A5046910578- Atomic and Subatomic Physics Research
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Quantum optics and atomic interactions
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Electrodynamics and Casimir Effect
- Advanced Chemical Physics Studies
- Particle Detector Development and Performance
- Geomagnetism and Paleomagnetism Studies
- Quantum, superfluid, helium dynamics
- Cosmology and Gravitation Theories
- Geophysics and Sensor Technology
- Magneto-Optical Properties and Applications
- Atomic and Molecular Physics
- Particle Accelerators and Free-Electron Lasers
- Mechanical and Optical Resonators
- Electron and X-Ray Spectroscopy Techniques
- Advanced Fiber Laser Technologies
- Scottish History and National Identity
- X-ray Spectroscopy and Fluorescence Analysis
- Magnetic Field Sensors Techniques
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Optical Polarization and Ellipsometry
- Spectroscopy and Laser Applications
Institute of Nanostructured Materials
2024
Institute of Structure of Matter
2024
University of Siena
1962-2022
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
1998-2022
Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
2007-2018
University of Trieste
2006-2017
Universidad de Granada
2014
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro
2001-2013
Istituto Nazionale di Fisica Nucleare, Sezione di Pavia
2011
University of Modena and Reggio Emilia
1984-2010
We report the experimental observation of a light polarization rotation in vacuum presence transverse magnetic field. Assuming that data distribution is Gaussian, average measured (3.9 +/- 0.5) x 10(-12) rad/pass, at 5 T with 44 000 passes through 1 m long magnet, lambda = 1064 nm. The relevance this result terms existence light, neutral, spin-zero particle discussed.
Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several efforts are striving to reach this goal, the sequence of results promises success in next few years. This measurement generally accompanied by search for hypothetical light particles that couple two photons. The PVLAS experiment employs sensitive polarimeter based on high finesse Fabry–Perot cavity. In paper we report latest experiment. data analysed taking into account...
In 2006 the PVLAS collaboration reported observation of an optical rotation generated in vacuum by a magnetic field. To further check against possible instrumental artifacts, several upgrades to apparatus have been made during past year. Two data taking runs, at wavelength 1064 nm, performed new configuration with field strengths 2.3 and 5 T. The T value was chosen order avoid stray fields. observations do not show presence signal down levels...
This paper describes the 25 year effort to measure vacuum magnetic birefringence and dichroism with PVLAS experiment. The experiment went through two main phases: first using a rotating superconducting magnet second permanent magnets. was not able reach predicted value from QED. Nonetheless has set current best limits on for field of Bext=2.5 T, namely, Δn(PVLAS)=(12±17)×10−23 |Δκ|(PVLAS)=(10±28)×10−23. uncertainty Δn(PVLAS) is about factor 7 above Δn(QED)=2.5×10−23 @ 2.5 T.
Several groups are carrying out experiments to observe and measure vacuum magnetic birefringence, predicted by quantum electrodynamics (QED). We have started running the new PVLAS apparatus installed in Ferrara, Italy, measured a noise floor value for unitary field birefringence of $\mathrm{\ensuremath{\Delta}}{n}_{u}^{(\mathrm{vac})}=(4\ifmmode\pm\else\textpm\fi{}20)\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}23}\text{ }\text{ }{\mathrm{T}}^{\ensuremath{-}2}$ (the error represents...
We describe the principle and status of PVLAS experiment which is presently running at INFN section Ferrara, Italy, to detect magnetic birefringence vacuum. This related QED vacuum structure can be detected by measuring ellipticity acquired a linearly polarized light beam propagating through strong field. Such an effect predicted Euler-Heisenberg Lagrangian. The method also sensitive other hypothetical physical effects such as axion-like particles in general any fermion/boson millicharged...
The PVLAS collaboration is presently assembling a new apparatus (at the INFN section of Ferrara, Italy) to detect vacuum magnetic birefringence (VMB). VMB related structure QED and predicted by Euler-Heisenberg-Weisskopf effective Lagrangian. It can be detected measuring ellipticity acquired linearly polarised light beam propagating through strong field. Using very same optical technique it also possible search for hypothetical low-mass particles interacting with two photons, such as...
