aspuru-list January 2016

aspuru-list@lists.fas.harvard.edu

16 participants
42 discussions

[Aspuru-Guzik Group List] Visit of postdoc candidate Yudong Cao

by Borja Peropadre

Hi group, Yudong Cao will be visiting our group on Tuesday 26th (next week). He is a postdoc candidate with research interests in Quantum Computing, Quantum Complexity and Machine Learning. There are still a couple of available slots in the morning. If anyone is interested in meeting with Yudong, please let me know. Yudong will be also giving a talk at the group meeting (*Tuesday 26th 3.30pm in the Division Room*). Please find the title and abstract below. Title: Quantum algorithms and quantum complexity for quantum chemistry Abstract: Recent advances in quantum algorithms and quantum complexity theory could bring new possibilities in applications. Of particular interest is the quantum algorithm for solving linear systems of equations proposed by Harrow, Hassidim and Lloyd. I will talk about my past work with theorists and experimentalists on practical issues of realizing the algorithm, as well as some potential applications for quantum chemistry. On the quantum complexity end, my work is inspired by the observation that some of the tools developed by complexity theorists could be significantly improved and applied on practical adiabatic simulation of many-body quantum systems. I will present some results along this line of inquiry and also how it could be useful for quantum chemistry. Best, Borja

8 years, 3 months

[Aspuru-Guzik Group List] Undergraduate & Graduate students/visitors - 2015

by Marlon Cummings

Team: Please forward the names (and projects) of your undergraduate students, as well as all visiting graduate students that worked with our group in 2015. Please include REU. I'd like to have those by the end of the day if possible. Thanks a million!! MC. ------------------- *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/>*

8 years, 3 months

[Aspuru-Guzik Group List] Visit of postdoc candidate Cyril Stark tomorrow

by benjamin sanchez lengeling

Dear All, Postdoctoral candidate Cyril Stark will be visiting tomorrow. As part of his visit he will give a talk at the *2:30 in the Division Room.* Talk tittle and abstract is below: Title: Learning quantum models for arbitrary datasets Abstract: In this talk I address the problem of simultaneously learning unknown quantum states and unknown quantum measurements from empirical data. This task goes beyond conventional state tomography because we are not assuming anything about the measurement devices. I am going to talk about the time complexity and sample complexity of the inference of states and measurements, and I am going to talk about the robustness of the minimal Hilbert space dimension under measurement uncertainty. Moreover, I will describe a very simple heuristic algorithm (alternating optimization) to fit states and measurements to empirical data. For this algorithm to work the dataset does not need to be generated by a physical system. Hence, the proposed algorithm enables us to interpret arbitrary datasets from a quantum perspective. By analyzing movie ratings, we evaluate the power of quantum models in the context of item recommendation which is a key discipline in machine learning. We observe that quantum-inspired recommender systems can compete with state-of-the-art algorithms for item recommendation. Based on joint work with Aram Harrow. Relevant preprints: arXiv:1412.7437 and arXiv:1510.02800. *We still have some slots for mourning chats (10-12) and lunch if anyone is interested (12-ish)* Hope all is well, Ben

8 years, 3 months

[Aspuru-Guzik Group List] Excitonics/Perovskite Seminar: Sandeep Pathak, TODAY. Jan 19, 4:30 in 36-428

