Research lines

Analyses of the data from the Large Hadron Collider

As high-energetic collisions are happening at the LHC, data analyses are needed to enhance the statistical precision of previous measurements, like the properties of the Higgs boson, and investigate evidences for New Physics, namely Supersymmetry, Dark Matter, Extra Dimensions, etc. Within the LHC Collaborations, distinct subgroups are dedicated to study aspects of the theories of the Standard Model of the elementary particles. The analyses are carried out in a collaboration between the various groups involved in technical work, like interface of data acquisition, statistical treatment of measurements, simulation effects in the theoretical predictions, among many others. In this research line, it is meant to build a set of computational tools of small and large scales, like (i) estimate of experimental signatures of physical processes and (ii) extraction of information about the data reconstruction in the experiment. In the CMS Collaboration, we currently focus on the studies of exclusive processes related to photon fusion and diffractive interactions for the production of particle pairs using the data collected by the forward sub-detector Precise Proton Spectrometer (PPS).

Related researchers:
– Gustavo Gil da Silveira


Complex Fluids

Biologically motivated problems. Simple models of cooperative behavior and competition in biological populations. Theoretical and simulational models to describe ionic fluids. Water, its anomalies and water-biomolecules interactions. Evolution of systems with long-range interactions. Glass transition and jamming transition. Properties of amorphous solids. Superhydrophobicity.

Related researchers:
– Alexandre Pereira dos Santos
– Carolina Brito
– Heitor Carpes Marques Fernandes
– Jeferson Arenzon
– Marcia Barbosa
– Mendeli Henning Vainstein
– Yan Levin


Electron Spectroscopy

The Lab on Electron Spectroscopy (LEe-, established in 2006) is an Applied Physics research group dedicated to produce new nano-structured materials, and to explore their unique electronic and structural properties. The investigations aim at the development of more efficient and lower cost heterogeneous catalysts, electrocatalysts, as well as biosensors, which can be applied to clean energy production, to reduce greenhouse effect gases emission, or for industrial processes. The infrastructure allows for synthesizing metallic and bimetallic nanoparticles, as well as films and nanostructure oxides using physical and chemical methods. In addition, Surface Science techniques based on Electron Spectroscopy, associated with Synchrotron radiation experiments, are routinely used as characterization tools.

Related researchers:
– Jonder Morais
– Maria do Carmo Martins Alves


Extragalactic Astrophysics

Galaxies in the nearby Universe look very different from their high redshift counterparts. Understanding how galaxies changed over the last 13 billion years is one of the main goals of extragalactic astrophysics.
– Galaxies can be found in different neighborhoods, from mostly empty voids to densely packed galaxy clusters. Depending on where they live, galaxies can look very different. When moving from one neighborhood to another, they can be caught in-transformation;
– Galaxies are made up of stars, gas, dust and, also, dark matter. We can shed light on their past evolution through detailed studies of their properties;
– The study of gravitational lensing effects allow us to investigate the physics of dark matter;
– Studies of globular cluster systems allow us to understand the assembly history of their host galaxies;
– Supermassive black holes in the center of massive galaxies, when accreting large amounts of matter, radiate enormous quantities of energy that can shape the evolution of their hosts.
We address these issues observationally, by looking at large volumes of the Universe with deep surveys and by targeting nearby objects with detailed studies. Learn more at http://www.ufrgs.br/astronomia/.

Related researchers:
– Allan Schnorr Muller
– Ana Chies Santos
– Basilio Xavier Santiago
– Cristina Furlanetto
– Horácio Dottori
– Marina Trevisan
– Miriani Pastoriza
– Rogério Riffel
– Thaisa Storchi Bergmann


High-Energy Particle Physics Phenomenology

High energy physics addresses questions about matter and energy in a fundamental level. The current physical framework helping to answer those questions is the Standard Model of particle physics and its extensions. Several aspects of Collider Physics phenomenology are studied, specially in the studies related to the fundamental strong interactions among quarks and gluons. The theoretical formalism within the Standard Model addressing interaction among these objects is the Quantum Chromodynamics. There is interested in a range of theoretical problems with a phenomenological emphasis and our projects are often focused on aspects of theoretical physics that can be tested in ongoing (RHIC, LHC) or future experiments (ILC, CLIC, FCCs). Therefore, it is essential to work closely to the experimental particle physicists. The research topics can be listed as follows:
– Quantum Chromodynamics at short and long distances;
– Phenomenology of the electroweak interaction, high energy neutrino interactions;
– Higgs physics;
– Some aspects of Physics beyond the Standard model;
– Models of Dark Matter, direct|indirect searches and cosmology;
– Heavy ion collisions and the Quark Gluon Plasma;
– Several aspects of Quantum Field Theory.

