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Universidad de Salamanca
María Jesús Santos Sánchez
Facultad de Ciencias - Departamento Física Aplicada
 
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Using computational tools to study the geometry of moduli spaces

Seminario del IUFFyM

Using computational tools to study the geometry of moduli spaces

que impartirá el profesor

David Sánchez Alfaya

 

Universidad Pontificia de Comillas, Madrid

 

este jueves 20 (mañana) a las 13:00h en la sala de seminarios del IUFFyM, Facultad de Ciencias, Universidad de Salamanca.

 

Some features about the geometry of certain moduli spaces (e.g, topological invariants)

suffer naturally a combinatorial explosion as the parameters used to build the moduli (like

the rank or genus of a curve) increase, making their analysis difficult. In this talk we will

explore some ways in which computers can help algebraic geometers tackle this situation.

Concretely, we will focus on two applications to moduli spaces of bundles on curves.

On the one hand, we will see how we can use binary classification trees to count the

number of possible non-isomorphic moduli spaces of parabolic vector bundles on a marked

curve and obtain their automorphism groups.

On the other hand, a new Python package will be presented which allows an efficient

computation and simplification of motivic expressions in the Grothendieck ring of varieties,

and we will see that the package can be used to verify computationally Mozgovoy’s

conjecture on motive of the moduli space of twisted Higgs bundles.

Joint works with Sergio Herreros, Javier Rodrigo, Daniel Sánchez, Jaime Pizarroso and José

Portela.

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Nevo: illuminating the dark cosmos – Farbod Hassani

Title: Nevo: illuminating the dark cosmos 

Speaker: Farbod Hassani (University of Oslo)

Abstract:

The Universe has entered an accelerating expansion phase in the last few billion years of its evolution, a phenomenon that is caused by the mysterious entity known as dark energy.
To understand the nature of dark energy, we must carefully investigate different candidates and observe how they affect the Universe at various stages. Then we may utilize data to select the best candidate. However, the consistent and accurate modeling of dark energy candidates has been largely neglected so far due to significant challenges, including the absence of relativistic N-body codes, the immense computational costs involved, and the limited availability of relevant data to date. To address this gap, we have proposed the development of a novel framework, called NEVO, that utilizes state-of-the-art “relativistic” N-body simulations along with the advanced Boltzmann codes, to accurately model dark energy candidates in both linear and non-linear scales. In this presentation, I will go into detail about the awarded NEVO proposal and discuss its challenges in depth.
Wednesday 19th, 11:30, Aula VII  del Edificio Trilingüe – Faculta de Ciencias Universidad de Salamanca
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GeoGebra Discovery a tool based on symbolic computation for automated reasoning in Elementary Geometry

pilar-velez-melon-600x350

Pilar Vélez Melón

GeoGebra Discovery a tool based on symbolic computation for automated reasoning in Elementary Geometry

M. Pilar Vélez

Universidad Antonio de Nebrija 

GeoGebra Discovery is a fork version of the dynamic geometry system GeoGebra that provides GeoGebra with the ability to automatically conjecture, discover and prove Geometry statements from a plane construction. The algorithms behind these features are based on complex and real algebraic geometry. 

In this talk we introduce, first the current performance of the program GeoGebra Discovery regarding some automatic reasoning tools features. Then we focus on the computational algebraic geometry methods used, mostly in the complex setting, and some pending theoretical and algorithmic issues to extend (in the same technological and educational framework) such methods to deal with Geometry statements in the real algebraic geometry context.

https://github.com/kovzol/geogebra-discovery

Date: Friday, January 17th, 2025

Time: 13:00

Place: Aula I Trilingüe

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Salamanca Summer International Course on Advanced Biophysics and Structural Biology

IAdvanceBiophysiscBiologyCoruseThe first “Salamanca Summer International Course on Advanced Biophysics and Structural Biology” (https://biophysal.org/) will take place at the University of Salamanca, one of the world oldest universities (the third oldest, after Bologna and Oxford), and located in the beautiful city of Salamanca, a World Heritage city. The course is organized by Profs. Carlos Bustamante and Eva Nogales from the University of California at Berkeley.

The 5-day course (June 30 – July 5) will cover single molecule studies and biological imaging at the molecular and cellular levels and will have both lectures and hands-on components. It will be preceded by a one-day symposium (June 29) on “Advanced Structural and Molecular Biology” open to the scientific community.

