Colóquios do Departamento

Calendário de Colóquios do Departamento de Física

(nota: os Colóquios do Departamento de Física recomeçam em 10 de Março de 2017)

Docentes responsáveis: Prof. Luís Viseu Melo e Prof. Gonçalo Figueira


O próximo Colóquio do Departamento de Física do IST terá lugar na quarta-feira dia 10 de Maio, às 16h30m

"Coherent x-ray sources for ultrafast science"

Oradora: Marta Fajardo, Dep. Física do IST

Data: quarta-feira, dia 24 de Maio de 2017, às 16h30

Local: Anfiteatro PA1, piso -1 do Pavilhão de Matemática, IST - Alameda


The study of matter in extreme conditions of pressure, density and temperature, from the core of massive planets to igniting inertial fusion plasmas, requires ultrafast and highly-resolved diagnostics, and is currently pushing the limits of ultrafast imaging. In this colloquium, we will see why to see the ultra-small, and record the ultra-fast, X-ray pulses below the femtosecond (1e-15 s) range are needed.

Ultrafast X-ray imaging has only become possible with the 21st century revolution in X-ray sources. These new sources, that can range from a km-long accelerator-based laser in world scale facilities, to a tabletop system here at IST, are as short as attoseconds (10-18 s) in duration. Yet they are sufficiently bright to record pictures of matter undergoing ultrafast changes in a single frame, opening exciting prospects for electronics, plasma laboratory astrophysics, and even structural biology.  For the first time, we are now able to record movies of atomic movement, electron clouds and electron-electron scattering in real-time.

In this talk I will review some of the most important developments in coherent X-ray sources and describe how we are working on these sources to make them shorter and brighter, and using them for ultrafast coherent imaging of exploding plasmas.

Já Realizados:

2º Semestre, 2016/2017

Quarta-feira dia 10 de Maio, às 16h30m

"Molecular Biophysics: taking optics to the limit"

Orador: Heinrich Hörber, IST Phys. Dept. Distinguished Visiting Professor; H. H. Wills Physics Laboratory, University of Bristol, UK

Data: quarta-feira, dia 10 de Maio de 2017, às 16h30

Local: Anfiteatro PA1, piso -1 do Pavilhão de Matemática, IST - Alameda


During the last decade the interdependence of function and structure of proteins became more and more obvious, as well as the need for techniques to study this relation at the single molecule level. Beside Scanning Probe Techniques, optical techniques came back as major player to the field of cell biology, acknowledged with a Nobel Prize in 2014. The combination of both techniques is the most powerful approach we have today to study how molecular structure provide specific function, in the context of a living cell, by undergoing a well defined and controlled sequence of structural changes. The timeline of such structural changes is essential and only can be studied at the single molecule level or the measurements will get blurred by the distribution of molecules at different stages of the process, unavoidable due to thermodynamic principles. Thermodynamics on the other hand provides a very effective way to evaluate measurements at the single molecule level and in this way to understand structure and function relation.

Quarta-feira dia 3 de Maio, às 16h30m

"From College to Corporate"

Oradora: Lara Próspero, Microsoft, WW Customer Service and Support

Local: Anfiteatro PA1, piso -1 do Pavilhão de Matemática, IST - Alameda


How to be a Physicist on a Corporate environment?
In a traditional competences-based work environment, experience comes before the hiring, so if you’re not experienced in the field that you’re proposed to work for, how will you do it?
Making a deep analysis on do and don’ts, looking for the skills needed for each role that I wanted to apply for, and showing that you can acquire the needed competences by activating your skills, was my survival strategy. My Physics background did not block me, instead it empowered me to be the unicorn on the IT world that I’ve been working for almost 20 years.

Quarta-feira dia 26 de Abril, às 16h30m

"Synthesising light pulses"

Orador: Gonçalo Figueira, Dep. Física do IST

Local: Anfiteatro PA1, piso -1 do Pavilhão de Matemática, IST - Alameda


Ultrashort laser pulses, whose durations approach the timescales of fundamental atomic and molecular processes, have revolutionized a wide range of scientific domains. Because they are able to deliver energy in the form of light almost instantaneously, they have given rise to the new field of ultrafast science.
Light pulse synthesis, or shaping in a custom way the electric field waveform of these laser pulses, opens the door to a precise control of physical processes at these extreme scales. This approach has enabled a whole new generation of techniques for producing new forms of radiation, from terahertz frequencies to attosecond pulses and optical vortexes.
In this talk I will review some of the most important developments and applications of this concept and discuss some interesting prospects in different scientific fields.

