Hemeroteca de la sección ‘Ciencia y tecnología’

Voter models on subcritical inhomogeneous random graphs

Por • 6 dic, 2019 • Category: Ciencia y tecnología

The voter model is a classical interacting particle system modelling how consensus is formed across a network. We analyse the time to consensus for the voter model when the underlying graph is a subcritical scale-free random graph. Moreover, we generalise the model to include a `temperature’ parameter. The interplay between the temperature and the structure of the random graph leads to a very rich phase diagram, where in the different phases different parts of the underlying geometry dominate the time to consensus. Finally, we also consider a discursive voter model, where voters discuss their opinions with their neighbours. Our proofs rely on the well-known duality to coalescing random walks and a detailed understanding of the structure of the random graphs.

Quantum Cryptography in the US-China Tech Race

Por • 28 nov, 2019 • Category: Ciencia y tecnología

There are two right now that most worry the United States. The first is that in a few years, China will go dark behind a wall of quantum cryptography, and the U.S. will not be able to decode any of the information that is transmitted. The second is that the Chinese might develop the universal quantum computer first and be able to decipher all of the data being carried over the internet in the U.S. — since the U.S. has almost no effort in developing quantum cryptography nationwide.

Response to NITRD, NCO, NSF Request for Information on «Update to the 2016 National Artificial Intelligence Research and Development Strategic Plan»

Por • 24 nov, 2019 • Category: Ciencia y tecnología

We present a response to the 2018 Request for Information (RFI) from the NITRD, NCO, NSF regarding the «Update to the 2016 National Artificial Intelligence Research and Development Strategic Plan.» Through this document, we provide a response to the question of whether and how the National Artificial Intelligence Research and Development Strategic Plan (NAIRDSP) should be updated from the perspective of Fermilab, America’s premier national laboratory for High Energy Physics (HEP). We believe the NAIRDSP should be extended in light of the rapid pace of development and innovation in the field of Artificial Intelligence (AI) since 2016, and present our recommendations below. AI has profoundly impacted many areas of human life, promising to dramatically reshape society — e.g., economy, education, science — in the coming years.

La esencia de la guerra y el concepto NEC

Por • 19 nov, 2019 • Category: Ciencia y tecnología

El esquema de tres niveles de conducción –que es el que está en vigor, no sólo en la Doctrina Conjunta Española (6) sino prácticamente en todas las naciones de la Alianza Atlántica–, no ha estado, sin embargo, libre de ataques durante su ya largo siglo de vida. Pero es en el nacimiento del siglo XXI cuando se habla de la aparición de una profunda transformación de los «asuntos militares», y reputados oficiales y pensadores creen que una buena parte de la doctrina sobre la que se ha edificado la conducción de la guerra en Occidente ya no es válida. Y ello porque ha aparecido un concepto, que ciertamente todavía es difuso, el NEC (Network Engagement Capability o Network Enabled Capability (7), que para estos autores invalida, al menos parcialmente, la división de las operaciones militares en los tres niveles clásicos de conducción; pero que además pone también en cuestión algunos otros fundamentos teóricos de cómo entendemos la guerra, sobre todo los clausewitzianos, para introducir conceptos nuevos, tales como el combate en red, los efectos, o la auto-sincronización.

Google revives controversial cold-fusion experiments

Por • 18 nov, 2019 • Category: Ciencia y tecnología

Since 2015, Google has been funding experiments into the controversial science of cold fusion — the theory that nuclear fusion, the process that powers the Sun, can produce energy in a table-top experiment at room temperature. Two scientists first made sensational claims about achieving the phenomenon — promising endless, cheap energy — 30 years ago, but their results were quickly debunked and the topic is now considered a scientific taboo. The Google team explored three experimental set-ups that have been proposed to generate cold fusion — two involving palladium and hydrogen, and one involving metallic powders and hydrogen. None found evidence of fusion. The results have been published across 12 papers over the past 2 years: 9 in peer-reviewed journals and 3 on the arXiv preprint server.

On low-energy nuclear reactions

Por • 16 nov, 2019 • Category: Ciencia y tecnología

Based on our recent theoretical findings (Phys. Rev. C 99, 054620 (2019)) it is shown that proton and deuteron capture reactions of extremely low energy may have accountable rate in the case of all elements of the periodic table. Certain numerical results of rates of nuclear reactions of two final fragments of extremely low energy are also given. New way of thinking about low-energy nuclear reactions (LENR) phenomena is suggested. Possible explanations for the contradictory observations announced between 1905-1927 and possible reasons for negative results of ‘cold fusion’ experiments published recently by the Google-organized scientific group (this https URL) are given.

Concepts for a deuterium-deuterium fusion reactor

Por • 5 nov, 2019 • Category: Ciencia y tecnología

We revisit the assumption that reactors based on deuterium-deuterium (D-D) fusion processes have to be necessarily developed after the successful completion of experiments and demonstrations for deuterium-tritium (D-T) fusion reactors. Two possible mechanisms for enhancing the reactivity are discussed. Hard tails in the energy distribution of the nuclei, through the so-called kappa-distribution, allow to boost the number of energetic nuclei available for fusion reactions. At higher temperatures than usually considered in D-T plasmas, vacuum polarization effects from real e + e − and μ + μ − pairs may provide further speed-up due to their contribution to screening of the Coulomb barrier.

Brain Reaction Times. From Individual to Collective Description

Por • 1 nov, 2019 • Category: Ciencia y tecnología

An individual’s reaction time data to visual stimuli have usually been represented in Experimental Psychology by means of an ex-Gaussian function (EGF). In most previous works, researchers have mainly aimed at finding a meaning for the three parameters of the EGF in relation to psychological phenomena. We will focus on interpreting the reaction times (RT) of a group of individuals rather than a single person’s RT which is relevant for the different contexts of social sciences. In doing so, the same model as for the Ideal Gases (IG) emerges from the experimental reaction time data. We show that the law governing the experimental RT of a group of individuals is the same as the law governing the dynamics of an inanimate system, namely, a system of non-interacting particles (IG). Both systems are characterized by a collective parameter which is k_BT for the system of particles and what we have called life span parameter for the system of brains.

Leveraging Secondary Storage to Simulate Deep 54-qubit Sycamore Circuits

Por • 25 oct, 2019 • Category: Ciencia y tecnología

In a recent paper, we showed that secondary storage can extend the range of quantum circuits that can be practically simulated with classical algorithms. Here we refine those techniques and apply them to the simulation of Sycamore circuits with 53 and 54 qubits, with the entanglement pattern ABCDCDAB that has proven difficult to classically simulate with other approaches. Our analysis shows that on the Summit supercomputer at Oak Ridge National Laboratories, such circuits can be simulated with high fidelity to arbitrary depth in a matter of days, outputting all the amplitudes.

Quantifying Complexity

Por • 20 oct, 2019 • Category: Ciencia y tecnología

In spite of all the interest and importance of complexity, this concept remains elusive. In particular, several attempts at defining and/or quantifying complexity have, at some point, run into intrinsic difficulties. This didactic text provides a brief review of some of the approaches that have been used to characterize complexity, and also suggests a possible definition of complexity based on the cost assigned to mapping the entity of interest, as well as on the cost of the error implied by its respective reconstruction.