Related Researchers:
– Gustavo Gil da Silveira
– Magno Machado
– Maria Beatriz Gay Ducati


High-Pressure Physics and Advanced Materials

The ability to process materials under extreme conditions in absolute values of different thermodynamic variables (temperature, pressure) and their gradients (rapid cooling, high deformation rates), has allowed both the discovery of new phases and compounds with unusual properties, as well as the production of materials with properties designed to meet specific needs. The lines of research in progress are:
– Carbon nanostructures produced at high pressures and high temperatures;
– The effect of high pressure on structural properties of glasses;
– The effect of high pressure on optical properties of glasses doped with rare earth ions;
– Nitrogen solubility in minerals in the earth’s mantle and the genesis of potassium magmas;
– Effect of high pressures on vitreous and metallic matrices;
– Sintering under extreme conditions.

Related researchers:
– Naira Maria Balzaretti
– Silvio Buchner


Ion Implantation

The Ion Implanter Laboratory has two accelerators dedicated to the study basic and applied science. While basic science focuses on the understanding of the interaction of energetic ions with matter, applied science extends across a vast field that includes materials technology, forensic science, science and technology of advanced foods and materials among others. With more than a dozen researchers, and with 35 years of experience, the Ion Implanter Laboratory stands out not only for the training of masters and doctors, but also for high-level research with great international recognition.

Specifically, our research topics involve the analysis and synthesis of advanced materials with ion beams, including nanostructured materials, elemental and molecular identification used in forensic science, biotechnology, food science and toxicology, among others. Add to that the investigation of the effects of ion irradiation in matter, important for nuclear and space technology.

Related researchers:
– Pedro Luis Grande
– Johnny Ferraz Dias
– Livio Amaral
– Paulo Fernando Papaleo Fichtner
– Henri Ivanov Boudinov
– Fernanda Chiarello Stedile
– Raul Carlos Fadanelli Filho
– Rogério Luis Maltez
– Jonder Morais
– Claudio Radtke
– Cristiano Krug
– Daniel Lorscheitter Baptista
– Gabriel Viera Soares
– Leandro Langie Araujo
– Raquel Giulian
– José Henrique Rodrigues dos Santos

Emerita:
– Fernando Claudio Zawislak
– Moni Behar
– Israel Jacob Rabin Baumvol


Related researchers:
– Alexandre Da Cas Viegas
– Antônio Marcos Helgueira de Andrade
– João Edgar Schmidt
– Julian Penkov Geshev
– Sabrina Nicolodi Viegas

Magnetism

The research activities of the Laboratory of Magnetism [LAM, http://www.if.ufrgs.br/pes/lam] are based on the acquisition and characterization of new magnetic materials using advanced technologies, which allow obtaining structures with thicknesses in order of some atomic distances. These nanostructured magnetic systems present a new horizon in scientific research, being of interest both in Basic Physics (whose interest is to know better our universe), as well as in Applied Physics (use of knowledge for creation and manufacturing of new devices). The work developed in LAM is focused on the study of the new properties which appear due to the reduction of the dimensionality of the magnetic nanostructures. The main research lines of the group are: Synthesis of nanostructured magnetic materials using various physical or chemical techniques, such as electrodeposition and physical deposition by sputtering; Exchange coupling in ultrathin ferromagnet/antiferromagnet layers presenting exchange bias; Transport properties and giant magnetoresistance in nanostructures; Spin transfer in nanostructured systems; Development of models for simulations of remnant and hysteresis curves, ferromagnetic resonance and magnetoresistance; Graphene associated with magnetic materials.


Mathematical Physics and Field Theory

Our group performs basic research in Mathematical Physics and Integrable Systems. We investigate conceptual as well as algebraic aspects related to the application on exactly solvable models in distinct areas like Field Theory, Statistical Mechanics, and ultra cold Quantum Gases. The integrable models provide a precise understanding of many physical properties, revealing the essence of the models. Our main research topics are the quantum tunnelling in multiples wells, entanglement, few-body particle systems, spin chains, form factors, and correlation functions. More information can be found at http://www.if.ufrgs.br/fmtqc.

Related researchers:
– Angela Foerster


Microelectronics

Microelectronic devices are present in all the goods produced by the electronics industry, forming the basis of one of the most dynamic economic sectors in the world. Therefore, the degree of development of microelectronics plays an important role in the economy of the country. Microelectronics research projects include: Development of semiconductor devices. Technological processes. Defects engineering in semiconductor processing. Synthesis of new electronic materials. Electrical measurements in micro and nanostructures.

