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Campus de Excelencia InterncionalCampus of International Excellence

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Total 100 eventos
Agenda de eventos
FechaEvento
17/01/2018 - 17/01/2018The Mechanics of Cell Shape in Early Embryonic Development

 

 

 

 

 

 

15/12/2017 - 15/12/2017Geometry invariant phenomena in near zero index media

Abstract:  

Continuous media and metamaterials with a near-zero refractive index (NZI media) provide alternative pathways for the control and manipulation of light-matter interactions.  The exotic behavior of NZI media is rooted in the fact that the wavelength gets effectively stretched as the refractive index vanishes. This allows for pathological solutions to the wave equation, including   spatially static fields distributions which nevertheless dynamically oscillate in time. This paradoxical behavior gives access to a regime of qualitatively different wave dynamics, where the importance of the geometry is lessened, and certain observables are invariant with respect to geometrical deformations, even including changes in the topology of the system.

 

In this talk, I’ll review and discuss some of the geometry-invariant phenomena related to near-zero-index media. Examples will include: (i) transmission (tunneling) of waves through deformed waveguides. (ii) Unconventional resonators supporting modes whose eigenfrequency is independent of the geometry of their external boundary. (iii) Violation of effective medium theory geometrical restrictions, enabling, for example, single unit-cell metamaterials. (iv) Existence of bound states in open 3D compact resonators with arbitrarily shaped boundaries.

Different technological applications and implementations of these concepts will be discussed.

 

Más información: http://www.ifimac.uam.es/category/seminars/

 

12/12/2017 - 12/12/2017Charge and energy noise in ac driven conductors

 

Abstract:  

The  time-dependent driving of nanoscale conductors allows for the controlled creation of single-electron excitations. This effect has been demonstrated experimentally both by application of time-dependent driving to gates coupled to confined systems, such as quantum dots [1], and by specifically shaped ac-driving of two-dimensional conductors [2,3].

However, the spectral properties of the injected signal are in general not known; moreover, the particle emission goes along with the excitation of electron-hole pairs with some unknown energy distribution. These issues can be addressed by studying fluctuations in the detected currents: not only do such fluctuations provide more insight into how to increase the precision of the single-particle emission, but also they allow for obtaining more information about the character of the emitted signal.

 

Here, I will present a theoretical study of charge and energy currents and their fluctuations in coherent conductors driven by different types of time-periodic bias voltages, based on a scattering matrix approach [4,5].  Specifically, we investigate the role of electron-like and hole-like excitations created by the driving in the charge current noise, where they only contribute separately. In contrast, additional features due to electron-hole correlations appear in the energy noise.

We then compare two different types of driving schemes [6], that is for a driven mesoscopic capacitor [1] as well as for a Lorentzian-shaped bias voltage [3], which do not differ in the number of injected particles, but only in their energetic properties.

Finally, I will discuss proposals for the detection of charge and energy noise, either through power fluctuations [4], or via frequency-dependent temperature and electrochemical-potential fluctuations in a probe reservoir [7].

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References:

[1] G. Fève, A. Mahé, J.-M. Berroir, T. Kontos, B. Plaçais, D. C. Glattli, A. Cavanna, B. Etienne, Y. Jin: Science 316, 1169 (2007).

[2] J. Gabelli and B. Reulet, Phys. Rev. B 87, 075403 (2013).

[3] J. Dubois, T. Jullien, F. Portier, P. Roche, A. Cavanna, Y. Jin, W. Wegscheider, P. Roulleau, and D. C. Glattli, Nature 502, 659 (2013).

[4] F. Battista, F. Haupt, and J. Splettstoesser, Phys. Rev. B 90, 085418 (2014)

[5] F. Battista, F. Haupt, and J. Splettstoesser, J. Phys. Conf. Ser. 568, 052008 (2014)

[6] N. Dashti, M. Misiorny, P. Samuelsson, and J. Splettstoesser, in preparation

[7] N. Dashti, M. Misiorny, P. Samuelsson, and J. Splettstoesser, in preparation.

