Lindhard Lecture, May 13, 2011 at 14:15
Andrew Chi-Chih Yao, Tsinghua University, Beijing (abstract)
Lindhard Lecture, 14 June 2010
Professor Peter Hänggi
University of Augsburg, Germany
With pioneering contributions ranging from fundamental statistical mechanics to quantum transport, Peter Hänggi (born 1950) of the University of Augsburg has made a variety of seminal advances in physics. His most impressive body of work includes that of applying the laws of Brownian motion for the phenomenon of Stochastic Resonance, his invention and design of Brownian motors and his discovery of coherent destruction of quantum tunneling and, as well, his conceptional advances of relativistic thermodynamics. He is a member of several academies and has been awarded up to seven honorary doctor degrees already. He is also the author of several review articles which serve as a reference for the respective fields. See also www.physik.uni-augsburg.de/theo1/hanggi/
Title: The Ring of Brownian motion: the good, the bad and the simply silly (see poster)
Time & place: Monday 14 June 2010 at 15:15, in Auditorium F (1534-125), Aarhus University
Abstrakt: Since the turn of the 20-th century the jittery dynamics of Brownian motion has continuously disclosed a rich variety of phenomena in and around physics. The understanding of this noisy phenomenon has undoubtedly helped to reinforce and substantiate those pillars on which the basic modern physical theories are resting: Its formal description provided the key to great achievements in statistical mechanics, the foundations of quantum mechanics and also astrophysical phenomena. Although noise is usually thought of as the enemy of order it in fact also can be of constructive influence. The phenomena of Stochastic Resonance and Brownian motors present two such archetypes wherein random Brownian dynamics together with unbiased nonequilibrium forces beneficially cooperate in enhancing detection and/or in facilitating directed transmission of information. The applications range from innovative information processing devices in physics, chemistry, and in physical biology to new hardware for medical rehabilitation. Particularly, those additional non-equilibrium disturbances enable the rectification of haphazard Brownian noise so that quantum and classical objects can be directed around on a priori designed routes (Brownian motors).
Organiser: Professor, Centre Leader, Klaus Mølmer, Center for Theory in Natural Science (CTN), Department of Physics and Astronomy, AU.
Lindhard Lecture, 12 November 2009
Professor Eörs Szathmáry
Collegium Budapest, Hungary
Parmenides Foundation, Munich, Germany
Eörs Szathmáry (born 1959) is a theoretical evolutionary biologist. His work focuses on the common principles behind the major transitions in evolution, such as the origin of life, the emergence of cells, the origin of animal societies, and the appearance of human language. Together with his mentor, John Maynard Smith, he has published two important books which serve as main references in the field (The Major Transitions in Evolution, Freeman, 1995, and The Origins of Life, Oxford University Press, 1999).
Title: The Major Transitions in Evolution
Time & place: Thursday 12 November 2009 at 10.20, in the AULA, building 1412, Aarhus University
Abstract: Units of evolution multiply and show inheritance with variation. It happened a number of times in evolution that lower-level units joined to form higher-level ones. In the fraternal transitions (such as the origin of multicellularity or social insects) the units that come together are alike, and the control of conflict is basically settled by the mechanism of kin selection. Complexity increases by epigenesis and the greatest hurdle is the initial advantage of staying together. In the egalitarian transitions the units that come together are initially unlike (such as different replicating genes in protocells or different reproducing cell organelles in an eukaryotic
cell), therefore reproductive division of labour is impossible. The greatest hurdle is the control of conflicts, whereas the initial advantage is the combination of functions. Conflict is resolved mainly by group (multilevel) selection. The analysis of major transitions has become part of an extended evolutionary synthesis.
The lecture is part of the seminar "Evolution Today", where leading experts will debate the major issues in evolution today. For more information on the full programme of the seminar, visit www.darwin.au.dk/2009.
Organisers : Professor Volker Loeschcke, Department of Biological Sciences, AU, and Professor, Centre Leader, Klaus Mølmer, Center for Theory in Natural Science (CTN), Department of Physics and Astronomy, AU.