Related researchers:
– Henri Boudinov
– Rogério Maltez
– Daniel Baptista
– Carlo Requião


Network Theory and Complex Systems

The line of research “Network Theory and Complex Systems” is at the interface between the traditional physics of condensed matter and statistical mechanics with networks and social phenomena. The focus is on the application of statistical mechanics techniques to understand the dynamics and emerging properties of social, economic, and biological systems. It is an extension of physics beyond its traditional object of study, using similarities between the movement of atoms of a gas exchanging energy and people exchanging money or goods, for example. This is one of the analogies that make possible the use of techniques and models embodied in condensed matter physics for social systems. The emphasis of the line is the theoretical-computational study of so-called “socio-physics” problems, for example the study of the income distribution among people with binary exchange models (econophysics) or the study of the adoption of an innovation. However, some results have the potential to be applied to real systems such as the simulation of attacks on real criminal networks.

Related researchers:
– Sebastián Gonçalves


Physical-Chemistry of Solid Surfaces and Interfaces

We investigate the physical-chemistry properties of solid surfaces and interfaces. Our focus are nanostructured dielectrics used in advanced micro and nanoelectronic devices, such as high-k materials, oxides, and oxynitrides deposited or thermally grown on silicon, on silicon carbide, or on germanium. We also investigate the growth and modifications of bidimensional materials (2D), such as graphene and molybdenum disulphide. For that, we have reactors, an equipment that aggregates various surface analysis techniques, and an X-ray refractometer. For further details, please visit our website: https://plone.ufrgs.br/fqsis.

Related researchers:
– Fernanda Chiarello Stedile
– Cláudio Radtke
– Gabriel Vieira Soares
– Silma Alberton Corrêa
– Cristiano Krug
– Emeritus Professor: Israel Jacob Rabin Baumvol


Physics of Correlated Electronic Systems

The research line on “Physics of correlated electronic systems” deals with theoretical aspects related to electronic, magnetic, and transport properties of solids. The main focus in on the so-called strongly correlated electronic systems, which include, for example, high-critical-temperature superconductors. Special attention is also devoted to effects of disorder and frustration, which may yield exotic states like spin liquids. The theoretical approach involves usual techniques to deal with quantum many-body systems, including Dynamical Mean Field Theory, and utilizes analytical and computational methods in a complementary way.

Related researchers:
– Miguel Gusmão
– Sérgio Garcia Magalhães


Physics of Nanostructures

The main research topics of the Physics of Nanostructures Lab are divided in (a) synthesis and theoretical-experimental study of nanoparticles with potential catalytic properties for application in the global warming issue; (b) improvement of nanostructure systems used as renewable energy sources; (c) synthesis and characterization of nanostructured functional enzyme mimetics. The Lab facilities are dedicated to the synthesis of nanostructures, mainly via physical (sputtering) and via chemical methods. After, the nanostructures are characterized by several state-of-the-art experimental techniques of expertise of our group. The measurements are based on the photon, electron or ion interaction with the matter. Particularly, measurements at Synchrotron facilities around the world are frequently carried out by our group. Finally, the explanation of the results is supported by DFT calculations at the cluster existing in our lab and at CESUP-UFRGS. More information can be found at http://www.ufrgs.br/physnanolab/.

Related researchers:
– Fabiano Bernardi
– Fernanda Poletto
– Sérgio R. Teixeira
– Sherdil Khan


