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Anderson localization is a universal phenomenon affecting non-interacting quantum particles in a disordered environment. In three spatial dimensions, theory predicts a quantum phase transition from localization to diffusion at a critical energy, the mobility edge, which depends on the disorder strength. Although it has been recognized already long ago as a prominent feature of disordered systems, a complete experimental characterization of the mobility edge is still missing. Here we report the measurement of the mobility edge for ultracold atoms in a disordered potential created by laser speckles. We are able to control both the disorder strength and the energy of the system, so as to probe the position of the localization threshold in the disorder-energy plane. Our results might allow a direct experiment-theory comparison, which is a prerequisite to study the even more challenging problem of disorder and interactions. [ABSTRACT FROM AUTHOR]

Clarifying the interplay of interactions and disorder is fundamental to the understanding of many quantum systems, including superfluid helium in porous media, granular and thin-film superconductors and light propagating in disordered media. One central aspect for bosonic systems is the competition between disorder, which tends to localize particles, and weak repulsive interactions, which instead have a delocalizing effect. As the required degree of independent control of disorder and of interactions is not easily achievable in most available physical systems, a systematic experimental investigation of this competition has not so far been possible. Here we use a degenerate Bose gas with tunable repulsive interactions in a quasiperiodic lattice potential to study this interplay in detail. We characterize the entire delocalization crossover through the study of the average local shape of the wavefunction, the spatial correlations and the phase coherence. Three different regimes are identified and compared with theoretical expectations: an exponentially localized Anderson glass and the formation of locally coherent fragments as well as a coherent, extended state. These results provide insight into the role of weak repulsive interactions in disordered bosonic systems, but our approach should also enable investigations of disordered systems with interactions in the strongly correlated regime. [ABSTRACT FROM AUTHOR]

In 1970, Vitaly Efimov predicted that three quantum particles subjected to a resonant pair-wise interaction can join into an infinite number of loosely bound states, even if each pair of particles cannot bind. The properties of these aggregates, such as the peculiar geometric scaling of their energy spectrum, are universal, that is, independent of the microscopic details of their components. Despite an extensive search in many different physical systems, including atoms, molecules and nuclei, the characteristic spectrum of Efimov trimer states has not been observed so far. Here, we report on the discovery of two bound trimer states of potassium atoms very close to the Efimov scenario, which we reveal by studying three-particle collisions in an ultracold gas. Our observation provides the first evidence of an Efimov spectrum and enables a direct test of its scaling behaviour, providing potentially general insights into the physics of few-body systems. [ABSTRACT FROM AUTHOR]

We report on a system of well-characterized source masses and their precision positioning system for a measurement of the Newtonian gravitational constant G using atoms as probes. The masses are 24 cylinders of 50 mm nominal radius, 150.2 mm nominal height, and mass of about 21.5 kg, sintered starting from a mixture of 95.3% W, 3.2% Ni, and 1.5% Cu. Density homogeneity and cylindrical geometry have been carefully investigated. The positioning system independently moves two groups of 12 cylinders along the vertical direction by tens of centimeters with a reproducibility of a few microns. The whole system is compatible with a resolution ΔG/G<10-4. [ABSTRACT FROM AUTHOR]

We report on a scheme to improve the pointing stability of the first order beam diffracted by an acousto-optic modulator (AOM). Due to thermal effects inside the crystal, the angular position of the beam can change by as much as 1 mrad when the radio-frequency power in the AOM is reduced to decrease the first order beam intensity. This is done, for example, to perform forced evaporative cooling in ultracold atom experiments using far-off-resonant optical traps. We solve this problem by driving the AOM with two radio frequencies f1 and f2. The power of f2 is adjusted relative to the power of f1 to keep the total power constant. Using this, the beam displacement is decreased by a factor of 20. The method is simple to implement in existing experimental setups, without any modification of the optics. [ABSTRACT FROM AUTHOR]

Adiabatic demagnetization is an efficient technique for cooling solid samples by several orders of magnitude in a single cooling step. In gases, the required coupling between dipolar moments and motion is typically too weak, but in dipolar gases—of high-spin atoms or heteronuclear molecules with strong electric dipole moments, for example—the method should be applicable. Here, we demonstrate demagnetization cooling of a gas of ultracold 52Cr atoms. Demagnetization is driven by inelastic dipolar collisions, which couple the motional degrees of freedom to the spin degree. In this way, kinetic energy is converted into magnetic work, with a consequent temperature reduction of the gas. Optical pumping is used to magnetize the system and drive continuous demagnetization cooling. We can increase the phase-space density of our sample by up to one order of magnitude, with almost no atom loss, suggesting that the method could be used to achieve quantum degeneracy via optical means. [ABSTRACT FROM AUTHOR]

