aspuru-list November 2014

aspuru-list@lists.fas.harvard.edu

20 participants
46 discussions

[Aspuru-Guzik group list] This week on Tuesday: ITAMP lunch seminar - Prof. Tilman Pfau, Stuttgart (12/02)

by Richard Schmidt

- please note the unusual DATE and LOCATION - Dear colleagues, This week we have our ITAMP lunch discussion with Prof. Tilman Pfau on TUESDAY instead of the usual Friday. Kind regards, Richard Schmidt and Swati Singh Special ITAMP Topical Lunch Discussion [on TUESDAY] Date: TUESDAY, December 2nd Time: 12:00-1:30 pm Pizza will be served. Location: Philipps Auditorium @ Center for Astrophysics (60 Garden Street) Directions: Instead of entering via the main entrance, go to the rear of the historic building and enter from the parking lot. The entrance is up the stairs, just across from of the old telescope. Speaker: Prof. Tilman Pfau, University of Stuttgart Title: Coherent control of strongly interacting Rydberg gases in thermal vapor cells Abstract: Rydberg atoms are of great interest due to their prospects in quantum information processing. 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 [1]. 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 [2]. 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 [3]. As an example we observe evidence for aggregate formation of Rydberg atoms in a vapor cell [4]. Besides these many body physics phenomena also electric field sensing applications have been demonstrated [5] and recently it was shown that coherent Rydberg excitation is also possible in photonic crystal fibers [6]. Several applications from THz sensing to singe photon sources seem within reach. References: [1] M. Saffman et al., RMP 82, 2313 (2010) and references therein  [2] B. Huber et al., PRL 107, 243001 (2011)  [3] T. Baluktsian et al., PRL 110, 123001 (2013)  [4] A. Urvoy et al., arXiv:1408.0039  [5] J. Sedlacek, et al. Nature Physics 8, 819 (2012)  [6] G. Epple, et al, Nature Communications 5, 4132 (2014) --------------------------- Dr. Richard Schmidt 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. richard.schmidt(a)cfa.harvard.edu Tel. +1 (617) 496-7610 Fax +1 (617) 496-7668 --------------------------- Dr. Richard Schmidt 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. richard.schmidt(a)cfa.harvard.edu Tel. +1 (617) 496-7610 Fax +1 (617) 496-7668

9 years, 4 months

[Aspuru-Guzik group list] Excitonics Seminar: Xiaodong Xu, Tues. Nov 25, 4:30 PM, rm: 6-120

by Catherine M Bourgeois

Please post and forward to your groups ______________________ CENTER FOR EXCITONICS Optoelectronics of 2D Materials November 25, 2014 at 4:30 PM/ 6-120 Xiaodong Xu University of Washington [xiaodongXu-02] Abstract: Electronic valleys are extrema of Bloch energy bands in momentum space. Having multiple valleys gives the electron states pseudospin degrees of freedom in addition to their real spin. In this talk, I will discuss our experimental progress on the investigation of spins and pseudospins using atomically thin semiconductors, which are either single or bilayer group VI transition metal dichalcogenides [1-3]. These new 2D semiconductors behave as remarkable excitonic systems, providing an exciting laboratory for optical, electrical and magnetic control of the valley degrees of freedom. I will also discuss strong coupling effects between spin, valley, and layer pseudo-spins in bilayers, which lead to spin polarization in electronic bands in the presence of bulk inversion symmetry and allow electrical control of spin states. I will conclude the talk with the discussion of spatially indirect exciton properties in monolayer semiconducting heterostructures [4] and single quantum emitters in monolayers [5]. References [1] Xu et al., Nature Physics 10, 343(2014). [2] Jones et al., Nature Nanotechnology 8, 634-638 (2013). [3] Aivazian et al., http://arxiv.org/abs/1407.2645. [4] Rivera et al., http://arxiv.org/abs/1403.4985; [5] He et al., http://arxiv.org/abs/1411.2449. Bio: Xiaodong Xu has been an Assistant Professor in the Department of Physics and the Department of Materials Science and Engineering at the University of Washington since Sept. 2010. He received his PhD (Physics, 2008) from the University of Michigan and then performed postdoctoral research (2009-2010) at the Center for Nanoscale Systems at Cornell University. His nanoscale optoelectronics group at University of Washington focuses on creation, control, and understanding of novel optoelectronic devices based on two-dimensional quantum materials. Selected awards include DAPRA YFA, NSF Early Career Award, DoE Early Career Award, Cottrell Scholar Award, and IUPAP Young Scientist Prize in Semiconductor Physics. Light refreshments will be served