Related researchers:
– Cesar Zen Vasconcelos
– Dimiter Hadjimichef

Physics of New States of Matter: from quarks to the Cosmos

Our understanding of the origin of the Universe, of its evolution and the physical laws that govern its behavior, as well as on the different states of matter that makes up its evolutionary stage, reached in recent years levels never before imagined. This is due mainly to the new and recent discoveries in astronomy and relativistic astrophysics as well as to experiments on particle and nuclear physics that made the traditional boundaries of knowledge on physics to be overcome. As a result we have presently a new understanding about the Universe in its two extreme domains, the very large and the very small: the recognition of the deep connections that exist between quarks and the cosmos. The intimate relationship between quarks and cosmos has motivated the interest of our research group on the following scientific topics: new phenomena and new states of matter in the Universe; General Relativity, gravitation, cosmology; new directions for general relativity: past, present and future of general relativity; FRW cosmologies; cosmic microwave background radiation; first stars, hypernovae, and faint supernovae in the early Universe; quantum gravity and quantum cosmology; gravity and the unification of fundamental interactions; Supersymmetry and Inflation; String Theory; white dwarfs, neutron stars and pulsars; black hole physics and astrophysics; Gamma-ray emission in the Universe; high energy cosmic rays; gravitational waves; dark energy and dark matter; strange matter and strange stars; antimatter in the Universe; high-energy cosmic neutrinos; Blazars; quantum chromodynamics, nuclear and particle physics and new states of matter in the Universe; heavy ion collisions and the formation of the quark-gluon plasma in heavy ion collisions and in the first instants of the Universe; strong magnetic fields in the Universe, strong magnetic fields in compact stars and in galaxies, ultra-strong magnetic fields in neutron star mergers, quark stars and magnetars, strong magnetic fields and the cosmic microwave background; laboratories, observatories, telescopes and other experimental and observational facilities that will define the future directions of astrophysics, astronomy, cosmology, nuclear and astro-particle physics as well as the future of physics at the energy frontiers, and topics related to these.


Physics of Ultra-Cold Atoms

This research line utilizes theoretical and numerical approaches to investigate quantum models that describe relevant phenomena in ultra-cold quantum gases. The main research topics are:
– Anderson localization of one-dimensional Bose-Einstein condensates;
– Quantum phase transitions in one-dimensional systems of ultra-cold atoms;
– Bose-Hubbard model and generalizations;
– Spinor Bose gases in optical lattices;
– Ground-state properties of spinor bosons in multiple wells;
– Quantum dynamics and spin effects in few quantum wells, aiming to possible applications in Atomtronics.

Related researchers:
– Angela Foerster
– Miguel Gusmão


Related researchers:
– Antonio Endler
– Felipe Barbedo Rizzato
– Fernando Haas
– Luiz Fernando Ziebell
– Renato Pakter
– Rudi Gaelzer

Plasma Physics

Plasmas may be described as ionized gases, whose behavior is ruled by collective interactions among the charged particles. Plasmas are present in Nature in astrophysical and spatial environments, and also in the terrestrial environment. For instance, the matter constituting the stars and the clouds of gas in the interior of galaxies are in the state of plasma, and the rarefied matter found in the magnetosphere of planets also constitute a plasma. Plasmas are present in fluorescent lamps, in arc discharges, in flames in general, and in equipments used for research aiming the control of nuclear fusion for energy production.
The relevance of studies about plasmas stems from two aspects which are fundamental and complementary: one aspect is that the increase in the knowledge about the Universe, from the point of view of Astrophysics and the Physics of space and terrestrial magnetosphere, relies fundamentally on the investigation about the plasma behavior. A second aspect is that plasmas are connected with many technological applications, in particle accelerators, in surface treatment systems, in waste management, plasma screens, etc., and play fundamental role in the research aiming at a technology which may become a future and vital energetic alternative.
The Plasma Physics Group at UFRGS develops theoretical research, with use of analytical and computational methods, about subjects like the following: Waves and instabilities in plasmas; turbulence in plasmas; waves and instabilities in dusty plasmas; heating, current generation and electromagnetic radiation in plasmas; nonlinear dynamics and chaos in plasmas; optimization of plasma particle accelerators; dynamics of systems with long range interactions; waves and instabilities in quantum plasmas.
For the study of plasmas, basic areas of Physics such as Electromagnetic Theory, Classical Mechanics, and Statistical Mechanics, play fundamental role.


R&D of Particle Detectors

The LHC experiments are subdivided into distinct componentes employed to detector different types of particles. Some of this components are used to determine the particle track in the detector and measure its energy deposity. The measurements currently performed at the LHC demand high-precision particle detectors with high radiation hardness. Hence, the Research and Development (R&D) pf new componentes is constant, especially with the ongoing upgrade of the LHC experiments. The supervisors of the Physics Graduate Program are members of the ALICE Collaboration, with the Muon Forward Tracker (MFT) sub-detector, and the CMS Collaboration, in the development of the Precise Proton Spectrometer (PPS). The ongoing investigations are meant to design and build parts of the sub-detectors and the software development for their simulation and for data analyses.

Related researchers:
– Gustavo Gil da Silveira
– Luis Gustavo Pereira
– Maria Beatriz Gay Ducati
– Rafael Pezzi


Semiconductor foams

This research line investigates semiconductor foams to develop more efficient devices by exploring the potentiality of semiconductors with the efficiency of materials with giant surface areas (foams). Using experiments and simulations we aim at understanding the formation of porosity in semiconductors irradiated by ion beams, and how to tune their properties to better exploit their advantages.

