BEGIN:VCALENDAR VERSION:2.0 PRODID:-//RLASKEY//CALENDEROUS//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120105T170000Z DTEND:20120105T180000Z UID:event519@buphy.bu.edu URL:http://physics.bu.edu/events/show/519 SUMMARY:Clustering financial investors from their trading activity DESCRIPTION:Featuring Rosario Mantegna\, University of Palermo\nHosted by: H. Eugene Stanley\n\nPart of the Biophysics/Condensed Matter Seminar Series .\n\n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120213T170000Z DTEND:20120213T180000Z UID:event868@buphy.bu.edu URL:http://physics.bu.edu/events/show/868 SUMMARY:Detection of Orbital Fluctuations Above the Structural Transition T emperature in the Iron Pnictides and Chalcogenides DESCRIPTION:Featuring Laura H. Greene\, University of Illinois\, Urbana-Cha mpaign\nHosted by: David Bishop\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\nAbstract:\nThe role of quantum criticality in Fe-based s uperconductors is studied using quasiparticle scattering spectroscopy (QPS) \, also called point contact spectroscopy [1].  With this technique\, we probe the electronic structure of the parent\, electron-doped\, and hole -doped Fe-pnictides AEFe2As2 (AE=Ca\,Sr\,Ba)\, and Fe-chalcogenides Fe1+yTe .  For AE=Sr\,Ba and Fe1+yTe.  The onset of a conductance enhance ment is reproducibly observed at To\, well above the structural (Ts) and ma gnetic (TN) transition temperatures.  For Ba(Fe1-xCox)2 As2\,the condu ctance enhancement exists only in the underdoped regime\, allowing us to ad d a new region of strong correlations in the phase diagram:  For x = 0 to 5.5\, To ~ 175 K to ~ 150K\, respectively.  The onset of these str ong correlations has been identified as arising from orbital fluctuations:& nbsp; As To is crossed\, the dzx and dzy orbital degeneracy is broken by a Pomeranchuk instability\, causing an increase in the zero-energy density of states; hence the excess conductance [2].  We associate this orbital ordering with a resistance anisotropy observed in detwinned crystals above Ts [3].  The prediction that the orbital ordering fluctuations above T s would not be observed in detwinned crystals that do not exhibit this resi stance anisotropy above Ts (CaFe2As2 and BaxK1-x Fe2 As2) [2] was verified [1]. Due to inherent difficulties in detwinning Fe1+yTe\, it has not been t ested for resistive anisotropy\, but since we observe conductance enhanceme nt above TS\, we predict an in-plane resistive anisotropy of Fe1+yTe above TS.  We discuss the role of orbital fluctuations and nematicity in the quantum criticality of these materials. [4]\n \nThis work is supporte d by the Center for Emergent Superconductivity\, an Energy Frontier Researc h Center funded by the US DOE\, Office of Science\, Award No. DE-AC0298CH10 88. Work at Cambridge is supported by EPSRC\, and work at Ames Lab is suppo rted by the US DOE under Award No. DE-AC02-07CH11358. 
\n \n\nH . Z. Arham et al\, arXiv:1201.2479.\nW.-C. Lee and P. Phillips\, arXiv:1110 .5917.\nI. R. Fisher et al\, Rep. Prog. Phys. 74\, 124506 (2011) and refere nces therein.\nS. Kasahara et al\, Phys. Rev. B 81\, 184519 (2010); S. Kasa hara et al.\, Bull. Am. Phys. Soc. 56\, Z26.00010 (2011); Y. Matsuda\, priv ate commun.\n\n  LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120217T170000Z DTEND:20120217T180000Z UID:event676@buphy.bu.edu URL:http://physics.bu.edu/events/show/676 SUMMARY:Femtosecond Coherent Optical Control of Electronic and Magnetic Ord er DESCRIPTION:Featuring Ilias Perakis\, University of Crete\nHosted by: Richa rd Averitt\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\nAb stract:\nThe idea of using femtosecond laser pulses to control material pro perties at the quantum level has led to some exciting developments at the f rontier of condensed-matter physics and materials science. Interactions amo ng coupled degrees of freedom make it possible to switch and modulate elect ronic and magnetic properties in new ultrafast ways by using photons. Recen t advances in laser technology provide access to non-equilibrium many-body states and non-thermal phases. Prominent examples that challenge our presen t understanding are femtosecond photoinduced phase transitions and femto-ma gnetism. In this talk I will discuss a non-equilibrium theory that engages the elements of transient coherence\, correlation\, and nonlinearity to add ress the following fundamental questions in different systems:\n\nWhat happ ens during the coherent nonlinear photoexcitation of a correlated system?