We describe a type of phase and frequency detector employing both an analog phase detector and a digital phase and frequency detector. The analog and digital detectors are mutually exclusive so that only one of them is active at any given time, resulting in a phase detector with both the broad capture range of digital circuits and the high speed and low noise of analog mixers. The detector has been used for phase locking the diode lasers generating the sequence of Raman pulses in an atom interferometer. The rms phase error of the phase lock is about 100 mrad in a 5 Hz–10 MHz bandwidth. The limit set on the interferometer phase resolution by the residual phase noise is 1.1 mrad. Since the digital circuitry is implemented with a programmable logic device the detector can be easily adapted to other experiments requiring frequency/phase stabilization of lasers sources. [ABSTRACT FROM AUTHOR]

We report on progress towards an atom interferometric determination of the Newtonian gravitational constant. Free-falling laser-cooled atoms will probe the gravitational potential of nearby source masses. To reduce systematic errors, we will perform double differential measurements between two vertically separated atom clouds and with different source mass positions. [Copyright &y& Elsevier]

An abstract of the study "Antiproliferative Effect of Sildenafil on Pulmonary Artery Smooth Muscle Cells," by B. Tantini and A. Manes, is presented.

Self-bound quantum droplets are a newly discovered phase in the context of ultracold atoms. In this Letter, we report their experimental realization following the original proposal by Petrov [Phys. Rev. Lett. 115, 155302 (2015)], using an attractive bosonic mixture. In this system, spherical droplets form due to the balance of competing attractive and repulsive forces, provided by the mean-field energy close to the collapse threshold and the first-order correction due to quantum fluctuations. Thanks to an optical levitating potential with negligible residual confinement, we observe self-bound droplets in free space, and we characterize the conditions for their formation as well as their size and composition. This work sets the stage for future studies on quantum droplets, from the measurement of their peculiar excitation spectrum to the exploration of their superfluid nature. [ABSTRACT FROM AUTHOR]

Gravity gradients represent a major obstacle in high-precision measurements by atom interferometry. Controlling their effects to the required stability and accuracy imposes very stringent requirements on the relative positioning of freely falling atomic clouds, as in the case of precise tests of Einstein's equivalence principle. We demonstrate a new method to exactly compensate the effects introduced by gravity gradients in a Raman-pulse atom interferometer. By shifting the frequency of the Raman lasers during the central π pulse, it is possible to cancel the initial position- and velocity-dependent phase shift produced by gravity gradients. We apply this technique to simultaneous interferometers positioned along the vertical direction and demonstrate a new method for measuring local gravity gradients that does not require precise knowledge of the relative position between the atomic clouds. Based on this method, we also propose an improved scheme to determine the Newtonian gravitational constant G towards the 10 ppm relative uncertainty. [ABSTRACT FROM AUTHOR]

We explore the interplay between tunneling and interatomic interactions in the dynamics of a bosonic Josephson junction. We tune the scattering length of an atomic 39K Bose-Einstein condensate confined in a double-well trap to investigate regimes inaccessible to other superconducting or superfluid systems. In the limit of small-amplitude oscillations, we study the transition from Rabi to plasma oscillations by crossing over from attractive to repulsive interatomic interactions. We observe a critical slowing down in the oscillation frequency by increasing the strength of an attractive interaction up to the point of a quantum phase transition. With sufficiently large initial oscillation amplitude and repulsive interactions, the system enters the macroscopic quantum self-trapping regime, where we observe coherent undamped oscillations with a self-sustained average imbalance of the relative well population. The exquisite agreement between theory and experiments enables the observation of a broad range of many body coherent dynamical regimes driven by tunable tunneling energy, interactions and external forces, with applications spanning from atomtronics to quantum metrology. [ABSTRACT FROM AUTHOR]