by Catherine M Bourgeois

SEMINAR TODAY! - Please post and forward to your group(s) Excitonics/Perovskite Seminar Series Fabrication of Organic-inorganic Perovskites for Highly Efficient Solar Cells and Light Emitting Diodes January 19, 2016 at 4:30pm/36-428 Sandeep Pathak Oxford University [Pathak] The unprecedented worldwide interest in organic−inorganic lead halide-based perovskite (HC(NH2)2PbX3 or CH3NH3PbX3) solar cells is rooted in its solution process-ability at low temperature as well as its extraordinary device performance. Perovskite thin films can be crystalized via a broad range of solution-based routes, but the quality of the final films varies strongly with small changes in solution composition and the processing parameters. I will highlight the mechanism of perovskite crystallization and discuss ways to judiciously control the crystal nucleation and growth processes during the perovskite film fabrication to achieve a high quality perovskite film. Here I will highlight the influence of a toluene drenching method on hybrid organic-inorganic perovskite (CH3NH3PbX) films upon three different precursor compositions, CH3NH3I (MAI): PbI2, 3MAI: PbI2 and 3MAI: PbCl2, and show that the mixed halide precursor (3MAI: PbCl2) results in the highest quality films with the toluene treatment, including high surface coverage, large grains, long PL lifetimes and high photoluminescence quantum efficiency (PLQE). I will also discuss the synthesis of perovskite (MAPbX3) Nano-crystals with broad spectral tuneability. By blending perovskite crystals with different emission wavelengths in a polymer host, we demonstrate the potential to replace conventional phosphors and provide the means to replicate natural white light when excited by a blue GaN LED. Sandeep Pathak gained his PhD at the University Of Cambridge, U.K. in 2011, working on High Temperature Superconductors with Prof David Cardwell. He joined Clarendon Laboratory (University of Oxford, U.K.) to work with Prof. Henry Snaith as a postdoctoral fellow to work on Dye-Sensitized and Perovskite Solar Cells. He has been working with Prof Snaith on perovskite solar cell except for a brief period when he moved back to Cavendish Laboratory to work with Prof Ullrich Steiner (University of Cambridge, UK). Recently, he has joined Prof. Bulovic’s lab at MIT as a visiting Scholar. His current research work predominantly involves fabrication of highly efficient perovskite solar cells and development of new materials for photovoltaic applications. 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 Light refreshments will be served

8 years, 3 months

[Aspuru-Guzik Group List] Visit of postdoc candidate Cyril Stark (Jan 19)

by benjamin sanchez lengeling

Dear All, Postdoctoral candidate Cyril Stark will be visiting us next Tuesday (January 19th). His research interest are quantum information, quantum tomography, optimization, machine learning. So a lot of overlap for discussion in the group, *anyone interested in meeting him for a chat during the morning (10-12), please send me a note. We will also have lunch (12-ish) if interested.* Also at 2.30 pm he will be giving a talk (title and abstract pending), will send another notice when the time is closer. Hope all is well, Ben

8 years, 3 months

[Aspuru-Guzik Group List] TODAY-Prof. Ed Narevicius-Special HQOC/ITAMP Joint Quantum Sciences Seminar

by Ploucha, Clare Dolores

Special HQOC/ITAMP Joint Quantum Sciences Seminar Thursday, January 14, 2016 1:30 PM, Jefferson 356 Prof. Ed Narevicius, Weizmann Institute of Science "Molecular Rotor in Cold Reactions" The role of the internal molecular degrees of freedom, such as rotation, in low energy reactions has been unexplored experimentally despite their significance to cold and ultracold chemistry. Particularly important to astrochemistry is the case of the most abundant molecule in interstellar space, hydrogen, where two spin isomers with rotationally ground and excited levels have been detected. Here we demonstrate that quantization of molecular rotation plays a key role in cold reaction dynamics, where rotationally excited ortho-hydrogen reacts faster due to a stronger long-range attraction. We observe rotational state dependent non-Arrhenius universal scaling laws in chemi-ionization reactions of para-[cid:51A53432-AF67-4076-BF68-ED1286C6ED02] and ortho-[cid:684FB474-BF36-4D23-82C2-5A547F3855D4] by [cid:CB168553-35B4-4C89-B236-D5A16A0C5CD3] , spanning three orders-of-magnitude in temperature. Different scaling laws serve as a sensitive gauge enabling us to directly determine the exact nature of the long-range intermolecular interactions. Our results show that the quantum state of the molecular rotor determines whether or not anisotropic long-range interactions dominate cold collisions [1]. We will also discuss the effect of molecular rotation on orbiting resonances that we have observed in our earlier work [2,3] in the case of normal H2. We will demonstrate that orbiting resonance structure is highly dependent on the rotational state of a molecule. [1] Y. Shagam, A. Klein, W. Skomorowski, R. Yun, V. Averbukh, C. Koch and E. Narevicius, "Molecular hydrogen interacts more strongly when rotationally excited at low temperatures leading to faster reactions", Nature Chemistry, 7 (11) 921, (2015) [2] A. B. Henson, S. Gersten, Y. Shagam, J. Narevicius, E. Narevicius, “Observation of Resonances in Penning Ionization Reactions at Sub-Kelvin Temperatures in Merged Beams” Science 338, 234–238 (2012). [3] E. Lavert-Ofir, Y. Shagam, A. B. Henson, S. Gersten, J. Klos, P. S. Zuchowski, J. Narevicius and E. Narevicius, “Observation of the isotope effect in sub-kelvin reactions” Nature Chemistry 6, 332–335 (2014). Coffee will be served -- 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, 3 months

