Collective modes of type-II Weyl fermions with repulsive S-wave interaction

Three-dimensional type-II Weyl fermions possess overtilted conelike low-energy band dispersion. Unlike the closed ellipsoidal Fermi surface for type-I Weyl fermions, the Fermi surface is an open hyperboloid for type-II Weyl fermions. We evaluate the spin and density susceptibility of type-II Weyl fermions with repulsive S-wave interaction by means of Green’s functions. We obtain the particle-hole continuum along the tilted momentum direction and perpendicular to the tilted momentum direction, respectively. We find the zero sound mode in some repulsive interaction strengths by numerically solving the pole equations of the susceptibility within the random-phase approximation.

DERIVATION OF GENERALIZED THOMAS–BARGMANN–MICHEL–TELEGDI EQUATION FOR A PARTICLE WITH ELECTRIC DIPOLE MOMENT

General classical equation of spin motion is explicitly derived for a particle with magnetic and electric dipole moments in electromagnetic fields. Equation describing the spin motion relative to the momentum direction in storage rings is also obtained.

On the Singular Spectrum for Adiabatic Quasiperiodic Schrödinger Operators

We study spectral properties of a family of quasiperiodic Schrödinger operators on the real line in the adiabatic limit. We assume that the adiabatic iso-energetic curve has a real branch that is extended along the momentum direction. In the energy intervals where this happens, we obtain an asymptotic formula for the Lyapunov exponent and show that the spectrum is purely singular. This result was conjectured and proved in a particular case by Fedotov and Klopp (2005).

Pitch angle distribution of trapped energetic protons and helium isotope nuclei measured along the Resurs-01 No. 4 LEO satellite

The NINA detector on board the Resurs-01 No. 4 satellite (835 km, 98° inclination) is equipped with particle trackers based on silicon strip detectors. From the energy deposited in each of its silicon layers the mass, the momentum direction and energy of incident particles have been determined. The resolutions in mass and energy allow identification of H and He isotopes over the 10-50 MeV/n energy range. The angular resolution is about 2.5°. We present the direct measurements of proton and helium isotopes pitch angle distributions derived from Resurs-01 No.4/NINA observations and their variations as functions of (B, L) coordinates and energy. The measurements of trapped helium isotopes spectrum are also presented.

MASSLESS POINT PARTICLE WITH RIGIDITY

The model of relativistic particle with rigidity whose action A=−α∫ kds depends on the curvature of particle world trajectory k, is studied. The classical motion of the particle is shown to go along a helical line at superrelativistic velocity and its translational motion along the momentum direction—at the velocity of light (c). After quantization, the parameter a becomes integer, α=n, n>0. The quantum states of the system are massless states of helicities λ=n and λ=−n in which the evolution of gauge-invariant coordinate occurs at velocity c.

Inverse Compton Model of Gamma Ray Burst Spectra

We study gamma ray spectra produced by the inverse Compton upscattering of soft photons by relativistic electrons with a one dimensional momentum distribution, which is relevant to gamma ray burst if the source magnetic field is strong enough so that the synchrotron cooling time of transverse energy becomes much shorter than isotropization time via couloub or Compton collisions. We find that for high electron longitudinal temperatures the output power is strongly beamed in the momentum direction and the spectrum softens rapidly with increasing view angle from the momentum direction.