Lindhard Lecture, 9 June 2009
Professor Stuart Kauffman
University of Calgary
Title : The Open Universe and the Sacred
Abstract : Darwinian "preadaptations" are features of an organism of no selective use in its current envi-ronment that might come to be of selective use in some different environment. In that case, due to natural selection, a new functionality can arise. An example is a swim bladder that adjusts buoyancy in some fish; paleontologists believe swim bladders arose from the lungs of lung fish. Such phenom-ena challenge the view, common in Western science since Descartes, Galileo, Newton, and Einstein, that all that unfolds in the evolution of the universe is describable by natural law.
The essential issue is the determination of possible preadaptations. How would we list all pos-sible selective conditions and specify the feature(s) that might become preadaptations? Indeed, the universe is "open" in complexity but its partially lawless becoming is also not random. We have no model of this in standard science. And yet, if we do not know what CAN happen then reason is an in-sufficient guide to living our lives.
I believe we need a new Enlightenment and a new symbol to denote the natural creativity of the universe.
Time & place : Tuesday, 9 June 2009 at 15.15 in the Large Anatomy Lecture Theatre (1232-115), Aarhus University.
Contact : Professor Carsten Wiuf, Bioinformatics Research Center (BiRC), or CTN director, professor Klaus Mølmer, Department of Physics and Astronomy
Lindhard Lecture, 10 December 2008
Professor Alexei V. Finkelstein
Institute of Protein Research, Russian Academy of Science
Title : Understanding folding rates and folding nuclei of globular proteins
Abstract : In the first part of this lecture, I overview protein structures, their spontaneous formation (“folding”) and thermodynamic and kinetic aspects of this phenomenon. It is stressed that protein folding is best studied for single-domain water-soluble proteins, and that most universal features of folding are observed near the point of thermodynamic equilibrium between the "native" (completely folded and structured) and "denatured" (loose and not-structured) states of the protein. Here the "two-state" ("denatured state" « "native state") transition is reversible and proceeds without accumulation of metastable intermediates, and only here the transition state, i.e., the most unstable state in the folding pathway, can be outlined experimentally by its essential influence on the folding/unfolding kinetics. In the second part of the lecture, a theory of protein folding rates and related phenomena is presented. This theory is similar to basic theories of rates of initiation of the first order phase transitions. It shows that protein size determines, in a reasonable agreement with experimental data, a range of possible protein folding rates in the vicinity of the point of thermodynamic equilibrium between the native and denatured states of the protein. Some overview of the other competing theoretical approaches to protein folding will also be given.
Time & place : Wednesday, 10 December 2008 at 15.15 in Auditorium F (1534-125)
Department of Mathematical Sciences, Aarhus University.
Contact : Professor Jørgen Ellegaard Andersen, IMF, or CTN center leader professor Klaus Mølmer, IFA
Professor Bernd Sturmfels
University of California, Berkeley
"Algebraic Statistics for Computational Biology"
Abstract: "This lecture gives an introduction to recent interactions between algebra and statistics and some emerging applications to computational biology. Statistical models of independence and sequence alignment will be illustrated by means of a fictional character, DiANA. She wears a pink skirt, plays hopscotch and rolls tetrahedral dice with face labels "A", "C", "G", and "T"."
Thursday 15 November 2007 at 14.15 in Auditorium E, Department of Mathematical Sciences, building 1533.
Contact: Niels Lauritzen, IMF.
Professor Warren Ewens
University of Pennsylvania
"Genetics and Mathematics: A Two-Way Interaction"
Abstract: "Like any other area of science, genetics has benefited greatly from a mathematical analysis of the questions that it considers. In particular, the Darwinian theory of evolution through natural selection is validated by a mathematical analysis. More recently, research that has occupied evolutionary geneticists for many years is finding applications in mathematics and in other areas of science. These include combinatorial analysis, fragmentation and coagulation phenomena in physics and elsewhere, ecology and economics. Some of these will be described, together with an application to the "law of succession"."
Tuesday, 15 May 2007, at 14.15 in Lakeside Lecture Theatres, University of Aarhus, followed by a reception.
