Search results for "oscillation"
showing 10 items of 1257 documents
Non-markovian dynamics and spectrum of a moving atom strongly coupled to the field in a damped cavity
1993
Abstract We study the internal dynamics of an atom entering in its excited state in a damped cavity and strongly coupled to the field. We show that the time evolution of its dipole operator is described by a second order Langevin-like equation with time dependent coefficients. We use this equation to investigate the time dependence of the average population inversion and the spectrum of the emitted radiation. We discuss how Rabi oscillations are modified by the motion of the atom and how the spectrum changes from the vacuum Rabi doublet to a more complex structure having new lines, different frequency localizations and modified widths.
A calorimeter for the precise determination of the activity of the 144Ce-144Pr anti-neutrino source in the SOX experiment
2018
We describe the design and the performance of a high precision thermal calorimeter, whose purpose was the measurement of the total activity of the 144Ce-144Pr anti-neutrino source of the SOX (Short distance neutrino Oscillation with BoreXino) experiment. SOX aimed at the search for eV-scale sterile neutrinos by means of the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy and of a very powerful artificial anti-neutrino source located at 8.51 m from the detector center. In order to obtain the required sensitivity, the activity of the source (approximately 150 kCi) had to be known at 1% precision. In this work we report the design of the experimental apparatus and the res…
Influence of the AC voltage frequency on the oscillation trajectory and path length of particles inside a planar–type electric curtain
2015
Abstract Experimental investigations of the average path length of oscillating dust particles inside a planar –type electric curtain (PTEC) are presented as a function of the frequency of the AC voltage. The frequency was adjusted within the range of 10–300 Hz. The oscillation paths of feldspar particles of diameter 40–60 μm inside a small cloud were recorded photographically. The main purpose of this investigation was to study the changes in average path length as a function of the supply voltage frequency. These results can be used to improve the precipitation and separation processes for charged dust particles inside a PTEC.
A 3D Meshless Approach for Transient Electromagnetic PDEs
2012
A full wave three dimensional meshless approach for electromagnetic transient simulations is presented. The smoothed particle hydrodynamic (SPH) method is used by considering the particles as interpolation points, arbitrarily placed in the computational domain. Maxwell’s equations in time domain with the assigned boundary and initial conditions are numerically solved by means of the proposed method. The computational tool is assessed and, for the first time, a 3D test problem is simulated in order to validate the proposed approach.
Neutrino flux prediction at MiniBooNE
2009
The booster neutrino experiment (MiniBooNE) searches for nu(mu)->nu(e) oscillations using the O(1 GeV) neutrino beam produced by the booster synchrotron at the Fermi National Accelerator Laboratory). The booster delivers protons with 8 GeV kinetic energy (8.89 GeV/c momentum) to a beryllium target, producing neutrinos from the decay of secondary particles in the beam line. We describe the Monte Carlo simulation methods used to estimate the flux of neutrinos from the beam line incident on the MiniBooNE detector for both polarities of the focusing horn. The simulation uses the Geant4 framework for propagating particles, accounting for electromagnetic processes and hadronic interactions in the…
Dynamic measurement of the elastic constant of an helicoidal spring by a smartphone
2021
Abstract We describe an educational activity that can be done by using smartphones to collect data in physics experiments aimed to measure the oscillating period of a spring-mass system and the elastic constant of the helicoidal spring by the dynamic method. Results for the oscillating period and for the elastic constant of the spring agree very well with measurements obtained by different methods. We also discuss the error analysis that can be done in an introductory physics laboratory at undergraduate level.
Expected performance of an ideal liquid argon neutrino detector with enhanced sensitivity to scintillation light
2014
Scintillation light is used in liquid argon (LAr) neutrino detectors to provide a trigger signal, veto information against cosmic rays, and absolute event timing. In this work, we discuss additional opportunities offered by detectors with enhanced sensitivity to scintillation light, that is with light collection efficiencies of about $10^{-3}$. We focus on two key detector performance indicators for neutrino oscillation physics: calorimetric neutrino energy reconstruction and neutrino/antineutrino separation in a non-magnetized detector. Our results are based on detailed simulations, with neutrino interactions modelled according to the GENIE event generator, while the charge and light respo…
The effect of cooling on time dependent behaviour of accretion flows around black holes
2004
We present the results of several numerical simulations of two dimensional axi-symmetric accretion flows around black holes using Smoothed Particle Hydrodynamics (SPH) in the presence of cooling effects. We consider both stellar black holes and super-massive black holes. We observe that due to {\it both radial and vertical oscillation} of shock waves in the accretion flow, the luminosity and average thermal energy content of the inner disk exhibit very interesting behaviour. When power density spectra are taken, quasi-periodic variabilities are seen at a few Hz and also occasionally at hundreds of Hz for stellar black holes. For super-massive black holes, the time scale of the oscillations …
Many-electron transport in Aharonov-Bohm interferometers: Time-dependent density-functional study
2012
We apply time-dependent density-functional theory to study many-electron transport in Aharonov-Bohm interferometers in a non-equilibrium situation. The conductance properties in the system are complex and depend on the enclosed magnetic flux in the interferometer, the number of interacting particles, and the mutual distance of the transport channels at the points of encounter. Generally, the electron-electron interactions do not suppress the visibility of Aharonov-Bohm oscillations if the interchannel distance -- determined by the positioning of the incompressible strips through the external magnetic field -- is optimized. However, the interactions also impose an interesting Aharonov-Bohm p…