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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 25 de Octubre de 2018, a les 16:00h

Seminari de l'Institut de Nanociència i Nanotecnologia

Títol: SENSING THE MATRIX: TRANSDUCING MECHANICAL SIGNALS FROM INTEGRINS TO THE NUCLEUS
Conferenciant: Pere Roca-Cusachs, Institute for Bioengineering of Catalonia (IBEC) and IN2UB
Abstract:

Cell proliferation and differentiation, as well as key processes in development, tumorigenesis, and wound healing, are strongly determined by the properties of the extracellular matrix (ECM), including its mechanical rigidity and the density and distribution of its ligands. In this talk, I will explain how we combine molecular biology, biophysical measurements, and theoretical modelling to understand the mechanisms by which cells sense and respond to matrix properties. I will discuss how the properties under force of integrin-ECM bonds, and of the adaptor protein talin, drive and regulate matrix sensing. I will further discuss how this sensing can be understood through a computational molecular clutch model, which can quantitatively predict the role of integrins, talin, myosin, and ECM receptors, and their effect on cell response. Finally, I will analyze how signals triggered by rigidity at cell-ECM adhesions are transmitted to the nucleus, leading to the activation of the transcriptional regulator YAP.

Lloc: Eduard Fontseré
Contacte: isaborit@ub.edu
Web: http://www.ub.edu/in2ub/files/IN2UB_IRS_25_10_2018.pdf

Facultat de Física, Dijous 25 de Octubre de 2018, a les 14:00h

Confèrencia de l'Institut de Ciències del Cosmos

Títol: Ten years with Timepix
Conferenciant: Becky Parker (Director, Institute for Research in Schools, Queen Mary, University of London)
Abstract:

Engaging school children with cutting edge physics and technology has led to the development of a school research institute where students contribute in space science, particle physics and now across the sciences. The talk will discuss what students have achieved and how the approach of genuine involvement in cutting edge science is empowering and inspiring for both student and teacher.

Lloc: Aula Fontserè
Contacte: secretariacientifica@icc.ub.edu
Web: http://icc.ub.edu/activity/1258

Facultat de Física, Dijous 25 de Octubre de 2018, a les 15:45h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: Quantum Machine Learning
Conferenciant: Prof. Seth Lloyd (MIT)
Abstract:

Quantum systems can generate patterns in data that are hard for classical systems to generate. This talk shows that quantum
information processors can also recognize and classify patterns that are hard for classical learning systems to find.
The ability of quantum computers to perform linear algebra operations such as matrix inversion exponentially faster than
classical computers translates into the ability to perform multiple data analysis tasks such as principal component
analysis more efficiently. The talk discusses how to load classical data into quantum learners, and explores
prospects for deep quantum learning.

Lloc: Aula Pere Pascual (507)
Contacte: bruno@fqa.ub.edu
Web:

Facultat de Física, Dijous 25 de Octubre de 2018, a les 14:00h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: TBA
Conferenciant: Francesco d Eramo
Abstract:

TBA

Lloc: Aula 507 (Pere Pascual)
Contacte: vicente.atal@icc.ub.edu
Web:

Facultat de Física, Dijous 25 de Octubre de 2018, a les 15:45h

Seminari de l'Institut de Ciències del Cosmos

Títol: Quantum machine learning
Conferenciant: Seth Lloyd (MIT)
Abstract:

Quantum systems can generate patterns in data that are hard for classical systems to generate. This talk shows that quantum information processors can also recognize and classify patterns that are hard for classical learning systems to find.

The ability of quantum computers to perform linear algebra operations such as matrix inversion exponentially faster than classical computers translates into the ability to perform multiple data analysis tasks such as principal component analysis more efficiently.

The talk discusses how to load classical data into quantum learners, and explores prospects for deep quantum learning.

Lloc: Aula 507 (Pere Pascual)
Contacte: secretariacientifica@icc.ub.edu
Web: http://icc.ub.edu/activity/1262

Facultat de Física, Dimecres 31 de Octubre de 2018, a les 12:00h

Seminari del Dep. de Física de la Matèria Condensada

Títol: An operational approach to stochastic thermodynamics
Conferenciant: Philipp Strasberg (Universitad Autónoma de Barcelona)
Abstract:

Stochastic thermodynamics is a powerful theory to treat the nonequilibrium thermodynamics of small systems provided that it is possible to perfectly measure the system without disturbing its dynamics. In practice, measurement resolution is finite and often the system is passively or actively (e.g., via feedback control) disturbed. In this talk I will start with a brief review of classical measurement theory and causal modelling, which allows to extend the theory of perfectly observed stochastic processes to arbitrary experimental interventions. For this general framework of a stochastic process, I will then propose definitions for stochastic internal energy, heat, work and entropy, which fulfill a first law (at the trajectory level) and a second law (on average) and which do not need to be modified in presence of arbitrary feedback control operations (even if they are time-delayed). I will also compare my definitions with the ones of standard stochastic thermodynamics and give an analysis of a recent experiment (if time permits).

