Imatge de diagramació Imatge de diagramació Imatge de diagramació Imatge de diagramació
Logo Universitat de Barcelona

Facultat de Física

Imatge de diagramaci�
Inici Facultat Inici UB   
Imatge de diagramació
Agenda/Conferències i seminaris Imatge de diagramació
Imatge de diagramació Imatge de diagramació
Imatge de diagramació Imatge de diagramació Imatge de diagramació
Imatge de diagramació

 
 
   

El límit per poder anunciar en paper seminaris i conferències en els ascensors és el divendres a les 12 hores de la setmana anterior. Amb posterioritat a aquesta data el seminari o conferència quedarà només recollit al web de la Facultat. Aleshores la publicitació en paper serà responsabilitat dels organitzadors.



Facultat de Física, Dijous 29 de Setembre de 2016, a les 14:00h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: Constraining models of Extended Gravity using Gravity Probe B and LARES experiments
Conferenciant: Salvatore Capozziello (Università Napoli)
Abstract:

We consider models of extended gravity and in particular, generic models containing scalar-tensor and higher-order curvature terms, as well as a model derived from noncommutative spectral geometry. Studying, in the
weak-field approximation (the Newtonian and post-Newtonian limit of the theory), the geodesic and Lense-Thirring processions, we impose constraints on the free parameters of such models by using the recent experimental results of the Gravity Probe B (GPB) and Laser Relativity Satellite (LARES) satellites. The imposed constraint by GPB and LARES is
independent of the torsion-balance experiment, though it is much weaker.

Lloc: Aula 507
Contacte: hofer@fqa.ub.edu
Web:

Facultat de Física, Dijous 29 de Setembre de 2016, a les 11:45h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: Excess of Social Behavior Reduces the Capacity to Respond to Perturbations
Conferenciant: Dr. David Mateo (Singapore University of Technology and Design)
Abstract:

Social interaction increases significantly the performance of a wide range of cooperative systems, from flocking bids and schooling fish to social networks. However, it has been pointed out that some natural swarms seem to limit the number of social connections, which suggests there are detrimental consequences to excessive social activity.
Using a canonical model of collective motion, we find that the
responsiveness of a swarm to local perturbations is reduced when the social interaction exceeds a certain threshold. This effect is mirrored in collective decision-making models of distributed consensus operating over a range of networks.
While increasing the amount of interaction always increases the capacity of these systems to adapt to slow changes, an excess of social behavior can hinder the swiftness of their response to fast disruptions.

Lloc: Aula 507, Pere Pascual
Contacte: bruno@fqa.ub.edu
Web: http://www.ecm.ub.es/~bruno/semweb/fansem.html

Facultat de Física, Divendres 30 de Setembre de 2016, a les 12:00h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: On-shell effective field theory: a new tool in thermal field theory
Conferenciant: Cristina Manuel (Instituto de Ciencias del Espacio)
Abstract:

It is well-known that at high temperature T naive perturbation in QFT breaks down. Both in QED and QCD for momenta of order gT, where g is the coupling constant, there are one loop thermal corrections, the so called hard thermal loops (HTLs), which are as relevant as tree amplitudes and have to be resummed in effective propagators and vertices.
HTLs arise in one-loop diagrams from the so called hard scales, or scales of order T, in the loop. The HTL resummed perturbation theory has been successfully used in a variety of computations of different physical properties of
the QED and QCD, but little is known on how to push these computations to higher orders. On the other hand, it was shown that the hard scales in the plasmas in the system can be viewed as classical on-shell particles, described by simple
classical transport equations, which correctly describe the HTLs. Based on this observation, and first for QED, we derive an effective field theory describing the quantum fluctuations around an on-shell fermion with energy p, described as a set of high dimension operators over the on-shell energy p. When applied to systems close to equilibrium, when for most on-shell particles p ~ T, we show that the on-shell effective field theory (OSEFT) properly describes the HTL photon polarization tensor of QED, and its 1/T corrections, which represent perturbative corrections to the HTLs. The proposed OSEFT might be used as a tool to improve many perturbative computations of several quantities
computed both for QED and QCD. We also show how with the OSEFT one can derive quantum corrections to classical transport equations.

Lloc: Aula 507
Contacte: hofer@fqa.ub.edu
Web:

Facultat de Física, Dimarts 04 de Octubre de 2016, a les 12:00h

Seminari de l'Institut de Ciències del Cosmos

Títol: Cosmology with the Baryon Oscillations Spectroscopic Survey (SDSS-III)
Conferenciant: Anze Slosar (Brookhaven National Laboratory )
Abstract:

BOSS (Baryon Oscillations Spectroscopic Survey) was a premier spectroscopic experiment for cosmology that has recently completed its observational program. It has measured spectra of nearly 2 million objects spanning significant amounts of the total cosmic volume. I will discuss how we constrain properties of the Universe using two tracers of large scale structure measured by BOSS: galaxies and Lyman-alpha forest. I will show recent results on cosmology observables, including neutrino masses and properties of dark energy. I will conclude by briefly discussing open questions and future experiments.

