arXiv subjects

D. Iannuzzi

Publications and source records attributed to D. Iannuzzi.

8 recordsLinked to original sources

arXiv2016

Investigation of the concept of beauty via a lock-in feedback experiment

Lock-in feedback circuits are routinely used in physics laboratories all around the world to extract small signals out of a noisy environment. In a recent paper (M. Kaptein, R. van Emden, and D. Iannuzzi, paper under review), we have shown that one can adapt the algorithm exploited in those circuits to gain insight in behavioral economics. In this paper, we extend this concept to a very subjective socio-philosophical concept: the concept of beauty. We run an experiment on 7414 volunteers, asking them to express their opinion on the physical features of an avatar. Each participant was prompted with an image whose features were adjusted sequentially via a lock-in feedback algorithm driven by the opinion expressed by the previous participants. Our results show that the method allows one to identify the most attractive features of the avatar.

physics.soc-ph↗

arXiv2011

Measurement of the Casimir force with a ferrule-top sensor

We present a Casimir force setup based on an all-optical ferrule-top sensor. We demonstrate that the instrument can be used to measure the gradient of the Casimir force between a gold coated sphere and a gold coated plate with results that are comparable to those achieved by similar atomic force microscope experiments. Thanks to the monolithic design of the force sensor (which does not require any optical triangulation readout) and to the absence of electronics on the sensing head, the instrument represents a significant step ahead for future studies of the Casimir effect under engineered conditions, where the intervening medium or the environmental conditions might be unsuitable for the use of more standard setups.

quant-ph↗

arXiv2010

Tuning the Mass of Chameleon Fields in Casimir Force Experiments

We have calculated the chameleon pressure between two parallel plates in the presence of an intervening medium that affects the mass of the chameleon field. As intuitively expected, the gas in the gap weakens the chameleon interaction mechanism with a screening effect that increases with the plate separation and with the density of the intervening medium. This phenomenon might open up new directions in the search of chameleon particles with future long range Casimir force experiments.

quant-ph↗

arXiv2009

Halving the Casimir force with conductive oxides

The possibility to modify the strength of the Casimir effect by tailoring the dielectric functions of the interacting surfaces is regarded as a unique opportunity in the development of Micro- and NanoElectroMechanical Systems. In air, however, one expects that, unless noble metals are used, the electrostatic force arising from trapped charges overcomes the Casimir attraction, leaving no room for exploitation of Casimir force engineering at ambient conditions. Here we show that, in the presence of a conductive oxide, the Casimir force can be the dominant interaction even in air, and that the use of conductive oxides allows one to reduce the Casimir force up to a factor of 2 when compared to noble metals.

quant-ph↗

arXiv2009

No anomalous scaling in electrostatic calibrations for Casimir force measurements

In a recent paper (Phys.Rev.A78, 020101(R) (2008)), Kim at al. have reported a large anomaly in the scaling law of the electrostatic interaction between a sphere and a plate, which was observed during the calibration of their Casimir force set-up. Here we experimentally demonstrate that in proper electrostatic calibrations the scaling law follows the behavior expected from elementary electrostatic arguments, even when the electrostatic voltage that one must apply to minimize the force (typically ascribed to contact potentials) depends on the separation between the surfaces.

quant-ph↗

arXiv2005

Environment influence on the IR fluorescence of Xe$_{2}^{*}$ molecules in electron beam excited Ar--Xe mixture at high density

We report new measurements of the near infrared (NIR) Xe$_2^*$ excimer fluorescence in an electron--beam--excited Ar (90%)--Xe (10 %) mixture at room temperature. Previous measurements up to a density $N\approx 2\times 10^{26}$ m$^{-3}$ discovered a broad excimer fluorescence band at $\approx 7800$ cm$^{-1},$ whose center is red--shifted by increasing $N$ (A. F. Borghesani, G. Bressi, G. Carugno, E. Conti, and D. Iannuzzi, {\em J. Chem. Phys.}, {\bf 115}, 6042 (2001)). The shift has been explained by assuming that the energy of the optical active electron in the molecule is shifted by the density--dependent Fermi shift and by accounting for the solvation effect due to the environment. We have extended the density range up to $N\approx 6\times 10^{26}$ m$^{-3}, $ confirming the previous measurements and extending the validity of the interpretative model. A detailed analysis of the width of the fluorescence band gives a value of 2.85 nm for the size of the investigated excimer state. Such a large value lends credence to the validity of the proposed explanation of the experimental findings.

physics.atom-ph↗

arXiv2003

Comment on Repulsive Casimir Forces

A recent theoretical calculation shows that the Casimir force between two parallel plates can be repulsive for plates with nontrivial magnetic properties (O. Kenneth et al., Phys. Rev. Lett. 89, 033001 (2002)). According to the authors, the effect may be observed with known materials, such as ferrites and garnets, and it might be possible to engineer micro- or nanoelectromechanical systems (MEMS or NEMS) that could take advantage of a short range repulsive force. Here we show that on the contrary the Casimir force between two parallel plates in vacuum at micron and submicron distance is always attractive.

quant-ph↗

arXiv2000

Infrared Fluorescence of Xe2 Molecules in beam-excited Xe Gas at high Pressure

We report experimental results of proton- and electron-beam-induced near-infrared (NIR) fluorescence in high-pressure Xe gas at room temperature. The investigated wavelength band spans the range $0.7 \leqλ\leq 1.8 μ{m}.$ In the previously unexplored range for $λ> 1.05 μ{m}$ we have detected a broad continuum NIR fluorescence at $λ\approx 1.3 μ{m}$ that shifts towards longer wavelengths as pressure is increased up to $1.5 {MPa}.$ We believe that this continuum is produced in a way similar to the VUV continua of noble gas excimers and that the pressure-dependent shift can be explained by the interaction of the outer electron of the excimer with the gas.

physics.plasm-ph↗