Guglielmo M. Tino

Bio: Guglielmo M. Tino is an academic researcher from University of Florence. The author has contributed to research in topics: Atom interferometer & Interferometry. The author has an hindex of 45, co-authored 221 publications receiving 7149 citations. Previous affiliations of Guglielmo M. Tino include University of Naples Federico II & École Normale Supérieure.

Precision measurement of the Newtonian gravitational constant using cold atoms

Abstract: Determination of the gravitational constant G using laser-cooled atoms and quantum interferometry, a technique that gives new insight into the systematic errors that have proved elusive in previous experiments, yields a value that has a relative uncertainty of 150 parts per million and which differs from the current recommended value by 1.5 combined standard deviations. The Newtonian gravitational constant G, also known as the universal gravitational constant or 'big G', is a fundamental physical constant that is used in the calculation of gravitational attraction between two bodies. There are several ways to measure G with high precision, but these measurements disagree, presumably because of the intervention of unknown errors in the different experiments. With the aim of identifying and ultimately removing the systematic errors that give rise to these discrepancies, Gabriele Rosi and colleagues have carried out a high-precision measurement of G using quantum interferometry with laser-cooled atoms, an experimental approach that differs radically from previous determinations. The authors obtain a value for G with a precision of ∼0.015% — approaching that of the traditional measurements, and with prospects for considerable further improvement. Although this result doesn't yet solve the problem of the discrepant measurements, the use of such a radically different technique holds promise for identifying the systematic errors that have plagued previous determinations. About 300 experiments have tried to determine the value of the Newtonian gravitational constant, G, so far, but large discrepancies in the results have made it impossible to know its value precisely1. The weakness of the gravitational interaction and the impossibility of shielding the effects of gravity make it very difficult to measure G while keeping systematic effects under control. Most previous experiments performed were based on the torsion pendulum or torsion balance scheme as in the experiment by Cavendish2 in 1798, and in all cases macroscopic masses were used. Here we report the precise determination of G using laser-cooled atoms and quantum interferometry. We obtain the value G = 6.67191(99) × 10−11 m3 kg−1 s−2 with a relative uncertainty of 150 parts per million (the combined standard uncertainty is given in parentheses). Our value differs by 1.5 combined standard deviations from the current recommended value of the Committee on Data for Science and Technology3. A conceptually different experiment such as ours helps to identify the systematic errors that have proved elusive in previous experiments, thus improving the confidence in the value of G. There is no definitive relationship between G and the other fundamental constants, and there is no theoretical prediction for its value, against which to test experimental results. Improving the precision with which we know G has not only a pure metrological interest, but is also important because of the key role that G has in theories of gravitation, cosmology, particle physics and astrophysics and in geophysical models.

AEDGE: Atomic experiment for dark matter and gravity exploration in space

Abstract: We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity.

Proposed antimatter gravity measurement with an antihydrogen beam

Abstract: The principle of the equivalence of gravitational and inertial mass is one of the cornerstones of general relativity. Considerable efforts have been made and are still being made to verify its validity. A quantum-mechanical formulation of gravity allows for non-Newtonian contributions to the force which might lead to a difference in the gravitational force on matter and antimatter. While it is widely expected that the gravitational interaction of matter and of antimatter should be identical, this assertion has never been tested experimentally. With the production of large amounts of cold antihydrogen at the CERN Antiproton Decelerator, such a test with neutral antimatter atoms has now become feasible. For this purpose, we have proposed to set up the AEGIS experiment at CERN/AD, whose primary goal will be the direct measurement of the Earth's gravitational acceleration on antihydrogen with a classical Moire deflectometer.

