aspuru-list April 2014

aspuru-list@lists.fas.harvard.edu

35 participants
87 discussions

[Aspuru-Guzik group list] Aspuru Group Meeting tomorrow at 2:30 pm in Cabot Division Room

by Felipe Herrera Urbina

Hi everyone, This Thursday April 3rd, Suleyman Er will tell us about his work on organic batteries. Below are the title and abstract of his talk. Best, Felipe Title: *Organic-Based Flow Batteries for Massive Electrical Energy Storage* Abstract: Flow batteries offer promising new technologies for electrical energy storage in the face of rising electricity production from intermittent renewables such as wind and solar. Large-scale utilization of flow batteries is limited due to the cost of redox-active and electrocatalytic precious metals. In this presentation, I will introduce a special type of flow battery that does not require expensive electroactive or electrocatalytic components. This new flow battery is currently being developed at Harvard and it uses small organic molecules as electroactive materials. The extensive chemical space of these small molecules offers ample possibilities in lowering the cost and improving the battery performance. Theoretical and computational modeling that can quickly and accurately predict the properties of new molecules is accordingly highly beneficial in the search for the best performing molecular candidates. Using first-principles calculations, we study an emerging library of quinone-derived small organic molecules, with special interest on their electrochemical properties and solubilities. Our initial aim is to discover new candidate molecules with interesting redox properties.

10 years, 1 month

[Aspuru-Guzik group list] Fwd: Postponing Joint IACS/Aspuru-Guzik Social

by Marlon Cummings

Dear Aspuru-Guzik group, As Professor Aspuru-Guzik will now be away on April 18th, we've decided to postpone this joint event until next fall. Kind regards, Meg Hastings Interim Executive Director, Institute for Applied Computational Science Harvard School of Engineering and Applied Sciences 52 Oxford Street, Northwest B165 Cambridge, MA 02138 http://iacs.seas.harvard.edu/ hastings(a)seas.harvard.edu | 617-384-9091 ~~~~~~~~~~~~~~~~~~~~~~~~~~ Dear Aspuru-Guzik group, I am delighted to invite you to the first ever joint Institute for Applied Computational Science/Aspuru-Guzik group Social. Join the master's students in Computational Science and Engineering, PhD secondary field students, and IACS lecturers and staff for snacks, drinks, and computational conversation. Friday, April 18 4:30pm-5:30pm 52 Oxford St. Northwest Cafe Looking forward to meeting you all! Kind regards, Meg Hastings Interim Executive Director, Institute for Applied Computational Science Harvard School of Engineering and Applied Sciences 52 Oxford Street, Northwest B165 Cambridge, MA 02138 http://iacs.seas.harvard.edu/ hastings(a)seas.harvard.edu | 617-384-9091

10 years, 1 month

[Aspuru-Guzik group list] Triple Feature - HQOC/ITAMP Joint Quantum Sciences Seminar - April 2

by Hamilton, Joan

HQOC/ITAMP Joint Quantum Sciences Seminar Wednesday, April 2, 4:00 PM, Jefferson 250 Triple Feature Refreshments served from 4-4:15 PM Sarang Gopalakrishnan, HQOC Moving Magnetic Impurities in a Fermi Superfluid Tony Lee, ITAMP Quantum Synchronization of Quantum van der Pol Oscillators with Cold Atoms Thibault Peyronel, HQOC Quantum Nonlinear Optics with Slow Photons and Strongly Interacting Cold Atoms Joan Hamilton Faculty Assistant to Profs. Greiner and Lukin HQOC Laboratory Administrator HUCTW Local Union Representative Harvard University Department of Physics 17 Oxford Street Cambridge, MA 02138 P: (617) 496-2544 F: (617) 496-2545

