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Continuity of Quantum Entropic Quantities via Almost Convexity
(IEEE, 2023-09-01) Bluhm, Andreas; Capel, Angela; Gondolf, Paul; Pérez Hernández, Antonio; Agencia Estatal de Investigación; Comunidad de Madrid
Based on the proofs of the continuity of the conditional entropy by Alicki, Fannes, and Winter, we introduce in this work the almost locally affine (ALAFF) method. This method allows us to prove a great variety of continuity bounds for the derived entropic quantities. First, we apply the ALAFF method to the Umegaki relative entropy. This way, we recover known almost tight bounds, but also some new continuity bounds for the relative entropy. Subsequently, we apply our method to the Belavkin-Staszewski relative entropy (BS-entropy). This yields novel explicit bounds in particular for the BS-conditional entropy, the BS-mutual and BS-conditional mutual information. On the way, we prove almost concavity for the Umegaki relative entropy and the BS-entropy, which might be of independent interest. We conclude by showing some applications of these continuity bounds in various contexts within quantum information theory.
Exponential Decay of Mutual Information for Gibbs states of local Hamiltonians
(Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften, 2022-02-10) Bluhm, Andreas; Capel, Ángela; Pérez Hernández, Antonio; Agencia Estatal de Investigación; European Union’s Horizon 2020; Comunidad de Madrid
The thermal equilibrium properties of physical systems can be described using Gibbs states. It is therefore of great interest to know when such states allow for an easy description. In particular, this is the case if correlations between distant regions are small. In this work, we consider 1D quantum spin systems with local, finite-range, translation-invariant interactions at any temperature. In this setting, we show that Gibbs states satisfy uniform exponential decay of correlations and, moreover, the mutual information between two regions decays exponentially with their distance, irrespective of the temperature. In order to prove the latter, we show that exponential decay of correlations of the infinite-chain thermal states, exponential uniform clustering and exponential decay of the mutual information are equivalent for 1D quantum spin systems with local, finite-range interactions at any temperature. In particular, Araki's seminal results yields that the three conditions hold in the translation-invariant case. The methods we use are based on the Belavkin-Staszewski relative entropy and on techniques developed by Araki. Moreover, we find that the Gibbs states of the systems we consider are superexponentially close to saturating the data-processing inequality for the Belavkin-Staszewski relative entropy.
Improved radiation shielding analysis considering vector calculus
(Wiley, 2020-09-08) Juárez Mañas, Rafael; Loughlin, Michael; López Revelles, Antonio Jesús; Pedroche Sánchez, Gabriel; Kolsek, Aljaz; Sauvan, Patrick; Sanz Gozalo, Javier
The future of nuclear energy in the energy mix faces a permanent scrutiny of safety aspects in conciliation with bridled costs, either fission- or fusion-based. This affects to all the exciting milestones pursued in XXIst. To name few in the field of fission, the deployment of the IVth generation reactors is expected or the definitive solution to the radioactive wastes is sought. A mention apart is made to fusion technology, with ITER as the flagship project. It seeks a virtually infinite energy source, intrinsically safe and with reduced radioactive waste production with respect to fission the first commercial reactor. All these, and many other endeavors, share the operation of sophisticated devices in the presence of intense ionizing radiation fields. Humans and electronics must be protected to ensure safe and reliable performance, while shielding normally represents a large fraction of the budget. This involves nuclear analysis in the design phase to forecast the radiation conditions. The complexity of the simulation of 3D radiation fields that is computationally affordable nowadays is unprecedented. While sophistication in geometries and source definitions has become routine, the resulting complexity of these scalar fields makes their analysis increasingly difficult. The need of enhancement of the analysis techniques is evident today. Vector calculus is proposed following a physical interpretation of the field lines that boosts the analysis capabilities. It identifies the trajectories around which shielding is weakest in an automated errorless and effortless approach. Its power is illustrated with an example relevant to the ITER reactor.