Determination of the Newtonian Gravitational Constant Using Atom Interferometry

Abstract: We present a new measurement of the Newtonian gravitational constant G based on cold-atom interferometry. Freely falling samples of laser-cooled rubidium atoms are used in a gravity gradiometer to probe the field generated by nearby source masses. In addition to its potential sensitivity, this method is intriguing as gravity is explored by a quantum system. We report a value of G � 6:667 � 10 � 11 m 3 kg � 1 s � 2 , estimating a statistical uncertainty of � 0:011 � 10 � 11 m 3 kg � 1 s � 2 and a systematic uncertainty of � 0:003 � 10 � 11 m 3 kg � 1 s � 2 . The long-term stability of the instrument and the signal-tonoise ratio demonstrated here open interesting perspectives for pushing the measurement accuracy below the 100 ppm level. The Newtonian constant of gravity G is one of the most measured fundamental physical constants and at the same time the least precisely known. Improving the knowledge of G has not only a pure metrological interest, but is also important for the key role that it plays in theories of gravitation, cosmology, and particle physics, in geophysical models, and in astrophysical observations. However, the extreme weakness of the gravitational force and the impossibility of shielding the effects of gravity make it difficult to measure G, while keeping systematic effects well under control. Many of the measurements performed to date are based on the traditional torsion pendulum method [1], direct derivation of the historical experiment performed by Cavendish in 1798. Recently, many groups have set up new experiments based on different concepts and with completely different systematics: a beam-balance system [2], a laser interferometry measurement of the acceleration of a freely falling test mass [3], experiments based on Fabry-Perot or microwave cavities [4,5]. However, the most precise measurements available today still show substantial discrepancies, limiting the accuracy of the 2006 CODATA recommended value for G to 1 part in 10 4 . From this point of view, the realization of conceptually different experiments can help to identify still hidden systematic effects and therefore improve the confidence in the final result. Cold-atom interferometry has demonstrated outstanding performances for the measurement of tiny rotations and accelerations, and it is widely used for many applications: precision measurements of gravity [6], gravity gradient [7], and rotation of the Earth [8,9], but also tests of Einstein’s weak equivalence principle [10], tests of Newton’s law at short distances [11], and measurement of fundamental physical constants [12,13]. Applications of these techniques for fundamental physics experiments in space are under study [14]. In this Letter, we present a new determination of the Newtonian constant of gravity based on cold-atom interferometry. An atomic gravity gradiometer is used to measure the differential acceleration experienced by two freely falling samples of laser-cooled rubidium atoms under the influence of nearby tungsten masses. The measurement is repeated in two different configurations of the source masses and modeled by a numerical simulation. From the evolution of the atomic wave packets and the distribution of the source masses, we evaluate the expected differential acceleration, having G as a unique free parameter. Avalue for Newton’s constant of gravity is finally extracted by comparing experimental data and numerical simulations. Proof-of-principle experiments with similar schemes using lead masses were already presented in [15,16]. In the present work, specific efforts have been devoted to the control of systematic effects related to atomic trajectories, positioning of source masses, and stray fields. In particular, FIG. 1 (color online). Schematic of the experiment showing the gravity gradiometer setup with the Raman beams propagating along the vertical direction. During the G measurement, the position of the source masses is alternated between configuration C1 (left) and C2 (right). PRL 100, 050801 (2008)

Test of Einstein equivalence principle for 0-spin and half-integer-spin atoms: search for spin-gravity coupling effects.

Abstract: We report on a conceptually new test of the equivalence principle performed by measuring the acceleration in Earth's gravity field of two isotopes of strontium atoms, namely, the bosonic $^{88}\mathrm{Sr}$ isotope which has no spin versus the fermionic $^{87}\mathrm{Sr}$ isotope which has a half-integer spin The effect of gravity on the two atomic species has been probed by means of a precision differential measurement of the Bloch frequency for the two atomic matter waves in a vertical optical lattice We obtain the values $\ensuremath{\eta}=(02\ifmmode\pm\else\textpm\fi{}16)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ for the E\"otv\"os parameter and $k=(05\ifmmode\pm\else\textpm\fi{}11)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ for the coupling between nuclear spin and gravity This is the first reported experimental test of the equivalence principle for bosonic and fermionic particles and opens a new way to the search for the predicted spin-gravity coupling effects

Theory of Bose-Einstein condensation in trapped gases

Abstract: The phenomenon of Bose-Einstein condensation of dilute gases in traps is reviewed from a theoretical perspective. Mean-field theory provides a framework to understand the main features of the condensation and the role of interactions between particles. Various properties of these systems are discussed, including the density profiles and the energy of the ground-state configurations, the collective oscillations and the dynamics of the expansion, the condensate fraction and the thermodynamic functions. The thermodynamic limit exhibits a scaling behavior in the relevant length and energy scales. Despite the dilute nature of the gases, interactions profoundly modify the static as well as the dynamic properties of the system; the predictions of mean-field theory are in excellent agreement with available experimental results. Effects of superfluidity including the existence of quantized vortices and the reduction of the moment of inertia are discussed, as well as the consequences of coherence such as the Josephson effect and interference phenomena. The review also assesses the accuracy and limitations of the mean-field approach.

The Observation of Gravitational Waves from a Binary Black Hole Merger

Abstract: On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160) Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Bose-Einstein condensation in a gas of sodium atoms

Abstract: Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

CODATA Recommended Values of the Fundamental Physical Constants: 2006

Abstract: This paper gives the 2010 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. The 2010 adjustment takes into account the data considered in the 2006 adjustment as well as the data that became available from 1 January 2007, after the closing date of that adjustment, until 31 December 2010, the closing date of the new adjustment. Further, it describes in detail the adjustment of the values of the constants, including the selection of the final set of input data based on the results of least-squares analyses. The 2010 set replaces the previously recommended 2006 CODATA set and may also be found on the World Wide Web at physics.nist.gov/constants.