Journal club: “Quantum Correlations and Coherence in Spin-1 Heisenberg Chains”

We explore quantum and classical correlations along with coherence in the ground state of spin-1 Heisenberg chains, namely the one-dimensional XXZ model and the one-dimensional bilinear biquadratic model, with the techniques of density matrix renormalization group theory. Exploiting the tools of quantum information theory, that is, by studying quantum discord, quantum mutual information, and three recently introduced coherence measures in the reduced matrix of two nearest neighbor spins in the bulk, we investigate the quantum phase transitions and special symmetry points in these models. We point out the relative strengths and weaknesses of correlation and coherence measures as figures of merit to witness the quantum phase transitions and symmetry points in the considered spin-1 Heisenberg chains. In particular, we demonstrate that as none of the studied measures can detect the infinite-order Kosterlitz-Thouless transition in the XXZ model, they appear to be able to signal the existence of the same type of transition in the bilinear quadratic model. However, we argue that what is actually detected by the measures here is the SU(3) symmetry point of the model, rather than the infinite order quantum phase transition. Moreover, we show in the XXZ model that examining even single-site coherence can be sufficient to spotlight the second-order phase transition and the SU(2) symmetry point.

Seminário do Grupo de Polímeros: “Micro/Nanomotors: Synthesis, Application and Future”

Micro/nanomotors, based on a multiples propulsion mechanisms, have been developed over the past decade toward diverse applications. The ability of the micro/nanomotors to rapidly move in different mediums represents a novel approach in areas like environmental remediation, diseases treatment, self-healing and biosensors. In this presentation, we journey from the production and use of chemically powered to externally actuated (fuel-free) micro/nanovehicles platforms and its prospects and challenges for such practical propelling systems.

Seminário do Grupo de Polímeros: “Size effects in physically prepared metal nanoparticles”

In this presentation I willdiscuss different experimental methods for the fabrication and characterization of mono- and bi-metallic clusters and nanoparticlesin the gas phase by physical means. When embedded in stable solid matrices, they form cluster-assembled nanostructures with variable properties. In particular I will address the following topics as ex-amples:

– Fabrication of cluster-assembled nanostructures: magnetron sputtering/aggregation versus laser vaporization.

– Size effects in the magnetic anisotropy of embedded cobalt nanoparticles: from sur-face to shape.

– Size effects in the electronic and vibrational relaxation in small silver clusters as evi-denced by ultrafast femtosecond spectroscopy: the departure from the scalable size regime.

– Study of size effects in the electronic structure of size-selected very small silver clus-ters: preliminary results from optical spectroscopy and electron energy loss spectros-copy.

– Structural, optical and magnetic properties of bi-metallic FexAuy and FexAgy nanoparti-cles: optical spectroscopy, magnetometry and synchrotron-based XMCD and EXAFS.

I will conclude by an outlook on possibilities of research on polymer-embedded metal na-noparticles as scheduled in collaboration with IFSC-USP.

Schematic view of the fabrication principle of cluster-assembled nanostructures and high resolution electron micrograph of a small cobalt nanoparticle in a carbon matrix.

High-Energy Physics Seminars: “Long-term and new challenges in lattice QCD”

Regularising QCD on a lattice is by now a well established tool to study the strong interaction in the low-energy regime where perturbation theory is not reliable anymore. Theoretical and algorithmic developments combined with facilities of large scale high performance computers induced significant progresses to explore the parameter space, even reaching the physical point: now, simulations are performed at the correct pion mass.

Those steps forward offer also the opportunity to solve difficult questions, either on old problems or on hot topics of the moment. After a brief presentation of the general state of the art, we will illustrate our statement by discussing cases of the strong coupling constant, g-2 anomaly of the muon and Delta I = 1/2 rule in K –> pi pi.

De Anatomia a Função, de Diagnose a Terapias: Imagens (Moleculares) em Farmacologia

Desenvolvimento de um novo fármaco é um processo longo e pleno de desafios.

Quanto mais informação se dispõe sobre o(s) mecanismo(s) de uma doença, maior é a probabilidade de encontrar uma terapia apropriada.

Por outro lado, o quanto melhor e mais cedo uma enfermidade puder ser diagnosticada, maiores são as chances de poder interferir no processo patológico com uma entidade química ou biológica.

Esta premissa estabelece a base para o uso de técnicas de imagens no campo da farmacologia. A relevância dessas técnicas para a obtenção e quantificação de informação anatômica, funcional, metabólica ou molecular no contexto da pesquisa farmacológica in vivo será discutida e ilustrada através de exemplos oriundos de diferentes especialidades, da neurologia à oncologia.