Intermittent demand forecasting of aerospace rotable parts. A framework for unpredictable flight patterns
(Elsevier, 2026-02-22) Olmo, Manuel del; Domingo Navas, María Rosario
Demand forecasting of aerospace spare parts has a high impact on aircraft maintenance operations, aircraft serviceability and companies’ profitability. Traditional forecasting methods used in the industry utilise past consumption for forecasting future demand, often overlooking operational data. Incorporating fleet usage-data for capturing service variability in demand forecasting methods is crucial in operations with unpredictable flight patterns, like military aircrafts, business jets, and different air services, like air ambulances, search and rescue or policing operations. In this paper, we present the development of a machine learning (ML) framework for the forecasting of aerospace rotable components, generally life limited or inspected regularly. Different traditional and ML-based forecasting methods are reviewed, the impact of different service-related features is analysed, and a framework for addressing the potential service variability of an asset during its lifetime is proposed. The framework is validated with historical spare parts consumption of a European maintenance, repair and overhaul (MRO) service centre, achieving the most accurate demand forecast in 99.2% of the stock keeping units (SKUs) analysed compared to traditional baselines.
ITER full model in MCNP for radiation safety demonstration
(Nature Research, 2024-10-03) Juárez Mañas, Rafael; Belotti, Mario; Kolsek, Aljaz; López Ochoa, Víctor; Alguacil Orejudo, Javier; Pedroche Sánchez, Gabriel; López Revelles, Antonio Jesús; Martínez Albertos, Pablo; De Pietri, Marco; Guijosa Araez, Pol; Tonqueze, Y. Le; Loughlin, M. J.; Polunovskiy, E.; Pampin, R.; Fabbri, M.; Sanz, J.
The development of nuclear fusion as a safe and virtually limitless power source is receiving growing attention in the context of looming energy crisis and climate change. ITER project stands as the flagship international initiative and is advancing steadily. The construction of the Tokamak Complex is nearly finished, and the assembly of core components has begun on site. Simultaneously, the design is being finalized, and the safety case is becoming more concrete. Current approaches to radiation safety demonstration using 3D nuclear analysis with the Monte Carlo code MCNP require sophisticated artifacts to sew together simulations in separate models for the Tokamak and the rest of the facility. This results in cumbersome studies and, consequently, challengeable conclusions. To address this issue, we have built the an integral MCNP model of the ITER facility: the ITER full model. Along with improvements to the D1SUNED code, we illustrate its computational practicality and pertinence in two meaningful simulations for ITER safety case. This work represents the culmination of a two-decade-long effort of ITER modelling aiming to demonstrate adequate radiation safety. Beyond supporting the remaining design tasks, this model simplifies the corresponding 3D nuclear analysis and improves the robustness of the ITER safety case.
ITER plasma source and building modelling to produce radiation maps
(IOP Publishing, 2018-09-27) Juárez Mañas, Rafael; Catalán Pérez, Juan Pablo; López Revelles, Antonio Jesús; Sauvan, Patrick; Jakhar, Shrichand; Polunovskyi, Edouard; Loughlin, Michael; Sanz Gozalo, Javier; Ogando Serrano, Francisco M.
The ITER Tokamak Complex is the civil structure that will host the ITER Tokamak and the largest part of the associated systems. The dimensions are 120 m × 80 m × 60 m, built mostly of concrete, with over one thousand penetrations. During ITER operation, a radiation field will spread throughout the complex from diverse radiation sources. It must be characterized to check the compliance with the limits for electronics allocation and human intervention. However, the production of radiation maps in the ITER Tokamak Complex is a task of paramount sophistication due to challenges to adequately model in MCNP the radiation sources involved. In this work, two important methodological upgrades are presented. First, a new MCNP model of the Tokamak Complex, conceived to be computationally stable while capturing a conservative representation of the baseline. Second, a novel approach to model the plasma source, called a mosaic source, allows an unprecedented degree of realism and accuracy in terms of capturing the port specificities. Both represent a step change in the capacity to produce ITER radiation maps with increased reliability, augmenting previous versions. Examples of partial radiation maps are provided considering both methodological upgrades.