\n What is the nonlinear optical and magneto-optical response to this photoexc itation?\nWhat non-equilibrium many-body mechanisms govern the non-thermal temporal regime?\nWhich experimental schemes can best visualize the resulti ng transient phases?\n\nThis theory is tightly integrated with femtosecond nonlinear optical and magneto-optical spectroscopy experiments. I will pres ent recent results in three model systems: ferromagnetic (III\,Mn)V semicon ductors\,  two- dimensional electron gas in a strong magnetic field\, and the manganites. I will also discuss some possible applications for all- optical magnetic memory control at THz speeds. \n  LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120224T170000Z DTEND:20120224T180000Z UID:event679@buphy.bu.edu URL:http://physics.bu.edu/events/show/679 SUMMARY:Statistical mechanics of classical and quantum computational comple xity DESCRIPTION:Featuring Roderich Moessner\, Max Planck Institute\, Dresden\nH osted by: Claudio Chamon\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\nAbstract:\nThe quest for quantum computers is motivated by thei r potential for solving problems that defy existing\, classical\, computers . The theory of  computational complexity provides a rigorous framewor k for classifying  the hardness of problems according to the computati onal resources\, most  notably time\, needed to solve them. Its extens ion to quantum computers  allows the relative power of quantum compute rs to be analyzed. This framework identifies families of problems which are likely hard for classical computers (``NP-complete'') and those which are likely hard for quantum computers (``QMA-complete'') by indirect methods. T hat is\, they identify problems of comparable worst-case difficulty without directly determining the individual hardness of any given instance. Statis tical mechanical methods can be used to complement this classification by d irectly extracting information about particular families of instances---typ ically those that involve optimization---by studying random ensembles of th em. These pose unusual and interesting (quantum) statistical mechanical que stions and the results shed light on the difficulty of problems for large c lasses of algorithms as well as providing a window on the contrast between typical and worst case complexity. This talk presents an introduction to th is set of ideas with our recent work on quantum satisfiability as primary e xample. It also touches on the connection of computational hardness with th e physical notion of glassiness. arXiv:1009.1635 \, arXiv:0910.2058 \, arXiv:0903.190 4 LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120302T170000Z DTEND:20120302T180000Z UID:event700@buphy.bu.edu URL:http://physics.bu.edu/events/show/700 SUMMARY:Cancelled DESCRIPTION:Featuring Geetha Balakrishnan\, University of Warwick\nHosted b y: Richard Averitt\n\nPart of the Biophysics/Condensed Matter Seminar Serie s.\n\n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CANCELLED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120309T170000Z DTEND:20120309T180000Z UID:event853@buphy.bu.edu URL:http://physics.bu.edu/events/show/853 SUMMARY:Spontaneous quantum Hall effect and fractionalization in itinerant chiral magnets DESCRIPTION:Featuring Ivar Martin\, Los Alamos National Laboratory\nHosted by: Claudio Chamon\n\nPart of the Biophysics/Condensed Matter Seminar Serie s.\n\nAbstract:\nWhen electrons move in a magnetic material\, their transpo rt can be profoundly affected by scattering off magnetic ions. Converse is also true: Itinerant electrons themselves can define the magnetic state int o which the system orders. Even though typically these magnetic states are simple ­ e.g. ferromagnetic or antiferromagnetic ­ sometimes\, comp lex chiral magnetism can appear. In this talk I will present several exampl es of two- and three-dimensional itinerant models of magnetism that exhibit complex non-coplanar ordering even in the absence of spin orbit interactio n; I will describe possible material realizations. Non-coplanar itinerant m agnets are expected to exhibit highly unusual transport phenomena that stem from a quantum coherent effect of non-coplanar magnetic ordering on electr ons\, which is similar to the Aharonov-Bohm effect.  