Quarta-feira dia 5 de Abril, às 16h30m

"The heart of matter"

Oradora: Teresa Peña, Dep. Física do IST

Local: Anfiteatro Abreu Faro, Complexo Interdisciplinar, IST


Nuclear science is a broad and diverse subject.
From the hot dense soup of quarks and gluons after the Big Bang, up to the formation of protons and neutrons that started the evolution of the cosmic chemistry, the physics of nuclei is crucial for our understanding the universe. At the same time, it is intertwined in the fabric of our lives, from applications in industry, medicine, space and advanced material science, to complicated nonproliferation issues and national security.
Nuclear Physics explores the strange world of the heart of matter, and addresses overarching questions that also reach out to other areas of science, and define nuclear physics today.
I will give examples of inspiring questions and methods, both from the theoretical and the applied viewpoints.

Quarta-feira dia 22 de Março, às 16h00m

"Observing the early Universe"

Orador: Paolo de Bernardis, University of Rome "La Sapienza"

Local: Anfiteatro Abreu Faro, Complexo Interdisciplinar, IST


Observations of the early phases of the evolution of our Universe have recently gained hig precision and accuracy. The surveys of the Cosmic Microwave Background (CMB) observed the recombination epoch (13.7 billion years ago, 380,000 years after the big bang) which is the deepest possible source observable using electromagnetic waves. The feeble structures visible in the maps of the CMB are the result of a sequence of physical processes happening during the "primeval fireball” phase of the evolution of the universe, and can be used to constrain the geometry, composition and evolution of the universe. 

After a review of the relevant physics, we focus on the observations, describing the custom instrumentation developed to this purpose, including mm-wave detecotors, space-borne telescopes, and sophisticated analysis techniques. We finally describe the impact of these and of future CMB measurements for our knowledge of cosmology and fundamental physics.

Quarta-feira dia 10 de Março, às 12h00m

"New (and new routes to) carbon materials"

Orador:Rodney S. Ruoff, Ulsan National Institute of Science & Technology

Local: Anf. Abreu Faro (Complexo Interdisciplinar), IST

I offer a personal perspective of several types of new carbons and related materials that appear to me to be “on the horizon”. These include sp3-rich carbon materials, diamond possibly made by new approaches, ‘diamane’, and ‘negative curvature carbons’. Our conversion of large area polycrystalline metal foils to large area single crystal metal foils allows us to pursue one strategy to attempt to achieve diamane, as well as large area single crystal graphene and h-BN.

1º Semestre, 2016/2017

Quarta-feira dia 16 de Novembro, às 16h30m

"In silico plasmas under extreme conditions:  from particle accelerators to pair plasmas in pulsars"

Orador: Luís Oliveira e Silva, Dep. Física do Instituto Superior Técnico

Local: Anfiteatro VA3, Pav. Civil, IST


The advent of ultra intense lasers and particle beams is opening new frontiers in physics by triggering the exploration of scenarios with unprecedented extreme conditions dominated by relativistic effects ranging from plasma based accelerators and intense light sources to collisionless shocks and the magnetospheres of pulsars. In some of these conditions, even QED effects play an importance role, with the production of hard photons and electron-positron pairs. These scenarios are highly nonlinear and can only be fully captured via self consistent ab initio massively parallel kinetic simulations.

I will revise some of the most important advances and the open challenges in the field, illustrating how large scale numerical simulations are helping us to capture in silico these extreme laboratory and astrophysical environments.

Quarta-feira dia 09 de Novembro, às 16h30m

"Some formal problems in studying evolutionary cell biology"

Orador: José Pereira Leal, Instituto Gulbenkian de Ciência

Local: Anfiteatro VA3, Pav. Civil, IST


At the Computational Genomics Laboratory we study the evolutionary cell biology of intracellular compartmentalisation, using mostly computational approaches. While our work is very basic, the use of formal, quantitative approaches has led to interesting translational developments in the context of human health. I will discuss some of these more formal aspects of our work, part of which have been developed by graduates from the Physics Engineering degree at the IST.

Quarta-feira dia 02 de Novembro, às 16h30m

"Gene splicing in evolution and disease"

Orador: Nuno Barbosa Morais, Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa

Local: Anfiteatro VA3, Pav. Civil, IST

Alternative splicing is a gene expression regulatory mechanism that allows a single gene to code for multiple proteins. Most human genes have evolved to undergo alternative splicing, thereby fine-tuning their expression and expanding their coding potential and functional versatility. The evolution of alternative splicing is indeed shown to have paralleled organism complexity. Given its regulatory role in physiological processes, it is unsurprising that altered splicing is associated with diverse pathologies but its involvement in their molecular etiology has been seldom elucidated.

Our lab studies the mechanisms responsible for the association between aberrant splicing and disease. We develop computational biology approaches for the analysis of molecular information to consolidate our hypotheses for the deregulation of alternative splicing in different pathologies, namely cancer and neurodegenerative disorders. In this talk, I will outline some of our most recent findings.

