David Yllanes
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davidyllanes.bsky.social
David Yllanes
@davidyllanes.bsky.social
69 followers 120 following 29 posts
Físico teórico en BIFI-ZCAM (Unizar), aficionado a la historia y operófilo viajero.

Statistical mechanics, complex systems, biophysics, wargames and opera.
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davidyllanes.bsky.social
David Yllanes @davidyllanes.bsky.social · Dec 12
Spin glasses are the paradigmatic complex systems, but there had been a wide gap between theory and experiment (in time scales and in the accessible observables).

This disconnect has now been bridged, quantitatively. We have marked this progress by writing a joint experimental-theoretical review.
The study of spin-glass dynamics, long considered the paradigmatic complex system, has reached important milestones. The availability of high-quality single crystals has allowed the experimental measurement of spin-glass coherence lengths of almost macroscopic dimensions, while the advent of special-purpose massive computers enables dynamical simulations that approach experimental time and length scales. This review provides an account of the quantitative convergence of these two avenues of research, with precise experimental measurements of the expected scaling laws and numerical reproduction of classic experimental results, such as memory and rejuvenation. The article opens with a brief review of the defining spin-glass properties, randomness and frustration, and their experimental consequences. These apparently simple characteristics are shown to generate rich and complex physics. Models are introduced that enable quantitative descriptions. After a summary of the main numerical results in equilibrium, paying particular attention to the concept of temperature chaos, this review examines off-equilibrium dynamics in the absence of a magnetic field and shows how it can be related to equilibrium structures through the fluctuation-dissipation relations. The nonlinear response at a given temperature is then developed, including experiments and scaling in the vicinity of the transition temperature Tg. The consequences of temperature change -- including temperature chaos, rejuvenation, and memory -- are reviewed. The interpretation of these phenomena requires identifying several length scales relevant to dynamics, which, in turn, generate new insights. Finally, issues for future investigations are introduced, including what is to be nailed down theoretically, why the Ising Edwards-Anderson model is so successful at modeling spin-glass dynamics, and experiments yet to be undertaken. Table of contents of the review.
Reposted by David Yllanes
morganegr.bsky.social
At the invitation of the organization team (which includes one of my star beta testers, @davidyllanes.bsky.social, I got to present my new game @gmtgames.bsky.social Hubris - Twilight of the Hellenistic World, which was a ton of fun for the players and myself!
November 23, 2025 at 10:05 PM
Reposted by David Yllanes
morganegr.bsky.social
Back home tired but delighted after a wonderful 4-days trip to Zaragoza to attend the top notch Batalladores 2025 convention masterfully organized by @clubbatallador.bsky.social
So impressed, and not a little jealous, by the super dynamic ConSim community in Spain.
November 23, 2025 at 10:01 PM
davidyllanes.bsky.social
¡Gracias a todos por venir a #Batalladores2025 y os esperamos el año que viene!

@clubbatallador.bsky.social
Foto de conjunto de la organización de la convención de juegos de simulación histórica Batalladores 2025.
November 23, 2025 at 5:04 PM
davidyllanes.bsky.social
Happy to report that our project "From Neural Networks to Proteins: Modelling Complexity Through Spin-Glass Physics" is being funded by the Spanish MICIU.

