Comment on the Pion Pole Part of the Light-by-Light Contribution to the Muon g−2g-2

We comment on the recent calculations of the pion pole part of the light-by-light contribution to the muon anomalous magnetic moment and we point out where the analysis in our previous work was mistaken.Comment: 2 page

Nonequilibrium identities of granular vibrating beds

We derive the integral fluctuation theorem around a nonequilibrium stationary state for frictionless and soft core granular particles under an external vibration achieved by a balance between an external vibration and inelastic collisions. We also discuss the connection between the integral fluctuation theorem and the generalized Green-Kubo formula.Comment: 15 pages, no figures to be published in Comptes rendus - M\'ecanique as Proceedings of EuroMech2012 at Graz, Austri

Generalized Green-Kubo formula for a dissipative quantum system

A generalized Green-Kubo formula is derived for a quantum dissipative system of driven Brownian particle, in which the coupling between the system and the environment is linear. The structure is essentially the same as that for the generalized Green-Kubo formula for driven granular particles. It is demonstrated that the correction to the conventional Green-Kubo formula is zero for a free Brownian particle.Comment: 12 pages, no figures. Prog. Theor. Phys. Suppl. (to be published

Impact-Induced Hardening in Dense Frictional Suspensions

By employing the lattice Boltzmann method, we perform simulations of dense suspensions under impacts, which incorporate the contact between suspended particles as well as the free surface of the suspension. Our simulation for a free falling impactor on a dense suspension semi-quantitatively reproduces experimental results, where we observe rebounds of the impactor by the suspension containing frictional particles for high speed impact and high volume fraction shortly after the impact before subsequently sinking. We observe that the response depends on the radius of the impactor, which leads to fitting our simulation data to a phenomenological model based on the Hertzian contact theory. When the rebound takes place, percolated force chains are formed by the frictional contacts between suspended particles. Furthermore, persistent homology analysis is used to elucidate the significance of the topological structure of the force chains, where the total persistence of connected components correlates with the force supporting the impactor