14 Apr
2015
14 Apr
'15
11:25 a.m.
Please post and forward to your groups
_________________
CENTER FOR EXCITONICS Seminar Series
Spectroscopy and Topological Phases for Organic Excitons
April 21, 2015 at 4:30 PM/ RLE Haus 36-428
Joel Yuen
The Research Laboratory of Electronics, Massachusetts Institute of Technology
[yuen_001]
abstract
The understanding and control of energy flow at the nanoscale via exciton dynamics is of
fundamental chemical and physical interest, but is also technologically relevant for the
design of novel light-harvesting materials. In the first part of my talk, I will explain
some of our work designing spectroscopic protocols to understand exciton dynamics under
coherent illumination via ultrafast Quantum Process Tomography (QPT), a technique which
retrieves the time evolution of the quantum state of excitons via nonlinear spectroscopy
(1,2). As an application, I will describe the first ultrafast QPT experiment carried out
with the Nelson and Bawendi groups at MIT on a nanotubular J-aggregate system at room
temperature. I will also clarify the possible relevance of strongly coupled chromophores
in natural light-harvesting under incoherent illumination from sunlight (3). Then, I will
proceed to explain how one can in principle distinguish excitonic coherences and their
vibrational counterparts in nonlinear spectroscopy (4,5).
In the last part of my talk, I will describe current work (6) designing topologically
nontrivial phases that robustly and selectively move excitons in particular spatial
directions of a molecular crystal, simulating solid state "topologically
protected" phenomena like the Quantum Hall Effect, which are robust against material
imperfections and static disorder. I will end by presenting our most recent work on
creating one-way waveguides of plexcitons (strongly coupled excitons and surface-plasmon
polaritons).
(1) J. Yuen-Zhou, Jacob J. Krich, Masoud Mohseni, and A. Aspuru-Guzik, Quantum state and
process tomography of energy transfer systems via ultrafast spectroscopy, Proc. Nat. Acad.
Sci. USA. 108, 43, 17615 (2011).
(2) J. Yuen-Zhou, D. Arias, D. Eisele, J. J. Krich, C. Steiner, K. A. Nelson, and A.
Aspuru. Guzik, Coherent exciton dynamics in supramolecular light-harvesting nanotubes
revealed by ultrafast quantum process tomography, ACS Nano 8 (6) 5527 (2014).
(3) I. Kassal, J. Yuen-Zhou, and Saleh Rahim-Keshari, Does coherence enhance transport in
photosynthesis, J. Phys. Chem. Lett. 4 (3), 362 (2012).
(4) J. Yuen-Zhou, Jacob J. Krich, and A. Aspuru-Guzik, A witness for coherent electronic
vs vibronic-only oscillations in ultrafast spectroscopy, J. Chem. Phys. 136, 234501
(2012).
(5) A. Johnson, J. Yuen-Zhou, A. Aspuru-Guzik, and J. Krich, Practical witness for
electronic coherences, J. Chem. Phys. 141, 244109 (2014).
(6) J. Yuen-Zhou, S. Saikin, N. Yao, and A. Aspuru-Guzik, Topologically protected excitons
in porphyrin thin films, in press, Nature Materials 13, 1026 (2014).
bio
Joel Yuen-Zhou got his BSc in 2007 from the MIT, where he worked as a UROP with the late
Robert J. Silbey, simulating the absorption spectra of light-harvesting antennae in purple
bacteria. He then obtained his PhD in 2012 from Harvard under the supervision of Alán
Aspuru-Guzik working on various aspects of time-dependent density functional theory,
quantum information, and nonlinear spectroscopy. In 2013, he came back to MIT to work at
the Center for Excitonics as the Robert J. Silbey postdoctoral fellow, where he got
interested in the connections between excitonic systems and topologically nontrivial
phases in condensed matter. He will start his own research group in theoretical chemical
physics as an assistant professor at the University of California San Diego in the
Department of Chemistry and Biochemistry as of July 2015.
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
14 Apr
14 Apr
11:27 a.m.