Especially since this is a UCM-Unizar coordinated grant, whose Madrid PI is my friend and long-time collaborator
@betapata.bsky.social.
The co-PIs in more carefree times, attending the 2013 Statphys conference in Seoul as postdocs from La Sapienza Università di Roma.
July 30, 2025 at 9:06 AM
davidyllanes.bsky.social
Ya tenemos montado el mapa y todas las plantillas y registros para la gran campaña del GTS de Utah de MMP en el Club Dragón de Madrid. Mucho bocage que atravesar. Luce estupendo en la mesa el mapa de Nicolás Eskubi. Ahora a empezar con las fichas.
Vista general del mapa de la campaña completa de Utah (siete piezas). La playa de desembarco se aprecia en la esquina superior derecha. El área cubierta atraviesa la península de Cotentin, una zona cubierta de terreno difícil y denso. Alrededor, las plantillas de las seis divisiones alemanas y las cinco estadounidenses y del apoyo naval y de cuerpo, así como el registro de turnos y diversas tablas. Ampliación de la zona de desembarco. Otra perspectiva de la vista general, con las divisiones alemanas y las tablas de terreno en primer plano. Esquema de la disposición de los mapas individuales para la campaña. El juego incluye también multitud de escenarios que utilizan solo parte de la zona (por ejemplo, asaltos paracaidistas en Ste.-Mère-Église o simulación exclusivamente del desembarco en la playa, pero también encuentros en otras zonas del mapa a largo de las dos semanas de campaña).
April 6, 2025 at 8:17 AM
davidyllanes.bsky.social
Mi primera visita a la Staatsoper Stuttgart. En cartel, «El jugador» de Prokófiev. Aušrinė Stundytė, Goran Jurić, Daniel Brenna, Véronique Gens.
Fachada de la ópera de Stuttgart poco antes de la función el 15 de marzo de 2025. Cartel de «El jugador» («Игрок») de Prokófiev. Antes de la función, sobre el telón bajado se proyecta una carta de Alekséi a Polina en inglés, alemán y ruso. Interior de la ópera de Stuttgart antes de la función.
March 16, 2025 at 7:12 AM
Reposted by David Yllanes
davidyllanes.bsky.social
Fin de semana en la Oper Frankfurt que demuestra perfectamente las singulares fortalezas de esta compañía. Dos nuevas producciones de obras muy difíciles de ver que combinan de maravilla y funciones que descansan sobre su excelente grupo de cantantes de ensemble y sobre sus cuerpos estables.
David Yllanes entre los carteles de «Guercœur» y «Le Postillon de Lonjumeau», dos nuevas producciones de la Oper Frankfurt vistas este fin de semana. Saludos finales del «Guercœur». Se aprecia al fondo el escenario que muestra el edificio del Parlamento, derrumbado al final del segundo acto. Domen Križaj, AJ Glueckert y Claudia Mankhe lideran el el reparto, con dirección musical de Marie Jacquot y escénica de David Hermann. Römerberg de Fráncfort preparada para el desfile del domingo de Carnaval.
March 3, 2025 at 9:20 AM
davidyllanes.bsky.social
Fin de semana en la Oper Frankfurt que demuestra perfectamente las singulares fortalezas de esta compañía. Dos nuevas producciones de obras muy difíciles de ver que combinan de maravilla y funciones que descansan sobre su excelente grupo de cantantes de ensemble y sobre sus cuerpos estables.
David Yllanes entre los carteles de «Guercœur» y «Le Postillon de Lonjumeau», dos nuevas producciones de la Oper Frankfurt vistas este fin de semana. Saludos finales del «Guercœur». Se aprecia al fondo el escenario que muestra el edificio del Parlamento, derrumbado al final del segundo acto. Domen Križaj, AJ Glueckert y Claudia Mankhe lideran el el reparto, con dirección musical de Marie Jacquot y escénica de David Hermann. Römerberg de Fráncfort preparada para el desfile del domingo de Carnaval.
March 3, 2025 at 9:20 AM
davidyllanes.bsky.social
Hoy ha tocado «Der Kreidekreis» de Zemlinsky, compositor que debería poder verse mucho más, en la Deutsche Oper am Rhein de Düsseldorf.

Antes, visita al pequeño pero muy apañado Filmmuseum Düsseldorf.
Interior de la Opernhaus Düsseldorf antes de empezar la función. Mesa de montaje original que utilizó Lotte Reiniger en su etapa en la BBC en los años 50, parte de una completa exposición permanente sobre la directora. Maqueta que recrea el sistema empleado por Méliès para crear el efecto de una cabeza hinchable en «El hombre de la cabeza de goma».
January 12, 2025 at 9:09 PM
davidyllanes.bsky.social
Deliciosa «Čert a Káča» («El diablo y Catalina», Dvořák) en el Teatro Nacional de Praga. Una divertida y vistosa producción con una estética de ilustración infantil que refuerza su carácter de cuento de hadas.
Saludos al final de la función. Se aprecian algunos de los diseños del ilustrador Alfred Born. Interior del Teatro Nacional de Praga, todavía sin público antes de empezar la función. Vista del río Moldova y del puente de Carlos, con el castillo de Praga asomando al fondo. La torre de la Pólvora por la noche.
January 12, 2025 at 9:22 AM
davidyllanes.bsky.social
Our first paper of 2025 is now published (open access) on Physical Review Research (doi.org/10.1103/Phys...)