Lloc: V724 Seminar room, 7th floor
Contacte: secretaria@icc.ub.edu
Web: http://icc.ub.edu/activity/787

Facultat de Física, Dimecres 05 de Octubre de 2016, a les 12:00h

Seminari del Dep. de Física de la Matèria Condensada

Títol: At the heart of the matter: physics, biology and the function of the myocardium
Conferenciant: Jorge Alegre-Cebollada (CNIC)
Abstract:

Our lab takes a multidisciplinary approach to learn more about molecular determinants of the mechanical properties of the heart in health and disease. We specialize in single molecule methods using atomic force microscopy (AFM), which are able to measure the effects of mechanical forces on cardiac structural proteins. Our main lines of research are:
1. Regulation of protein elasticity by redox posttranslational modifications (PTM). Using in vitro experiments, we have recently described that PTM of buried cysteines in the giant protein titin makes heart tissue more elastic (Cell 2014, 156:1235). We are using mass spectrometry techniques to detect native redox PTMs from heart tissue. Once relevant redox PTMs are identified, we use single-molecule methods by AFM to determine their effect in protein elasticity. We want to explore how these mechanical PTMs are differentially present during heart disease.
2. Genotype/phenotype relations in familial cardiomyopathies. The majority of familial cardiomyopathies are caused by mutations in sarcomeric genes that code for proteins with mechanical roles. We are exploring the connection between dysregulation of protein mechanics and development of cardiomyopathy. Using single-molecule AFM, we measure the mechanical properties of proteins whose mutation cause cardiomyopathy. We also examine several other cellular functions that may be affected by mutations.
3. Development of engineered muscle-mimicking biomaterials. Using a directed crosslinking strategy, we are able to polymerize proteins into hydrogels whose stiffness can be measured in the lab using tensile testers built by us (Macromolecular Materials and Engineering 2015, 300, 369). We are developing experimental platforms that allow us to predict the stiffness of the resulting biomaterials from the mechanical properties of the constituent proteins measured at the single-molecule level.

Lloc: Aula Seminari 3.20, Dept. Física de la Matèria Condensada, 3rd floor of physics building
Contacte: ritort@ub.edu
Web: http://ffn.ub.es/ritort/news-activities/

Facultat de Física, Dijous 06 de Octubre de 2016, a les 14:00h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: Electroweak standard model with very special relativity
Conferenciant: Jorge Alfaro (Universidad Católica de Chile)
Abstract:

The Very Special Relativity Electroweak Standard Model (VSR EW SM) is a theory with SU(2)_L x U(1)_R symmetry, with the same number of leptons and gauge fields as in the usual Weinberg-Salam (WS) model. No new particles are introduced. The model is renormalizable and unitarity is preserved. However, photons obtain mass and the massive bosons obtain different masses for different polarizations. Besides, neutrino masses are generated. A VSR invariant term will produce neutrino oscillations and new processes are allowed. In particular, we compute the rate of the decays mu -- > e+ga. All these processes, which are forbidden in the Electroweak Standard Model, put stringent bounds on the parameters of our model and measure the violation of Lorentz invariance. We investigate the canonical quantization of this non-local model. Second quantization is carried out obtaining a well defined particle concept. Additionally, we do a counting of the degrees of freedom associated to the gauge bosons involved in this work, after Spontaneous Symmetry Breaking has been realized. Violations of Lorentz invariance have been predicted by several theories of Quantum Gravity. It is a remarkable possibility that the low energy effects of Lorentz violation induced by Quantum Gravity could be contained in the non-local terms of the VSR EW SM.

Lloc: Aula 507
Contacte: hofer@fqa.ub.edu
Web:

Facultat de Física, de Dilluns 17 de Octubre de 2016 a Divendres 21 de Octubre de 2016, a les h

Curs de l'Institut de Ciències del Cosmos

Títol: ICCUB School: Machine Learning and Data Mining in Physics
Conferenciant:
Abstract:

This school is addressed to doctorates and post-docs working in particle physics, with special emphasis on those working on LHCb, Belle II, Gaia, CTA or MAGIC.

The School will be structured around two Kaggle-challenge-like projects, one in the domain of particle physics and one in astrophysics which highlight the two big groups of Machine Learning and Data Mining techniques: classification and separation. With around 5-6 hours of lessons per day, the basics of these techniques will be covered, both from the theoretical and from the practical (hands-on) point of view. Two pieces of software, covering most needs, will be introduced and students will be free to use any of them for tackling the projects. Additional time will be devoted to covering some other innovative techniques.

The school includes the development of a hands-on assignment where the students (in teams of 2-3) will have to choose one of two proposed projects and work on it during the week applying the techniques that they have learned in the classroom. The first days will be more theory heavy, with less time for working, and towards the end the students will have more hands-on sessions and more time to work on these projects. On the last day, each student (or group of students) will present their work that will be ranked; a prize will be given to the best work.

Lloc: DAM Meeting Room, 7th floor. Physics Faculty
Contacte: secretaria@icc.ub.edu
Web: http://icc.ub.edu/congress/ICCUB_DM_SCHOOL/

Facultat de Física, de Dijous 20 de Octubre de 2016 a Dimecres 26 de Octubre de 2016, a les 15:00h

Curs de l'Institut de Ciències del Cosmos

Títol: Intensive course on Bayesian methods
Conferenciant: Stefano Andreon (INAF-O. Astron. di Brera, Milan)
Abstract:

The course is free and open to anyone who is interested to become familiar with Bayesian methods applied to particle physics or astrophysics and own the appropriate tools to use them. It is mandatory that all attendants implement some computer codes in their laptops before the course starts (see the attached file for details).

Dates: 20-26 October:
- Thursday and Friday from 15:00 to 18:00.
- Monday, Tuesday and Wednesday from 9:30 to 12:30.

*Master students can only attend the first part of the course (20 and 21 October). PhD students, postdocs and seniors can attend all days of the course (October 20th to 26th).

We invite all of you who are interested to attend the course to please contact the Secretariat of the ICCUB (secretaria@icc.ub.edu) in order to enrole. The deadline is the 15 of October.

Lloc: TBA
Contacte: secretaria@icc.ub.edu
Web: http://icc.ub.edu/activity/780