We discuss the possibility of spin-triplet superconductivity in a two-dimensional Hubbard model on a triangular lattice within the third-order perturbation theory. When we vary the symmetry in the dispersion of the bare energy band from D2 to D6, spin-singlet superconductivity in the D2-symmetric system is suppressed and we obtain spin-triplet superconductivity in near the D6-symmetric system. ...

Spin fluctuations in nearly magnetic metals from ab-initio dynamical spin susceptibility calculations: application to P d and Cr 95 V 5 Abstract We describe our theoretical formalism and computational scheme for making ab-initio calculations of the dynamic paramagnetic spin susceptibilities of metals and alloys at finite temperatures. Its basis is Time-Dependent Density Functional Theory within...

We study theoretically competition between the charge ordering and the superconductivity in the two-dimensional organic conductor β-(meso-DMBEDT-TTF)2PF6. We analyze the extended Hubbard model on a weakly-dimerized lattice based on the random phase approximation and Eliashberg equations. We found the reentrant behavior of the checkerbord-type charge-ordered phase in the phase diagram, and the t...

The Gallavotti—Cohen fluctuation theorem suggests a general symmetry in the fluctuations of the entropy production, a basic concept in the theory of irreversible processes, based on results in the theory of strongly chaotic maps. We study this symmetry for some standard models of nonequilibrium steady states. We give a general strategy to derive a local fluctuation theorem exploiting the Gibbsi...

We consider stochastic rotational dynamics of a macrospin at a constant temperature, in presence of an external magnetic field. Starting from the appropriate Langevin equation which contains multiplicative noise, we calculate entropy production (EP) along stochastic trajectories, and obtain fluctuation theorems. The system remains inherently out of equilibrium due to a spin torque supporting az...

Using neutron diffraction, 170Yb Mössbauer and muon spin relaxation spectroscopies, we have examined the pyrochlore Yb2Ti2O7, where the Yb3+S' = 1/2 ground state has planar anisotropy. Below approximately 0.24 K, the temperature of the known specific-heat lambda transition, there is no long range magnetic order. We show that the transition corresponds to a first-order change in the fluctuation ...

In order to take account of the spatial fluctuation beyond the dynamical mean field theory (DMFT), the two-particle self-consistent theory is carefully reinvestigated and is proved to be unable to reproduce the correct low energy scale in the strong correlation limit. An improved theory is proposed which starts from DMFT and is combined with the spin-fluctuation theory (SFT) in a phenomenologic...

Using the decay of the out equilibrium spin-spin correlation function we compute the equilibrium Edward-Anderson order parameter in the three dimensional binary Ising spin glass in the spin glass phase. We have checked that the EdwardAnderson order parameter computed from out of equilibrium numerical simulations follows with good precision the critical law as determined in experiments and in nu...