The Origin of Non-chaotic Behavior in Identically Driven Systems

Recently it has been found that different physical systems driven by identical random noise behave exactly identical after a long time. It is also suggested that this is an outcome of finite precision in numerical experiments. Here we show that the origin of the non-chaotic behavior lies in the structural instability of the attractor of these systems which changes to a stable fixed point for strong enough drive. We see this to be true in all the systems studied in literature. Thus we affirm that in chaotic systems, synchronization can not occur only by addition of noise unless the noise destroys the strange attractor and the system is no longer chaotic.Comment: Figures could be obtained from [email protected]. The document below is a latex fil

Decoherence and entanglement degradation of a qubit-qutrit system in non-inertial frames

We study the effect of decoherence on a qubit-qutrit system under the influence of global, local and multilocal decoherence in non-inertial frames. We show that the entanglement sudden death can be avoided in non-inertial frames in the presence of amplitude damping, depolarizing and phase damping channels. However, degradation of entanglement is seen due to Unruh effect. It is shown that for lower level of decoherence, the depolarizing channel degrades the entanglement more heavily as compared to the amplitude damping and phase damping channels. However, for higher values of decoherence parameters, amplitude damping channel heavily degrades the entanglement of the hybrid system. Further more, no ESD is seen for any value of Rob's acceleration.Comment: 16 pages, 5 .eps figures, 1 table; Quantum Information Processing, published online, 5 July, 201

Simulation of Beam-Beam Effects and Tevatron Experience

Effects of electromagnetic interactions of colliding bunches in the Tevatron had a variety of manifestations in beam dynamics presenting vast opportunities for development of simulation models and tools. In this paper the computer code for simulation of weak-strong beam-beam effects in hadron colliders is described. We report the collider operational experience relevant to beam-beam interactions, explain major effects limiting the collider performance and compare results of observations and measurements with simulations.Comment: 23 pages, 17 figure

General analysis of self-dual solutions for the Einstein-Maxwell-Chern-Simons theory in (1+2) dimensions

The solutions of the Einstein-Maxwell-Chern-Simons theory are studied in (1+2) dimensions with the self-duality condition imposed on the Maxwell field. We give a closed form of the general solution which is determined by a single function having the physical meaning of the quasilocal angular momentum of the solution. This function completely determines the geometry of spacetime, also providing the direct computation of the conserved total mass and angular momentum of the configurations.Comment: 3 pages, REVTEX file, no figure

Long-term passive monitoring of solar UV radiation using radiochromic films

Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.The solar ultraviolet (UV) spectrum spans over a range of wavelengths, namely, UVA (315–400 nm), UVB (280–315 nm) and UVC (100–280 nm). The UV radiation reaching the surface of the Earth comprises of mainly UVA, a small amount of UVB and essentially no UVC. Solar UV can affect the human health. An under-dose will lead to diseases such as rickets and osteoporosis, while an over-dose will cause sunburns, skin cancers and cataracts. It is therefore pertinent to design methods for integrated long-term measurements of UV radiation (e.g., over 1 day). Recently, we succeeded in demonstrating the feasibility of using the Gafchromic EBT3 radiochromic film to quantify solar (UVA+UVB) exposures (in Jcm-2). These radiochromic-film products were originally developed for clinical dosimetric applications, with visible-light absorption changes upon X-ray irradiation, but were understood to be also responsive to UV radiations. We found that the usable range of UV exposures for the EBT3 film was from ~0.2 to ~30 Jcm-2. However, the maximum UV exposure could reach 50 Jcm-2 per day, so we need a wider usable range. The current work proposed modifications to the EBT3 film for longer-term measurements (e.g., over 1 day). We explored the UV responses of EBT3 films covered with 2 and 5 barriers, each barrier being a blue polypropylene film with a thickness of 0.3 mm. The usable range for the film with 2 barriers was from ~4 to ~40 Jcm-2, while the usable range for the film with 5 barriers was from ~30 to ~300 Jcm-2. Using both EBT3 films covered with 2 and 5 barriers will give a continuous usable range from 4 to 300 Jcm-2, which will be useful for a consecutive 6-d UV exposure measurement.cf201

Magnetoresistance of nondegenerate quantum electron channels formed on the surface of superfluid helium

Transport properties of quasi-one-dimensional nondegenerate quantum wires formed on the surface of liquid helium in the presence of a normal magnetic field are studied using the momentum balance equation method and the memory function formalism. The interaction with both kinds of scatterers available (vapor atoms and capillary wave quanta) is considered. We show that unlike classical wires, quantum nondegenerate channels exhibit strong magnetoresistance which increases with lowering the temperature.Comment: 8 pages, 7 figure

Nonlinear alternating current responses of graded materials

When a composite of nonlinear particles suspended in a host medium is subjected to a sinusoidal electric field, the electrical response in the composite will generally consist of alternating current (AC) fields at frequencies of higher-order harmonics. The situation becomes more interesting when the suspended particles are graded, with a spatial variation in the dielectric properties. The local electric field inside the graded particles can be calculated by the differential effective dipole approximation, which agrees very well with a first-principles approach. In this work, a nonlinear differential effective dipole approximation and a perturbation expansion method have been employed to investigate the effect of gradation on the nonlinear AC responses of these composites. The results showed that the fundamental and third-harmonic AC responses are sensitive to the dielectric-constant and/or nonlinear-susceptibility gradation profiles within the particles. Thus, by measuring the AC responses of the graded composites, it is possible to perform a real-time monitoring of the fabrication process of the gradation profiles within the graded particles.Comment: 18 pages, 4 figure

Entanglement in quantum computers described by the XXZ model with defects

We investigate how to generate maximally entangled states in systems characterized by the Hamiltonian of the XXZ model with defects. Some proposed quantum computers are described by such model. We show how the defects can be used to obtain EPR states and W states when one or two excitations are considered.Comment: 4 pages, 1 figur

On Hoyle-Narlikar-Wheeler mechanism of vibration energy powered magneto-dipole emission of neutron stars

We revisit the well-known Hoyle-Narlikar-Wheeler proposition that neutron star emerging in the magnetic-flux-conserving process of core-collapse supernova can convert the stored energy of Alfven vibrations into power of magneto-dipole radiation. We show that the necessary requirement for the energy conversion is the decay of internal magnetic field. In this case the loss of vibration energy of the star causes its vibration period, equal to period of pulsating emission, to lengthen at a rate proportional to the rate of magnetic field decay. These prediction of the model of vibration powered neutron star are discussed in juxtaposition with data on pulsating emission of magnetars whose radiative activity is generally associated with the decay of ultra strong magnetic field.Comment: Accepted for publication in Astrophysics & Space Scienc