Quarta-feira dia 26 de Outubro, às 16h30m

"From physics to safety critical engineering"

Orador: Luís Gargaté, Critical Software

Local: Anfiteatro VA3, Pav. Civil, IST

It is generally accepted by the public that airplanes (and trains, for that matter) are very reliable and safe machines. Why is that and what is behind this fact? Safety-critical engineering is, along with solid processes that determine everything in this kind of product's life cycle. From concept, to development, to prototyping, to testing, to production, operations, maintenance and disposal, safety-critical engineering practices are in place to assure that an airplane (or a train, or a car) will perform as specified and as expected, and that it is intrinsically as safe as possible.

In this presentation we will show a broad overview of what safety-critical engineering is, how it touches many aspects of our lives, and how it affects the way many systems are developed. Going into more detail, we will then dedicate some time to the specifics of embedded systems and how these play a key role in the safety of many of these systems. Finally, some specific examples will be presented on work that has been done by Critical Software in this field, and on how the knowledge and specific capacities of engineering students from physics (and other related engineering subjects) are important to this kind of work.

Quarta-feira dia 19 de Outubro, às 16h30m

"Satellite remote sensing for hazard assessment and disaster response"

Oradora: Sandra Heleno, CERENA (Centre for Natural Resources and the Environment), IST

Local: Anfiteatro VA3, Pav. Civil, IST

The world population is exposed to several types of natural hazards and has experienced an increasing impact of disasters in the past decades. An overview is given of the use of satellite remote sensing data and image processing techniques to map and monitor hazards such as earthquakes, floods, volcanic eruptions, and landslides, and the damages associated with each.  In particular, operational services focused on the rapid provision of space-based information for disaster response are presented.

Quarta-feira dia 12 de Outubro, às 16h30m

"Matter meets Topology - The Physics behind the Nobel Prize"

Orador: Pedro Ribeiro, CeFEMA & Dep. Física, IST

Local: Anfiteatro VA3, Pav. Civil, IST


The Nobel Prize in Physics 2016 was awarded “for theoretical discoveries of topological phase transitions and topological phases of matter”. Unlike the few previous Nobel Prizes, the object of this year’s prize seems rather immaterial.

In this colloquium we argue that it is, in fact, quite the opposite and show how these ideas are used to describe the physics of real materials. 


First, we focus on the physics behind the Kosterlitz-Thouless phase transitions and on the idea of topological defects introduced by D. J. Thouless and J. M. Kosterlitz. Subsequently, we give an  overview of the different topological phases studied by D. J. Thouless and F. D. M. Haldane, from the quantum Hall effect to spin chains and topological insulators


Sexta-feira dia 30 de Setembro, às 14h00m

"High-resolution Kelvin-probe force microscopy"

Oradora: Regina Hoffmann-Vogel, Karlsruhe Institute of Technology

Local: Anfiteatro GA1, Pav. Central, IST


The work function is the energy needed to remove an electron from a sample and bring it to the vacuum level. In Kelvin-probe Force Microscopy, the work function difference between the tip and the sample of a scanning force microscope (SFM) is determined by applying a voltage between tip and sample. Electrons flow from the higher potential to the lower potential until equilibrium is reached. When the applied voltage matches the work function difference, the measured electrostatic force is minimal. The work function is often thought to be constant for a given material. In this talk, three examples will be given, where the work function reveals important local information.

The first example is the Quantum Size Effect. Quantum size effects (QSE) become pronounced when the thickness of a metal film approaches the de Broglie wavelength of the confined electrons. QSE lead to an oscillatory behavior of physical properties as a function on the thickness of the metallic film. We have studied the influence of QSE on the work function of Pb islands grown on Si(111). The measurements show an even-odd oscillatory dependence of the local work-function difference on the island’s height], in good agreement to calculations [1].

The second example are molecular layers, where the work function measurement yields information about step edges and other line defects as well as the orientation of the molecular layers [2].

The third example are vicinal Si surfaces. Stepped well-ordered surfaces are important nanotemplates for the fabrication of one-dimensional nanostructures with intriguing electronic properties, for example they have been candidates for Luttinger liquid behavior. For the Kelvin probe force microscopy experiments we obtained – on stepped surfaces - unprecedented atomic resolution. DFT calculations allow us to interpret the experimental KPFM data in terms of specific structural features and the electronic properties of the surface. The distribution of surface dipoles is mainly governed by the Smoluchowski effect and is in agreement with the measurements even without including the influence of the tip [3].


1. C. M. Wei and M. Y. Chou, Phys. Rev. B 66, 233408 (2002).
2. J. L. Neff, P. Milde, C. Pérez León, M. D. Kundrat, L. M. Eng, Chr. R. Jacob, and R. Hoffmann-Vogel, ACS Nano 8, 3294 (2014).
3. C. Pérez León, H. Drees, S. Wippermann, M. Marz, and R. Hoffmann-Vogel, J. Phys. Chem. Lett. 7, 426 (2016).