New subject: [Aspuru-Guzik group list] Fwd: Excitonics Seminar, Tues Apr 21, 4:30, 36-428
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/
---------- Forwarded message ----------
From: Catherine M Bourgeois <cmbourg(a)mit.edu>
Date: Tue, Apr 14, 2015 at 11:25 AM
Subject: [Aspuru-Guzik group list] Excitonics Seminar, Tues Apr 21, 4:30,
36-428
To: "efrc-all(a)mit.edu" <efrc-all(a)mit.edu>
Please post and forward to your groups
_________________
*CENTER FOR EXCITONICS Seminar Series*
Spectroscopy and Topological Phases for Organic Excitons
April 21, 2015 at 4:30 PM/ RLE Haus 36-428
*Joel Yuen*
*The Research Laboratory of Electronics, Massachusetts Institute of
Technology*
[image: yuen_001]
*abstract*
The understanding and control of energy flow at the nanoscale via exciton
dynamics is of fundamental chemical and physical interest, but is also
technologically relevant for the design of novel light-harvesting
materials. In the first part of my talk, I will explain some of our work
designing spectroscopic protocols to understand exciton dynamics under
coherent illumination via ultrafast Quantum Process Tomography (QPT), a
technique which retrieves the time evolution of the quantum state of
excitons via nonlinear spectroscopy (1,2). As an application, I will
describe the first ultrafast QPT experiment carried out with the Nelson and
Bawendi groups at MIT on a nanotubular J-aggregate system at room
temperature. I will also clarify the possible relevance of strongly coupled
chromophores in natural light-harvesting under incoherent illumination from
sunlight (3). Then, I will proceed to explain how one can in principle
distinguish excitonic coherences and their vibrational counterparts in
nonlinear spectroscopy (4,5).
In the last part of my talk, I will describe current work (6) designing
topologically nontrivial phases that robustly and selectively move excitons
in particular spatial directions of a molecular crystal, simulating solid
state “topologically protected” phenomena like the Quantum Hall Effect,
which are robust against material imperfections and static disorder. I will
end by presenting our most recent work on creating one-way waveguides of
plexcitons (strongly coupled excitons and surface-plasmon polaritons).
(1) J. Yuen-Zhou, Jacob J. Krich, Masoud Mohseni, and A. Aspuru-Guzik,
Quantum state and process tomography of energy transfer systems via
ultrafast spectroscopy, Proc. Nat. Acad. Sci. USA. 108, 43, 17615 (2011).
(2) J. Yuen-Zhou, D. Arias, D. Eisele, J. J. Krich, C. Steiner, K. A.
Nelson, and A. Aspuru. Guzik, Coherent exciton dynamics in supramolecular
light-harvesting nanotubes revealed by ultrafast quantum process
tomography, ACS Nano 8 (6) 5527 (2014).
(3) I. Kassal, J. Yuen-Zhou, and Saleh Rahim-Keshari, Does coherence
enhance transport in photosynthesis, J. Phys. Chem. Lett. 4 (3), 362 (2012).
(4) J. Yuen-Zhou, Jacob J. Krich, and A. Aspuru-Guzik, A witness for
coherent electronic vs vibronic-only oscillations in ultrafast
spectroscopy, J. Chem. Phys. 136, 234501 (2012).
(5) A. Johnson, J. Yuen-Zhou, A. Aspuru-Guzik, and J. Krich, Practical
witness for electronic coherences, J. Chem. Phys. 141, 244109 (2014).
(6) J. Yuen-Zhou, S. Saikin, N. Yao, and A. Aspuru-Guzik, Topologically
protected excitons in porphyrin thin films, in press, Nature Materials 13,
1026 (2014).
*bio*
Joel Yuen-Zhou got his BSc in 2007 from the MIT, where he worked as a UROP
with the late Robert J. Silbey, simulating the absorption spectra of
light-harvesting antennae in purple bacteria. He then obtained his PhD in
2012 from Harvard under the supervision of Alán Aspuru-Guzik working on
various aspects of time-dependent density functional theory, quantum
information, and nonlinear spectroscopy. In 2013, he came back to MIT to
work at the Center for Excitonics as the Robert J. Silbey postdoctoral
fellow, where he got interested in the connections between excitonic
systems and topologically nontrivial phases in condensed matter. He will
start his own research group in theoretical chemical physics as an
assistant professor at the University of California San Diego in the
Department of Chemistry and Biochemistry as of July 2015.
*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*
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1 comments
2 participants
participants (2)
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Catherine M Bourgeois -
Marlon Cummings