Lloc: Aula Seminari 3.20
Contacte: fritort@gmail.com
Web: http://ffn.ub.es/ritort

Facultat de Física, Dijous 08 de Novembre de 2018, a les 12:00h

Seminari del Dep. de Física de la Matèria Condensada

Títol: Slow dynamics, glasses and thermodynamics of trajectories
Conferenciant: Juan P. Garrahan (School of Physics and Astronomy, University of Nottingham)
Abstract:

In condensed matter science the glass transition is the paradigm for the slowdown and dynamical arrest into non-equilibrium states which is found to occur in a vast range of many-body systems. While the theoretical understanding of this phenomenon is still under debate, an important lesson is that dynamical behaviour can be far richer and more complex than what static properties often suggest. A proper characterisation of dynamics therefore requires a method which focusses on statistical properties of trajectories. Via large deviation techniques such a "thermodynamics of trajectories" method can be readily devised. In this talk I will review the glass transition problem, describe basic ideas for modelling slow dynamics, and explain what the dynamical large deviation approach tells us about glasses and non-equilibrium more generally.

Lloc: Aula Seminari 3.20
Contacte: fritort@gmail.com
Web: http://ffn.ub.es/ritort

Facultat de Física, Dimecres 21 de Novembre de 2018, a les 12:00h

Seminari del Dep. de Física de la Matèria Condensada

Títol: Time and Length for spin glasses
Conferenciant: Victor Martin-Mayor (Universidad Complutense de Madrid)
Abstract:

The dynamics of glass formers (such as spin-glasses) is so slow that they never reach equilibrium in macroscopic samples: in analogy with
living beings, glasses are said to age. Simulating aging is a big challenge. In fact, the custom built computers Janus and Janus II aim to study the aging dynamics of spin glasses.

Here, we report a study of the linear responses of an aging Ising spin-glass to an external magnetic field, carried out by means of large-scale simulations on Janus and Janus II [1].

We show that linear responses relate experimentally relevant quantities with the experimentally unreachable low-temperature equilibrium phase. We have performed an accurate computation of the non-equilibrium fluctuation-dissipation ratio. This ratio (computed for finite times on very large, effectively infinite, systems) is compared with the equilibrium probability distribution of the spin overlap for finite sizes. The resulting quantitative statics-dynamics dictionary, based on observables that can be measured with current experimental methods, could allow the experimental exploration of important features of the spin-glass phase without uncontrollable extrapolations to infinite times or system sizes.

As a first step [2], we consider the time growth of the size of the spin-glass domains, ξ. Excellent experimental measurements of this growth, as characterized by the so-called dynamic exponent, are now possible in films [3]. These improved experimental studies show that the dynamic exponent is significantly larger than anticipated by previous experiments and simulations. Our new computation of the dynamic exponent finds a mild dependence on ξ. A modest extrapolation to ξ similar to the thickness of the experimental films produces a dynamic exponent in fair agreement with [3].

[1] Janus coll., Proc. Natl. Acad. Sci. USA 114 (2017), 1838-1843

[2] Janus coll., Phys. Rev. Lett. 120, 267203 (2018).

[3] Q. Zhai, et al. Phys. Rev. B 95, 054304 (2017).

Lloc: Aula Seminari 3.20 (Planta 3)
Contacte: fritort@gmail.com
Web: http://ffn.ub.es/ritort

Facultat de Física, Dijous 29 de Novembre de 2018, a les 12:00h

Seminari de l'Institut de Ciències del Cosmos

Títol: Neutrinos: A little Physics for a Lot of Fun
Conferenciant: Concha González Garcia (ICCUB)
Abstract:

Neutrinos are ubiquitous, in Nature and in Physics.
They are the least standard particle of the sacrosanct Standard Model of Particle Physics. Being neutral and weakly interacting they are the perfect messengers to bring us information from the core of complex objects, from nucleons to distant stars. They fill the Universe and determine its evolution and may even explain why it is not much more empty. They rain over us whether we like it or not... we cannot beat them, so we may as well "enjoy them".

In this talk I will present a scientific (but personal and bias) review on some of the topics in which neutrinos are the main players --the evidence of their mass, the present understanding of the lepton sector, the infamous sterile neutrinos, their role in the understanding of their sources and of the medium they encounter in their way... -- all from the perspective of a particle physicists (admittedly a particle-centric view) who has spent almost 30 yrs loving to hate them.

Lloc: Aula Magna
Contacte: secretariacientifica@icc.ub.edu
Web: http://icc.ub.edu/activity/1260