Colóquios do DF - Realizados em 2015/2016

Quarta-feira dia 8 de Junho, às 16h30m

"The bright side of dark matter"

Orador: Nuno Peres, Universidade do Minho, Braga

Local: Anfiteatro PA2, Pav. Matemática, IST


The basic aspects of the elementary physics of graphene plasmonics will be analysed in detail. The case of a single and double layer will be discussed. A model for the case of a periodic array of ribbons will be developed and compared with the experimental results. Some simple graphene nano-structures are briefly discussed.  


Quarta-feira dia 25 de Maio, às 16h30m

"The bright side of dark matter"

Orador: Ilídio Lopes, CENTRA - Instituto Superior Técnico

Local: Anfiteatro PA1, Pav. Matemática, IST


Dark matter is now identified as being an invisible substance made of non-standard particles, that by the action of gravity alters the motion of stars and galaxies, bending the light emitted by distant luminous sources. This unknown matter makes almost 90% of the matter of our own Galaxy, similarly to the other galaxies in the Universe. In this talk, I start by reviewing the fundamental results that lead to the discovery of dark matter since more than 80 years ago. In the following, I discuss how the Sun and stars are used to study the properties of dark matter, either: to limit the number of proposed non-standard dark matter particle candidates, or as a template to study the impact of dark matter in the formation of the stars, stellar populations and galaxies in the early stages of the Universe.

Quarta-feira dia 18 de Maio , às 12h00m

"Detection and characterization of other planets: results from high resolution spectroscopy"

Orador: Nuno C. Santos, Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto

Local: Anfiteatro VA4, Pavilhão de Engª Civil, Piso -1,  IST Alameda-campus

As the number of known exoplanetary systems increases, the focus of exoplanet research is now pointed towards two major lines of research: i) the detection of very low mass planets, with the goal of finding an Earth sibling and understanding the frequency of Earths in our Galaxy, and ii) the detailed characterization of the planets, including their internal structure and atmospheres. New instrumentation projects are being developed towards these goals, using both ground- and space-based instrumentation. These efforts, led by the major international players (ESA, ESO, NASA) are driven by the long-lasting hope of detecting an Earth-like planet where life may have evolved.
In this talk I will review some of the major results in this field, with emphasis on those coming from high resolution spectroscopy. A focus will then be given to recent results we published regarding the detection of the reflected light spectrum from exoplanets. The potential of future instruments where our team is deeply involved will be discussed: the ESPRESSO and HIRES high resolution spectrographs (ESO VLT and E-ELT telescopes) and the CHEOPS and PLATO photometric missions (ESA).

Quarta-feira dia 11 de Maio, às 16h30m

"Clinical experience with the EDGE accelerator"

Oradora: Sandra Vieira, Department of Radiotherapy, Champalimaud Foundation, Lisbon

Local: Anfiteatro PA1, piso 01 do Pavilhão de Matemática,  IST Alameda-campus

The first clinical EDGE accelerator was installed in our department at the beginning of 2014. This accelerator is fully integrated with the Calypso and the Optical Surface Monitoring system (OSMS). A 6 Degree-of-Freedom couch is also a part of the assemble. Both Calypso and the OSMS are used to setup and monitor patient position during treatment. Using the Calypso system patient position is found with the help of beacon transponders whereas the OSMS relies on the surface of the patient. In this presentation a description of the EDGE clinical treatment delivery will be given. Patient cases treated at the EDGE with intensity beam modulation will also be shown including patient quality assurance procedures.  Reasons for the increasing use of hypofractionated treatments (using 1, 3 or 5 treatment sessions) will also be discussed.

Quarta-feira dia 04 de Maio, às 16h30m

"Novel approaches in photovoltaics: Materials, devices and prospects"

Orador: Jorge Morgado, Organic Electronics Group, IT-LX

Local: Anfiteatro PA1, piso 01 do Pavilhão de Matemática,  IST Alameda-campus

Since the discovery of the photovoltaic effect, a significant effort has been made to develop the technology of the photovoltaic solar cells. Inorganic semiconductors, namely silicon, for a wider use, and compound semiconductors, for specific applications, have been the materials of choice. In this seminar I will describe the novel approaches that are being developed, with special emphasis on the new materials and fabrication techniques. I will also discuss the current limitations and possibilities of these new technologies.

Quarta-feira dia 13 de Abril, às 16h30m

"Microscopic black holes and (most) perfect fluid"

Orador: Elias Kiritsis, Universidade de Creta, Grécia

Local: Anfiteatro PA1, piso 01 do Pavilhão de Matemática,  IST Alameda-campus

Two tales will be told: The first involves Quantum Chromodynamics, the theory of the strong interaction. This theory is mostly intractable calculationally at low energies  but was subjected over many years to a lot of experimental scrutiny. In the last 20 years, heavy ion experiments have provided a glimpse into a new phase of quark matter, that of the quark gluon plasma. On the other hand, a theoretical breakthrough relates strongly coupled gauge theories to string theories and gravity. Black holes are some of the strange beasts in such theories. The two approaches meet each other via a duality and they provide us with the opportunity to study (among other things) microscopic black holes in the laboratory.

