Role of the spin anisotropy of the interchain interaction in weakly coupled antiferromagnetic Heisenberg chains

In quasi-one-dimensional(q1D) quantum antiferromagnets, the complicated interplay of intrachain and interchain exchange couplings may give rise to rich phenomena. Motivated by recent progress on field-induced phase transitions in the q1D antiferromagnetic(AFM) compound YbAlO3, we study the phase diagram of spin-1/2 Heisenberg chains with Ising anisotropic interchain couplings under a longitudinal magnetic field via large-scale quantum Monte Carlo simulations,and investigate the role of the spin anisotropy of the interchain coupling on the ground state of the system. We find that the Ising anisotropy of the interchain coupling can significantly enhance the longitudinal spin correlations and drive the system to an incommensurate AFM phase at intermediate magnetic fields, which is understood as a longitudinal spin density wave(LSDW). With increasing field, the ground state changes to a canted AFM order with transverse spin correlations. We further provide a global phase diagram showing how the competition between the LSDW and the canted AFM states is tuned by the Ising anisotropy of the interchain coupling.

On the Gamma-Ray Bursts Origin

Gamma-ray (GRBs) and X-ray Bursts are millisecond-10 and 1000 seconds-long events of unknown origin. Recent simulations of the merger of binary neutron star systems do not generate a magnetically dominated called funnel nor a relativistic outflow. New models for the detection the afterglow of GRB 121024A, measured 0.15 days after the burst, invoke anisotropy as required to produce the complex microphysics of realistic shocks in relativistic jets. On the other hand the non-thermal gamma-rays are supposed to be produced by a fireball of relativistic e?e+ pairs that are created by annihilation of neutrino-antineutrino pairs in the vicinity of the hot, merged object. It is also known that in a system of a large number of fermions with pairs, gravitational interaction occurs a spontaneous breaking of the vacuum spatial symmetry, accompanied by gravitational mass defect. If spherical symmetry is broken, as in the known case of the merger scenario where a rapidly rotating disk can be formed and material is pulled away from rotation axis by centrifugal forces, then a baryon-free funnel along the rotation axes may allow relativistic beam of γ’s and e?e+ to escape. It might lead to matter ejection with Lorentz factors of ~102 - 103 which are in the right range to enable copious gamma production during shock interaction with ambient interstellar gas. Here we show that the space rays generation mechanism on a method of direct transformation of intergalactic gamma-rays to the proton current on spin shock-waves ensure precise agreement between generated proton currents (spin shock waves theory) with the angular distribution data of Galactic gamma-rays as well as for the individual pulses of gamma-/X-ray bursts. There is a precise confirmation of the generated currents (theory) with the burst radiation data characterized by the standard deviation of ±1% in intensity in relative units within the sensitivity of the equipment. Thus, it was found that the spin angular momentum conservation law (equation of dynamics of spin shock waves) in the X-ray/gamma ranges is fulfilled exactly in real time. The next step involves setting the inverse problem of determining the wave function disturbance on the differential of measured smoothing pulses. In the asymptotic large times the problem is reduced to the solutions of the functional equation with shift of the argument. This will give additional information about the change speed of the wave, as well as on the interaction.