Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:p>The standard model of particle physics<jats:sup>1–4</jats:sup> describes the known fundamental particles and forces that make up our Universe, with the exception of gravity. One of the central features of the standard model is a field that permeates all of space and interacts with fundamental particles<jats:sup>5–9</jats:sup>. The quantum excitation of this field, known as the Higgs field, manifests itself as the Higgs boson, the only fundamental particle with no spin. In 2012, a particle with properties consistent with the Higgs boson of the standard model was observed by the ATLAS and CMS experiments at the Large Hadron Collider at CERN<jats:sup>10,11</jats:sup>. Since then, more than 30 times as many Higgs bosons have been recorded by the ATLAS experiment, enabling much more precise measurements and new tests of the theory. Here, on the basis of this larger dataset, we combine an unprecedented number of production and decay processes of the Higgs boson to scrutinize its interactions with elementary particles. Interactions with gluons, photons, and <jats:italic>W</jats:italic> and <jats:italic>Z</jats:italic> bosons—the carriers of the strong, electromagnetic and weak forces—are studied in detail. Interactions with three third-generation matter particles (bottom (<jats:italic>b</jats:italic>) and top (<jats:italic>t</jats:italic>) quarks, and tau leptons (<jats:italic>τ</jats:italic>)) are well measured and indications of interactions with a second-generation particle (muons, <jats:italic>μ</jats:italic>) are emerging. These tests reveal that the Higgs boson discovered ten years ago is remarkably consistent with the predictions of the theory and provide stringent constraints on many models of new phenomena beyond the standard model.</jats:p>

<jats:title>Abstract</jats:title><jats:p>In July 2012, the ATLAS and CMS collaborations at the CERN Large Hadron Collider announced the observation of a Higgs boson at a mass of around 125 gigaelectronvolts. Ten years later, and with the data corresponding to the production of a 30-times larger number of Higgs bosons, we have learnt much more about the properties of the Higgs boson. The CMS experiment has observed the Higgs boson in numerous fermionic and bosonic decay channels, established its spin–parity quantum numbers, determined its mass and measured its production cross-sections in various modes. Here the CMS Collaboration reports the most up-to-date combination of results on the properties of the Higgs boson, including the most stringent limit on the cross-section for the production of a pair of Higgs bosons, on the basis of data from proton–proton collisions at a centre-of-mass energy of 13 teraelectronvolts. Within the uncertainties, all these observations are compatible with the predictions of the standard model of elementary particle physics. Much evidence points to the fact that the standard model is a low-energy approximation of a more comprehensive theory. Several of the standard model issues originate in the sector of Higgs boson physics. An order of magnitude larger number of Higgs bosons, expected to be examined over the next 15 years, will help deepen our understanding of this crucial sector.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Quantum networks promise to provide the infrastructure for many disruptive applications, such as efficient long-distance quantum communication and distributed quantum computing<jats:sup>1,2</jats:sup>. Central to these networks is the ability to distribute entanglement between distant nodes using photonic channels. Initially developed for quantum teleportation<jats:sup>3,4</jats:sup> and loophole-free tests of Bell’s inequality<jats:sup>5,6</jats:sup>, recently, entanglement distribution has also been achieved over telecom fibres and analysed retrospectively<jats:sup>7,8</jats:sup>. Yet, to fully use entanglement over long-distance quantum network links it is mandatory to know it is available at the nodes before the entangled state decays. Here we demonstrate heralded entanglement between two independently trapped single rubidium atoms generated over fibre links with a length up to 33 km. For this, we generate atom–photon entanglement in two nodes located in buildings 400 m line-of-sight apart and to overcome high-attenuation losses in the fibres convert the photons to telecom wavelength using polarization-preserving quantum frequency conversion<jats:sup>9</jats:sup>. The long fibres guide the photons to a Bell-state measurement setup in which a successful photonic projection measurement heralds the entanglement of the atoms<jats:sup>10</jats:sup>. Our results show the feasibility of entanglement distribution over telecom fibre links useful, for example, for device-independent quantum key distribution<jats:sup>11–13</jats:sup> and quantum repeater protocols. The presented work represents an important step towards the realization of large-scale quantum network links.</jats:p>