LQMC/CIBFar: “New mechanisms to accelerate drug discovery for Neglected Tropical Diseases (NTDs)”

The Drugs for Neglected Diseases initiative (DNDi) is a patient-needs driven, not-for-profit research and development (R&D) organization that develops safe, effective, and affordable medicines for the millions of neglected patients across the world. DNDi focuses on developing new treatments for the most neglected patients suffering from diseases such as human African trypanosomiasis (sleeping sickness), leishmaniasis, Chagas disease, filariasis, paediatric HIV, mycetoma, and hepatitis C. The initiative’s primary objective is to deliver a total of 16 to 18 treatments by 2023 and to establish a strong R&D portfolio for these diseases. The R&D strategies developed by DNDi since its inception aim to address the immediate needs of patients by improving existing therapeutic options in the short term, whilst undertaking longer term research to identify and develop entirely new compounds which will be valuable adapted tools, particularly for elimination targets set by the World Health Organization. In 2013, DNDi began building a new consortium in Latin America (LOLA), providing support and mentoring for young scientists in the region. The consortia conduct hit-to-lead and lead optimization activities for visceral leishmaniasis and Chagas disease via a decentralized virtual model, and the talk focus will be the innovative R&D model and the efforts aiming at strengthening research capacities in the region. Jadel Kratz joined DNDi in June 2016 as Lead Optimization Latin America Coordinator focused in drug discovery projects in the region. He supports both the global and local R&D teams, and promotes the expansion of a regional consortia of scientific partners. Prior to joining DNDi, Dr. Kratz participated and coordinated academic research projects across various areas. Recently, he worked as R&D Coordinator at Cristália, a Brazilian-based pharmaceutical company. Dr Kratz is a pharmacist, and earned his PhD in Pharmaceutical Sciences (2011) at the Universidade Federal de Santa Catarina, Florianópolis, Brazil, with a visiting researcher period at the Uppsala University, Sweden. He completed postdoctoral fellowships at the University of Innsbruck and the University of Vienna, Austria.

LQMC/CIBFar: “Advances in Ligand-based and Structure-based Drug Design Software”

In recent years we have seen a rise in the use of computer-aided drug design tools in pharmaceutical companies as a result of advances in the underlying methods coupled with vast increases in computational resources. Here, we present an overview of the tools in the Schrödinger Suites, including ligand-based and structure-based approaches. We show that improvements in the underlying force field can improve results across a broad range of applications. We also show that molecular dynamics simulations can be used to accurately predict protein conformational states and protein-ligand binding free energies. Woody Sherman is Vice President of Applications Science at Schrödinger. He received his B.S. in Physical Chemistry from the University of California at Santa Barbara where he studied nonlinear optical properties of organic polymers using computational quantum mechanics. He completed his Ph.D. at MIT working in Professor Bruce Tidor’s lab where he examined the role of electrostatics in protein-ligand binding and implemented a novel method for optimizing ligand binding specificity across a panel of targets. While in graduate school he completed an internship at Biogen where he helped develop novel methods to enhance antibody affinity through electrostatic charge optimization, resulting in a publication and patent. At Schrödinger, he is involved in applications projects, product development, methods development, and scientific software support. He also works closely with customers on research projects and collaborations. Woody has published on a broad range of topics, including induced-fit docking, ensemble docking, protein design, small molecule optimization, cheminformatics, hybrid ligand/structure-based methods, free energy simulations, charge optimization, pharmacophore modeling, and more. He is a reviewer for top journals in computational chemistry and drug design and is on the Editorial Board of both Chemical Biology & Drug Design and Journal of Chemical Information and Modeling.

LQMC/CIBFar: “Residue Coevolution via Direct Coupling Analysis”

Faruck Morcos is an assistant professor in the Department of Biological Sciences and Department of Bioengineering at the University of Texas at Dallas. He is also member of the Center for Systems Biology at UT Dallas. Before starting his lab at UT Dallas, he was a postdoctoral fellow at the Center for Theoretical Biological Physics, first at the University of California San Diego and later at Rice University. He received his Ph.D. in Computer Science (Computational Biology) from the University of Notre Dame. He also holds a M.S. in Electrical Engineering from the Technical University of Munich and a M.S. in Applied Mathematics from Notre Dame. He has a B.S. (Honors) in Electronics and Communications Engineering from ITESM Campus Monterrey. In 2010, he received the Research Excellence Award given by the Computer Science Department at the University of Notre Dame. In 2005, the Kellogg Institute for International Studies awarded him the Kellogg Fellowship for Graduate Studies at the University of Notre Dame and in 2002 he received the Werner von Siemens Excellence Award to pursue graduate studies in Germany. His research focuses on applications of information theory, statistical inference and physical modeling to study molecular structure, function and interactions. His current interests include molecular coevolution and the analysis of biological information to study disease.

LQMC/CIBFar: “Biopharmaceuticals: Myth vs. Facts”

– What is a pharmaceutical (small molecule vs biologic), innovative, branded, generic product?

– Relative market sizes and evolution over time: market sizes by type, by geographies, by therapeutic area (by sales);

– Top biopharma players; some key products (noticeable breakthroughs rather than simply size);

– Increase in number of companies and products under development (in numbers and by therapeutic area) has been large;

– However, only a small number is approved each year;

– And the cost of developing a drug has increased significantly;

– Industry R&D productivity has been in serious decline for years;

– But opportunities for successful products still exist…

– What does it take to develop a product?