[Aspuru-Guzik Group List] TOMORROW, Jan. 14-Prof. Ed Narevicius-Special HQOC/ITAMP Joint Quantum Sciences Seminar

by Ploucha, Clare Dolores

Special HQOC/ITAMP Joint Quantum Sciences Seminar Thursday, January 14, 2016 1:30 PM, Jefferson 356 Prof. Ed Narevicius, Weizmann Institute of Science "Molecular Rotor in Cold Reactions" The role of the internal molecular degrees of freedom, such as rotation, in low energy reactions has been unexplored experimentally despite their significance to cold and ultracold chemistry. Particularly important to astrochemistry is the case of the most abundant molecule in interstellar space, hydrogen, where two spin isomers with rotationally ground and excited levels have been detected. Here we demonstrate that quantization of molecular rotation plays a key role in cold reaction dynamics, where rotationally excited ortho-hydrogen reacts faster due to a stronger long-range attraction. We observe rotational state dependent non-Arrhenius universal scaling laws in chemi-ionization reactions of para-[cid:326CD7C3-DF03-43EE-A171-890161D3FA4D] and ortho-[cid:EF40C9AA-996E-4268-A336-128A0D101E4D] by [cid:D903A082-F8EC-45C2-95A6-454A100DF0F3] , spanning three orders-of-magnitude in temperature. Different scaling laws serve as a sensitive gauge enabling us to directly determine the exact nature of the long-range intermolecular interactions. Our results show that the quantum state of the molecular rotor determines whether or not anisotropic long-range interactions dominate cold collisions [1]. We will also discuss the effect of molecular rotation on orbiting resonances that we have observed in our earlier work [2,3] in the case of normal H2. We will demonstrate that orbiting resonance structure is highly dependent on the rotational state of a molecule. [1] Y. Shagam, A. Klein, W. Skomorowski, R. Yun, V. Averbukh, C. Koch and E. Narevicius, "Molecular hydrogen interacts more strongly when rotationally excited at low temperatures leading to faster reactions", Nature Chemistry, 7 (11) 921, (2015) [2] A. B. Henson, S. Gersten, Y. Shagam, J. Narevicius, E. Narevicius, “Observation of Resonances in Penning Ionization Reactions at Sub-Kelvin Temperatures in Merged Beams” Science 338, 234–238 (2012). [3] E. Lavert-Ofir, Y. Shagam, A. B. Henson, S. Gersten, J. Klos, P. S. Zuchowski, J. Narevicius and E. Narevicius, “Observation of the isotope effect in sub-kelvin reactions” Nature Chemistry 6, 332–335 (2014). Coffee will be served -- 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, 3 months

[Aspuru-Guzik Group List] Group meetings continuing (two Tuesdays then back to Thursdays)

by Ian Kivlichan

Hi all, Group meeting will return starting next week, on Tuesday January 19th at 2:30 PM. We'll also have group meeting on Tuesday the week after that, at 3:30 PM on the 26th (both are postdoc candidates). We'll return to the Thursday 2:30 PM time slot starting in February (on the 4th), and will continue on the Thursday slot indefinitely. All meetings will be in the Div Room, and everything's reflected on the group calendar. All the best, Ian

8 years, 3 months

[Aspuru-Guzik Group List] Fwd: Reminder: BASF is recruiting engineers and scientists

