BEGIN:VCALENDAR VERSION:2.0 PRODID:-//RLASKEY//CALENDEROUS//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT DTSTAMP:20120516T121915Z LAST-MODIFIED:19991130T050000Z DTSTART:20120208T160000Z DTEND:20120208T170000Z UID:event870@buphy.bu.edu URL:http://physics.bu.edu/events/show/870 SUMMARY:The search Majorana fermions and non-Abelian statistics in semicond uctor-superconductor systems. DESCRIPTION:Featuring Jay Deep Sau\, Harvard University\n\nPart of the Cond ensed Matter Theory Seminar Series.\n\nAbstract: Majorana fermions are hith erto unobserved exotic excitations\, which are their own anti-particles. De spite the nomenclature\, Majorana fermions are neither fermions nor bosons but have novel exchange statistics that categorizes them as non-Abelian any ons. Non-Abelian anyons are associated with a ground state degeneracy of th e entire system\, which cannot be broken by any external fields. Observing such a topologically robust ground state degeneracy would not only be a fun damental breakthrough in physics\, but could also be used to create topolog ical quantum computers which are free of the decoherence problem. I will de scribe our work which suggests that topological superconductors containing Majoranas are fairly generic and a large class of spin-orbit coupled system s can be used to realize Majorana fermions. Possible experimental tests of these ideas range from simple tunneling experiments to test the existence o f zero-energy Majorana states to explicit demonstration of non-Abelian stat istics through tunneling coupled nanowire arrays and interferometry. Finall y\, we will discuss how the spin-orbit coupled models motivate an intrinsic ally number conserving microscopic model of a topological superconductor me diated by attractive interactions\, which supports Majorana fermions. The b osonization approach used to study this one-dimensional model makes transpa rent the connection between the topological order described by Majorana fer mions and the emergent Ising order in such spin-orbit coupled superconducto rs. LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121915Z LAST-MODIFIED:19991130T050000Z DTSTART:20120216T180000Z DTEND:20120216T190000Z UID:event871@buphy.bu.edu URL:http://physics.bu.edu/events/show/871 SUMMARY: Non-equilibrium dynamic critical scaling of the transverse-field I sing chain DESCRIPTION:Featuring Michael Kolodrubetz\, Princeton University\nHosted by : Anatoli Polkovnikov\n\nPart of the Condensed Matter Theory Seminar Series .\n\nAbstract:\nThe one-dimensional transverse-field Ising chain is a proto typical example of system that undergoes a continuous quantum phase transit ion. While its equilibrium scaling has been understood for more than half a century\, I will discuss the non-equilibrium quantum critical dynamics as the system is swept slowly through the critical point (a Kibble-Zurek ramp) . Kibble-Zurek scaling is well understood for ramps that end at the quantum critical point or deep in the ordered phase. In this talk\, I will describ e our solution for the full finite-size scaling functions of excess heat an d spin-spin correlation function at an arbitrary time during the ramp. Thes e scaling functions yield a number of surprises\, including negative spin c orrelations on the ferromagnetic side of the transition\, demonstrating qua litatively the athermal nature of the ramp. We then confirm the universalit y of the scaling functions by numerically simulating Mott-insulating bosons in a tilted potential\, an experimentally-realizable system in the same un iversality class [J. Simon et. al.\, Nature 472\, 307 (2011)]. Our results indicate that the time scales necessary to see this dynamic scaling should be within the reach of present-day cold atom experiments.\nKrishnendu Sengu pta (Indian Assoc. for the Cultivation of Science) LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121915Z LAST-MODIFIED:19991130T050000Z DTSTART:20120223T160000Z DTEND:20120223T170000Z UID:event879@buphy.bu.edu URL:http://physics.bu.edu/events/show/879 SUMMARY:Reconstructing Phase Dynamics of Oscillator Networks DESCRIPTION:Featuring Michael Rosenblum\, Potsdam University\nHosted by: Pl amen Ivanov\n\nPart of the Condensed Matter Theory Seminar Series.\n\n LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121915Z LAST-MODIFIED:19991130T050000Z DTSTART:20120404T150000Z DTEND:20120404T160000Z UID:event909@buphy.bu.edu URL:http://physics.bu.edu/events/show/909 SUMMARY:Non-Equilibrium Transport and Current Imaging in Nanoscopic Quantum Networks DESCRIPTION:Featuring Dirk Morr\, University of Illinois\, Chicago\n\nPart of the Condensed Matter Theory Seminar Series.\n\nAbstract: Understanding c harge transport in nanoscale systems has attracted significant interest ove r the last few years in the context of molecular and nano-electronics and t hrough advances in the fabrication of artificial quantum structures.  The coherent nature of such nanoscopic systems is of particular interest: i t leads to the formation of eigenmodes in the density of states\, which pos sess distinct spatial patterns and are the basis for the engineering of nov el quantum phenomena\, such as quantum imaging.  