The course will be imparted by:

  • Carlos Bustamante (University of California, Berkeley, USA)
  • José María Carazo (Centro Nacional de Biotecnología, Madrid, Spain)
  • Taek Jip Ha (Harvard University, Children’s Hospital, USA)
  • Borja Ibarra (IMDEA Nanociencia, Madrid, Spain)
  • Miguel Vicente Manzanares (Universidad de Salamanca, Spain)
  • Steve Smith (Steve Smith Engineering)
  • Eva Nogales (University of California, Berkeley, USA)
  • David Rueda (Imperial college London, UK)
  • José María Valpuesta (Centro Nacional de Biotecnología, Madrid, Spain)
  • Elizabethe Villa (University of California, San Diego, USA)
  • Xiaowei Zhuang (Harvard University, USA)

Keynote speaker

  • Richard Henderson (LMB-MRC, Cambridge, UK; Nobel Prize in Chemistry, 2017)

The course will be open to 22 students of any nationality. The registration fee is 150 €, which will cover the course and the lodging. There is the possibility of travel grants.

For more information and for application, see https://biophysal.org/

Deadline for registration: December 20, 2024

Contact: Fundación General de la Universidad de Salamanca, fgu@usal.es

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Machine learning tests of the cosmological constant model and beyond – Savvas Nesseris

Captura de pantalla 2024-11-08 a las 7.55.09Title: Machine learning tests of the cosmological constant model and beyond

Speaker:  Savvas Nesseris (IFT, UAM-CSIC)
Thursday, Dec 5, 10:00, Seminar room IUFFyM, Edificio de La Merced (Matemáticas), Facultad de Ciencias, Universidad de Salamanca
Abstract: We use a plethora of machine learning tools to test the cosmological constant model ΛCDM and probe for covariant modifications of general relativity (GR). In particular, we use genetic algorithms (a type of evolutionary symbolic regression algorithm) to first test the swampland conjectures and second, to reconstruct the Weyl potential, which is a probe of modifications of GR, such as f(R) theories. In a different vein, we also use neural networks to perform model selection between f(R) models and ΛCDM, and we compare with the traditional statistical analyses. In all cases we highlight the interpretability of our methodology and how it impacts current and future large scale structure surveys.
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THz dynamics of quantum materials, also under pressure – Also Abreu

OPSesion_ElsaAbreuEl próximo viernes 29 de noviembre, a las 12h, tendrá lugar en el Aula IV del Edificio Trilingüe de la Faculta de Ciencias, de la Universidad de Salamanca,  el Seminario:

THz dynamics of quantum materials, also under pressure

impartido por Elsa Abreu, de

Quantum Material Dynamics Institute for Quantum Electronics ETH Zürich

 

 

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Astrophysical solutions in the generalized SU(2) Proca theory

Seminar Title: Astrophysical solutions in the generalized SU(2) Proca theoryJahnNMartinezIUFFyM

Speaker: Jhan N. Martínez

Universidad Industrial de Santander
Date and time:  Thursday, July 18th, (12:30)
Room: Aula V  - Edificio trilingüe – Facultad de Ciencia – Universidad de Salamanca

Abstract: This talk will be divided into three pieces. In the first part of the talk, I will introduce the common ideas surrounding the modified gravity proposals starting from their main motivation: Einstein gravity, despite all its success on the observational side, is an effective theory. In the second part of the talk, I will present the generalized SU(2) Proca theory (GSU2P for short). As a modified gravity theory that introduces new gravitational degrees of freedom, the GSU2P is the non-Abelian version of the well known generalized Proca theory where the action is invariant under global transformations of the SU(2) group. This theory was formulated for the first time in Phys. Rev. D 94 (2016) 084041, having implemented the required primary constraint to make the Lagrangian degenerate and remove one degree of freedom from the vector field in accordance with the irreducible representations of the Poincaré group. It was later shown in Phys. Rev. D 101 (2020) 045009 that a secondary constraint, which trivializes for the generalized Proca theory but not for the SU(2) version, was needed to close the constraint algebra. The implementation of this secondary constraint in the GSU2P was performed in Phys. Rev. D 102 (2020) 104066 where, as a side effect, the construction of the theory was made more transparent. Since several terms in the Lagrangian were dismissed in Phys. Rev. D 94 (2016) 084041 via their equivalence to other terms through total derivatives, not all of the latter satisfying the secondary constraint, the work was not so simple as directly applying the secondary constraint to the resultant Lagrangian pieces of the old theory. Thus, my collaborators and I were motivated to reconstruct the theory from scratch. In the process, we found the beyond GSU2P. In the third part of the talk, I will show what the impact of the GSU2P is on the cosmic primordial inflation epoch and what its main challenges are.