– Tunnel charts: show how long it takes to develop a drug (pre-competitive and competitive spaces);

– Approval rates and costs by phase (and by therapeutic area?);

– Product lifecycle;

– Characterization of industry segments;

– Forces of change: overview of strategic.

Filosofísica: “Desculpe o transtorno, mas precisamos conversar sobre mecânica bohmiana”

As interpretações que lhe contaram de mecanica quântica são realmente as que saem dos experimentos? Ou mesmo as que saem dos postulados formais da teoria? Que argumentos descartaram a possibilidade de uma interpretação causal para a mecânica quântica na época em que a controversia ainda tinha lugar entre os principais pesquisadores da área, marginalizando todas as tentativas posteriores de formular descrições não probabilísticas (não causais) de processos quânticos? A mecânica bohmiana, resultado dos trabalho de David Bohm nos anos 50, é atualmente mencionada por físicos quase sempre como uma curiosidade histórica e não como uma alternativa teórica de fato, sendo subestimada e amplamente ignorada por esses. Nesse Filosofísica, o nosso queridíssimo filosofísico Iago Israel, vai nos explicar (bem do começo) o que a teoria de Bohm tem de diferente, interessante e como ela tenta contornar alguns aspectos problemáticos (para alguns) da interpretação usual, puramente probabilística.

Vejamos se ainda têm sentido hoje as indagações de John Bell que, para alguns, já teria colocado um ponto final nessas questões: “Por que será que a visão da onda piloto está ignorada nos livros de mecânica quântica? Não seria o caso de ensiná-la, não como a via única, mas como um antídoto a autossatisfação vigente?”

High-Energy Physics Seminars: “Hydrodynamics with polarization”

Using the Lagrangian hydrodynamic approach [1] we derive the ideal hydrodynamic limit of a fluid with a net polarization of the microscopic degrees of freedom. We discuss the relevance of this dynamics in the light of the experimental study of Hadron (Lambda and vector meson) polarization and other spin-dependent observables in heavy ion collisions, and conclude that our approach is the first term in an effective theory expansion appropriate to study these phenomena quantitatively.

[1] D.Montenegro, G.Torrieri, PRD, in press, arXiv:1604.05291

Hydrodynamics with polarization

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IFSC OSA Student Chapter: “Professor Eric Van Stryland seminars”

We from IFSC OSA Student Chapter have the honour to receive Prof. Eric Van Stryland as part of the Travelling Lecturer program of the Optical Society. Prof. Stryland will give two seminars, a brief one about the history of The Optical Society and other pointing out fundamental aspects of his cutting-edge research. You are welcome to attend both seminars that will be held at Sala F-210 (Administration building) at 2 p.m of November 11th. Take a look below for further information about Prof. Stryland and the seminars.

History of The Optical Society (OSA)

I’ll give a brief introduction of how OSA began in 1916 and how it has turned into an international professional home for nearly 20,000 scientists and engineers. Its offerings are highly respected international refereed journals along with international conferences on optics and photonics. However, it is also a professional network for students and professionals to interact, develop careers in optics and photonics, and much more. It is my professional home and should become yours.

Nonlinear spectroscopy: absorption and refraction

At high optical irradiance of short pulse lasers, the absorption and refraction of materials changes temporarily. We have been developing nonlinear spectroscopic tools for measuring these changes of nonlinear absorption (NLA) and nonlinear refraction (NLR). The tools include Z-scan that separately yields the sign and magnitude of both NLA and NLR, pump-probe for the dynamics of NLA, and our newly developed Beam-Deflection technique that gives the dynamics of NLR. This last technique is so sensitive that it can measure the nonlinear refraction of air (λ/20,000 induced phase change). I will also discuss the interesting and intuitive relations between NLR and NLA determined by causality (nonlinear Kramers-Kronig relations). This leads to a discussion of nondegenerate nonlinearities, e.g. 2-photon absorption (2PA) with two different energy photons. We find orders of magnitude enhancement of 2PA for photon energy rations of ~10. We then utilize these nonlinearities for devices including gated IR detection with uncooled wide-gap semiconductors for 3D LIDAR and the possibility of a 2-photon laser.

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“Measurement of leptonic cosmic rays with AMS-02, interpretation in terms of dark matter and pulsar”

Over the last two decades, there has been a strong interest in the cosmic ray positron fraction which exhibit an excess of high energy positrons whose origin is still highly uncertain. The Alpha Magnetic Spectrometer (AMS-02) is a general purpose high-energy particle physics detector operational on the International Space Station since May 2011. During its unique long duration mission AMS-02 is collecting large amount of data to study the behaviour of cosmic ray electrons and positrons with unprecedented precision. The latest measurements of positron fraction, positron flux and electron flux with AMS-02 will benpresented. The interpretation of the positron excess in terms of pulsar or dark matter will be presented in this talk.

Filosofísica: “Mais um breve passeio pela Filosofia contemporânea da Matemática”

Nesse seminário, o membro do grupo de estudos Uirá Matos prosseguirá nos guiando em incursão pelos territórios da Filosofia da Matemática, em uma continuação do seu panorama das mais atuais (ou nem tanto) questões do campo.

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