Related researchers:
– Antônio Marcos Helgueira de Andrade
– Daniel L. Baptista
– Fabiano Bernardi
– Gilberto Lima Thomas
– Paulo F. P. Fichtner
– Raquel Giulian
– Rita M. C. de Almeida


Statistical Physics

Modelling of complex systems from microscopic interactions. Modelling of disordered systems: glasses, spin glasses, neurons. Magnetism of disordered systems. Theory of random matrices and complex networks. Applications in biology, economy, information theory, etc.

Related researchers:
– Fernando Lucas Metz
– Rubem Erichsen Jr.
– Sérgio Garcia Magalhães


Stellar and Galactic Astrophysics

Stars are key building blocks of galaxies and ideal astrophysical laboratories to study the physical properties of different stellar populations. Our galaxy, the Milky Way, is one of billions of galaxies in the Universe; it is the only known galaxy that we can describe in detail the basic properties of its different stellar populations. Topics of investigation:
– Details of the physical processes that led to the formation of the components of the Milky Way;
– Where and how the different chemical elements come from;
– Understand the life of stars with masses <10 times the mass of the Sun and their contribution to the interstellar medium; – The connection between star and planet formation (if any); – The formation of stellar associations and clusters; – Explain the multiple stellar populations found in globular clusters. Researchers from the Department of Astronomy are engaged in answering key scientific questions by using high quality photometric and spectroscopic data obtained at different telescopes, big data surveys and sophisticated stellar evolution models. See more at http://www.ufrgs.br/astronomia/.

Related researchers:
– Alan Alves Brito
– Alejandra Daniela Romero
– Basilio Xavier Santiago
– Charles Bonatto
– Eduardo Bica
– José Eduardo Costa
– Kepler de Souza Oliveira Filho (S.O. Kepler)


Superconductivity and Magnetism

The main topics investigated in this researcher line are:
(a) High temperature superconductivity;
(b) Supercondutivity in ferro-pnictide compounds;
(c) Effects of electronic correlations in the normal phase of the superconducting cuprates: the pseudogap;
(d) Magnetism of disordered systems: spin glasses, reentrant magnetic systems, effects of chirality;
(e) Heusler intermetallic compounds;
(f) Rare-earth compounds and alloys;
(g) Spin- polarized transport;
(h) Magnetism in semiconductors;
(i) Interaction between magnetism and supercondutivity in thin film heterostructures;
(j) Electronic properties of graphite.
Available experimental techniques: Electrical condutivity; magnetoresistance; Hall effect; magnetization; ac magnetic susceptibility; impedance; specific heat; magnetostriction.

Related researchers:
– Gilberto L. F. Fraga
– Milton André Tumelero
– Paulo Pureur
– Jacob Schaf (convidado)


Thin filmes and nanoestructures

The mission of the Laboratory of Thin Film and Nanostructure Fabrication (L3Fnano) is to explore visible light absorbing advanced nanomaterials applied in solar energy generation; particularly in artificial photosynthesis. We synthesize nitride and oxide semiconducting nanostructures via bottom up and top down approaches, including; Magnetron Sputtering on powders, liquids and film substrates, electrochemical anodization, hydro and solvothermal syntheses and many other physical and chemical deposition techniques. We develop doping methodologies for the visible light activation of UV-light absorbing oxide nano-architectured semiconductor devices and theoretical understanding of defect modification is complimented via density functional theory (DFT). The optical, morphological, electronic and structural properties of nanomaterials are investigated via state of the art advanced techniques and are co-related to solid/liquid interfaces via electrochemical and photoelectrochemical techniques. The nanostructures are applied in a variety of technologies such as photocatalytic hydrogen production, self-cleaning superhydrophobic surfaces and pollutant degradation. Our long-term goal is fabrication of large scale hydrogen production plant utilizing photoelectrochemical water splitting process.

Related researchers:
– Sérgio Ribeiro Teixeira
– Sherdil Khan


Topological and Emergent Systems

In this group we investigate the topological and emergent properties that arise in Condensed Matter Physics as a result of the interactions between the particles and the low dimensionality. These include the quantum Hall effect, topological superconductors, Majorana fermions, non-abelian anyons, and fractional statistics. We also investigate quantum spin liquids, where the quantum entanglement properties play an important role. Finally, the discrete non-linear Schrödinger equation is studied numerically to describe discrete breathers or localized emergent modes.

Related researchers:
– Gerardo Martinez