665 research outputs found
Non-Deterministic and Polynomial Time Problem Simulator
The Non-Deterministic and Polynomial Time Problem is a problem in combinatorial op-timization. Finding the quickest route for an object to travel through a list of cities and return to the starting city is the goal of this problem. Cities are listed, along with the dis-tance between each pair. It belongs to the category of computer problems known as NP-complete problems, for which no effective algorithmic solution has yet been discov-ered; at this time, there is no polynomial solution. In order to discover a near-optimal solution as quickly as possible, we attempted to tackle this extremely challenging prob-lem in this study utilizing a variety of heuristics, including Simulated Annealing and Ge-netic Algorithm. Using these sophisticated heuristic techniques, we at-tempt to depart from the local optimum
Active Brownian particles can mimic the pattern of the substrate
Active Brownian particles (ABPs) are termed out to be a successful way of
modeling the moving microorganism on the substrate. In recent studies, it is
shown that such organisms can sense the characteristics of the substrate.
Motivated by such work, we studied the dynamics and the steady state of ABP
moving on a substrate with space-dependent activity. On the substrate, some
regions are marked as high in activity, and other regions are such that
particles behave as passive Brownian particles. The system is studied in two
dimensions with step, sigmoid, Gaussian and cone shape distribution of activity
profile on the substrate. The whole interface of the activity profile is
symmetrically divided into two regions. This lead to the flow of particles from
the active region to the passive region. The final steady state of particle
density profile, polarisation and flux very much follows the structure of the
inhomogeneous activity and the density in high activity region is lower,
maximum at the interface and nearly constant with mean density in the passive
region. Further, the steady state density profile for various shapes and
designs on two-dimensional substrates. Hence the collection of ABPs on an
inhomogeneous substrate can mimic the inhomogeneity of the substrate
Ordering kinetics and steady states of XY-model with ferromagnetic and nematic interaction
The two-dimensions XY model, undergoes the Berezinskii Kosterlitz Thouless
(BKT) transition through unbinding of defect pairs of opposite signs. When the
interaction between spins is purely ferromagnetic, these defects have +-1
charge, whereas for pure nematic interaction between spins, they have charge
+-1/2. Two-dimensional XY-model in the presence of both ferromagnetic and
nematic interactions has been studied both theoretically and experimentally. In
this paper, we have studied dynamics of defects in the presence of both
ferromagnetic and nematic interactions on a square lattice. Varying the
strength of ferromagnetic and nematic interactions, we have observed behavior
of both integer and half integer defects and based on that we propose a phase
diagram which exhibit three distinct regions in the phase diagram below the
critical TBKT : polar phase, nematic phase and coexistence phase and a
disordered regions above it. Also, for pure polar and pure nematic case, our
results show that the exponent, for algebraic decay of number of defects with
time, decays linearly with temperature
- …