 

 

Más información: http://www.ifimac.uam.es/category/seminars/

01/12/2017 - 01/12/2017Centrosomes and exosomes molecualr pacemakers of immune synapse

 

 

 

 

 

 

15/11/2017 - 15/11/2017Pair correlation function of a 2D molecular gas directly visualized by scanning tunneling microscopy

 

Abstract:  

The state of matter in fluid phases, determined by the interactions between particles, can be characterized by a pair correlation function (PCF). At the nanoscale, the PCF has been so far obtained experimentally only by means of reciprocal-space techniques. We use scanning tunneling microscopy (STM) at room temperature in combination with lattice-gas kinetic Monte Carlo (KMC) simulations to study a two-dimensional gas of highly mobile molecules of fluorinated copper phthalocyanine on a Si(111)/Tl-(1×1) surface. A relatively slow mechanism of STM image acquisition results in time-averaging of molecular occurrence under the STM tip. We prove by the KMC simulations that in the proximity of fixed molecules STM images represent the PCF. We demonstrate that STM is capable of visualizing directly the pair correlation function in real space.

 

Más información: http://www.ifimac.uam.es/category/seminars/

 

Destacados

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Generales

Total 100 eventos
Agenda de eventos
FechaEvento
22/02/2018 - 22/02/2018Genetic mechanisms of structural plasticity and regeneration in the central nervous system

Ponente: Alicia Hidalgo (School of Biosciences, University of Birmingham, Edgbaston Park Road, Birmingham, UK)

 

19/02/2018 - 19/02/2018Mesa Redonda "Quiero ser Científica. Un análisis de los sesgos de género en ciencia"

 

 

 

13/02/2018 - 13/02/2018A jellium pseudopotential generator for modelling the plasmonic response of complex-shaped nanostructures

Abstract:  

Experimental advances in the fabrication and control of nanometallic architectures, achieving nanometric and even sub-nanometric precision, have underlined the significance of quantum effects for systems with plasmonic functionalities, thereby challenging classical descriptions of their optical properties. In the interest of capturing both global geometrical features, as well as the intrinsically quantum nature of the electronic response at optical frequencies, we introduce a flexible jellium pseudopotential generator (JPG) for time-dependent density functional computations. We demonstrate the predictive capacity afforded by the JPG through a study of both single gold nanocubes, as well as of a sequence of morphological transformations that relate the cubic and spherical geometries. Plasmon-induced charge distributions for the cube are found to be in qualitative agreement with classical predictions, not withstanding deviations that originate in electronic delocalisation. The evolution in the absorption spectrum, during the cube-sphere transition, highlights the role of not only the polyhedral vertices, but also of the manner in which they are connected. Conclusions of this nature may bear important implications for the design of complex-shaped nanoparticles with desirable optical properties.

 

 

Más información: http://www.ifimac.uam.es/category/seminars/

 

08/02/2018 - 08/02/2018Large deviations and quantum non-equilibrium

 

Abstract:  

 

I will review recent developments in applying dynamical large deviations

(LD) to quantum systems.  I will consider in particular open quantum

systems - quantum systems interacting with an environment - which in

many cases can be described in terms of quantum Markovian dynamics.  LD

methods provide a "thermodynamic" framework for understanding the

statistical properties of dynamics, revealing the existence of dynamical

phases and phase transitions, often associated to intermittent emission

patterns.  Problems of interest include interacting atomic ensembles,

quantum glasses, and systems where there is an interplay between

coherent transport and dissipation.  I will describe concepts relating

to quantum trajectory ensemble equivalence, prediction and

"retrodiction", matrix product states, and quantum Doob transforms. Time

permitting, I will also discuss the connection to ideas about slow

quantum relaxation and metastability.