Locality Estimates for Complex Time Evolution in 1D
(Springer, 2023-01-03) Pérez García, David; Pérez Hernández, Antonio; Agencia Estatal de Investigación; Comunidad de Madrid
It is a generalized belief that there are no thermal phase transitions in short range 1D quantum systems. However, the only known case for which this is rigorously proven is for the particular case of finite range translationally invariant interactions. The proof was obtained by Araki in his seminal paper of 1969 as a consequence of pioneering locality estimates for the time-evolution operator that allowed him to prove its analyticity on the whole complex plane, whenappliedtoalocalobservable. However, as for nowthere is no mathematical proof of the absence of 1D thermal phase transitions if one allows exponential tails in the interactions. In this work we extend Araki’s result to include exponential (or faster) tails. Our main result is the analyticity of the timeevolution operator applied on a local observable on a suitable strip around the real line. As a consequence we obtain that thermal states in 1D exhibit exponential decay of correlations above a threshold temperature that decays to zero with the exponent of the interaction decay, recovering Araki’s result as a particular case. Our result however still leaves open the possibility of 1D thermal short range phase transitions. We conclude with an application of our result to the spectral gap problem for Projected Entangled Pair States (PEPS) on 2D lattices, via the holographic duality due to Cirac et al.
MCNP model of the ITER Tokamak Complex
(Elsevier, 2018-04-11) López Revelles, Antonio Jesús; Catalán Pérez, Juan Pablo; Kolsek, Aljaz; Juárez Mañas, Rafael; Rodríguez García, Raquel; García Camacho, Mauricio; Sanz Gozalo, Javier
The Tokamak Complex will accommodate the ITER tokamak and some of the plant systems needed for the machine operation. In order to obtain radiation maps in the Tokamak Complex, a new MCNP model was released on September 2016. This model, based on a conservative representation of the latest baseline design, represents a version controlled, computationally stable, user-friendly and easy-to-update and maintain MCNP input of the Tokamak Complex. Every modification of the initial CAD models was reviewed, recorded and version controlled. The MCNP model of the Tokamak Complex uses the most stable MCNP geometry implementations, avoiding the use of universes and macrobodies. The input exhibits a low particle loss rate (<10−9) when running in void with a dispersed isotropic source. It is strongly organized and profusely commented. Information about the level, building, room, system and material is provided in the definition of every cell. The 36862 cells and 57085 surfaces are arranged by levels and by buildings. The cells are also arranged by rooms and by systems, resulting in a room-oriented organization of the model, which allows an easy isolation of every room.
Nuclear analysis of the ITER Torus Cryopumps
(IOP Publishing, 2019-09-09) Pedroche Sánchez, Gabriel; López Revelles, Antonio Jesús; Kolsek, Aljaz; Dremel, Matthias; Bansal, Gurpreet; Pearce, Robert; Sanz Gozalo, Javier; Juárez Mañas, Rafael
The ITER Tokamak will feature six torus cryopumps (TCP) to maintain the vacuum requirements inside the vacuum vessel for plasma operation. They will be connected to the ITER vacuum vessel through the lower ducts, which have limited shielding to ensure an efficient pumping. Therefore, these ducts will represent a relevant path for radiation to travel from the plasma and affect diverse aspects of the ITER facility, such as the electronics allocation or the maintenance operations during the machine shutdown. Previous analyses have addressed these important aspects. Nonetheless, limitations in those studies and design evolution have justified a new analysis, specifically dedicated to the TCP final design review. The results of the nuclear analysis are presented here focusing on the B1 level port cell #4. The TCP design and the associated and neighboring equipment have evolved and updated models have been considered. The TCP modelling has required an explicit heterogeneous treatment of the internal parts. The radiation source from the divertor cooling water pipes running along the port cell ceiling has been considered with the latest available source definition. In terms of methodology, one major improvement has been the modelling of the radiation transmission from C-model to the Tokamak Complex model. Another important improvement has been the consideration of D1SUNED for the determination of shutdown dose rates, covering a broader fraction of the radioactive inventory than in previous studies. The following quantities have been determined: neutron flux, absorbed dose to silicon, 1 MeV equivalent neutron fluence and shutdown dose rates (SDDR) after 106 s of cooling time. Finally, a set of proposals have been made to considerably mitigate the SDDR after 106 s of cooling. This work represents a realistic and matured source of information of the radiation environment in the ITER TCP port cells as presented in the final design review.