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Modified gravity, generalized SU(2) Proca theory, and inflation – Yeinzon Rodríguez García

Title seminar: Modified gravity, generalized SU(2) Proca theory, and inflationYeinzonSeminarIUFFyM

Speaker: Yeinzon Rodríguez García

Date and time:  Tuesday, July 16th, (12:00)
Room: Aula V (Edifício Trilingüe) – Facultad de Ciencias – Universidad de Salamanca
Universidad Industrial de Santander, Universidad Antonio Nariño.Abstract: This talk will be divided into three pieces. In the first part of the talk, I will introduce the common ideas surrounding the modified gravity proposals starting from their main motivation: Einstein gravity, despite all its success on the observational side, is an effective theory. In the second part of the talk, I will present the generalized SU(2) Proca theory (GSU2P for short). As a modified gravity theory that introduces new gravitational degrees of freedom, the GSU2P is the non-Abelian version of the well known generalized Proca theory where the action is invariant under global transformations of the SU(2) group. This theory was formulated for the first time in Phys. Rev. D 94 (2016) 084041, having implemented the required primary constraint to make the Lagrangian degenerate and remove one degree of freedom from the vector field in accordance with the irreducible representations of the Poincaré group. It was later shown in Phys. Rev. D 101 (2020) 045009 that a secondary constraint, which trivializes for the generalized Proca theory but not for the SU(2) version, was needed to close the constraint algebra. The implementation of this secondary constraint in the GSU2P was performed in Phys. Rev. D 102 (2020) 104066 where, as a side effect, the construction of the theory was made more transparent. Since several terms in the Lagrangian were dismissed in Phys. Rev. D 94 (2016) 084041 via their equivalence to other terms through total derivatives, not all of the latter satisfying the secondary constraint, the work was not so simple as directly applying the secondary constraint to the resultant Lagrangian pieces of the old theory. Thus, my collaborators and I were motivated to reconstruct the theory from scratch. In the process, we found the beyond GSU2P. In the third part of the talk, I will show what the impact of the GSU2P is on the cosmic primordial inflation epoch and what its main challenges are.
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Flat Band Physics by Sergej Flach

Sergej_Flach_theoretical_physicist_2018 Esta semana tendremos un coloquio un tanto especial, que además será el último de este curso académico.
Este evento se enmarca en el contexto del “International Workshop on Disordered Systems 2024”, congreso organizando en Salamanca por miembros del IUFFyM y que cuenta con el apoyo económico del Instituto.
La charla tendrá lugar el jueves 20 a las 16:50 horas en la Capilla del Colegio Arzobispo Fonseca.
De 16:10 a 16.50 se servirá un coffee break en el claustro inferior del Colegio Fonseca, al que están invitados los miembros del IUFFyM.
El speaker del coloquio será Sergej Flach, que es actualmente director del IBS Center for Theoretical Physics of Complex Systems, South Korea, y líder del grupo on Complex Condensed Matter Systems en dicho instituto.
Os dejo los detalles más abajo, y adjunto además el anuncio del coloquio.
La dirección del IUFFyM agradece a los organizadores del congreso hacer partícipe al instituto de este coloquio. Os esperamos a todos allí.
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Flat Band Physics
Sergej Flach
IBS Center for Theoretical Physics of Complex Systems, South Korea
Certain lattice wave systems in translationally invariant settings have one or more spectral bands that are strictly flat (independent of momenta) in the tight binding approximation, arising from either internal symmetries or fine-tuned coupling. We will briefly touch on the theoretical design and experimental implementation of flat bands and classification schemes. We will then discuss the impact of disorder and interactions. We will observe quantum many body interacting systems embedded in flat band environments which lead to controlled currents of charge and heat, heat percolation, many body localization in translationally invariant systems, and interaction induced transport in Wannier-Stark flatbands.
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Why do galaxy sizes matter? by Fernando Buitrago

Speaker: Fernando Buitrago (Universidad de Valladolid)Title: Why do galaxy sizes matter?

Abstract: During the last decades, galaxy sizes have been a very active research topic in Astrophysics given the fact that they are one of the few direct observables from objects in the distant Universe. In this seminar, I will review the different approaches that were traditionally taken, showing what we have learned about how our Universe works over time. However, galaxies are fuzzy objects, and as such it is very hard to assign sizes to them. One would naively think that by observing for larger integration times and/or by using better telescopes these objects will grow bigger and bigger. I will prove you wrong by describing a novel physically-motivated size proxy (the galaxy edges or galaxy truncations) that my team GEELSBE (Galactic Edges and Euclid in the Low Surface Brightness Era) at the University of Valladolid is studying. We have utilized the deepest pointings of the Hubble Space Telescope (while now using the James Webb Space Telescope and Machine Learning algorithms) to obtain the evolution of this parameter last 8 Gyr promising to give us first hand information not only about the baryonic mass assembly but also the dark matter halo evolution.

Date and time:  Wednesday, June 05, (13:00)gracus_logo2

Room: Aula V, Edificio Trilingüe, Facultad de Ciencias, Universidad de Salamanca

https://gracus.usal.es/seminar.php?id=84

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