we identify pitfalls associated with influencers, such as inferences of manipulative intent, which negatively affect perceived trustworthiness and corporate reputation. The downside of engaging influencers in crisis communications can, however, be offset by influencer and the brand communicating values-driven motives of their partnership. Our findings imply that corporate brands should respond to crises through a bolstering strategy that promotes existing corporate goodwill, without influencer’s involvement. When leveraging on influencers’ support, however, brands should endeavor to inoculate manipulative inferences by communicating the values-driven motives behind the brand-influencer partnership