aspuru-list April 2016

aspuru-list@lists.fas.harvard.edu

25 participants
54 discussions

[Aspuru-Guzik Group List] Prof. Chris Wolverton visiting from Northwestern

by Sawaya, Nicolas Per Dane

Hey Group, Prof. Chris Wolverton of Northwestern will be visiting Harvard on Tuesday, May 3. His theochem talk at MIT will be the day after. Website: http://www.mccormick.northwestern.edu/research-faculty/directory/profiles/w… Wolverton is a well-known name, especially in materials discovery for energy applications. He researches topics that a lot of our group studies as well, including substantial work in: * hydrogen storage, batteries, light-weight metals, fuel cells, thermoelectrics * first-principles simulation methods (e.g. DFT) * predicting phase diagrams * big data/ML for materials discovery Please let me know if you're interested in meeting with him (lunch and dinner too). Cheerio, Nicolas

8 years, 1 month

[Aspuru-Guzik Group List] May 4, 2016 - ITAMP/HQOC Joint Quantum Sciences Seminar: Tilman Pfau

by Ploucha, Clare Dolores

HQOC/ITAMP Joint Quantum Sciences Seminar Wednesday, May 4, 2016 4:00 PM, Jefferson 250 Prof. Tilman Pfau, Universität Stuttgart, Germany "Strongly Interacting Rydberg Gases in Thermal Vapor Cells" Rydberg atoms are of great interest due to their prospects in quantum information processing[1]. Coherent control of the strong Rydberg-Rydberg interaction allows for the realization of quantum operations and devices such as quantum gates and single-photon sources. To date, impressive experimental progress has been limited to the ultracold domain [2]. Being able to exploit this interaction in a coherent manner in thermal vapor would eliminate the need for cooling and trapping of atoms and thus offer new prospects for integration and scalability. We present our progress on the coherent control and investigation of Rydberg atoms in small vapor cells. We show that we are able to drive Rabi oscillations on the nanosecond timescale to a Rydberg state by using a pulsed laser excitation and are therefore faster than the coherence time limitation given by the Doppler width [3]. A systematic investigation reveals a clear signature for a strong van der Waals interaction between Rydberg atoms. The strength of the interaction exceeds the energy scale of thermal motion (i.e. the Doppler broadening) and therefore enables many body quantum physics above room temperature [4]. As an example we observe evidence for aggregate formation of Rydberg atoms in a vapor cell [5]. Besides these many body physics phenomena also electric field sensing applications have been demonstrated [6] and recently it was shown that coherent Rydberg excitation is also possible in photonic crystal fibers [7]. Several applications from THz sensing to single photon sources seem within reach. [1] J. M. Raimond, M. Brune, S. Haroche, Rev. Mod. Phys. 73, 565 (2001), [2] M. Saffman et al., RMP 82, 2313 (2010) and references therein, [3] B. Huber et al., PRL 107, 243001 (2011), [4] T. Baluktsian et al., PRL 110, 123001 (2013), 5] A. Urvoy et al., PRL 114, 203002 (2015), [6] J. Sedlacek, et al. Nature Physics 8, 819 (2012), [7] G. Epple, et al, Nature Communications 5, 4132 (2014) Dr. Stefan Pabst "Attosecond pulse characterization with Rydberg wave packets" For attosecond dynamics, it is crucial to know the exact properties of isolated and trains of attosecond pulses. A full pulse characterization is, therefore, of high interest. Here, we propose a new method of fully characterizing these pulses by photoionizing an electronically excited Rydberg wavepackets. The different energy levels of the Rydberg states make it possible to interfere different spectral components with each other. The dipole phases, which normally enter in the ionization step, are eliminated here so that the spectral phase can be uniquely determined. This method is very versatile and offers several advantages over common pulse characterization methods. Student Presentation from 4:00-4:10 PM Refreshments Served from 4:00-4:30 PM Guest Presentation from 4:30-6:00 PM -- Clare Ploucha Faculty Assistant to Professors Lukin & Greiner and their labs Department of Physics 17 Oxford St., Lyman 324A Cambridge, MA 02138 P. (617) 496-2544

