Wavelet analysis and HHG in nanorings Their applications in logic gates and memory mass devices

We study the application of one nanoring driven by a laser field in different states of polarization in logic circuits. In particular we show that assigning boolean values to different state of the incident laser field and to the emitted signals, we can create logic gates such as OR, XOR and AND. We also show the possibility to make logic circuits such as half-adder and full-adder using one and two nanoring respectively. Using two nanorings we made the Toffoli gate. Finally we use the final angular momentum acquired by the electron to store information and hence show the possibility to use an array of nanorings as a mass memory device

Laser Assisted Dirac Electron in a Magnetized Annulus

We study the behaviour of a charge bound on a graphene annulus under the assump- tion that the particle can be treated as a massless Dirac electron. The eigenstates and relative en- ergy are found in closed analytical form. Subsequently, we consider a large annulus with radius ρ ∈ [5000, 10,000]a0 in the presence of a static magnetic field orthogonal to its plane and again the eigenstates and eigenenergies of the Dirac electron are found in both analytical and numerical form. The possibility of designing filiform currents by controlling the orbital angular momentum and the magnetic field is shown. The currents can be of interest in optoelectronic devices that are controlled by electromagnetic radiation. Moreover, a small radial force acts upon the annulus with a stretching effect. A linearly polarized electromagnetic field propagating in the orthogonal direction is added; the time evolution of the operators show that the acceleration of the electron is proportional to the rate of change of the spin of the particle

Constraints on the spatial variation of Planck constant: Is Earth motion acting on atoms as a field?

Inspired by recently published researches, we present two protocols for setting an upper limit to the claimed variation of h ̄ upon the position. The protocols, both within today state of art, involve the use of two delayed laser pulses driving an atom. The distinct positions of the laboratory, due to the Earth motion, affects h ̄ and hence the atomic dynamics. The first protocol measures the difference in population of the atomic ground state while the second one the red-shift of the harmonics emitted by the atom in the two moments of the experiment. The protocols improve the reported upper limit of Δh ̄ /h ̄ . The theory shows that h ̄(r) induces a chaotic evolution to the atom. This form of Chaos is generated by a variation of a physical parameter and is one example of Parametric Chaos

Momentum partition between constituents of exotic atoms during laser induced tunneling ionization

The tunneling ionization of exotic atoms such as muonic hydrogen, muonium and positronium in a strong laser field of circular polarization is investigated taking into account the impact of the motion of the center of mass on the the tunneling ionization dynamics. The momentum partition between the ionization products is deduced. The effect of the center of mass motion for the momentum distribution of the ionization components is determined. The effect scales with the ratio of the electron (muon) to the atomic core masses and is nonnegligible for exotic atoms, while being insignificant for common atoms. It is shown that the electron (muon) momentum shift during the under-the-barrier motion due to the magnetically induced Lorentz force has a significant impact on the momentum distribution of the atomic core and depends on the ratio of the electron to the atomic core masses

Piano Nazionale Lauree Scientifiche – Fisica: un percorso di laboratorio sulle tematiche energetiche

Il terremoto avvenuto in Giappone l'11 Marzo del 2011 ha riaperto il dibattito sull'energia quale elemento centrale di sviluppo della societa' moderna. L'esperienza didattica su tematiche energetiche, maturata a Palermo nell'ambito del Piano Nazionale Lauree Scientifiche - Fisica (PLS-Fisica), si inserisce in questo contesto. Noi proponiamo un percorso formativo di laboratorio riguardante tematiche energetiche, al fine di stimolare i docenti di fisica a portare in aula e in laboratorio questi argomenti e contribuire cosi' ad aumentare la consapevolezza che gli studenti hanno riguardo alle fonti energetiche rinnovabili, ma anche riguardo alle fonti basate sui combustibili fossili e nucleari. Le esperienze proposte sono state scelte sia per la loro valenza concettuale sia per la loro realizzazione semplice, volti a studiare quantitativamente i processi di trasformazione dell'energia. *** The catastrophic earthquake and subsequent tsunami occurred in Japan in March 11, 2011 gave rise again to a world-wide debate on the energy sources as a central issue for the development of the human society. The experience on the energy topics, gained at the University of Palermo in the framework of the Piano Nazionale Luree Scientifiche - Fisica (PLS-Fisica) (National Plan for Scientific Degrees - Physics), can be naturally integrated in this larger context. We propose a laboratory pedagogical path to stimulate physics teachers to introduce the energy concept by discussing the issue of renewable, fossil and nuclear energy sources. The activity can raise the awareness of students on this very important issue. We propose easy, but conceptually well-based, laboratory experiences with the purpose to study the energy transformation processes from a quantitative point of view

A didactic experiment and model of a flat-plate solar collector

We report on an experiment performed with a home-made flat-plate solar collector, carried out together with high-school students. To explain the experimental results, we propose a model that describes the heating process of the solar collector. The model accounts quantitatively for the experimental data. We suggest that solar-energy topics should be included in school programmes to give students the opportunity to gain experience with solar energy and increase their awareness of the benefits that can be obtained from this remarkable and renewable energy source

Measurement of the Convective Heat-Transfer Coefficient

We propose an experiment for investigating how objects cool down toward the thermal equilibrium with their surroundings. We describe the time dependence of the temperature difference of the cooling objects and the environment with an exponential decay function. By measuring the thermal constant τ, we determine the convective heat-transfer coefficient, which is a characteristic constant of the convection system

An experiment on wind energy

We discuss an experiment on wind energy performed with home-made apparatus. The experiment reproduces a laboratory windmill, which can pump water from a lower level to a higher one. By measuring the gain of the gravitational potential energy of the pumped water, one can determine the power extracted from the wind. The activity was carried out with high-school students, in the framework of the Italian National Plan for Scientific Degrees-Physics. The proposed experiment allows teachers to discuss renewable energy sources with students whose knowledge of physics is limited to mechanics. It gives students the possibility to gain experience with energy and to increase their awareness of this renewable energy source

Pulse-duration dependence of the isotopic effect in simple molecular ions driven by strong laser fields

In this paper we discuss isotopic effects in simple molecular ions subjected to strong laser fields. We show that the intensity of the emitted spectra strongly depends upon both the nuclear mass of the molecular ions and the laser pulse duration. In particular, for short pulse duration [up to 8 optical cycles (o.c.)], we confirm the trend described in the most studied case in which the high-order harmonic generation is more efficient for heavier isotopes; in contrast, an interesting physical phenomenon is predicted for pulses longer than 16 o.c. characterized by an inverse effect in which lighter molecular species are responsible for higher-order harmonic emission