10 years, 1 month

[Aspuru-Guzik group list] Excitonics Seminar - Richard Schaller - TOMORROW- April 3, 3pm 36-428

by Catherine M Bourgeois

Please forward to your groups. Thanks. ____________________________________________________________ [cid:image001.jpg@01CF4A83.C0BDA920] Richard Schaller Department of Chemistry Northwestern University Argonne National Laboratory Lattice and Carrier Dynamics in Quantum-Confined Materials on Ultrafast Timescales Thursday, April 3, 2014 RLE Conference Room - 36-428 3:00 - 4:00pm Abstract: Excess carrier energy, which many aim to utilize for advanced energy conversion technologies, rapidly dissipates from electrons and holes in both bulk and quantum confined semiconductors despite expectation of slowed cooling in the latter. We aim to characterize dissipation channels available to carriers via time-resolved optical spectroscopies. We utilize both femtosecond stimulated Raman spectroscopy (FSRS) and time-resolved photoluminescence in order to gain insights as to rates and modes of dissipation. Using FSRS, we characterize longitudinal optical (LO) phonon production and dissipation throughout the process of confinement-enhanced, ultrafast intraband carrier relaxation. Upon excitation, we observe a decrease in stimulated Raman amplitude and note a size-independent LO phonon formation time. Mode softening is observed along with evidence of phonon down-conversion processes. Furthermore, spectrally and temporally resolved photoluminescence suggest evidence of acoustic phonon dissipation times that follow diffusive transport, which we can manipulate. Bio Richard D. Schaller is a Staff Member at Argonne National Lab in the Center for Nanoscale Materials and is also an Assistant Professor in the Department of Chemistry at Northwestern University. He received his PhD with Prof. Rich Saykally from University of California Berkeley in 2002 in the area of nonlinear optical microscopy and near-field optics. Subsequently he was selected as a Reines Distinguished Postdoctoral Fellow and became a Permanent Technical Staff Member at Los Alamos National Lab for a combined total of 8 years under the advising of Dr. Victor Klimov. In 2012, he was selected as a Kavli Fellow by the National Academy of Sciences. He has worked on the electronic and optical properties of semiconductor nanocrystals for more than a decade, has published 75 publications, has delivered more than 40 invited presentations, and holds 3 patents. Light refreshments will be served 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

10 years, 1 month

[Aspuru-Guzik group list] [qip] today

by Edward Farhi

This week we have a special quantum information seminar given by Renato Renner. He will be speaking Wednesday April 2 at 4:30 (note time change from standard seminar!) in room 6C-442. Title and and abstract are below. Hope to see you there. Title: Reliable Quantum State Tomography Abstract: Quantum state tomography is the task of estimating the state of a quantum system using measurements. Typically, one is interested in the (unknown) state generated during an experiment which can be repeated arbitrarily often in principle. However, the number of actual runs of the experiment, from which data is collected, is always finite (and often small). As pointed out recently, this may lead to unjustified (or even wrong) claims when employing standard statistical tools without care. In this talk, I will present a method for obtaining reliable estimates from finite tomographic data. Specifically, the method allows the derivation of confidence regions, i.e., subsets of the state space in which the unknown state is contained with probability almost one. This is joint work with Matthias Christandl, see also arXiv:1108.5329. *********************************************** Edward Farhi Cecil and Ida Green Professor of Physics Director Center for Theoretical Physics Massachusetts Institute of Technology 6-300 Cambridge MA 02139 617 253 4871 *********************************************** _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

10 years, 1 month

[Aspuru-Guzik group list] FW: [Seas-faculty] [Ee-seminars] EE Seminar on Friday, April 4 - Richard Mirin