8 years, 1 month

[Aspuru-Guzik Group List] Gerhard Stock theochem visit

by Nicolas Sawaya

Hi Group, Michael Manhart of the Shakhnovich group asked me to pass this along. Let Michael know (at mmanhart(a)fas.harvard.edu) if you want to meet with Prof. Stock on this upcoming Thursday. ---- Hi everyone, Prof. Gerhard Stock of the University of Freiburg is visiting for the next Theochem lecture at MIT, and he *will be at Harvard next Thursday, May 5*. He research spans many topics in chemical physics and molecular biophysics, including *free energy landscapes*, protein structure, and *energy transport*. Please see his Theochem abstract below and check out his webpage at: http://www.moldyn.uni-freiburg.de/research/research.html If you would like to meet with him next Thursday, either independently or in a group, please let me know (mmanhart(a)fas.harvard.edu<mailto: mmanhart(a)fas.harvard.edu>) as soon as possible. You can also join for lunch and/or dinner if you’d like. Michael Title: “Theory and Simulation of Functional Dynamics of Biomolecules" Wednesday, May 11, 4 PM, MIT Building 4, room 163 Abstract: Driven by recent experimental and computational progress, structural dynamics has been recognized as an essential player for the functionality of proteins. The importance of functional dynamics, e.g., in folding, aggregation, binding and signaling, extends the classic structure-function paradigm of biochemistry to include the 'dynamical personality' of proteins. As an overview, I start with a brief introduction to classical all-atoms molecular dynamics simulations, with an emphasis on the dynamical description of biomolecules. In particular, I introduce dimensionality reduction methods to construct the system's free energy landscape, that characterizes its metastable conformational states as well as the barriers connecting these states. The second part is concerned with two topics. First I consider hierarchical dynamics of biomolecular processes which accounts for the nonlinear coupling of fast (picosecond) fluctuations to slow (microseconds) structural rearrangement. Then, I present recent extensive molecular dynamics simulations of the propagation of conformational change in intramolecular signaling in a photoswitchable PDZ domain.

8 years, 1 month

[Aspuru-Guzik Group List] Fwd: [CCB_Staff] Mallinckrodt Front Stairs/12 Oxford St. starting Monday, May 2

by Marlon Cummings

*Marlon G. CummingsLab Manager, Aspuru-Guzik GroupMallinckrodt M136Department of Chemistry and Chemical BiologyHarvard University12 Oxford StreetCambridge, MA 02138617-496-9964617-496-9411 (fax)http://aspuru.chem.harvard.edu/ <http://aspuru.chem.harvard.edu/>* ---------- Forwarded message ---------- From: Schwickrath, Helen L. <schwickrath(a)chemistry.harvard.edu> Date: Fri, Apr 29, 2016 at 3:06 PM Subject: [CCB_Staff] Mallinckrodt Front Stairs/12 Oxford St. starting Monday, May 2 To: "Schwickrath, Helen L." <schwickrath(a)chemistry.harvard.edu> Dear CCB Community, The front Mallinckrodt staircase will be closed for renovations beginning Monday, May 2nd and tentatively ending on Friday, July 29th, 2016. We ask that you please plan to use an alternate entrance during this time period. Thank you in advance for your cooperation. Please contact the Facilities Department at 5-3076 with any questions/concerns. Best, The Facilities Team _______________________________________________ ccb_staff mailing list ccb_staff(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/ccb_staff

8 years, 1 month

[Aspuru-Guzik Group List] talk of Bob Blankenship, Monday, May 2, Naito 205, 2-30pm

by Semion Saikin

Dear group, I would like to remind you that Bob Blankenship, http://pages.wustl.edu/blankenshiplab, will visit our group on Monday and you will have a great opportunity to learn about *Molecular Mechanisms of Photosynthetic Antenna Regulation. * *Please notice the unusual time and location: Naito 205, 2-30pm.* The abstract of the talk is attached. best, Semion -- ******************************************** Semion K. Saikin, PhD Department of Chemistry and Chemical Biology Harvard University 12 Oxford Street, Cambridge, MA 02138 email: saykin(a)fas.harvard.edu phone: (619)212-6649 ********************************************