Contact: Carsten Wiuf , BiRC, and Klaus Mølmer , IFA/CTN
Professor Elliott Lieb
Princeton University
"Quantum Mechanics, the Stability of Matter, and Quantum Electrodynamics"
"Ordinary matter is held together with electromagnetic forces, and the dynamical laws governing the constituents (electrons and nuclei) are those of quantum mechanics. These laws, found in the beginning of this century, were able to account for the fact that electrons do not fall into the nuclei and thus atoms are quite robust. It was only in 1967 that Dyson and Lenard were able to show that matter in bulk was also stable and that two stones had a volume twice that of one stone. Simple as this may sound, the conclusion is not at all obvious and hangs by a thread-- namely Pauli's "exclusion principle" (which states that two electrons cannot be in the same state). In the ensuing 3 decades much was accomplished to clarify, simplify and extend this result. We now understand that matter can, indeed, be unstable when relativistic effects and magnetic fields are taken into account -- unless the electron's charge is small enough (which it is, fortunately). These delicate and non-intuitive conclusions will be summarized. The requisite mathematical apparatus needed for these results is itself interesting. Finally, we can now hope to begin an analysis of the half-century old question about the ultimate theory of ordinary matter, called quantum electrodynamics (QED). This is an experimentally successful theory, but one without a decent mathematical foundation. Some recent, preliminary steps to resolve the problems of QED will be presented . "
Monday, 6 November 2006, at 14.15 in Auditorium F with refreshments afterwards, Department of Mathematical Sciences, University of Aarhus.
Contact: Jacob Schach Møller , IMF, and Klaus Mølmer , IFA/CTN
Professor Edward Witten
Institute for Advanced Study
School of Natural Sciences, Princeton:
"Quark Confinement and Black Holes" (see poster)Monday, 26 June, 2006 at 14:30 in the Lakeside Lecture Theatres , University of Aarhus.
Abstract: Quark confinement is the problem of understanding why quarks are permanently bound together into particles such as protons and neutrons. The talk will be a survey of old and new insights relating this question to string theory and black holes.
Contact: Jørgen Ellegaard Andersen, CTQM, and Klaus Mølmer, CTN
Sir Roger Penrose , Oxford University:
"Was Einstein right about quantum mechanics?
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Abstract 2:
The Statistical Physics of complex networks started a decade ago with the discovery of the small-world and scale-free structure of many observed, quite different networked systems, like e.g. the Internet, gene interactions and social relations. Besides a short general review of this, three topics will be presented in more detail: (1) the structure, dynamics and function of self-organizing communication networks, (2) self-organizing social systems, and (3) cascading failures and robustness of networked infrastructure.
The talks are presented by Professor Martin Greiner as "appetizers" for Complex Networks, his “package” of courses with lectures on Fluid Flows and Renewable Energies, offered in the spring of 2011.
CTN/Computer Science Seminar 28 May 2010
Grzegorz Rozenberg
Abstract:
Natural Computing is an interdisciplinary field of research that investigates human-designed computing inspired by nature as well as computation taking place in nature, i.e., it investigates models, computational techniques, and computational technologies inspired by nature as well as it investigates phenomena/processes taking place in nature in terms of information processing.
One of the research areas from the second strand of research is the computational nature of biochemical reactions. It is hoped that this line of research may contribute to a computational understanding of the functioning of the living cell, which is based on interactions between (a huge number of) individual reactions. These reactions are regulated and the main regulation mechanisms are facilitation/acceleration and inhibition/retardation. The interactions between individual reactions take place through their influence on each other, and this influence happens through the two mechanisms mentioned above.
In our lecture we present a formal framework for the investigation of biochemical reactions - it is based on reaction systems. We motivate this framework by explicitely stating a number of assumptions/axioms that hold for a great number of biochemical reactions, and we point out that these assumptions are very different from the ones underlying traditional models of computation. We discuss some basic properties of processes in reaction systems, and demonstrate how to capture and analyse, in our formal framework, some biochemistry related notions.
The lecture is of a tutorial style and self-contained, in particular no knowledge of biochemistry is required.
About the speaker:
Professor G. Rozenberg is one of the most influential persons within theoretical computer science. He has published 500 papers, 6 books, and is a (co-)editor of more than 70 books. He was the President of the European Association for Theoretical Computer Science (EATCS) in 1985-1994. He is editor-in-chief for five journals and book series including Theoretical Computer Science. He is the head of the Theoretical Computer Science group at Leiden Institute of Advanced Computer Science (LIACS), and the scientific director of Leiden Center for Natural Computing (LCNC).