It can lead to th e spontaneous quantum Hall effect and ground-state electrical and spin curr ents. The equivalent strength of the orbital magnetic field can exceed 104 Tesla. The stable topological excitations (magnetic vortices) in these stat es can carry fractional electronic charge and spin and realize anyonic exch ange statistics. LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120313T173000Z DTEND:20120313T183000Z UID:event885@buphy.bu.edu URL:http://physics.bu.edu/events/show/885 SUMMARY:DNA sequence analysis using methods of statistical physics DESCRIPTION:Featuring Ivo Grosse\, Luther University\, Halle\, Germany\nHos ted by: H. Eugene Stanley\n\nPart of the Biophysics/Condensed Matter Semina r Series.\n\n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120319T180000Z DTEND:20120319T190000Z UID:event893@buphy.bu.edu URL:http://physics.bu.edu/events/show/893 SUMMARY:Exact Solution of Percolation Problem in 4 Dimensions DESCRIPTION:Featuring Sasuke Miyazima\, Chuba University\, Japan\nHosted by : H. Eugene Stanley\n\nPart of the Biophysics/Condensed Matter Seminar Seri es.\n\n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120329T173000Z DTEND:20120329T183000Z UID:event882@buphy.bu.edu URL:http://physics.bu.edu/events/show/882 SUMMARY:The Influence of Topology on Sound Propagation in Granular Force Ne tworks DESCRIPTION:Featuring Mason Porter\, University of Oxford\, UK\nHosted by: David Campbell\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n \nAbstract: Granular materials exhibit numerous rich and complex dynamics\, which have been investigated from both continuum and particulate perspecti ves. In this talk\, I will represent granular materials as spatially-embedd ed networks composed of nodes (particles) and weighted edges (contact force s between particles) with definite locations in Euclidean space\, and I wil l use ideas from network science to provide insights into how sound propaga tes through granular materials. By performing experiments with photoelastic particles\, my collaborators and I can quantitatively characterise the int ernal force structure\, and the use of a network representation then allows one to probe its effect on sound propagation. I will discuss how network m odularity\, a meso-scale property\, characterizes the sound propagation bet ter than either system-scale or local-scale network features. I will also d emonstrate that geographic community structure of the (weighted) granular f orce chain network provides a fundamental constraint on sound propagation.\ nThis work\, which is available at http://arxiv.org/abs/1110.1858\, is join t work with Dani Bassett\, Eli Owens\, and Karen Daniels. LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120330T160000Z DTEND:20120330T170000Z UID:event873@buphy.bu.edu URL:http://physics.bu.edu/events/show/873 SUMMARY:Stripes in topological insulators DESCRIPTION:Featuring Vidya Madhaven\, Boston College\nHosted by: Claudio C hamon\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\nAbstrac t: Many of the unusual properties of topological insulators such as the Maj orana Fermions can only be realized through a delicate tuning of the Dirac surface state rendering their detection thus far elusive. Here we demonstra te that the surface state dispersion of a prototypical topological insulato r can be continuously tuned via a novel topographical route. STM topography of Bi_2 Te_3 shows one-dimensional stripes with 100nm periodicity. By stud ying the scaling behavior of the Landau level (LL) spectra as a function of magnetic field\, we show that the stripes induce a spatially modulated com ponent in the surface state dispersion close to the Dirac point. This abili ty to tune the surface state dispersion locally opens the door to a host of new phenomena in topological insulators. Importantly\, the stripes act as topological channels for chiral spin modes at the boundaries such that plac ing the Fermi energy between the LLs of these periodic stripes would result in the first experimental realization of the ideal 1D dissipationless quan tum wire. LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120406T160000Z DTEND:20120406T170000Z UID:event906@buphy.bu.edu URL:http://physics.bu.edu/events/show/906 SUMMARY:Creating and Destroying Optimal Transport Networks DESCRIPTION:Featuring Jose Soares Andrade\, University of Fortaleza\, Forta leza\, Brazil\nHosted by: H. Eugene Stanley\n\nPart of the Biophysics/Conde nsed Matter Seminar Series.