9 years, 4 months

[Aspuru-Guzik group list] Happy Thanksgiving!!

by Marlon Cummings

Wishing you and your family and Happy Thanksgiving! Be safe and enjoy your time away. Cheers. ------------------ Marlon G. Cummings Lab Manager, Aspuru-Guzik Group Mallinckrodt M112 Department of Chemistry and Chemical Biology Harvard University 12 Oxford Street Cambridge, MA 02138 617-496-9964 617-496-9411 (fax) http://aspuru.chem.harvard.edu/

9 years, 4 months

[Aspuru-Guzik group list] [qip] Fwd: Postdoctoral and PhD positions in Condensed Matter/Quantum Information at RWTH Aachen

by aram harrow

This ad is the research group of Norbert Schuch, but Aachen also has DiVincenzo and Terhal. ---------- Forwarded message ---------- From: Norbert Schuch <schuch(a)physik.rwth-aachen.de> Date: Mon, Nov 24, 2014 at 5:00 PM Subject: Postdoctoral and PhD positions in Condensed Matter/Quantum Information at RWTH Aachen To: Dear colleague, I would be very grateful if you could distribute the attached job advertisement to potential candidates. With best regards, Norbert Schuch --------------------------------------------------------------------------- Postdoctoral and PhD positions in Condensed Matter/Quantum Information at the Institute for Quantum Information, RWTH Aachen, Germany Applications are invited for postdoctoral and PhD positions at the Institute for Quantum Information at RWTH Aachen University in the group of Norbert Schuch. The research focus in the group is on the study of strongly correlated quantum many-body systems using concepts from quantum information theory, in particular Tensor Network methods, and encompasses both analytical and numerical aspects. Candidates should ideally have a strong background either in condensed matter or in quantum information, but outstanding applicants with other background will also be considered. Applicants should send their CV (including publications, a brief statement of research interests for postdoc applicants, and contact data of potential referees) to Norbert Schuch <schuch(a)physik.rwth-aachen.de>. Applications will be considered from now on until the positions are filled. Starting dates are flexible. Postdoc appointments will be initially for a 2-year term. -- Prof. Dr. Norbert Schuch Tel: +49 241 80 28411 Institute for Quantum Information Fax: +49 241 80 628411 RWTH Aachen University Email: schuch(a)physik.rwth-aachen.de 52056 Aachen, Germany _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

9 years, 4 months

[Aspuru-Guzik group list] Fwd: Postdoctoral and PhD positions in Condensed Matter/Quantum Information at RWTH Aachen

by Alan Aspuru-Guzik

---------- Forwarded message ---------- From: *Norbert Schuch* <schuch(a)physik.rwth-aachen.de> Date: Monday, November 24, 2014 Subject: Postdoctoral and PhD positions in Condensed Matter/Quantum Information at RWTH Aachen To: Dear colleague, I would be very grateful if you could distribute the attached job advertisement to potential candidates. With best regards, Norbert Schuch --------------------------------------------------------------------------- Postdoctoral and PhD positions in Condensed Matter/Quantum Information at the Institute for Quantum Information, RWTH Aachen, Germany Applications are invited for postdoctoral and PhD positions at the Institute for Quantum Information at RWTH Aachen University in the group of Norbert Schuch. The research focus in the group is on the study of strongly correlated quantum many-body systems using concepts from quantum information theory, in particular Tensor Network methods, and encompasses both analytical and numerical aspects. Candidates should ideally have a strong background either in condensed matter or in quantum information, but outstanding applicants with other background will also be considered. Applicants should send their CV (including publications, a brief statement of research interests for postdoc applicants, and contact data of potential referees) to Norbert Schuch <schuch(a)physik.rwth-aachen.de <javascript:;>>. Applications will be considered from now on until the positions are filled. Starting dates are flexible. Postdoc appointments will be initially for a 2-year term. -- Prof. Dr. Norbert Schuch Tel: +49 241 80 28411 Institute for Quantum Information Fax: +49 241 80 628411 RWTH Aachen University Email: schuch(a)physik.rwth-aachen.de <javascript:;> 52056 Aachen, Germany -- 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