Optimizing Radiation Shielding for Fusion Maintenance Facilities: Insights From a Comprehensive Analysis of ITER Hot Cell
(WILEY, 2025-05-19) Martínez Albertos, Pablo; Sauvan, Patrick; Catalán Pérez, Juan Pablo; Belotti, Mario; Javier, François; Germa, Joffrey; Tonqueze, Y. Le; Dammann, Alexis; Juárez Mañas, Rafael; ITER Organization (IO)
One of the primary goals of the ITER project is to demonstrate the safety characteristics of a fusion device, particularly in terms of radiation management. Radiation protection during maintenance periods is of special concern, as personnel performing maintenance-like activities will be exposed to delayed gamma fields from numerous and complex radioactive components. Ensuring a safe and equipped environment for such activities is the objective of the ITER hot cell. This facility requires extensive design optimization, balancing spatial and temporal availability constraints, radiation protection, and cost-effectiveness. In this paper, we present a comprehensive assessment of ITER hot cell’s radiation environment to support its efficient design and safe operation. The study evaluates the shielding efficiency of the conceptual design layout from 2021, providing meaningful insights for layout improvement. We show that substantial amounts of concrete (~2900 m3) could be saved from the currently evolving design while respecting radiological requirements. The evaluation of the occupational radiation exposure (ORE) associated with hot cell maintenance activities resulted in 179 man·mSv·year−1, which represents a significant fraction (36%) of the project’s annual budget. This highlights the importance of integrating shielding analysis, accounting for personnel radiation exposure, even in early design phases, to support the optimization of the maintenance plan according to safety requirements.
Resiliencia en llamas. Repensando la Seguridad frente a los Incendios Forestales en el marco de los Objetivos de Desarrollo Sostenible
(Servicio de Publicaciones e Imagen Institucional. Universidad de Burgos, 2026-04-06) Romero Barriuso, Álvaro; Rubio Rivas, Eduardo; Villena Escribano, Blasa María; Valle Maquinay, David del; González Gaya, Cristina
El libro analiza los incendios forestales (IIFF) como emergencias multirriesgo con efectos directos en la seguridad y la salud, y propone usar la Agenda 2030 y sus Objetivos de Desarrollo Sostenible (ODS) como marco operativo para pasar de la reacción a la gestión del riesgo y la prevención. Presenta evidencias de la magnitud del problema, más de 700 fallecidos en Europa entre 2000 y 2018, y una tendencia a incendios más extensos e intensos impulsados por el cambio climático. Pide priorizar resiliencia, anticipación y cooperación internacional. El texto actualiza conceptos. Describe la transición desde el “gran incendio” por superficie a categorías que consideran intensidad, velocidad y simultaneidad, con incendios capaces de generar pirocúmulos y comportamientos erráticos. Identifica umbrales de intensidad que delimitan la eficacia y seguridad de la extinción, 2000 kW/m para ataque terrestre, 4000 kW/m con apoyo aéreo, ausencia de eficacia por encima de 10000 kW/m. Documenta valores extremos en Pedrógão Grande en 2017, 20000 a 60000 kW/m y 65 m/min de propagación. Expone dos vectores críticos para la salud pública. Primero, la contaminación atmosférica asociada a los humos, especialmente PM2,5, que se desplaza a largas distancias y se asocia a incrementos de morbilidad y mortalidad respiratoria y cardiovascular, con episodios que han alcanzado 700 a 1800 µg/m³ en distintos países. Reclama más investigación en Europa y protección específica de los intervinientes. Segundo, la expansión de la interfaz urbano forestal incrementa evacuaciones, atrapamientos y daños en infraestructuras. En 2022 se evacuaron más de 30000 personas en España por IIFF, con múltiples heridos y fallecidos, dentro de un patrón que también se observa en Australia, Estados Unidos, Portugal y Grecia. El marco de acción propuesto se alinea con los ODS y