Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:p>Particle accelerators and storage rings have been transformative instruments of discovery, and, for many applications, innovations in particle-beam cooling have been a principal driver of that success<jats:sup>1</jats:sup>. Stochastic cooling (SC), one of the most important conceptual and technological advances in this area<jats:sup>2–6</jats:sup>, cools a beam through granular sampling and correction of its phase-space structure, thus bearing resemblance to a ‘Maxwell’s demon’. The extension of SC from the microwave regime up to optical frequencies and bandwidths has long been pursued, as it could increase the achievable cooling rates by three to four orders of magnitude and provide a powerful tool for future accelerators. First proposed nearly 30 years ago, optical stochastic cooling (OSC) replaces the conventional microwave elements of SC with optical-frequency analogues and is, in principle, compatible with any species of charged-particle beam<jats:sup>7,8</jats:sup>. Here we describe a demonstration of OSC in a proof-of-principle experiment at the Fermi National Accelerator Laboratory’s Integrable Optics Test Accelerator<jats:sup>9,10</jats:sup>. The experiment used 100-MeV electrons and a non-amplified configuration of OSC with a radiation wavelength of 950 nm, and achieved strong, simultaneous cooling of the beam in all degrees of freedom. This realization of SC at optical frequencies serves as a foundation for more advanced experiments with high-gain optical amplification, and advances opportunities for future operational OSC systems with potential benefit to a broad user community in the accelerator-based sciences.</jats:p>

<jats:title>Abstract</jats:title><jats:p>In many disciplines, states that emerge in open systems far from equilibrium are determined by a few global parameters<jats:sup>1,2</jats:sup>. These states can often mimic thermodynamic equilibrium, a classic example being the oscillation threshold of a laser<jats:sup>3</jats:sup> that resembles a phase transition in condensed matter. However, many classes of states cannot form spontaneously in dissipative systems, and this is the case for cavity solitons<jats:sup>2</jats:sup> that generally need to be induced by external perturbations, as in the case of optical memories<jats:sup>4,5</jats:sup>. In the past decade, these highly localized states have enabled important advancements in microresonator-based optical frequency combs<jats:sup>6,7</jats:sup>. However, the very advantages that make cavity solitons attractive for memories—their inability to form spontaneously from noise—have created fundamental challenges. As sources, microcombs require spontaneous and reliable initiation into a desired state that is intrinsically robust<jats:sup>8–20</jats:sup>. Here we show that the slow non-linearities of a free-running microresonator-filtered fibre laser<jats:sup>21</jats:sup> can transform temporal cavity solitons into the system’s dominant attractor. This phenomenon leads to reliable self-starting oscillation of microcavity solitons that are naturally robust to perturbations, recovering spontaneously even after complete disruption. These emerge repeatably and controllably into a large region of the global system parameter space in which specific states, highly stable over long timeframes, can be achieved.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Soft magnetic materials (SMMs) serve in electrical applications and sustainable energy supply, allowing magnetic flux variation in response to changes in applied magnetic field, at low energy loss<jats:sup>1</jats:sup>. The electrification of transport, households and manufacturing leads to an increase in energy consumption owing to hysteresis losses<jats:sup>2</jats:sup>. Therefore, minimizing coercivity, which scales these losses, is crucial<jats:sup>3</jats:sup>. Yet meeting this target alone is not enough: SMMs in electrical engines must withstand severe mechanical loads; that is, the alloys need high strength and ductility<jats:sup>4</jats:sup>. This is a fundamental design challenge, as most methods that enhance strength introduce stress fields that can pin magnetic domains, thus increasing coercivity and hysteresis losses<jats:sup>5</jats:sup>. Here we introduce an approach to overcome this dilemma. We have designed a Fe–Co–Ni–Ta–Al multicomponent alloy (MCA) with ferromagnetic matrix and paramagnetic coherent nanoparticles (about 91 nm in size and around 55% volume fraction). They impede dislocation motion, enhancing strength and ductility. Their small size, low coherency stress and small magnetostatic energy create an interaction volume below the magnetic domain wall width, leading to minimal domain wall pinning, thus maintaining the soft magnetic properties. The alloy has a tensile strength of 1,336 MPa at 54% tensile elongation, extremely low coercivity of 78 A m<jats:sup>−1</jats:sup> (less than 1 Oe), moderate saturation magnetization of 100 A m<jats:sup>2</jats:sup> kg<jats:sup>−1</jats:sup> and high electrical resistivity of 103 μΩ cm.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Multicellular systems, from bacterial biofilms to human organs, form interfaces (or boundaries) between different cell collectives to spatially organize versatile functions<jats:sup>1,2</jats:sup>. The evolution of sufficiently descriptive genetic toolkits probably triggered the explosion of complex multicellular life and patterning<jats:sup>3,4</jats:sup>. Synthetic biology aims to engineer multicellular systems for practical applications and to serve as a build-to-understand methodology for natural systems<jats:sup>5–8</jats:sup>. However, our ability to engineer multicellular interface patterns<jats:sup>2,9</jats:sup> is still very limited, as synthetic cell–cell adhesion toolkits and suitable patterning algorithms are underdeveloped<jats:sup>5,7,10–13</jats:sup>. Here we introduce a synthetic cell–cell adhesin logic with swarming bacteria and establish the precise engineering, predictive modelling and algorithmic programming of multicellular interface patterns. We demonstrate interface generation through a swarming adhesion mechanism, quantitative control over interface geometry and adhesion-mediated analogues of developmental organizers and morphogen fields. Using tiling and four-colour-mapping concepts, we identify algorithms for creating universal target patterns. This synthetic 4-bit adhesion logic advances practical applications such as human-readable molecular diagnostics, spatial fluid control on biological surfaces and programmable self-growing materials<jats:sup>5–8,14</jats:sup>. Notably, a minimal set of just four adhesins represents 4 bits of information that suffice to program universal tessellation patterns, implying a low critical threshold for the evolution and engineering of complex multicellular systems<jats:sup>3,5</jats:sup>.</jats:p>