9 years, 5 months

[Aspuru-Guzik group list] [IACS-events] REMINDER: IACS Seminar with Aaron Adcock and Shankar Kalyanaraman from FACEBOOK ---TODAY @ 1pm

by Baker, Natasha

Date: Friday, November 21, 2014--- TODAY!!! Location: Maxwell Dworkin G115, 33 Oxford Street, Cambridge MA 02138 Speakers: Aaron Adcock and Shankar Kalyanaraman (Facebook) Time: Informal lunch with speaker, 12:30pm; talk, 1:00pm gCal <https://www.google.com/calendar/render?cid=http://www.seas.harvard.edu/cale…> ; iCal<UrlBlockedError.aspx> Talk 1: Tree-like Structure in Social and Information Networks Presenter: Aaron Adcock It is often noted that social and information networks exhibit tree-like structure and properties. In the past few years several tools have been developed to more closely quantify this structure. I will discuss some of the results of applying these tools to real-world social and information networks. In particular, I will discuss two alternatives for measuring this structure: Gromov hyperbolicity and tree-width. Talk 2: Data-mining for development Presenter: Shankar Kalyanaraman Over the last few years, we have witnessed innovative uses of big data to model and predict complex human behavior and patterns. Google's use of search query data to accurately forecast flu incidence and Ushahidi's crowdsourced crisis maps following the Haiti earthquake in 2010 for quicker and more effective deployment of humanitarian aid are two leading examples in this domain. My research interests draw inspiration from these examples; and in this talk, I will showcase some previous work I have done in disease surveillance and post-conflict violence prevention. In the end, time-permitting, we’ll briefly chat about data science at Facebook. <UrlBlockedError.aspx> <https://email.seas.harvard.edu/owa/UrlBlockedError.aspx> _______________________________________________ Iacs-events mailing list Iacs-events(a)seas.harvard.edu https://lists.seas.harvard.edu/mailman/listinfo/iacs-events

9 years, 5 months

[Aspuru-Guzik group list] [qip] today

by Edward Farhi

Hi Quanta There will be a quantum group meeting today at 11:00 in 6-310. John Preskill will visit and Yoah Lahini will give a presentation. Also John will give the seminar at 1:30. Sorry I will not be there. I am still stuck at home with my immobilized leg. Hopefully I will be back in action soon! Best, Eddie Edward Farhi farhi(a)mit.edu _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

9 years, 5 months

[Aspuru-Guzik group list] Fwd: Food Division Room --

by Joseph Goodknight

---------- Forwarded message --------- From: Schwickrath, Helen <schwickrath(a)chemistry.harvard.edu> Date: Thu Nov 20 2014 at 1:23:25 PM Subject: Food Division Room -- To: Goodknight, Joseph <jgoodknight(a)fas.harvard.edu> Going fast – leftovers from Faculty Luncheon! Food! Please share the word! Helen L. Schwickrath Seminar & Events Coordinator Harvard University Department of Chemistry & Chemical Biology 12 Oxford St. Cambridge, MA 02138 Phone (617) 496-8190 Fax (617) 496-5618 http://www.chemistry.harvard.edu