Brain-computer interfaces (BCIs) are evolving toward higher electrode count and fully implantable solutions, which require extremely low power densities (<15mW cm -2 ). To achieve this target, and allow for a large and scalable number of channels, flexible electronics can be used as a multiplexing interface. This work introduces an active analog front-end fabricated with amorphous Indium-Gallium-Zinx-Oxide (a-IGZO) Thin-Film Transistors (TFTs) on foil capable of active matrix multiplexing. The circuit achieves only 70nV per sqrt(Hz) input referred noise, consuming 46µW, or 3.5mW cm -2 . It demonstrates for the first time in literature a flexible front-end with a noise efficiency factor comparable with Silicon solutions (NEF = 9.8), which is more than 10X lower compared to previously reported flexible front-ends. These results have been achieved using a modified bootstrap-load amplifier. The front end is tested by playing through it recordings obtained from a conventional BCI system. A gesture classification based on the flexible front-end outputs achieves 94% accuracy. Using a flexible active front end can improve the state-of-the-art in high channel count BCI systems by lowering the multiplexer noise and enabling larger areas of the brain to be monitored while reducing power density. Therefore, this work enables a new generation of high channel-count active BCI electrode grids., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Antimicrobial resistance (AMR) represents a critical global threat, compromising the effectiveness of antibacterial drugs as bacteria adapt and survive exposure to many classes of these drugs. This phenomenon is primarily fueled by the widespread overuse and misuse of antibacterial drugs, exerting selective pressure on bacteria and promoting the emergence of multi-resistant strains. AMR poses a top-priority challenge to public health due to its widespread epidemiological and economic implications, exacerbated not only by the diminishing effectiveness of currently available antimicrobial agents but also by the limited development of genuinely effective new molecules. In addressing this issue, our research aimed to examine the scientific literature narrating the Italian situation in the common European context of combating AMR. We sought to delineate the current state of AMR and explore future prospects through an analysis of strategies to counter antibacterial drug resistance. Adopting the "One Health" model, our objective was to comprehensively engage diverse sectors, integrate various disciplines, and propose programs, policies, and regulations. This narrative review, based on PubMed research related to antibiotic resistance, emphasizes the urgent need for a coordinated and proactive approach at both national and European levels to mitigate the impact of AMR and pave the way for effective strategies to counter this global health challenge., Competing Interests: Declarations. Ethical approval: Not applicable. Consent to participate: Not applicable. Consent for publication: The authors consent to the publication of the manuscript. Competing interests: The authors declare no competing interests. Disclaimer: The authors declare that the opinions expressed are of a personal nature and do not in any way commit the responsibility of the Administrations to which they belong., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Neural network training can be slow and energy-expensive due to the frequent transfer of weight data between digital memory and processing units. Neuromorphic systems can accelerate neural networks by performing multiply-accumulate operations in parallel using nonvolatile analog memory. However, executing the widely used backpropagation training algorithm in multilayer neural networks requires information-and therefore storage-of the partial derivatives of the weight values preventing suitable and scalable implementation in hardware. Here, we propose a hardware implementation of the backpropagation algorithm that progressively updates each layer using in situ stochastic gradient descent, avoiding this storage requirement. We experimentally demonstrate the in situ error calculation and the proposed progressive backpropagation method in a multilayer hardware-implemented neural network. We confirm identical learning characteristics and classification performance compared to conventional backpropagation in software. We show that our approach can be scaled to large and deep neural networks, enabling highly efficient training of advanced artificial intelligence computing systems.

Remote measurement of vital sign parameters like heartbeat and respiration rate represents a compelling challenge in monitoring an individual's health in a noninvasive way. This could be achieved by large field-of-view, easy-to-integrate unobtrusive sensors, such as large-area thin-film photodiodes. At long distances, however, discriminating weak light signals from background disturbance demands superior near-infrared (NIR) sensitivity and optical noise tolerance. Here, we report an inherently narrowband solution-processed, thin-film photodiode with ultrahigh and controllable NIR responsivity based on a tandem-like perovskite-organic architecture. The device has low dark currents (<10 -6 mA cm -2 ), linear dynamic range >150 dB, and operational stability over time (>8 hours). With a narrowband quantum efficiency that can exceed 200% at 850 nm and intrinsic filtering of other wavelengths to limit optical noise, the device exhibits higher tolerance to background light than optically filtered silicon-based sensors. We demonstrate its potential in remote monitoring by measuring the heart rate and respiration rate from distances up to 130 cm in reflection.