aspuru-list November 2012

aspuru-list@lists.fas.harvard.edu

28 participants
58 discussions

[Aspuru-Guzik group list] talk: Changwon Suh, today at 3:00

by Er, Suleyman

Hello everyone, This is a reminder that Dr. Changwon Suh is going to present at 3 pm in the Division room. Hope to see you, Suleyman

11 years, 5 months

[Aspuru-Guzik group list] CENTER FOR EXCITONICS SEMINAR - Tomorrow, Nov. 29, 3PM, 36-428

by Catherine M Bourgeois

Please post and forward to your groups. Center for Excitonics Seminar Series Thursday, Nov. 29, 2012 3:00 - 4:00 PM RLE HAUS and ALLEN rooms: 36-428 Excitons in highly efficient organic devices Karl Leo, Institute of Applied Photophysics, Dresden University of Technology Abstract: Organic semiconductors with conjugated electron system are currently intensively investigated for optoelectronic applications. This interest is spurred by novel devices such as organic light-emitting diodes (OLED), and organic solar cells. For both devices, high efficiency is a key parameter for many applications. In this talk, I will discuss some of the recent progress on highly efficient OLED and solar cells. In both classes of devices, excitons play crucial roles: in OLED, efficient radiative recombination is key, in solar cells, exciton separation is the key process. Specifically, I will briefly discuss results on white OLED where triplet harvesting allows to achieve high quantum efficiencies despite using fluorescent blue emitters. Even richer are the exciton phenomena in organic solar cells. I will discuss results of exciton separation dependence on energetic alignment and the influence of triplet generation in bulk heterojunction devices. Bio Karl Leo obtained the Diplomphysiker degree from the University of Freiburg in 1985, working with Adolf Goetzberger at the Fraunhofer-Institut für Solare Energiesysteme. In 1988, he obtained the PhD degree from the University of Stuttgart for a PhD thesis performed at the Max-Planck-Institut für Festkörperforschung in Stuttgart under supervision of Hans Queisser. From 1989 to 1991, he was postdoc at AT&T Bell Laboratories in Holmdel, NJ, U.S.A. From 1991 to 1993, he was with the Rheinisch-Westfälische Technische Hochschule (RWTH) in Aachen, Germany. He became Full Professor of Optoelectronics at the Technische Universität Dresden in 1993. Since 2002, he has worked at the Fraunhofer-Institution for Organics, Materials and Electronic Devices COMEDD and currently serves as director. His main interests are novel semiconductor systems like semiconducting organic thin films; with special emphasis to understand basics device principles and the optical response. His work was recognized by the following awards: Otto-Hahn-Medaille (1989), Bennigsen-Förder-Preis (1991), Leibniz-Award (2002), award of the Berlin-Brandenburg Academy (2002), Manfred-von-Ardenne-Preis (2006), and Zukunftspreis of the German president (2011). He is cofounder of several companies, including Novaled AG and Heliatek GmbH. Light refreshments will be provided The Center for Excitonics is an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science and Office of Basic Energy Sciences

11 years, 5 months

[Aspuru-Guzik group list] Special HQOC Seminar - Nov. 30 at 3:00 PM - Lyman 425

by Joan Hamilton

***Special HQOC Seminar*** ***Friday, November 30th at 3:00 PM*** ***Lyman 425*** Prof. Michael Fleischhauer Department of Physics, University of Kaiserslautern *"Many-body Dynamics in Open Systems: Optically Driven Rydberg Gases" * Quantum optical realizations of many-body systems must often be described as open systems and thus offer a way to study quantum correlations in the non-equilibrium steady-state rather than the ground state of a Hamiltonian. Being an attractor of the dynamics, stationary states have the advantage of being robust and providing a natural way of preparation. Little is known, however, about many-body phenomena such as phase transitions in open systems. These questions will be addressed for free lattice models and the experimentally relevant example of optically driven Rydberg gases. The strong and long-range van-der Waals repulsion drives the system into a state of Rydberg excitations with crystalline order which however competes with fluctuations inherent to the open system. Quantum correlations in the steady state are calculated by open-system DMRG simulations and discussed in terms of an analytically solvable effective model. Finally the build-up dynamics of the stationary state is discussed. -- Joan Hamilton Faculty Assistant to Profs. Lukin and Greiner HQOC Administrative Coordinator Harvard University Department of Physics 17 Oxford Street Cambridge, Ma 02138 Phone 617-496-2544 HUCTW Local Representative for the Department of Physics