We present a method to generate Markov-chain trajectories constrained to an initial and a final state (Markov bridges), which we apply to scRNA data to study cell-differentiation pathways.
We present a method to sample Markov-chain trajectories constrained to both the initial and final conditions, which we term Markov bridges. The trajectories are conditioned to end in a specific state at a given time. We derive the master equation for Markov bridges, which exhibits the original transition rates scaled by a time-dependent factor. Trajectories can then be generated using a refined version of the Gillespie algorithm. We illustrate the benefits of our method by sampling trajectories in the Müller-Brown potential. This allows us to generate transition paths which would otherwise be obtained at a high computational cost with standard kinetic Monte Carlo methods because commitment to a transition path is essentially a rare event. We then apply our method to a single-cell RNA sequencing dataset from mouse pancreatic cells to investigate the cell differentiation pathways of endocrine-cell precursors. By sampling Markov bridges for a specific differentiation pathway, we obtain a time-resolved dynamics that can reveal features such as cell types which behave as bottlenecks. The ensemble of trajectories also gives information about the fluctuations around the most likely path. For example, we quantify the statistical weights of different branches in the differentiation pathway to alpha cells. Markov bridges for the pancreas dataset, with N = 3696, αi = 1103 (ductal state) and tf = 100. We study the transition towards the final state (a) αf = 2379 (beta cell type) and (b) αf = 3437 (alpha cell type). We generated 512 bridge trajectories in each case. The state coordinates are the first two components of a UMAP analysis.
January 9, 2025 at 6:02 PM
Reposted by David Yllanes
davidyllanes.bsky.social
Lo más jugado por mí en 2024 (en tiempo total, en número de partidas el primero sería el «Ivanhoe», con 12). Creo que hay una buena mezcla de clásicos y novedades, así como una gran varianza en longitud y complejidad.

He compartido partidas con 53 jugadores y probado 42 juegos.
Mis 16 juegos con mayor tiempo total de juego en 2024: 1) OCS Hungarian Rhapsody (MMP), 63 h. 2) Advanced Squad Leader (MMP), 35 h. 3) OCS Tunisia II (MMP), 26 h. 4) OCS Sicily II (MMP), 25 h. 5) Downfall (GMT), 22 h. 6) Arcs (Leder Games), 19 h. 7) BCS Arracourt (MMP), 18 h. 8) GTS Strike-Counterstrike (MMP), 16 h. 9) Europe in Turmoil (Compass), 15 h. 10) Pursuit of Glory (GMT), 14 h. 11) BCS Brazen Chariots (MMP), 10 h. 12) La guerra del anillo (Devir), 9 h. 13) Star Wars Deckbuilding Game (FFG), 9 h. 14) John Company (Wehrlegig), 8 h. 15) Arcs: The Blighted Reach (Leder Games), 8 h. 16) Twilight Imperium (FFG), 8 h.
December 30, 2024 at 9:45 AM
davidyllanes.bsky.social
Lo más jugado por mí en 2024 (en tiempo total, en número de partidas el primero sería el «Ivanhoe», con 12). Creo que hay una buena mezcla de clásicos y novedades, así como una gran varianza en longitud y complejidad.

He compartido partidas con 53 jugadores y probado 42 juegos.
Mis 16 juegos con mayor tiempo total de juego en 2024: 1) OCS Hungarian Rhapsody (MMP), 63 h. 2) Advanced Squad Leader (MMP), 35 h. 3) OCS Tunisia II (MMP), 26 h. 4) OCS Sicily II (MMP), 25 h. 5) Downfall (GMT), 22 h. 6) Arcs (Leder Games), 19 h. 7) BCS Arracourt (MMP), 18 h. 8) GTS Strike-Counterstrike (MMP), 16 h. 9) Europe in Turmoil (Compass), 15 h. 10) Pursuit of Glory (GMT), 14 h. 11) BCS Brazen Chariots (MMP), 10 h. 12) La guerra del anillo (Devir), 9 h. 13) Star Wars Deckbuilding Game (FFG), 9 h. 14) John Company (Wehrlegig), 8 h. 15) Arcs: The Blighted Reach (Leder Games), 8 h. 16) Twilight Imperium (FFG), 8 h.
December 30, 2024 at 9:45 AM
Reposted by David Yllanes
davidyllanes.bsky.social
Spin glasses are the paradigmatic complex systems, but there had been a wide gap between theory and experiment (in time scales and in the accessible observables).