by Alan Aspuru-Guzik

Alán Aspuru-Guzik | Professor of Chemistry and Chemical Biology Harvard University | 12 Oxford Street, Room M113 | Cambridge, MA 02138 (617)-384-8188 | http://aspuru.chem.harvard.edu | http://about.me/aspuru ---------- Forwarded message ---------- From: Joanna Wozniak - Careers International <info(a)careersinternational.com> Date: Wed, Jan 13, 2016 at 10:44 AM Subject: Reminder: BASF is recruiting engineers and scientists To: alan(a)aspuru.com [image: ci logo] <http://r20.rs6.net/tn.jsp?f=001TS2P4KFVb28fFOjbTOEOY1JSivr_LGUsdolt4osnK-rx…> <http://r20.rs6.net/tn.jsp?f=001TS2P4KFVb28fFOjbTOEOY1JSivr_LGUsdolt4osnK-rx…> Dear Association/University Representative, This is a reminder for our upcoming Online Event with BASF on the *20th Jan 2016* (Central European time). BASF is currently looking for Engineers and Scientists to join their best R&D team in Asia Pacific. Candidates should speak English and have will to move/live in China. I would be really grateful if you could forward the e-mail below to your students/members who might be interested in joining BASF in Asia. To download the PDF containing all the information about this event, click here <http://r20.rs6.net/tn.jsp?f=001TS2P4KFVb28fFOjbTOEOY1JSivr_LGUsdolt4osnK-rx…> . In case you have any questions please let me know. Thank you very much for your cooperation. Joanna Wozniak Candidate Liaison Officer Careers International <http://r20.rs6.net/tn.jsp?f=001TS2P4KFVb28fFOjbTOEOY1JSivr_LGUsdolt4osnK-rx…> ---------------------------------------------------------- <http://r20.rs6.net/tn.jsp?f=001TS2P4KFVb28fFOjbTOEOY1JSivr_LGUsdolt4osnK-rx…> <http://visitor.constantcontact.com/do?p=un&m=001b1vbfeR4nUzbyy_i3C6u8Q%3D%3…> This email was sent to alan(a)aspuru.com by info(a)careersinternational.com | Update Profile/Email Address <http://visitor.constantcontact.com/do?p=oo&m=001b1vbfeR4nUzbyy_i3C6u8Q%3D%3…> | Rapid removal with SafeUnsubscribe <http://visitor.constantcontact.com/do?p=un&m=001b1vbfeR4nUzbyy_i3C6u8Q%3D%3…>™ | About our service provider <http://www.constantcontact.com/legal/service-provider?cc=about-service-prov…> . Careers International | Rue Blanche | Brussels | 1050 | Belgium

8 years, 3 months

[Aspuru-Guzik Group List] Excitonics/Perovskite Seminar: Sandeep Pathak, Tues. Jan 19, 4:30 in 36-428

by Catherine M Bourgeois

Please post and forward to your group(s) Excitonics/Perovskite Seminar Series Fabrication of Organic-inorganic Perovskites for Highly Efficient Solar Cells and Light Emitting Diodes January 19, 2016 at 4:30pm/36-428 Sandeep Pathak Oxford University [Pathak] The unprecedented worldwide interest in organic−inorganic lead halide-based perovskite (HC(NH2)2PbX3 or CH3NH3PbX3) solar cells is rooted in its solution process-ability at low temperature as well as its extraordinary device performance. Perovskite thin films can be crystalized via a broad range of solution-based routes, but the quality of the final films varies strongly with small changes in solution composition and the processing parameters. I will highlight the mechanism of perovskite crystallization and discuss ways to judiciously control the crystal nucleation and growth processes during the perovskite film fabrication to achieve a high quality perovskite film. Here I will highlight the influence of a toluene drenching method on hybrid organic-inorganic perovskite (CH3NH3PbX) films upon three different precursor compositions, CH3NH3I (MAI): PbI2, 3MAI: PbI2 and 3MAI: PbCl2, and show that the mixed halide precursor (3MAI: PbCl2) results in the highest quality films with the toluene treatment, including high surface coverage, large grains, long PL lifetimes and high photoluminescence quantum efficiency (PLQE). I will also discuss the synthesis of perovskite (MAPbX3) Nano-crystals with broad spectral tuneability. By blending perovskite crystals with different emission wavelengths in a polymer host, we demonstrate the potential to replace conventional phosphors and provide the means to replicate natural white light when excited by a blue GaN LED. Sandeep Pathak gained his PhD at the University Of Cambridge, U.K. in 2011, working on High Temperature Superconductors with Prof David Cardwell. He joined Clarendon Laboratory (University of Oxford, U.K.) to work with Prof. Henry Snaith as a postdoctoral fellow to work on Dye-Sensitized and Perovskite Solar Cells. He has been working with Prof Snaith on perovskite solar cell except for a brief period when he moved back to Cavendish Laboratory to work with Prof Ullrich Steiner (University of Cambridge, UK). Recently, he has joined Prof. Bulovic’s lab at MIT as a visiting Scholar. His current research work predominantly involves fabrication of highly efficient perovskite solar cells and development of new materials for photovoltaic applications. 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 Light refreshments will be served

8 years, 3 months

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aspuru-list January 2016