\n\n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120409T160000Z DTEND:20120409T170000Z UID:event896@buphy.bu.edu URL:http://physics.bu.edu/events/show/896 SUMMARY:Structure and Function in Complex Networks DESCRIPTION:Featuring Luciano Costa\, University of Sao Paulo\nHosted by: H . Eugene Stanley\n\nPart of the Biophysics/Condensed Matter Seminar Series. \n\n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120412T180000Z DTEND:20120412T190000Z UID:event913@buphy.bu.edu URL:http://physics.bu.edu/events/show/913 SUMMARY:Statistical Physics of Earthquake Aftershocks DESCRIPTION:Featuring Bikas K. Chakrabarti\, Saha Institute of Nuclear Phys ics\, Kolkata\, India\nHosted by: H. Eugene Stanley\n\nPart of the Biophysi cs/Condensed Matter Seminar Series.\n\n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120413T160000Z DTEND:20120413T170000Z UID:event874@buphy.bu.edu URL:http://physics.bu.edu/events/show/874 SUMMARY:Field induced phases in quantum magnets - theory and experiments DESCRIPTION:Featuring Cristian Batista\, Los Alamos National Laboratory\nHo sted by: Anders Sandvik\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\n Abstract:\nQuantum magnets that remain invariant under con tinuous rotations (along at least one axis) can be described as gases of in teracting bosons whose number is conserved. An external field that acts lik e a chemical potential controls the particle concentration\, while the sing le-ion anisotropy and exchange terms determine the kinetic energy and boson -boson interactions. We will see how these simple ingredients lead to unusu al phases and magnetic field induced quantum phase transitions. The region near the field induced transition between a quantum paramagnet and a magnet ically ordered state can be universally described as a dilute gas of bosons . Depending on the sign of the boson-boson interactions and the geometric f rustration of the underlying lattice\, the applied field can induce simple Bose-Einstein condensates (BECs)\, BECs of pairs of bosons that are similar to the condensation of diatomic molecules\, complex crystals or even the c oexistence of BEC and crystalline states that is also known as supersolid. We will see what is the magnetic interpretation of this spectrum of phases and what are the basic principles for finding them in simple materials. In particular\, I will present a few examples of compounds that exhibit some o f these states\, together with comparisons between experiments and theory. Finally\, I will propose a few ideas for finding experimental realizations of the exotic magnetic phases that remain to be discovered.\n \n  \n \n  LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120427T160000Z DTEND:20120427T170000Z UID:event895@buphy.bu.edu URL:http://physics.bu.edu/events/show/895 SUMMARY:Correlations in Graphene DESCRIPTION:Featuring Valeri Kotov\, University of Vermont\nHosted by: Ande rs Sandvik\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\nAb stract:\nDue to its unique electronic structure Graphene exhibitsunconventi onal interaction effects\, not found in other 2D systems.I will review some of the most spectacular phenomena arising fromelectron-electron interactio ns of Dirac fermions. In will then describerecent work on anisotropic Dirac fermions\, which arise naturally instrained graphene and graphene superlat tices. In such systemsinteractions can lead to formation of novel quasi-one dimensionalcorrelated states that seem quite distinct from other known non -Fermiliquids. LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120504T160000Z DTEND:20120504T170000Z UID:event918@buphy.bu.edu URL:http://physics.bu.edu/events/show/918 SUMMARY:Structural Polymorphism of misfolded proteins and its implication f or Alzheimer's and other neurodegenrative diseases DESCRIPTION:Featuring Ratnesh Lal\, UCSD\, Dept. of Bioengineering\nHosted by: Shyamsunder Erramilli\n\nPart of the Biophysics/Condensed Matter Semina r Series.\n\n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121842Z LAST-MODIFIED:19991130T050000Z DTSTART:20120511T160000Z DTEND:20120511T170000Z UID:event922@buphy.bu.edu URL:http://physics.bu.edu/events/show/922 SUMMARY:Energy transport in one-dimensional systems DESCRIPTION:Featuring Onuttom Narayan\, UC\, Santa Cruz\nHosted by: Shyamsu nder Erramilli\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n \n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT END:VCALENDAR