Quarta-feira dia 06 de Abril, às 16h30m

"101 Years of General Relativity: From Cosmology to Black Holes and Fundamental Theories"

Orador: José Sande Lemos, Centro Multidisciplinar de Astrofísica - CENTRA, Departamento de Física, Instituto Superior Técnico

Local: Anfiteatro PA1, piso 01 do Pavilhão de Matemática,  IST Alameda-campus

General relativity was conceived in its final form in November 25, 1915, by Einstein. It is a geometrical spacetime theory of gravitation and matter. In this Colloquium, a presentation of the main aspects of general relativity, as well as its major implications in the past 101 years, namely, cosmology, black holes, and fundamental theories, will be presented. In the wake of the recent detection of gravitational waves due to black hole collision, there is a bright road ahead for the physics of the gravitational field. What the future holds for research in general relativity and gravitation will also be alluded to. 

Quarta-feira dia 30 de Março, às 16h30m

"All-Electric Spintronics in Graphene"

Orador: Aires Ferreira, Department of Physics, University of York, United Kingdom

Local: Anfiteatro PA1, piso 01 do Pavilhão de Matemática,  IST Alameda-campus


Graphene—a one-atom thick layer of carbon atoms with unique electronic properties—is considered a promising candidate to implement novel electron-spin-based approaches to advanced storage and logic computing, an effort known as spintronics [1].

Recent evidence for giant spin–orbit coupling enhancement in graphene-based systems have opened up intriguing possibilities [2]. The presence of spin–orbit interactions in graphene is predicted to unlock a plethora of phenomena, including non-trivial Z2 topological phases [3]. Of particular interest is the spin Hall effect, a set of relativistic spin–orbit coupling phenomena whereby charge currents propagating in nonmagnetic materials generate spin currents and vice versa. In addition to their fundamental interest, spin Hall effects are a key ingredient in schemes for the manipulation and inter-conversion of spin and charge signals via pure electrical means, including spin Hall effect-induced spin–orbit torques at metal- ferromagnetic interfaces, and detection of spin currents generated from the spin Seebeck effect.

Theory predicts that dilute adatoms inducing short-range spin–orbit interactions in graphene can trigger a robust and gate-tunable spin Hall effect through the resonant skew scattering mechanism [4]. Recent experiments exploring non-local spin transport in H-bar graphene devices and spin pumping in graphene/magnetic insulator interfaces confirm the early theoretical predictions, paving the way for all- electric spintronics in two-dimensional carbon platforms [2,4].

This Colloquium will survey the rich interplay between intrinsic (topological) and extrinsic (disorder- related) mechanisms underlying the spin Hall effect in materials. The resonant scattering physics characteristic of two-dimensional massless Dirac fermions, and its importance to the giant spin Hall effect recently observed will be discussed. The solution of linear Boltzmann transport equations will be shown to disclose a hierarchy of relaxation times, accurately describing additional distortions of the Fermi surface due to spin–orbit coupling induced by extrinsic sources, such as adatoms [4].

The last part will discuss the intriguing role of bona fide quantum processes in the spin Hall effect, beyond Boltzmann transport theory. Based on calculations for a representative model system obtained through a nonperturbative diagrammatic treatment introduced recently [6], I will argue that a spin Hall effect induced by quantum coherent skew scattering is within reach the current state of the art.

1. W. Han et al. Nature Nanotech. 9, 794 (2014). M. Kamalakar et al. Nature Comm. 6, 6766 (2015)

2. J. Balakrishnan et al. Nat. Comm. 5, 4748 (2014); A. Avsar et al. Nat. Comm. 5, 4875 (2014); Z. Wang et al., Nat. Comm. 6, 8339 (2015). J. Mendes et al. Phys. Rev. Lett. 115, 226601 (2015)

3. C.L. Kane, and E.J. Mele, Phys. Rev. Lett. 95, 226801 (2005)

4. A. Ferreira et al. Phys. Rev. Lett. 112, 066601 (2014)
5. M. Milletari and A. Ferreira, arXiv pre-print: 1601.08076 (2016)

Quarta-feira dia 16 de Março, às 17h00m

"Gravitational waves: the sound of the universe"

Orador: Víctor Cardoso, CENTRA and Physics Department, IST

Local: Anfiteatro PA1, piso 01 do Pavilhão de Matemática,  IST Alameda-campus


A 14 de Setembro de 2015, às 09:50:45 UTC, os dois interferómetros LIGO detectaram um sinal de ondas gravitacionais provenientes da fusão de dois buracos negros. Esta descoberta histórica marca o nascimento da era da Astronomia de Ondas Gravitacionais, abrindo uma nova janela para o panorama do Universo Gravitacional, até agora invisível. Neste Colóquio será descrita a ciência envolvida nesta descoberta.