His current research interests are:
- natural computing, including molecular computing, computation in living cells, self-assembly, and theory of biochemical reactions.
- theory of concurrent systems, in particular theory of Petri nets, theory of transition systems, and theory of traces.
- theory of graph transformations.
- formal language and automata theory.
- mathematical structures useful in computer science, in particular theory of 2-structures.
- computer supported cooperative work.
CTN joint seminar, 5 February 2008
Jerzy Karczmarczuk
Abstract:
In most languages, when a procedure F takes an expression E as argument, E is evaluated, and its value passed to F. A different, "lazy" protocol (or "call by need") stipulates that E gets evaluated only when F needs it, and if only some part of it is used, the rest remains as a piece of code, to be computed later. This simple strategy permits to code in an extremely compact, yet readable way, some co-recursive algorithms, where typical for scientific computing iterations (loops) are replaced by recurring over the produced results (mainly composite data: lists, sequences, trees, etc. Reminder: a standard recursion reduces the input of the procedures).
Those co-recursive procedures seem "runaway". They have no termination clauses, and may generate "infinite" piece of data, representing unbound infinite power series, signals, chains of expressions with all derivatives wrt. Some variable, very long combinatorial sequences, etc. Such programs as the division or composition of series, which took a good half-page of code, reduce to two-, three-liners...
This strategy, in order to be safe, needs a side-effect-free programming discipline, and is available in functional languages (Haskell, Clean, a variant of Scheme), but it may also be implemented (unsafely) in such languages as Python, or Matlab, where the user can manipulate functions.
We will present a short introduction to the co-recursivity (using Haskell), and the main part of the talk are concrete examples, from the basic power series processing, through lazy automatic differentiation algorithms, generation of musical sound through the wave-guide simulations of musical instruments, up to the "shortest program in the West" which generates the full perturbation series for the anharmonic (x4) quantum oscillator, and a 2-line solution of the Dyson-Schwinger equation for a toy, 0-dimensional field theory (as presented in the NORDITA course of Cvitanovic), not realistic, but sufficiently lousy to induce students' headache.
Obviously "infinite" data should be understood /cum grano salis/. If the underlying computational algorithm has a fast rising complexity, the lazy programs may overflow the memory, or slow down the system considerably, there are no miracles. But the human effort of coding may be really economized, and since the programs are short, they are much less error-prone. After all, as you know, laziness in the main driving force of progress!
The speaker is a computer scientist from Caen, Normandy, France, born to professional life as a theoretical physicist in Cracow, Poland. He is interested mainly in application of functional techniques to scientific computing and to imagery.
Time and place: Tuesday, 5 February 2008 in building 1525-323,Department of Physics and Astronomy.
Kontakt: Klaus Mølmer, IFA
CTN joint seminar, 16 November 2007
Professor Bernd Sturmfels
University of California, Berkeley
Title: "Semigraphoids, Permutohedra, and Mice"
Abstract : Semigraphoids are combinatorial structures that arise in statistical learning theory. They are equivalent to convex rank tests, and to Minkowski summands of the permutohedron, a convex polytope whose vertices are labeled by the elements of the symmetric group. This lecture gives an introduction to this theory, and its application to the design of a new non-parametric test for finding periodically expressed genes from time course microarray experiments.
Time and place: Friday, 16 November 2007 at 14.15 in Physics Auditorium, Department of Physics and Astronomy, building 1523.
Contact: Niels Lauritzen, IMF.
