A one-parameter family of time dependent adiabatic indices is introduced for any given type of cosmological fluid of constant adiabatic index by a mathematical method belonging to the class of Darboux transformations. The procedure works for zero cosmological constant at the price of introducing a new constant parameter related to the time dependence of the adiabatic index. These fluids can be ...

A pair of recent Monte Carlo studies have reported evidence for and against a crossover from weakto strongdisorder criticality in the one-dimensional dirty boson problem. The Monte Carlo analyses rely on measurement of two observables: the effective Luttinger parameter Keff and the superfluid susceptibility χ . The former quantity was previously calculated analytically, using the strong-disorde...

We give two self-stabilizing algorithms for tree networks. The first computes an index, called guide pair, for each process P in O(h) rounds using O(δP log n) space per process, where h is the height of the tree, δP the degree of P , and n the number of processes in the network. Guide pairs have numerous applications, including ordered traversal or navigation in the tree. Our second algorithm, ...

A method is proposed for generating Bessel-like optical beams with arbitrary trajectories in free space. The method involves phase-modulating an optical wavefront so that conical bundles of rays are formed whose apexes write a continuous focal curve with pre-specified shape. These ray cones have circular bases on the input plane; thus their interference results in a Bessel-like transverse field...

In this paper we deal with integrals whose integrand has a rapidly oscillating zeroorder Bessel function of the first kind with real parameters in its argument which can become large. We introduce and tabulate model integrals which depend on a single parameter, which can determine the behavior of the original integral near the zeros of the argument of the Bessel function. As an example of the u...

This paper introduces and analyses a new algorithm for minimizing a convex function subject to a finite number of convex inequality constraints. It is assumed that the Lagrangian of the problem is strongly convex. The algorithm combines interior point methods for dealing with the inequality constraints and quasi-Newton techniques for accelerating the convergence. Feasibility of the iterates is ...

We find that the expansion of the universe is accelerating by analyzing the recent observation data of type Ia supernova(SN-Ia) .It indicates that the equation of state of the dark energy might be smaller than -1,which leads to the introduction of phantom models featured by its negative kinetic energy to account for the regime of equation of state parameter w < −1.In this paper the possibility ...

The Machian cosmological solution satisfying φ = O(ρ/ω) for the perfect-fluid with negative pressure is discussed. When the coefficient of the equation of state γ → −1/3, the gravitational constant approaches to constant. If we assume the present mass density ρ0 ∼ ρc (critical density), the parameter ǫ (γ = (ǫ− 1)/3) has a value of order 10−3 to support the present gravitational constant. The c...

This paper introduces and analyses a new algorithm for minimizing a convex function subject to a finite number of convex inequality constraints. It is assumed that the Lagrangian of the problem is strongly convex. The algorithm combines interior point methods for dealing with the inequality constraints and quasi-Newton techniques for accelerating the convergence. Feasibility of the iterates is ...