el Marco de Sendai. ODS 13 orienta medidas contra el cambio climático que agrava frecuencia y comportamiento del fuego. ODS 3 y 6 implican mitigar contaminación del aire y del agua tras incendios. ODS 11 impulsa planificación urbana, ordenación del territorio y adaptación de construcciones en IUF. ODS 15 promueve gestión forestal preventiva. ODS 17 exige alianzas, interoperabilidad y estándares de gestión de emergencias. El libro prioriza cuatro líneas estratégicas. Diseñar una estrategia global que integre clima y salud pública, con inversión sostenida y evaluación por indicadores. Reforzar la gestión integral de emergencias, con sistemas de mando estandarizados y modulares interoperables con Incident Command System (ICS) y Gestion Opérationelle et Commandement (GOC), y un uso eficaz del Mecanismo Europeo de Protección Civil. Desarrollar conocimiento y tecnología aplicada, IA y realidad virtual para planificación y entrenamiento, además de drones, robots y radiosondeos para apoyo táctico. Avanzar hacia la resiliencia mediante reequilibrio del gasto hacia prevención y manejo del combustible, educación y autoprotección, y participación comunitaria que fije población rural y reduzca vulnerabilidades locales
Sensitivity to nuclear data of the design of the IFMIF-DONES beam dump
(Frontiers, 2023-06-05) López Ochoa, Víctor; Ogando Serrano, Francisco M.; Sauvan, Patrick
During the commissioning and start-up phases of IFMIF-DONES, the 40MeV deuteron beam will be stopped in a conical beam stopper made of copper, giving rise to intense neutron fields. Accurate coupled deuteron-neutron transport simulations are required in order to prevent the potential risks to the workers andequipmentinvolved. However, theexperimental data concerning the neutron emission under these circumstances is scarce and limited to a particular range of energies. Different deuteron nuclear data libraries such as JENDL-5 and special f iles of TENDL-2021 exhibit some differences on the spectrum of the emitted neutrons. The differences are present in thehigh energy tails, beyond the available experimental data. Calculations of the prompt neutron fields have been performed employing both deuteron data libraries, as well as employing an estimation of the neutron energy-angle distribution derived from experimental data at different irradiation energies. Even though the high energy tails represent a small part of the flux, they have a major impact on the dose rates. The disparity of the results evinces large uncertainties in the IFMIF-DONES beam dump design process. Further experiments are required in order to resolve the differences among nuclear data libraries and reduce the uncertainty.
Shutdown dose rates calculations due to light ions induced activation using D1S methodology
(ELSEVIER, 2021-06-01) López Ochoa, Víctor; Sauvan, Patrick; Ogando Serrano, Francisco M.
One of the main radiation sources in nuclear facilities, which cause exposure of workers conducting maintenance activities, is the decay of radioactive nuclides. The determination of these radiation fields usually requires both radiation transport and activation calculations. The Direct-one-Step methodology allows obtaining response functions associated to the residual activity with a single Monte Carlo transport calculation. This methodology has been widely used in the analysis of nuclear fusion installations like ITER, JET or DEMO, proving to be a very efficient tool for Shutdown Dose Rate calculations. Yet, this methodology has only been applied when the material activation is due to the interaction with a neutron flux. Since, typically, in particle accelerators the D1S assumptions are met, it is proposed in this work to apply the D1S methodology to material activation induced by light ions interactions, namely: protons and deuterons. This methodology has been implemented in the D1SUNED code. In order to show its performance, the D1SUNED has been used to calculate the SDR in the LIPAc geometry, resulting in a good convergence with a reference calculation.