Quarta-feira dia 9 de Março, às 16h30m

"Valorização do Conhecimento: desafios e oportunidades"

Orador: José Carlos Caldeira, Presidente da Agencia Nacional de Inovação

Local: Anfiteatro PA1, piso 01 do Pavilhão de Matemática,  IST Alameda-campus

A valorização do conhecimento e a sua transferência entre os diversos agentes do Sistema Nacional de Inovação é um tema prioritário a nível nacional e internacional. A apresentação vai destacar alguns dos respetivos desafios e oportunidades, destacando as vertentes da cooperação e do financiamento

Quarta-feira dia 2 de Março, às 13h30m


Orador: Simone Calogero, Chalmers University of Technology

Local: Anfiteatro do Complexo Interdisciplinar, IST

Diffusion is a type of motion which is observed in a variety of physical systems and at different scales. The applications are ubiquitous and range over fields as different as physics, biology, economics and social sciences. In this talk I will discuss some classical topics in diffusion theory, including Brownian motion and plasma dynamics, as well as its recent application to explain the nature of dark energy in Cosmology. 

Colóquios do DF - Realizados no 1º Semestre de 2015/2016

Quarta-feira dia 9 de Dezembro, às 16h30m

"Neutrinos have mass! And so what?"

Orador: Filipe Rafael Joaquim, Departamento de Física & Centro de Física Teórica de Partículas, IST

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)

In this colloquium I will make a brief overview of theoretical aspects and open problems in Neutrino physics, and discuss the impact of the discovery of neutrino oscillations in our current understanding of fundamental interactions.

Quarta-feira dia 2 de Dezembro, às 16h30m

"Cloning the Higgs"

Orador: João Paulo Silva, Centro de Física Teórica de Partículas, IST

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)


CERNʼs LHC has recently discovered a spinless particle:the Higgs boson.
The electroweak and strong interactions are described by gauge groups, determining the number of spin 1 particles. The number of spin 1/2 families was determined by experiments at LEP, while nothing constrains the number of spin 0 particles. Determining their number and nature is a key problem in particle physics. Multi-Higgs models have many interesting features, which will be addressed here.

Quarta-feira dia 25 de Novembro, às 16h30m

"Magnetic tunnel junction devices and applications: from basic research to production"

Orador: Ricardo Ferreira, International Nanotechnology Laboratory, Braga

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)


Magnetoresistive devices and magnetic nanostructures are key building blocks in a large number of commercial electronic products across a wide range of applications covering industrial positioning sensors, automotive sensors, hard disk drive read heads and embedded memories.  Simultaneously, the research around this type of structures and devices that explore pure spin currents and the interaction between charge currents and spin currents is very active.  This creates an environment very favorable to the interaction between researchers and industry.  With such a strong interaction the research, development and optimization process is very often driven by very practical questions related with the deployment of technological solutions in a production environment.  How to optimize a device for a certain application, ensuring that it can be produced reproductively?  How to scale up the production capacity?  How to speed up the manufacturing process?  How to characterize a process, rather than a single, isolated device?
This presentation will focus on the key developments carried out at INL during the last 4 years, including the development of high yield and high uniformity processes for the production of state-of-the-art magnetoresistive devices using CoFeB/MgO/CoFeB Magnetic Tunnel Junctions both at micrometric (100 μm down to 2 μm)  and nanometric  (down to 50 nm) scales.
Some applications and collaborative projects concerning the use of magnetic tunnel junctions as magnetic field sensors will be presented, including the current plans and activities to produce complex hybrid devices which integrate MTJs, MEMS, CMOS and more technologies.
A description of the current activities and projects concerning the development of Spin Transfer Nano-Oscillators will also be presented with a focus on the current efforts to improve the endurance of <1nm thin MgO tunnel barriers aiming the production of large amplitude homogeneous nano-oscillators and nano-oscillators excited with pure spin currents.

Quarta-feira dia 18 de Novembro, às 16h30m

Physical approaches for the study of insect embryo development"

Orador: Ivo Telley, Instituto Gulbenkian de Ciência

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)


Embryogenesis is a phase of animal development in which cells multiply and migrate to specific places of the embryo where they engage in a determined function. The earliest phase of embryo development is dedicated for cell and genome multiplication. A beautiful example of embryo development in which cellular entities are to be placed at specific locations is the insect, for example the fruit fly. After fertilisation the egg transitions into and embryo and undergoes several fast rounds of nuclear multiplication, in which the genome is duplicated and segregated, while the egg cell membrane does not divide. These nuclei are then positioned and anchored at the cell cortex, and within one hour several thousand cells are formed at once. To date, we do not know much about the mechanisms underlying the migration of nuclei during the first nine divisions. It is fascinating, however, that the micrometer sized nuclei travel almost a millimetre. The insect embryo is challenging to study under the microscope because it is rather large and filled with diffractive particles. Our group has adopted an explant approach, in which we reduce the volume of the embryo artificially, to study nuclear and cytoskeletal dynamics in explants of the early (0–90 min) Drosophila melanogaster fertilized egg and embryo.