In this talk\, I will demonstrate that analogous spatial patterns also emerge in the charge tran sport through nanoscopic quantum networks in form of current eigenmodes. Th ese eigenmodes can be selected through gating or via constrictions\, thus a llowing new venues for manipulating charge transport at the nanoscale. More over\, I will show how the spatial patterns of current eigenmodes evolve wi th dephasing from the ballistic to the classical limit. Finally\, I will de monstrate how atomically resolved imaging of spatial current patterns can b e obtained using scanning tunneling microscopy. LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121915Z LAST-MODIFIED:19991130T050000Z DTSTART:20120411T150000Z DTEND:20120411T160000Z UID:event914@buphy.bu.edu URL:http://physics.bu.edu/events/show/914 SUMMARY:Condensation of Anyons in Quantum Magnets DESCRIPTION:Featuring Cristian Batista\, Los Alamos National Laboratory\nHo sted by: Anders Sandvik\n\nPart of the Condensed Matter Theory Seminar Seri es.\n\nAbstract:\nOne-dimensional (1D) quantum magnets can realize exotic s tates of matter such as Luttinger liquids (1\,2)\, valence bond solids (3\, 4)\, and spin supersolids (5). A unique characteristic of 1D systems is tha t transmutations of particle statistics preserve the range and local nature of interactions. This is the main reason behind the success of spin-fermio n transformations\, such as the Jordan-Wigner mapping (6)\, for solving one -dimensional quantum magnets (6-8). A simple generalization of such transfo rmations allows for a mapping between spins and anyons\, unusual particles that generalize the concept of fermions and bosons. By exploiting this gene ralization\, we find exact ground states of S = 1/2 frustrated spin XXZ lad ders\, and introduce an efficient method for computing relevant correlation functions. These novel states are anyon condensates that spontaneously bre ak the Hamiltonian symmetry associated with particle-number conservation. I n contrast to the familiar Bose-Einstein condensates\, the condensed partic les satisfy anionic statistics.\n \n1. Luttinger\, J. M. An Exactly So luble Model of a Many-Fermion System. J. Math. Phys. 4\, 1154 (1963).\n&nbs p;\n2. Mattis\, D.C. & Lieb\, E.H. Exact Solution of a Many-Fermion Sys tem and Its Associated Boson Field. J.\nMath. Phys. 6\, 304 (1965).\n  \n3. Haldane\, F.D.M. Nonlinear Field Theory of Large-Spin Heisenberg Antif erromagnets: Semiclassically Quantized Solitons of the One-Dimensional Easy -Axis N´eel State. Phys. Rev. Lett. 50\, 1153 (1983).\n \n4. Aff leck\, I. \, Kennedy\, T.\, Lieb\, E. & Tasaki\, H. Rigorous results on valence-bond ground states in antiferromagnets. Phys. Rev. Lett. 59\, 799 (1987).\n \n5. Sengupta\, P. & Batista\, C.D. Spin Supersolid in a n Anisotropic Spin-One Heisenberg Chain. Phys. Rev. Lett. 99\, 217205 (2007 ).\n \n6. Jordan\, P. & Wigner\, E. P. On Pauli’s Equivalenc e Ban. Z. Physik 47\, 631 (1928).\n \n7. Lieb\, E. \, Schultz\, T. &am p; Mattis\, D. Two Soluble Models of an Antiferromagnetic Chain. Ann. Phys. 16\,\n407 (1961).\n \n8. Lieb \, E. & Mattis\, D. Mathematical Ph ysics in One Dimension\, Academic Press\, New York and London\, (1966). LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121915Z LAST-MODIFIED:19991130T050000Z DTSTART:20120502T150000Z DTEND:20120502T160000Z UID:event925@buphy.bu.edu URL:http://physics.bu.edu/events/show/925 SUMMARY:Fluctuation-dissipation theorem for chiral systems in non-equilibri um steady states DESCRIPTION:Featuring Dmitri Feldman\, Brown University\nHosted by: Claudio Chamon\n\nPart of the Condensed Matter Theory Seminar Series.\n\nAbstract: We consider a three-terminal system with a chiral edge channel connecting the source and drain terminals. Charge can tunnel between the chiral edge a nd a third terminal. The third terminal is maintained at a different temper ature and voltage than the source and drain. We prove a general relation fo r the current noises detected in the drain and third terminal. It has the s ame structure as an equilibrium fluctuation-dissipation relation with the n onlinear response in place of the linear conductance. The result applies to a general chiral system and can be useful for detecting "upstream" modes o n quantum Hall edges. LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT BEGIN:VEVENT DTSTAMP:20120516T121915Z LAST-MODIFIED:19991130T050000Z DTSTART:20120509T150000Z DTEND:20120509T160000Z UID:event923@buphy.bu.edu URL:http://physics.bu.edu/events/show/923 SUMMARY:Building Synthetic Materials from Ultracold Atoms: Quantum Magnetis m in an Optical Lattice DESCRIPTION:Featuring Jonathan Simon\, Harvard University\nHosted by: Anato li Polkovnikov\n\nPart of the Condensed Matter Theory Seminar Series.\n\nAb stract:\nUltracold atoms in optical lattices form a unique testbed for quan tum many-body physics. Using such systems it has recently become possible t o engineer strongly-correlated materials from the ground up andI will descr ibe experiments in which we have synthesized the first magnetic material co mposed of ultracold atoms\, and watched it undergo a quantum phase transiti on from a paramagnet to an antiferromagnet. I will then introduce a ne w algorithmic cooling scheme that we have demonstrated\, which points the w ay to even more exotic quantum phases that exist at lower temperatures. In addition\, I will describe recent experiments studying bilayer quantum gase s\, with promising applications in generation and detection of even more va ried strongly correlated materials. LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215 STATUS:CONFIRMED CLASS:PUBLIC END:VEVENT END:VCALENDAR