Strong Decay of Correlations for Gibbs States in Any Dimension
(Springer, 2025-09-29) Bluhm, Andreas; Capel, Ángela; Pérez Hernández, Antonio; Agencia Estatal de Investigación; Comunidad de Madrid
Quantum systems in thermal equilibrium are described using Gibbs states. The correlations in such states determine how difficult it is to describe or simulate them. In this article, we show that if the Gibbs state of a quantum system satisfies that each of its marginals admits a local effective Hamiltonian with short-range interactions, then it satisfies a mixing condition, that is, for any regions A, C the distance of the reduced state on these regions to the product of its marginals, ρACρ−1 A ⊗ρ−1 C −1AC , decays exponentially with the distance between regions A and C. This mixing condition is stronger than other commonly studied measures of correlation. In particular, it implies the exponential decay of the mutual information between distant regions. The mixing condition has been used, for example, to prove positive log-Sobolev constants. On the way, we prove that the the condition regarding local effective Hamiltonian is satisfied if the Hamiltonian only has commuting interactions which also commute with every marginal of their products. The proof of these results employs a variety of tools such as Araki’s expansionals, quantum belief propagation and cluster expansions.
Thermalization in Kitaev’s quantum double models via tensor network techniques
(Cambridge Universirty Press, 2023-11-28) Lucia, Angelo; Pérez García, David; Pérez Hernández, Antonio; Agencia Estatal de Investigación; Comunidad de Madrid
We show that every ergodic Davies generator associated to any 2D Kitaev’s quantum double model has a nonvanishing spectral gap in the thermodynamic limit. This validates rigorously the extended belief that those models are useless as self-correcting quantum memories, even in the non-abelian case. The proof uses recent ideas and results regarding the characterization of the spectral gap for parent Hamiltonians associated to Projected Entangled Pair States in terms of a bulk-boundary correspondence.
Update in the nuclear responses of the European TBMs for ITER during operation and shutdown
(Elsevier, 2018-07-06) Juárez Mañas, Rafael; López Revelles, Antonio Jesús; Sauvan, Patrick; Pedroche Sánchez, Gabriel; Kolsek, Aljaz; Alguacil Orejudo, Javier; Ugolini, Daniele; Vallory, Joelle; Ricapito, Italo; Poitvein, Yves; Calvo, Francisco; Sanz Gozalo, Javier
The depiction of the nuclear responses of the ITER European Test Blanket Modules (TBMs), Helium Cooled Lithium Lead (HCLL) and Helium Cooled Pebbles Bed (HCPB) is presented in this work. Following important components update, and important methodological advances, the nuclear heat and the tritium production have been revisited, giving new estimations 10% higher than the previous evaluation for nuclear heat in both TBMs and to 15% higher for HCPB T production. This has an impact on the thermo-mechanical design of the TBM and the tritium handling. In addition, the Shutdown Dose Rates in the respective port interspace have been characterized in local approach. It shows a performance that could imply compatibility with planned in-situ maintenance activities when analysed in global approach, an improvement with respect to previous evaluations.
Variants of a multiplier theorem of Kislyakov
(Cambridge University Press, 2022-09-01) Defant, Andreas; Mastyło, Mieczysław; Pérez Hernández, Antonio; Agencia Estatal de Investigación
We prove stronger variants of a multiplier theorem of Kislyakov. The key ingredients are based on ideas of Kislaykov and the Kahane–Salem–Zygmund inequality. As a by-product we show various multiplier theorems for spaces of trigonometric polynomials on the n-dimensional torus Tn or Boolean cubes {−1, 1}N. Our more abstract approach based on local Banach space theory has the advantage that it allows to consider more general compact abelian groups instead of only the multidimensional torus. As an application we show that various recent ℓ1-multiplier theorems for trigonometric polynomials in several variables or ordinary Dirichlet series may be proved without the Kahane–Salem–Zygmund inequality.

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