Quarta-feira dia 11 de Novembro, às 16h30m

"From high-speed AFM to 4π holographic AFM"

Orador: Mervyn Miles, HH Wills Physics Laboratory, University of Bristol

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)

ABSTRACT: Conventional AFM has limitations: (i) low imaging rate, (ii) probe-sample force interaction, and (iii) samples that are non-planar.

The vertical probe high-speed force microscope operates in non-contact and is based on shear- force microscopy (ShFM). In this HS ShFM [1], a vertically-mounted laterally-oscillating probe detects the sample surface ~1 nm from it as a result of the change in the mechanical properties of the water in confined geometry between the probe tip and the sample. With this technique, very low normal forces are applied to the specimen.

Conventional AFMs require planar samples because the probe raster scans in a plane. It is as if the tip is only ‘seeing’ the sample from above. We have overcome this limitation by steering the tip of a nanorod, fabricated with 2-photon polymerisation, in a 3D scan using holographic optical traps [2], in order to scan around a sample from any direction.

1. Fletcher J, Harniman RL, et al., Science 340 (2013) 595-599.

2. Phillips DB, et al., Nature Photonics 8 (2014) 400–405.

Quarta-feira dia 04 de Novembro, às 16h30m

"Luminescent wide bandgap nanomaterials"

Orador: Teresa Monteiro, Departamento de Física e I3N, Universidade de Aveiro

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)

ABSTRACT: Low dimensional structures such as quantum wells, wires and nanoparticles are being increasingly  used in our daily life in a wide range of technological applications with a tremendous impact in the global and societal needs.

Nitrides and oxides-based nanostructures with large bandgap energy are nowadays of upmost interest in lighting technologies and emergent luminescent based bio-applications. In both fields, several approaches can be followed to the materials’ growth/synthesis and doping aiming the tuning of the nanomaterials light emission with enhanced functionalities. For the desired applications, a deep knowledge of the materials optical properties should be thoroughly investigated to improve their efficiency and device development.

In this talk an overview of the luminescent properties of undoped and lanthanide doped nitrides (GaN-based) and oxides (ZnO, ZrO2) nanomaterials will be given. The nature of the defects from where the nanomaterials emission is originated will be discussed and explored in order to tailor the materials properties for solid state light and biological applications.

Quarta-feira dia 28 de Outubro, às 16h30m

"Pendulum clocks hanging from a wall: a synchronization mystery from Huygens"

Orador: Professor Luís Viseu Melo, Departamento de Física do Instituto Superior Técnico

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)

In the XVII century Huygens observed the synchronization of two pendulum clocks hanging from a wall. We developed a model explaining this phenomenon, which is different from the problem of two clocks hanging from a moveable base. The data obtained in the laboratory are matched by the model and indicate that the communication between the clocks is done through sound pulses propagating in the wall.

Quarta-feira dia 21 de Outubro, às 16h30m

"A concise inventory of printable/flexible/stretchable sensors: technologies and applications for high volume applications"

Orador: Roger H. Grace, Roger Grace Associates

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)

Quarta-feira dia 14 de Outubro, às 16h30m

"The 2015 Nobel Prize in Physics"

Orador: Heinrich Hoerber, Univ. Bristol, Reino Unido

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)

The 2015 Nobel Prize in Physics was attributed to Takaaki Kajita and Arthur B. McDonald, "for the discovery of neutrino oscillations, which shows that neutrinos have mass". Kajita and McDonald have had leading roles in, respectively, the Super-Kamiokande (SK) and Sudbury Neutrino Observatory (SNO) experiments, that have solved the so-called "atmospheric neutrino anomaly" and "solar neutrino problem". With that, they have given huge insights into the fundamental nature of neutrinos.

After providing some general context, this seminar will describe the main challenges of the experiments and their results, briefly mentioning the portuguese participation in SNO.

It will conclude with the general picture of the consistency between the several experimental observations from many different sources, in the framework of three massive neutrinos, one of the most fascinating aspects of this field.

Colóquios Realizados em 2014/2015

Quarta-feira dia 1 de Julho, às 11h00m

"Perpendicular magnetic anisotropy: from ultralow power spintronics to cancer therapy"

Orador: Professor Russell Cowburn - IEEE distinguished Lecturer 2015, Univ. Cambridge, Reino Unido

Local: Anfiteatro VA3 (IST, Pavilhão de Civil)


Most thin magnetic films have their magnetization lying in the plane of the film because of shape anisotropy.  In recent years there has been a resurgence of interest in thin magnetic films which exhibit a magnetization easy axis along the surface normal due to so-called Perpendicular Magnetic Anisotropy (PMA).  PMA has its origins in the symmetry breaking which occurs at surfaces and interfaces and can be strong enough to dominate the magnetic properties of some material systems.  In this talk I explain the physics of such materials and show how the magnetic properties associated with PMA are often very well suited to applications.  I show three different examples of real and potential applications of PMA materials: ultralow power STT-MRAM memory devices for green computing, 3-dimensional magnetic logic structures and a novel cancer therapy.