8 years, 1 month

[Aspuru-Guzik Group List] [qip] today and tomorrow

by Edward Farhi

Hi Quanta Today at 2:00 Adam Bookatz will defend his thesis in the seminar room on the fourth floor of 6C. Please attend! Tomorrow we have our group meeting at 11:00 and Hari Krovi will tell us about his work. See you, Eddie --------------------------------------------------------- Edward Farhi Cecil and Ida Green Professor of Physics Director Center for Theoretical Physics Massachusetts Institute of Technology 6-300 Cambridge Massachusetts 02139 617-253-4871 --------------------------------------------------------- _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

8 years, 1 month

[Aspuru-Guzik Group List] Group meeting, April 28, 2:30 PM, Div Room

by Ian Kivlichan

Hi all, Tomorrow at 2:30 Salvatore will tell us about possible signatures of adiabatic quantum optimization. See you there, Ian ----------------------- Speaker: Salvatore Mandrà Title: A smoking gun for adiabatic quantum optimization?

8 years, 1 month

[Aspuru-Guzik Group List] Fun link for playing with ML

by Jennifer Wei

http://playground.tensorflow.org/#activation=tanh&batchSize=10&dataset=circ…

8 years, 1 month

[Aspuru-Guzik Group List] ML sub-group meeting (Today, 3:00pm)

by Benjamin Sanchez Lengeling

Hi all, The ML sub-group meeting is up and running and this time James is presenting. He will talk about *How to use Tensorflow for deep learning together with Skflow (Sklearn + Tensorflow).* This is happening today (27/04) at 3:00pm at the Acapulco-plex meeting area. If all works well, we will also *have two jupyter servers running with a prepared demo*. That means you can test out tensorflow/skflow without having to install anything, just from your browser. Hope to see you there, Ben and Jennifer

8 years, 1 month

[Aspuru-Guzik Group List] ITAMP/CCB Seminar: Prof. Nimrod Moiseyev Technion-Israel Institute of Technology, May 4th 11AM

by Siria Serrano

Prof. Nimrod Moiseyev Technion - Israel Institute of Technology Wednesday, May 4, 11:00 am Pfizer Auditorium Hall | 12 Oxford Mallinckrodt B23 “Non-Hermitian Quantum Mechanics (NHQM) theory for cold molecular collisions” In this talk I will described briefly the cold collision experiments conducted in Weizmann that motivated this work. Then I will describe the need for NHQM to study the dynamics in scattering experiments in which electrons and the nuclei motion are strongly coupled. In particular I will describe how NHQM enables us to use the Born Oppenheimer approximation for ionizing states that are embedded in the continuum part of the electronic spectra. A new ab-initio method will be presented that enables us the use of standard electronic molecular structure packages for calculating complex potential energy surfaces (CPES). These CPES are used for calculating the cross sections for cold collisions of an excited He (in a triplet spin state) with a (para/ortho) Hydrogen molecule. The products are He in its ground singlet electronic state, molecular hydrogen cation and a free electron. The agreement of our results (obtained from ab-initio non-perturbative calculations) with experiment is remarkable. Quantum Sciences Seminars (in Chemistry) are jointly sponsored with Harvard Department of Chemistry and Chemical Biology and the HarvardSmithsonian Center for Astrophysics. ITAMP sponsors talks and presentations on forefront AMO/Condensed Matter Physics from notable Scientists, Researchers and Professors. Information about speakers and ongoing dates can be found on the ITAMP Google Calendar. Go to: http://www.cfa.harvard.edu/itamp/gcalendar.html *ITAMP is funded by a grant from the National Science Foundation. -- *Siria Serrano* *Faculty Assistant* *Aspuru-Guzik Group* *Harvard University **Department of Chemistry and Chemical Biology* *12 Oxford St. M 136* *Cambridge, MA 02138* *P:** (617) 496-1716 <%28617%29%20496-1716>** F: **617-496-9411 <617-496-9411>*

8 years, 1 month

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aspuru-list April 2016