This disconnect has now been bridged, quantitatively. We have marked this progress by writing a joint experimental-theoretical review.
The study of spin-glass dynamics, long considered the paradigmatic complex system, has reached important milestones. The availability of high-quality single crystals has allowed the experimental measurement of spin-glass coherence lengths of almost macroscopic dimensions, while the advent of special-purpose massive computers enables dynamical simulations that approach experimental time and length scales. This review provides an account of the quantitative convergence of these two avenues of research, with precise experimental measurements of the expected scaling laws and numerical reproduction of classic experimental results, such as memory and rejuvenation. The article opens with a brief review of the defining spin-glass properties, randomness and frustration, and their experimental consequences. These apparently simple characteristics are shown to generate rich and complex physics. Models are introduced that enable quantitative descriptions. After a summary of the main numerical results in equilibrium, paying particular attention to the concept of temperature chaos, this review examines off-equilibrium dynamics in the absence of a magnetic field and shows how it can be related to equilibrium structures through the fluctuation-dissipation relations. The nonlinear response at a given temperature is then developed, including experiments and scaling in the vicinity of the transition temperature Tg. The consequences of temperature change -- including temperature chaos, rejuvenation, and memory -- are reviewed. The interpretation of these phenomena requires identifying several length scales relevant to dynamics, which, in turn, generate new insights. Finally, issues for future investigations are introduced, including what is to be nailed down theoretically, why the Ising Edwards-Anderson model is so successful at modeling spin-glass dynamics, and experiments yet to be undertaken. Table of contents of the review.
December 12, 2024 at 12:04 PM
davidyllanes.bsky.social
Spin glasses are the paradigmatic complex systems, but there had been a wide gap between theory and experiment (in time scales and in the accessible observables).

This disconnect has now been bridged, quantitatively. We have marked this progress by writing a joint experimental-theoretical review.
The study of spin-glass dynamics, long considered the paradigmatic complex system, has reached important milestones. The availability of high-quality single crystals has allowed the experimental measurement of spin-glass coherence lengths of almost macroscopic dimensions, while the advent of special-purpose massive computers enables dynamical simulations that approach experimental time and length scales. This review provides an account of the quantitative convergence of these two avenues of research, with precise experimental measurements of the expected scaling laws and numerical reproduction of classic experimental results, such as memory and rejuvenation. The article opens with a brief review of the defining spin-glass properties, randomness and frustration, and their experimental consequences. These apparently simple characteristics are shown to generate rich and complex physics. Models are introduced that enable quantitative descriptions. After a summary of the main numerical results in equilibrium, paying particular attention to the concept of temperature chaos, this review examines off-equilibrium dynamics in the absence of a magnetic field and shows how it can be related to equilibrium structures through the fluctuation-dissipation relations. The nonlinear response at a given temperature is then developed, including experiments and scaling in the vicinity of the transition temperature Tg. The consequences of temperature change -- including temperature chaos, rejuvenation, and memory -- are reviewed. The interpretation of these phenomena requires identifying several length scales relevant to dynamics, which, in turn, generate new insights. Finally, issues for future investigations are introduced, including what is to be nailed down theoretically, why the Ising Edwards-Anderson model is so successful at modeling spin-glass dynamics, and experiments yet to be undertaken. Table of contents of the review.
December 12, 2024 at 12:04 PM
davidyllanes.bsky.social
El plato fuerte del puente, «Palestrina» en la Wiener Staatsoper. Mucha expectación por un título tan difícil de ver.

