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Current projects

HUMOR (funded by Istituto Nazionale di Fisica Nucleare, since 2013). Different approaches to quantum gravity, such as string theory and loop quantum gravity, as well as doubly special relativity and gedanken experiments in black holes physics, all indicate the existence of a minimal measurable length of the order of the Planck length, about 1E-35 m. The emergency of a minimal length scale can originate relevant consequences also for low-energy quantum mechanics experiments. In fact the Heisenberg relation states that the position and the momentum of a particle cannot be determined simultaneously with arbitrarily high accuracy. However, an arbitrarily precise measurement of only one of the two observables, say position, is still possible at the cost of our knowledge about the other (momentum), a fact which is obviously incompatible with the existence of a minimal observable distance. This consideration motivates the introduction of generalized Heisenberg uncertainty principles (GUPs). As a consequence, an alternative way to check quantum gravitational effects would be to perform high-sensitivity measurements of the uncertainty relation, in order to reveal any possible deviation from predictions of standard quantum mechanics. In the experiment we propose to measure the Heisenberg uncertainty relation on the momentum position variables of a silicon microresonator probed by a laser readout system.

Past projects

QUANTOM (premiale MIUR, 2014-2016). The purpose of this project is strengthening the collaboration between the Italian groups aspiring to work in the field of quantum optomechanics, increasing their specific skills, creating the necessary synergies and interactions between groups with complementary expertise, providing the necessary tools for achieving objectives of excellence, putting together the necessary "critical mass" for a successful participation to the calls of "Horizon 2020". I am the responsible of the development of microresonators for generation and characterization of squeezing exploiting the pondero-motive effect, tailoring non-classical states of light through opto-mechanical interaction, and phenomenological tests of Generalized Uncertainty Relations (quantum gravity effects) by means of quantum limited mechanical resonators.

AURIGA (funded by Istituto Nazionale di Fisica Nucleare, 1993-2016). AURIGA represents the state-of-art in the class of acoustic gravitational wave detectors, and is continuously in operation from year 2004, searching for galactic astrophysical events in collaboration with a world network of detectors. It is located in Padua (Italy) and is based on a 2.2 tons, 3 meters long bar made of a low loss aluminium alloy (Al5056), cooled to liquid helium temperature. The fundamental longitudinal mode of the bar, sensitive to gravitational waves, has an effective mass M=1.1 tons and a resonance frequency of 900 Hz. It is monitored with a resolution better than 10-19 m/Ö{Hz} over a 100 Hz bandwidth. This outstanding sensitivity is accomplished by a multimode resonant capacitive transducer, which converts the motion of the bar into an electrical current, detected by a low noise dc SQUID amplifier through a low-loss high-ratio superconducting transformer. During the ten years needed for the realization of the detector, I was in charge of the design and commissioning of different components: the superconducting transformer with its shields, parts of the cryogenic system, the low frequency seismic isolators.

PRIN project (funded by Italian Ministry for Education, University and Research, 2013-2015 ) for the development of very low-loss optical interferometers in the ponderomotive regime for the reduction of quantum noise.  These opto-mechanical  systems offer a promising architecture for controlling the quantum states of light and matter, and for exploring the boundaries between quantum and classical  mechanics. The experimental requirements are still difficult to  be met, since quantum fluctuations of the radiation pressure produce weak effects on the oscillator with respect to the many noise sources of thermal origin  (e.g. Brownian and thermoelastic noises). To help overcome these problems, our experimental set up will include an optical cavity with high Finesse, which increases radiation pressure effects, as well as a mobile optical element with high mechanical susceptibility and low mechanical losses, which helps in enhancing its response to applied forces and in increasing the coherence time of the oscillator respectively. Moreover, the optical element, e.g. a micro-mirror or a semi-transparent membrane, will be cooled to  cryogenic temperatures.
I participate to the development of Micro Opto-Mechanical Systems (MOMS), which ensure high mechanical susceptibility and quality factor Q and  are suitable to preserve the high Finesse needed for the optical cavities. This will be pursued by using the most advanced expertise available to reduce mechanical  losses in silicon micro-resonators.

RareNoise (funded by European Research Council, 2008-2013) is a fundamental Physics project aiming at the understanding of the spontaneous vibration fluctuations of solid bodies subject to non equilibrium conditions. Although dissipative systems driven far from equilibrium involve many degrees of freedom, there is no complete and satisfactory statistical description of the behavior of global quantities (energy, power,...), defined on the whole volume, unlike the thermo-statistic theory describing the equilibrium states. This is mainly due to the energy fluxes between the energy input (at the boundaries of the systems) and the dissipation in the bulk. These fluxes generate correlations, inhomogeneities and large fluctuations which prohibit the use of the usual tools of statistical mechanics.
We will experimentally investigate spontaneous vibration fluctuations in very low losses mechanical macroscopic oscillators (made of aluminum and silicon, mass order of 0.1 kg, size order of 0.1 m) subject to non equilibrium steady-state conditions. Developments of the present theories and of the models of nonequilibrium systems will be sought for, in order to approach the specific problem of the nonequilibrium fluctuations in the mechanical oscillators which are the object of the experiment.
I am in charge of the design and testing of the silicon oscillators; I am also involved in the realization of the high sensitivity (10-14  m/Ö{Hz}) vibration readout.

DUAL RD (funded by Istituto Nazionale di Fisica Nucleare, 2006-2009). An innovative approach to the detection of gravitational waves is represented by the DUAL detector, a "non-resonant bar detector": it consists of an elastic test mass with low mechanical dissipation; a GW modifies its dimensions and the strain is measured on specifically selected surfaces leading to a profitable quadrupolar resonant modes superposition, thus reducing the noise contribution from the readout and from non gravitationally sensitive modes. The expected sensitivity may be of the order of 10-23 m/Ö{Hz} around 3 kHz with a bandwidth of few kHz. The R&D program aims to demonstrate the feasibility of such detector.
One of the open issues is the need of developing large silicon masses with extremely low mechanical losses. Silicon is already known to possess very low mechanical loss angles (d @ 10-8) from room to cryogenic temperatures but no measurements of losses contributed by bonding methods are available at such low temperatures. A setup for measuring mechanical losses of silicon wafers from room temperature to 4K has been realized: it consists of silicon wafers with nodal suspension and capacitive and optical vibration sensors. Major contributions to mechanical losses are investigated and compared with experimental data; in particular losses due to the thermoelastic effect and to the wafer clamp are modeled via FEM analysis.

ILIAS funded by (European Community, 2004-2009). It is an Integrated Infrastructure Initiative that has pulled together all of Europe's leading infrastructures in Astroparticle Physics to produce a focused, coherent and integrated project to improve the existing infrastructures and their operation as well as to organize and structure the scientific community to prepare the best infrastructures for the future. The activities in the field of GW detectors are coordinated around the Joint Research Project STREGA (Study of Thermal Noise Reduction in Gravitational Wave Detectors). The aim is a ten-fold reduction of thermal noise using new materials, new cryogenic techniques and studying fundamental noise mechanisms.