Pure electric Penrose and super-Penrose processes in the flat spacetime

Let a particle move in the flat spacetime under the action of the electric potential. If it decays to two fragments, the energy of debris can be larger than the original energy and, moreover, the efficiency of such a process can be unbounded. This effect can be considered as a limit of the Denardo–Ruffini process near the Reissner–Nordström black hole when the gravitational constant and/or black hole mass tend to zero. There are scenarios in which the energy of debris at infinity is much larger than the initial one. Comparison with other close but distinct effects is discussed.

Absolute negative mobility in the anomalous diffusion

Transport of an inertial Brownian particle driven by the multiplicative Lévy noise was investigated here. Numerical results indicate that: (i) The Lévy noise is able to induce absolute negative mobility (ANM) in the system, while disappearing in the deterministic case; (ii) the ANM can occur in the region of superdiffusion while disappearing in the region of normal diffusion, and the appropriate stable index of the Lévy noise makes the particle move along the opposite direction of the bias force to the maximum degree; (iii) symmetry breaking of the Lévy noise also causes the ANM effect. In addition, the intrinsic physical mechanism and conditions for the ANM to occur are discussed in detail. Our results have the implication that the Lévy noise plays an important role in the occurrence of the ANM phenomenon.

The Pressure Distribution around Particles in Fluid in Confined Wedge Space

The particle motion in fluid has attracted much attention in material engineering concerned the particle effects such as the debris in lubrication and the particles deposition in material processing. By taking the hydrodynamic effect into account, the pressure distribution around particles in fluid in confined wedge space is analyzed. The influences of the particle position, particle shape and its velocity on the pressure distribution are also investigated. Results show that in confined wedge space, the fluid pressure around the particle in the side near the upper slope plate is larger than that in another side, which may make the particle move downwards. And the pressure discrepancy between both sides of the particle increases with the particle shape, the particle velocity and the particle coordinates in both directions of x and z. These special phenomenons may be used in structured surfaces fabrication based on particle deposition by constructing special fluid field.

On the Expected Number of Visits of a Particle before Absorption in a Correlated Random Walk

Let a particle move along a straight line a unit distance during every interval of time τ. During the first interval τ it moves to the right with probability ρ1 and to the left with probability ρ2 = 1 - ρ1. Thereafter at the end of each interval τ, the particle with probability p continues its motion in the same direction as in the previous step and with probability q = l - p reverses it.