Experimental bounds on induced vacuum magnetic birefringence can be used to improve present photon-photon scattering limits in the electronvolt energy range. Measurements with Polarizzazione del Vuoto con Laser apparatus [E. Zavattini et al., Phys. Rev. D 77, 032006 (2008)] at both $\ensuremath{\lambda}=1064$ and 532 nm lead parameter ${A}_{e}$, describing nonlinear effects QED, of ${A}_{e}^{(1064)}<6.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}21}\text{ }\text{...
New measurements to test the neutrality of matter by acoustic means are reported. The apparatus is based on a spherical capacitor filled with gaseous SF$_6$ excited an oscillating electric field. has been calibrated measuring polarizability. Assuming charge conservation in $\beta$ decay neutron, experiment gives limit $\epsilon_\text{p-e}\lesssim1\cdot10^{-21}$ for electron-proton difference, same holding neutron. Previous critically reviewed and found incorrect: present result best obtained...
We report on the resonant Fabry Perot cavity of PVLAS (Polarization Vacuum with LASer) experiment operating at λ = 1064 nm a record decay time 2.7 ms, factor more than two larger any previously reported optical resonator. This corresponds to coherence length 8.1 · 10(5) m. The is 3.303 m, and resulting finesse 770,000.
We describe the principle and status of PVLAS experiment which is being assembled at INFN Laboratori Nazionali di Legnaro (Legnaro, Padua, Italy) to look for coherent effects, related QED vacuum structure, on propagation a polarized light beam in strong magnetic field.
In this paper we report the status of experiment MIR (Motion Induced Radiation), aimed at experimental verification dynamical Casimir effect. The stringent theoretical requirements to observe effect are satisfied in a scheme which conductivity semiconductor inside superconducting microwave resonant cavity is varied time. Free carriers periodically excited and recombine 5 GHz. process vacuum thermal photons parametrically amplified time interval 200-500 ns.
We report frequency locking of a Nd:YAG tunable laser to 2000 finesse 87-cm-long Fabry–Pérot cavity in air using the Pound–Drever technique. The novelty is that necessary phase modulation beam obtained directly instead an external modulator (Pockels cell). spurious relative amplitude this method was ∼3×10−5 with index β∼1 and spectral density difference between below 1 mHz/√Hz region 1–500 Hz.
Huge light-induced rubidium atom desorption has been observed from porous silica samples placed inside Pyrex cells kept at room temperature. The rate and the maximum vapour density change have measured as a function of desorbing light intensity. Their values are comparable with those recently obtained in coated organic films. A linear dependence square-root increase on intensity indicate that diffusion glass pores is key mechanism. application this effect to develop light-controlled atomic...
Dipole-forbidden f-f multiplet excitations are found to characterize the electron-energy-loss spectra of Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er when primary-electron energy is close binding 4d electrons. In Sm Gd transitions also detected at lower primary energies. The identification sharp peaks observed in as comes from straightforward comparison with absorption trivalent ions. excitation energies depend very weakly on chemical environment. exchange nature process explains strong decrease...
We demonstrate that single-terminated atomically flat surfaces of polar SrTiO3 (110) can be obtained by annealing in air at temperatures above 1000°C. show a morphological transition occurs from disordered step edges to faceted the range 1000–1100°C with appropriate conditions. The influence miscut angles (polar and azimuthal) on surface nanostructure, i.e., bunching faceting edges, is described. how azimuthal angle has critical role for step-edge step-bunching formation.
A novel polarisation modulation scheme for polarimeters based on Fabry-Perot cavities is presented. The application to the proposed HERA-X experiment aiming measuring magnetic birefringence of vacuum with HERA superconducting magnets discussed.
A well-established problem in surface structure determination is the experimental difficulty distinguishing a uniformly incommensurate from domain wall structure. Surface extended x-ray absorption fine (SEXAFS), as local structural probe, should provide an unambiguous means of making distinction. We have studied chlorine adsorbed on Ag{110} by SEXAFS at several coverages. The Cl–Ag nearest-neighbor distance, 2.56±0.04 Å, found to be substantially shorter than {111} and {100} faces,...