11 years, 5 months

[Aspuru-Guzik group list] Subj: ITAMP topical lunch discussion: Thursday November 29 @ 12:00

by Mikhail Lemeshko

Dear Friends, On Thursday, November 29, there will be an ITAMP topical lunch discussion. Tea Room (P-226) @ CfA (60 Garden Street) Time: 12:00-1:30 As always pizza will be served. Speaker: Vladimir Manucharyan Title: Artificial atoms with Bogolyubov quasiparticles. Abstract: Unlike quasiparticles in metals and semiconductors, superconducting quasiparticles can be confined by the variations in the superconducting pairing potential, without any electrostatic force. The process of reflection of a low-energy quasiparticle from a region with a high pairing potential is known as Andreev reflection. In case of a weak link (Josephson junction) between a pair of superconductors, a quasiparticle with energy below the superconducting gap undergoes a bound motion in the weak link region. This motion, according to quantum mechanics, has a discrete spectrum, just like a hydrogen atom. Moreover, the spectrum can be tuned widely with a superconducting phase-difference across the junction, applied externally using magnetic field. The phase-dependent discrete spectrum of a Josephson junction is in fact a key to modern understanding of the Josephson effect -- the dissipation-free current flow via superconducting junctions. In Addition, lots of attention has been given recently to the possibility of using such quasiparticle bound states (sometimes called Andreev bound states) to store and manipulate a qubit, either in the form of a microwave photon, or a spin, or even a Majorana fermion. We performed tunneling spectroscopy of a phase-biased Al Josephson junction through a section of semiconducting InAs nanowire (the weak link). Data reveals discrete sub-gap resonances in tunneling conductance, symmetric about zero-bias, and tunable by both gating the nanowire and varying the phase-bias. We establish that the observed single pair of discrete states is formed due to Andreev reflection at the InAs/Al interface. We argue that the proximity-induced superconducting state of InAs consists of a single Cooper pair, despite the absence of Coulomb interaction. If time permits, the low-density data will also be discussed. In this regime, InAs nanowire, for certain gate voltages, turns into a spin 1/2 quantum impurity, which gives rise to the Yu-Shiba-Rusinov sub-gap states. [1] W. Chang et al., arxiv:1211.3954 Looking forward to seeing you there, Misha Lemeshko -- Dr. Mikhail Lemeshko Institute for Theoretical Atomic, Molecular, and Optical Physics (ITAMP) Harvard-Smithsonian Center for Astrophysics MS-14 60 Garden St. Cambridge, MA 02138 U.S.A. mlemeshko(a)cfa.harvard.edu http://sites.google.com/site/mishalemeshko/ Tel. +1 (617) 496-7610 Fax +1 (617) 496-7668

11 years, 5 months

[Aspuru-Guzik group list] Nov 28 - Prof. Takhee Lee, Seoul National University

by Cynthia M. Chew

Hi Group, Just a reminder that Prof. Takhee Lee (Seoul National University) will be visiting on Nov 28. Our group is meeting with him on Wed Nov 28 @ 2:15-3pm in the Division Room if you are interested. Thanks to all who replied previously! *Bio*: Takhee Lee is currently Associate Professor in the Department of Physics and Astronomy, Seoul National University, Korea. He graduated from Seoul National University, Korea, and received his Ph.D. from Purdue University, USA in 2000. He was a postdoctoral researcher at Yale University, USA until 2004. And, he was a faculty member in Gwangju Institute of Science and Technology, Korea from 2004 until 2011. His current research interests are molecular electronics, polymer memory devices, and graphene-electrode optoelectronic devices. He has edited 2 books and wrote 9 book chapters, 10 review articles, and 150 journal articles. He was awarded Korean Scientist of the Month Award (2010 June), Prime Minister Award (2010 April), Minister of Education, Science and Technology Award (2008 April, 2010 August), and Nano-Korea Researcher Award (2007 August) *Abstract*:*Molecular- and polymer-based electronic devices* Idea of utilizing individual molecules as the electronic components in future ultrahigh-density electronic devices has generated tremendous attention. Obtaining transistor action from molecular orbital control has been the outstanding challenge of the field of molecular electronics nearly since its inception. In this talk, I will explain a direct electrostatic modulation of orbitals in a molecular transistor configuration, with both effective gate control and enhanced resonant coupling of the orbitals to the source and drain electrodes [1]. I will also explain recently developed understanding on the electrical transport characteristics through various types of molecular junctions on flat or flexible substrates [2]. In the second part of this talk, I will present a summary on general characteristics of the materials, device structures, and switching mechanisms used in organic resistive non-volatile memory devices. Strategies for performance enhancement, integration, and advanced architectures in these devices will be presented [3]. And, if time is allowed, I will briefly discuss other research results on nanoscale logic circuits and graphene-electrode optoelectronic devices [4]. Best, Cynthia Cynthia M. Chew Faculty Assistant | Aspuru-Guzik Research Group Department of Chemistry and Chemical Biology | Harvard University 12 Oxford Street | Cambridge, MA 02138 617.496.1716 office | 617.496.9411 fax http://aspuru.chem.harvard.edu/

11 years, 5 months

[Aspuru-Guzik group list] visitor - Hsieh Chen - Thur 29th

by Er, Suleyman

This week we will have a second visitor on Thursday 29th. Hsieh Chen is going to tell us about his work at MIT with Alexander-Katz. The abstract is given below. His talk is scheduled at 2 pm in the Division room. As usual, Hsieh Chen will be available in the rest of the day to talk to you personally. Greetings, Suleyman Title: Blood Clotting Inspired Polymer-Colloid Materials Abstract: Blood clotting is the ubiquitous process in our bodies where clotting materials (platelets and polymeric proteins) form self-healing aggregates at the sites of lesion. Such a process is usually inhibited under strong flow; however, nature has designed stimuli-responsive biopolymers that enhance the formation of such aggregates assuring correct healing. In this talk, I will first describe how these biopolymers respond to strong flow in the presence of flowing colloids (i.e. blood cells). Inspired by the blood clotting process, I will proceed to describe the reversible, flow-induced assembly of polymer-colloid composites that we believe represents a new paradigm in non-equilibrium self-assembly. I will end by briefly discussing our efforts of transferring our knowledge of solving hydrodynamic equations to polymer self-consistent field theory simulations.