by Hamilton, Joan

From: "Sweetland, Gioia" <gioia(a)seas.harvard.edu<mailto:gioia@seas.harvard.edu>> Subject: [Seas-faculty] [Ee-seminars] EE Seminar on Friday, April 4 - Richard Mirin Date: March 31, 2014 4:24:35 PM EDT To: "ee-seminars(a)eecs.harvard.edu<mailto:ee-seminars@eecs.harvard.edu>" <ee-seminars(a)eecs.harvard.edu<mailto:ee-seminars@eecs.harvard.edu>> Cc: "Sweetland, Gioia" <gioia(a)seas.harvard.edu<mailto:gioia@seas.harvard.edu>> [hseas-logo] Harvard EE Seminar Series Friday, April 4, 2014 3:00-4:00 p.m. Room 330 60 Oxford Street Light Refreshments Superconducting Single-Photon Detectors Richard Mirin National Institute of Standards and Technology High-efficiency, low noise single-photon detectors are a key enabling technology for the quantum optics and quantum information communities. Superconducting single-photon detectors now surpass their semiconductor counterparts in most important metrics. I will discuss my group’s research on two different types of superconducting single-photon detectors and various experiments in quantum optics that require these high-efficiency detectors. Transition edge sensors (TESs) formed from thin tungsten films have demonstrated 98% system detection efficiency, with a dark count rate around 10 Hz, at a wavelength of 1550 nm. The TESs are also capable of photon-number resolution, which is important for generating various quantum states of light, such as cat states formed by photon subtraction. Superconducting nanowire single-photon detectors (SNSPDs) formed from tungsten silicide have recently demonstrated 93% system detection efficiency at 1550 nm, with a dark count rate of ~ 1Hz, timing jitter of ~150 ps, and reset time of 40 ns. We have assembled an 8-channel system with all devices having > 85% system detection efficiency for multiphoton correlation measurements. Such a system can be used for rapid joint spectral distribution measurements from a spontaneous parametric downconversion source of correlated photon pairs. I will also discuss recent progress on integrating these detectors with chip-scale waveguides as a step towards on-chip quantum photonics, small arrays of SNSPDs, and progress towards loophole-free Bell inequality measurements with entangled photon pairs. Bio: : Dr. Mirin has a BS in Electrical Engineering from UC Berkeley and a PhD in Electrical Engineering from UC Santa Barbara. Since 1996 he has been working at the National Institute of Standards and Technology (NIST) in Boulder, Colorado. He is currently the Group Leader of the Optoelectronics Manufacturing Group as well as the Project Leader of the Nanostructure Fabrication and Modeling project in that group. His main research interests are superconducting single-photon detectors, quantum optics and information, III-V semiconductor growth with molecular beam epitaxy, and single quantum dot single-photon sources. Host: Evelyn Hu _______________________________________________ Ee-seminars mailing list Ee-seminars(a)eecs.harvard.edu<mailto:Ee-seminars@eecs.harvard.edu> https://lists.eecs.harvard.edu/mailman/listinfo/ee-seminars _______________________________________________ Seas-faculty mailing list Seas-faculty(a)seas.harvard.edu<mailto:Seas-faculty@seas.harvard.edu> https://lists.seas.harvard.edu/mailman/listinfo/seas-faculty

10 years, 1 month

[Aspuru-Guzik group list] Meeting with Professor George Schatz Today, 4-530

by Thomas Markovich

Hi All, We have a group meeting with Professor George Schatz from 4-530 at the theory couches. His abstract is below. I hope to see you all there. Best, Thomas Plasmon-molecule interactions George C. Schatz Northwestern University, Evanston IL 60208-3113 USA This talk describes recent theory developments concerned with the optical properties of plasmonic materials, with emphasis on understanding plasmon enhanced spectroscopic techniques such as surface enhanced Raman spectroscopy (SERS), plasmon-enhanced photochemistry, and the coupling of plasmons to excitons. The cornerstone of this work is computational electromagnetics, which provides the ability to solve Maxwell’s equations exactly for a given nanoparticle structure and with assumed dielectric functions. A number of methods for doing these calculations are available, and in the first part of the talk I will review how these calculations are done, and I will demonstrate their use to study the extinction spectra and SERS of silver and gold nanoparticles and other nanostructures. In addition, I will describe very recent applications concerned with the optical properties of nanoparticle superlattices that constitute a type of metamaterial that exhibits unusual optical properties. The second half of the talk will focus on problems where one needs to couple classical electrodynamics for metal particles to quantum mechanics (usually TDDFT) for molecules near the nanoparticles. These theories will be developed both in the frequency and time domains, and the inclusion of both electromagnetic interactions and chemical interactions between the metal nanoparticle and molecular adsorbate are considered. We demonstrate the use of these methods with applications to SERS and to plasmonic solar cells. In addition, we describe examples of plasmon-exciton interactions, such as occurs in plasmon-enhanced lasing. Here we show how plasmons can interact with molecules to enhance both spontaneous and stimulated emission.

10 years, 1 month

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aspuru-list April 2014