Dirigida magistralmente (y con perceptible entusiasmo) por un Thielemann aún en muletas. Muy convincente Michael Spyres en el papel protagonista. El tercer acto ha sido bellísimo.
Thielemann se apoya en sus muletas mientras saluda al público y a la orquesta. Programa de mano de «Palestrina» en la Wiener Staatsoper. Producción de Wernicke. Saludos finales en «Palestrina».
December 9, 2024 at 10:50 AM
davidyllanes.bsky.social
Continúa el puente lírico. Hoy, «Der Prozess» de Gottfried von Einem. No la conocía, pero me había gustado mucho «Dantons Tod», del mismo compositor, en una anterior escapada vienesa y tenía expectación.

Interesante adaptación de la novela de Kafka y buena producción del Theater an der Wien.
Programa de mano de «Der Prozess» de Gottfried von Einem en el Theater an der Wien. Producción de Stefan Herheim en colaboración con el director musical Walter Kobéra. Anne-Fleur Werner invita al director Walter Kobéra a salir a saludar. Vista general del elenco saludando al público en la Kammeroper de Viena. La pareja protagonista. Ambos firman exitosas interpretaciones.
December 7, 2024 at 8:47 PM
davidyllanes.bsky.social
Abrimos este puente con «The Pirates of Penzance» en la English National Opera. Muy divertida reposición de la producción de Mike Leigh. James Creswell hace un buen trabajo como el sargento de policía.
Interior del London Coliseum antes de la función. Programa de mano de la función. Saludos generales. Se aprecia de fondo el gag visual final: una enorme imagen de la reina Victoria que aparece cuando la policía apela al espíritu patriótico (y monárquico) de los piratas, que resultan ser todos miembros de la nobleza. Plano más corto de los saludos. En el centro, el sargento de policía de James Creswell.
December 7, 2024 at 6:41 AM
davidyllanes.bsky.social
Gran triunfo de Lise Davidsen como Salomé en la Opéra de Paris. Vocalmente, lo mejor que le he visto con diferencia.

Te caes de la butaca cuando canta «Gib' mir den Kopf den Jochaanan».
May 25, 2024 at 8:56 PM
davidyllanes.bsky.social
Our paper on vibrations in strained nanoribbons is now out as an editor's suggestion in Phys. Rev. Materials.

These ribbons exhibit unusual scale- and temperature-dependent dynamics that could be exploited in the development of graphene-based actuators.

journals.aps.org/prmaterials/...
Illustration of the different phases of a doubly clamped nanoribbon (relaxed, stretched, buckled) and of the double-well potential (up and down state) in the buckled phase. Crystalline sheets (e.g., graphene and transition metal dichalcogenides) liberated from a substrate are a paradigm for materials at criticality, because flexural phonons can fluctuate into the third dimension. Although studies of static critical behaviors (e.g., the scale-dependent elastic constants) are plentiful, investigations of dynamics remain limited. Here, we use molecular dynamics to study the time dependence of the midpoint (the height center of mass) of doubly clamped nanoribbons, as prototypical graphene resonators, under a wide range of temperature and strain conditions. By treating the ribbon midpoint as a Brownian particle confined to a nonlinear potential (which assumes a double-well shape beyond the buckling transition), we formulate an effective theory describing the ribbon's transition rate across the two wells and its oscillations inside a given well.
January 9, 2024 at 5:05 PM
davidyllanes.bsky.social
Our latest preprint, led by G. Le Treut, is up on the arXiv.

We present a method to generate Markov-chain trajectories constrained to an initial and a final state (Markov bridges), which we apply to scRNA data from pancreatic cells to study cell-differentiation pathways

arxiv.org/abs/2312.08605
We present a method to sample Markov-chain trajectories constrained to both the initial and final conditions, which we term Markov bridges. The trajectories are conditioned to end in a specific state at a given time. We derive the master equation for Markov bridges, which exhibits the original transition rates scaled by a time-dependent factor. Trajectories can then be generated using a refined version of the Gillespie algorithm. We illustrate the benefits of our method by sampling trajectories in the Müller-Brown potential. This allows us to generate transition paths which would otherwise be obtained at a high computational cost with standard Kinetic Monte Carlo methods because commitment to a transition path is essentially a rare event. We then apply our method to a single-cell RNA sequencing dataset from mouse pancreatic cells to investigate the cell differentiation pathways of endocrine-cell precursors. Markov bridges for a pancreas dataset.
December 15, 2023 at 5:40 PM