Dr. Dirk Brockmann
Max Planck Institute for Dynamics and Self-Organization, Göttingen
Title: "Feel sick? Follow the money!" - The scaling laws of human travel Abstract: In the light of increasing international trade, intensified human mobility and the emergence of novel human infectious diseases, the knowledge of dynamical and statistical properties of human travel is of fundamental importance. I will report on a recent discovery of universal scaling laws in global human movement patterns (Brockmann et al., Nature 2006). Based on the idea that the geographic circulation of money can serve as a proxy for human travel, we analyzed the movement patterns of over half a million individual dollar bills registered at www.wheresgeorge.com. In the second part of the talk I will show how an extended wheresgeorge.com dataset (11 mio. trajectories of bills) can be used to reconstruct an all-scale transportation network for the United States. I will show to what extent geographical boundaries and large scale communities are intrinsically encoded in the connectivity structure of this network. I will also speak about "travel bug dog tags" and geocaching, a modern GPS treasure hunt. Time and place: Thursday, 9 August 2007 at 14.15 in Physics Auditorium, Department of Physics and Astronomy, Building 1520. Contact: Klaus Mølmer, IFA/CTNMini Symposium
Mini Symposium on Mathematical and Computational Approaches to Study the Evolution and Epidemiology of Viruses, February 20, 2007Professor Immanuel Bloch
University of Mainz
Title: Exploring Quantum Matter in Artificial Crystals of Light
Abstract: "The realization of ultracold atomic gases marks a milestone of modern quantum physics. Dilute gas clouds of millions of atoms form fundamental quantum many body states of Bose-Einstein condensates or Fermi gases at temperatures of only a few Nanokelvin. By loading such ultracold quantum gases into periodic potentials made out of laser light – so called optical lattices – such quantum gases can serve as a starting point for the investigation of fundamental model systems of quantum physics, in which the original vision of R.P. Feynman of a quantum simulator has already today partly become true. Wideranging perspectives are thereby opened for novel experiments in Quantum Optics, Quantum information processing, Atomic and Molecular as well as Condensed Matter physics, some of which will be outlined in my talk."
Tuesday, 7 November 2006, at 10.15 in Auditorium F at the Department of Mathematical Sciences, Faculty of Science, University of Aarhus.
Professor Elliott Lieb
Princeton University
Title: The Dilute, Cold Bose Gas: A truly quantum-mechanical many-body problem
Abstract: "The peculiar quantum-mechanical properties of the ground states of Bose gases that were predicted in the early days of quantum-mechanics have been verified experimentally relatively recently. The mathematical derivation of these properties from Schroedinger's equation have also been difficult, but progress has been made in the last few years (with R. Seiringer, J-P. Solovej and J. Yngvason) and this will be reviewed. For the low density gas with finite range interactions these properties include the leading order term in the ground state energy, the validity of the Gross-Pitaevskii description in traps (including rapidly rotating traps), Bose-Einstein condensation and superfluidity in traps, and the transition from 3-dimensional behavior to 1-dimensional behavior as the cross-section of the trap decreases. The latter is a highly quantum-mechanical phenomenon. Finally, there is a model for the recent experiments on optical lattices in traps that rigorously displays the transition from a Bose-condensed state to a Mott insulator.
For the charged Bose gas at high density, the leading term in the energy found by Foldy in 1961 for the one-component gas and Dyson's conjecture of the N ^{7/5} law for the two-component gas has also been verified."
Tuesday, 7 November 2006, at 11.15 in Auditorium F at the Department of Mathematical Sciences, Faculty of Science, University of Aarhus.
Contact: Jacob Schach Møller , IMF, and Klaus Mølmer , IFA/CTN
Madalin Guta (Nottingham)
Friday September 15, 2006, 11.15-12.15 in 1520-616, Institut for Fysik og Astronomi.
"Non-relativistic Matter and Quantized Radiation."
Abstract: We propose an adaptive, two steps strategy, for the estimation of mixed qubit states. We show that the strategy is optimal in a local minimax sense for the norm one distance as well as other locally quadratic figures of merit. Local minimax optimality means that given n identical qubits, there exists no estimator which can perform better than the proposed estimator on a neighborhood of size n ^{-1/2} of an arbitrary state. In particular, it is asymptotically Bayesian optimal for a large class of prior distributions. We present a physical implementation of the optimal measurement based on continuous time measurements in a field that couples with the qubits. The crucial ingredient of the result is the concept of local asymptotic normality (or LAN) for qubits. This means that, for large n, the statistical model described by n identically prepared qubits is locally equivalent to a model with only a classical Gaussian distribution and a Gaussian state of a quantum harmonic oscillator. The idea is to approximate a complicated quantum statistical model by a simpler, Gaussian one, directly on the quantum level. Then one can solve the statistical decision problem for the latter, which will be asymptotically optimal for the former.