 

 

 

Más información: http://www.ifimac.uam.es/category/seminars/

 

 

 

 

 

 

19/01/2018 - 19/01/2018Interfacing magnetic molecules with 2D materials

 

Abstract:  

Graphene and other 2D materials have been a hot focus of interest in physics, chemistry and materials science. The emergence of van der Waals heterostructures formed by assembling two different monolayers of these materials through Van der Waals forces have opened new opportunities in this field. This concept can be further expanded by interfacing a layered 2D material with materials of other dimensionalities including 0D materials (molecules, nanoparticles,…), 1D materials (nanotubes, nanowires,…) and 3D materials, which can interact non only through VdW forces but also through covalent or ionic interactions [1].

In this talk I will focus on an emergent class of hybrid heterostructures formed by interfacing a 2D material with a molecular system. In particular, I will show how the properties of the “all surface” 2D material can be tuned through the interactions established with the molecular system. As 2D materials, I will focus on those exhibiting superconductivity or magnetism. As molecular systems, I will focus on stimuli-responsive magnetic molecules able to change their properties upon the application of an external stimulus (temperature, light or pressure) [2]. I will show that this concept can provide examples of smart molecular/2D heterostructures [3], which may be at the origin of a novel generation of hybrid materials and devices of direct application in highly topical fields like electronics, spintronics, molecular sensing and energy storage.

 

References:

[1] D. Jariwala, et al., Nature Mater 2017, 16, 170

[2] A. Bousseksou et al. Chem. Soc. Rev., 2011, 40, 3313.

[3] J. Dugay et al. Nano Lett. 2017, 17, 186

 

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Más información: http://www.ifimac.uam.es/category/conferences-events

 

 

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La UAM presenta el nuevo Centro de Investigación Madrid Institute for Advanced Study (MIAS)
"Diálogos con la Cultura": Carmen Pellicer
La Autónoma cumple 50 años

Agentes y colaboradores

  • Universidad Autónoma de Madrid
  • CSIC
  • ASEYACOVI
  • ACENOMA
  • AICA
  • Centro de Microanálisis de Materiales (CMAM)
  • Centro de Investigación en Física de la Materia Condensada (IFIMAC)
  • CBMSO - Centro de Biología Molecular Severo Ochoa
  • CIAL - Centro de Investigación en Ciencias de la Alimentación
  • CNB - Centro Nacional de Biotecnología 
  • Centro de Iniciativas Emprendedoras (CIADE)
  • Cámara de Madrid
  • FEMAN
  • Fundación Universitaria Autónoma de Madrid
  • ICMAT - Instituto de Ciencias Matemáticas
  • ICMM - Instituto de Ciencia de Materiales de Madrid
  • ICP - Instituto de Catálisis y Petroquímica
  • ICV - Instituto de Cerámica y Vidrio
  • IFT - Instituto de FísicaTeórica
  • IIBM - Instituto de Investigaciones Biomédicas Alberto Sols
  • IMDEA - Alimentación
  • IMDEA - Nanociencia
  • IMM - Instituto de Microelectrónica de Madrid
  • InNorMadrid
  • Parque Científico de Madrid
  • Oficina de Transferencia de Resultados de la Investigación (OTRI) de la UAM
  • Facultad de Ciencias
  • Facultad de Ciencias Económicas y Empresariales
  • Facultad de Derecho
  • Facultad de Filosofía y Letras
  • Facultad de Medicina
  • Facultad de Formación de Profesorado y Educación
  • Facultad de Psicología
  • Escuela Politécnica Superior
Proyecto realizado con ayudas concedidas por el Ministerio de Economía y Competitividad / EXPEDIENTE: CEI10-1-0009 CEI UAM+CSIC: INNOCAMPUS 2010 Proyecto financiado por el Ministerio de Educación, Cultura y Deporte, y el Ministerio de Economía y Competitividad en el marco del Programa Campus de Excelencia Internacional/ EXPEDIENTE: CEI10-1-0009 CEI UAM+CSIC: INNOCAMPUS 2010