9 years, 5 months

[Aspuru-Guzik group list] [qip] Fwd: [CMT Seminar] Announcing Condensed Matter Physics Seminar on Wednesday 10/22: Zheng-Cheng Gu

by Ramis Movassagh

fyi. It's unfortunate that I will be out of town. Best, Ramis ---------- Forwarded message ---------- From: Zhengcheng Gu <zhengchenggu(a)gmail.com> Date: Wed, Nov 19, 2014 at 4:00 PM Subject: Re: [CMT Seminar] Announcing Condensed Matter Physics Seminar on Wednesday 10/22: Zheng-Cheng Gu To: "cmt_seminar(a)mit.edu" <cmt_seminar(a)mit.edu> Dear All: Prof. Kitaev will give talk at Harvard on Thursday 1:30pm. The lecture room is 530, Science Center(Math Department). Here is the title and abstact. Title: "Short-range entangled phases and homotopy theory" Abstract I will give an informal definition of a short-range entangled state of spins or fermions on an n-dimensional lattice. The set of such states (say, in the spin case) is some topological space B_n, and the sequence B_0, B_1,.. is a homotopy spectrum. Although only a few members of this sequence are known, there is a formal procedure to construct a similar sequence for short-range entangled states that are invariant under a local action of a compact Lie group. best regards, Zhengcheng 2014-10-17 15:43 GMT-04:00 Chong Wang <phchong(a)mit.edu>: Dear all, > > Please join us at 12:00 on Wednesday, October 22nd, for a Condensed Matter > Physics Seminar by Zheng-Cheng Gu from Perimeter Institute. The seminar > will be held in the Duboc Seminar Room (4-331). Please see details of > Zheng-Cheng's presentation below: > > > Speaker: Zheng-Cheng Gu, Perimeter Institute > > Title : Vortex-line condensation in three dimensions: A physical mechanism > of bosonic topological insulators > > Abstract : > > Bosonic topological insulators (BTI) in three spatial dimensions are > symmetry-protected topolog- > ical phases (SPT) with U(1) and Z_2^T symmetry, where U(1) is boson > particle number conservation, and > Z_2^T is time-reversal symmetry with T^2 = 1. Such kinds of new quantum > phases were recently pro- > posed based on group cohomology theory, later, their corresponding surface > anomalous topological > orders were proposed, which even leads to new BTI phases beyond group > cohomology classiffication. > Nevertheless, it is still unclear what is the universal physical mechanism > for BTI phases and what > kinds of microscopic Hamiltonians can realize them. In this talk, I > propose a universal physical > mechanism for BTI phases via vortex-line condensation. Based on such a > simple physical picture, we > find three kinds of BTI root phases, in which two of them are classiffied > by group cohomology theory > while the rest is beyond group cohomology class. The vortex-line > condensation picture also leads > to a "natural" bulk dynamic topological quantum field theory(TQFT) > description for BTI phases > and gives rise to a physical way of thinking towards experimental > realizations. Finally, we gener- > alize the vortex-line condensation picture into other symmetries and find > that in three dimensions, > even for a unitary Z_2 symmetry, there is a nontrivial Z_2 SPT phase > beyond the group cohomology > classification. > > Date: October 22, 2014 > Time: 12:00 > Location: Duboc Seminar Room (4-331) > Host: Xiao-Gang Wen _______________________________________________ CMT_seminar mailing list CMT_seminar(a)mit.edu http://mailman.mit.edu/mailman/listinfo/cmt_seminar _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

9 years, 5 months

[Aspuru-Guzik group list] [Aspuru-meetings-list] Group Meeting tomorrow, 2:30pm Div Room

by Jennifer Wei

Hi Everyone, Thomas will be giving group meeting tomorrow at 2:30pm in the division room. Please see below for his title and abstract. Jennifer -------------------------- Title: Finite Temperature Electronic Structure Abstract: I've been thinking about how to build temperature into electronic structure for quite a while, and I'm finally going to present some thoughts on how to do so. I'll start by making a few observations about uncertainty relations and temperature in many-body theory, as well as stating a few of my own results that motivated me to pursue this idea seriously. I'll then discuss how to build temperature into an arbitrary hamiltonian with known degrees of freedom, and how to make them useful for chemistry. Finally, I'll discuss some possible next steps. _______________________________________________ Aspuru-meetings-list mailing list Aspuru-meetings-list(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/aspuru-meetings-list

9 years, 5 months

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aspuru-list November 2014