Contact: Ole Barndorff-Nielsen and Klaus Mølmer
Marcel Griesemer (Stuttgart)
Friday April 21, 2006, 11.15-12.15 in Auditorium G2.
"Non-relativistic Matter and Quantized Radiation."
Abstract: For about ten years the mathematical analysis of non-relativistic matter and quantized radiation has been persued with renewed vigor by more and more mathematical physicists, and their efforts led to many beautiful results. In this talk we review some of the highlights, report on the current status of the field and conclude with selected open problems.
Contact: Dmitri Fedorov, Aksel Jensen, and Jacob Shach Møller.
Hans Hammer (Bonn)
Friday April 21, 2006, 12.15-13.15 in Auditorium G2.
"Effective Field Theories in Physics."
Abstract: Effective field theories provide a powerful framework to exploit a separation of scales in physical systems.They are widely used in many branches of physics ranging from condensed matter to nuclear and particle physics. I will give an introduction into this method and discuss some applications to non-relativistic few-body systems
with large scattering length. These systems have many interesting properties, such as a geometric spectrum of three-body bound states and log-periodic dependence of observables on the low-energy parameters characterizing the system.
Contact: Dmitri Fedorov, Aksel Jensen, and Jacob Shach Møller.
Sir Roger Penrose , Oxford University:
"What is Twistor (-string) Theory?"
Contacts: Jørgen Ellegaard Andersen, IMF and Klaus Mølmer, IFA
Go to the workshop webpage for more information.
Hosts: Bioinformatics Research Center (BiRC) and Centre for Theory in Natural Science (CTN)
Go to the workshop webpage for schedule and list of speakers.
Hosts: Bioinformatics Research Center (BiRC) and Centre for Theory in Natural Science (CTN)
Go to the workshop webpage for list of speakers, participants, and programme.
Organizers: Dmitri Fedorov (AU), Aksel Jensen (AU), Arne Jensen (AAU), and Jacob Schach Møller (AU)
Webpage for Workshop and PhD School: dars.dk
Contact: Jørgen Ellegaard Andersen, CTQM, and Steen Hannestad, DARS
CTQM Nielsen lecture, June 26 2006
Professor Witten will also give the CTQM lecture:
"Gauge Theory and The Geometric Langlands Program"Monday, 26 June, 2006 at 10:30 in Auditorium F at the Department of Mathematical Sciences, Faculty of Science, University of Aarhus.
Abstract: A twisted version of four-dimensional supersymmetric gauge theory can be used to study the geometric Langlands program. The twist involved is analogous to the twist by which Donaldson theory can be obtained from supersymmetric gauge theory.
Contact: Jørgen Ellegaard Andersen, CTQM, and Klaus Mølmer, CTN
"Perspectives on Hidden Markov Models"
As a collaboration between the Center for Theory in Natural Science, the department of mathematical science, the computer science department and BirC, a graduate course "Perspectives on Hidden Markov Models" will be held in Q4, starting April 7, 2006.
The webpage of the course is www.daimi.au.dk/~bromille/PHM/
The course is open to all graduate students (i.e., post-bachelor students) at the faculty of science. It would be of particular interest to computer science students having caught an interest in stochastic modeling from computer science courses such as the ones on the topics of bioinformatics and data compression (and possibly other courses).
Because of the mixed background of students attending the course, it will not be graded. To get 5 ECTS from attending the course, an assignment has to be completed. The assignment may be a practical programming assignment or a more theoretically oriented report.
To sign up for the course, please email Peter Bro Miltersen as soon as possible and preferably before the start of the course.
October 5., 13.15-14.10, in Aud. G.2., Department of Mathematics
Nicolai Nygaard (Aarhus)
" The Physics of the Fermi Gas "
Contact: Klaus Mølmer and Jacob Schach Møller.
October 5., 16.15-17.15, in Aud. G.2., Department of Mathematics.
Jan Philip Solovej (Copenhagen)
" The Mathematics of the Bose Gas "
Contact: Klaus Mølmer and Jacob Schach Møller.
Jens Lindhard (1922-1997) was professor at the Department of Physics and Astronomy, University of Aarhus, and one of the departments most prominent scientists.