11 years, 5 months

[Aspuru-Guzik group list] visitor - Changwon Suh - Wed 28th

by Er, Suleyman

Dear All, Dr. Changwon Suh (NREL) will be visiting our group on Wednesday 28th. He will give a group talk at 3 pm in the Division room. The abstract is attached. He will be available in the rest of the day to talk to you personally. I believe his work is interesting to many members of our group. So, please make this in your own benefit. Greetings, Suleyman

11 years, 5 months

[Aspuru-Guzik group list] CENTER FOR EXCITONICS SEMINAR - Thursday, Nov. 29, 3PM, 36-428

by Catherine M Bourgeois

11 years, 5 months

[Aspuru-Guzik group list] Fwd: physical chemistry instructor position available at MIT - please disseminate

by Alan Aspuru-Guzik

Relevant teaching opportunities at MIT -- Alan Aspuru-Guzik Associate Professor of Chemistry and Chemical Biology Harvard University http://aspuru.chem.harvard.edu Forwarded message: > From: Sylvia Ceyer <stceyer(a)mit.edu> > To: jacobsen(a)chemistry.harvard.edu <jacobsen(a)chemistry.harvard.edu>, zhuang(a)chemistry.harvard.edu <zhuang(a)chemistry.harvard.edu>, xie(a)chemistry.harvard.edu <xie(a)chemistry.harvard.edu>, aspuru(a)chemistry.harvard.edu <aspuru(a)chemistry.harvard.edu>, jaiz(a)seas.harvard.edu <jaiz(a)seas.harvard.edu>, anderson(a)huarp.harvard.edu <Anderson(a)huarp.harvard.edu>, gordon(a)chemistry.harvard.edu <gordon(a)chemistry.harvard.edu>, heller(a)chemistry.harvard.edu <heller(a)chemistry.harvard.edu>, cohen(a)chemistry.harvard.edu <cohen(a)chemistry.harvard.edu>, cfriend(a)seas.harvard.edu <cfriend(a)seas.harvard.edu>, Shakhnovich(a)chemistry.harvard.edu <Shakhnovich(a)chemistry.harvard.edu>, hbach(a)chemistry.harvard.edu <hbach(a)chemistry.harvard.edu>, billk(a)otto.harvard.edu <billk(a)otto.harvard.edu> > Date: Friday, November 23, 2012, 5:22:44 PM > Subject: physical chemistry instructor position available at MIT - please disseminate > > Dear Eric, Xiaowei, Sunney, Alan, Joanna, Jim, Adam, Roy, Cyndy, Eugene, Rick, Dudley and Bill, > > We have an immediate need for an instructor to teach one of either of the following two subjects this spring semester: > > 1) Half semester (Jan. 15, 2013 through March 25, 2013 plus May 15 - May 24, 2013) of 5.62 Physical Chemistry. This subject is the third semester of undergraduate physical chemistry covering statistical mechanics. (See http://ocw.mit.edu/courses/chemistry/5-62-physical-chemistry-ii-spring-2008/). > > 2) Either a half semester (Jan. 15, 2013 through March 25, 2013) or a full semester (Jan. 15, 2013 through May 24, 2013) of 5.74 Quantum Mechanics. This subject is the second semester of a graduate quantum mechanics course covering time dependent quantum mechanics. (See http://ocw.mit.edu/courses/chemistry/5-74-introductory-quantum-mechanics-ii…). > > Candidates should send me their CV, a statement of teaching experience, teaching evaluations and a cover letter expressing their interests and availability. > > Please forward this email to anyone who might be interested in this opportunity. > > Thank you so much for your help, > Sylvia > > Sylvia T. Ceyer > Head, Department of Chemistry > J. C. Sheehan Professor of Chemistry > stceyer(a)mit.edu > > Massachusetts Institute of Technology > 77 Massachusetts Avenue > Cambridge, MA 02139 > Bldg. 18-399 Headquarters > 617-253-1801 Headquarters > 617-258-7500 Headquarters Fax > > Bldg. 6-217 Research > 617-253-4537 Research > 617-253-7030 Research Fax > >

11 years, 5 months

[Aspuru-Guzik group list] [qip] bbc article

by Ramis Movassagh

Hi all, I thought this might be of interest to some of us: http://www.bbc.co.uk/news/science-environment-13940928 Best, Ramis _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

11 years, 5 months

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aspuru-list November 2012