Russell Cowburn has research interests in nanotechnology and its application to magnetism, electronics and optics.  Before returning to Cambridge in 2010 he held positions at the CNRS Paris, University of Durham and Imperial College London.  He is the founder of two start-up companies and the inventor of the anti-counterfeiting technology ‘Laser Surface Authentication’.  He has had over 60 patents granted and is a frequent invited speaker at international conferences.  He is the winner of the GSK Westminster Medal and Prize, the Degussa Science to Business Award, the Hermes International Technology Award and the Institute of Physics Paterson Medal and Prize.  He is a Fellow of the Royal Society.

27 de Maio, às 16h30m

"Topological Matter and Why You Should be Interested"

Orador: Steve Simon, Universidade de Oxford

Local: Anfiteatro PA1 (IST, Pavilhão de Matemática, piso -1)

In two dimensional topological phases of matter, processes depend on gross topology rather than detailed geometry. Thinking in 2+1 dimensions, particle world lines can be interpreted as knots or links, and the amplitude for certain processes becomes a topological invariant of that link. While sounding rather exotic, we believe that such phases of matter not only exist, but have actually been observed in quantum Hall experiments, and could provide a uniquely practical route to building a quantum computer. Possibilities have also been proposed for creating similar physics in systems ranging from superfluid helium to strontium ruthenate to semiconductor-superconductor junctions to quantum wires to spin systems to cold atoms.

20 de Maio, às 16h30m

"Light Forces"

Orador: Heinrich Hoerber, Univ. Bristol, Reino Unido

Local: Anfiteatro PA1 (IST, Pavilhão de Matemática, piso -1)

The Year of Light 2015 emphasises the significance of the natural phenomenon of light for us. Our sense of seeing establishes the main channel that provides us with information about the world we are living in and it is the only channel that provides information about distant objects like planets and stars.

In my talk, I would like to focus on a very special effect of light when it interacts with matter: it can exert forces. The first one that we know of, who recognised this effect, was Johann Kepler when he thought about why comet tails always point away from the sun. The linear momentum of light involved is meanwhile used in many applications from cooling atoms to optical tweezers. For me the most fascinating application in future might be to accelerate space ships.

Beside the linear momentum light also has an angular momentum related to the spin of a photon or to an additional orbital momentum, which some modes of laser light can exhibit. As we know from fundamental Mechanics, an angular momentum can be converted into a linear momentum when a force acts in an unsymmetric way on a rotation. For instance, if the wheel of a bicycle turns in air and then touches ground, a part of the angular momentum is transferred into a linear motion by a counteracting force to the friction force on the axel. A force generated in a comparable way from the angular momentum of light, obviously, will be very small and it is rather challenging to measure it. I will describe such a measurement that complements measurements by Raman and Beth in the 1930ties of the torque generated by light hoping to add to the understanding of the phenomenon of light.

29 de Abril de 2015, às 16h30

"Tokamak fusion plasmas and modelling infrastructures"

Orador: Rui Coelho, Instituto de Plasmas e Fusão Nuclear, IST

Local: Anfiteatro PA1 (IST, Pavilhão de Matemática, piso -1)

The quest for competitive advantage in modern societies boosts research. Fusion research is a vibrant field with an ambitious goal of mastering controlled fusion burning plasmas in devices on Earth and producing clean electricity with virtually unlimited resources. Extensive research on magnetic plasma confinement devices known as Tokamaks have revealed the essential role that modelling plays in data interpretation of present experiments and building up predictive capability for future devices. In this talk, the spur behind Tokamak research and physics is reviewed and focused on computational infrastructures implementations dedicated to Tokamak modelling.

22 de Abril de 2015, às 16h30

"HiSPARC: Undergraduate research, outreach and development"

Orador: Filipe Freire, Instituut-Lorentz for Theoretical Physics, Univ. Leiden

Local: Anfiteatro PA1 (IST, Pavilhão de Matemática, piso -1)
HiSPARC is a physics outreach cosmic rays experiment initiated in the Netherlands that brings together, research, education and networking.  Using low cost scintillator plates as cosmic ray detectors placed in universities, secondary schools and public institutions, this experiment brings secondary school students in contact with real research data involving the mysterious high energy cosmic rays. In addition students in this project have an opportunity to have first hand contact with the technology, data analysis and networking required to run physics experiments.  A summary of the present status and aims of this project is presented.