[Aspuru-Guzik Group List] TODAY-Franco Nori-HQOC/ITAMP Joint Quantum Sciences Seminar
by Ploucha, Clare Dolores
HQOC/ITAMP Joint Quantum Sciences Seminar
Wednesday, September 7 , 2016
4:00 PM, Jefferson 250
Prof. Franco Nori, RIKEN, Saitama, Japan; University of Michigan
"Extraordinary properties of light: Evanescent waves and quantum spin Hall effect"
Maxwell's equations ultimately describe properties of light, from classical electromagnetism to quantum and relativistic aspects. The latter ones result in remarkable geometric and topological phenomena related to spin-1 massless nature of photons. By analyzing fundamental spin properties of Maxwell waves, we show that free-space light exhibits an intrinsic quantum spin Hall effect-surface modes with strong spin-momentum locking. These modes are evanescent waves that form, for example, surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate the unusual transverse spin in evanescent waves and explain recent experiments that have demonstrated the transverse spin-direction locking in the excitation of surface optical modes.
Optical systems combining balanced loss and gain provide a unique platform to implement classical analogues of quantum systems described by non-Hermitian parity-time (PT)-symmetric Hamiltonians. Such systems can be used to create synthetic materials with properties that cannot be attained in materials having only loss or only gain. We report PT-symmetry breaking in coupled optical resonators and observe non-reciprocity in the PT-symmetry-breaking phase due to strong field localization, which significantly enhances nonlinearity. Our results could lead to a new generation of synthetic optical systems enabling on-chip manipulation and control of light propagation.
References:
K.Y. Bliokh, D. Smirnova, F. Nori, Quantum spin Hall effect of light, Science 348, 1448-1451 (2015).
K. Y. Bliokh, A. Y. Bekshaev, F. Nori, Extraordinary momentum and spin in evanescent waves, Nature Communications 5, 3300 (2014).
B. Peng, et al., Parity-time-symmetric whispering-gallery microcavities, Nature Physics 10, 394-398 (2014).
Ivan Kozyryev, Doyle Group
"Sisyphus Laser Cooling of a Polyatomic Molecule"
The use of laser radiation to cool atomic motion is a common prerequisite for creating ultracold quantum gases. We demonstrate magnetically-assisted Sisyphus laser cooling of the triatomic free radical strontium monohydroxide (SrOH) using two different electronic transitions. We also study loss channels to vibrational states (including the bending mode) and highlight proposed extensions to more complex species. This approach opens a path towards creating a variety of ultracold polyatomic molecules, including much larger ones, by means of direct laser cooling.
Student Presentation from 4:00-4:10 PM
Refreshments Served from 4:10-4:30 PM
Guest Presentation from 4:30-6:00 PM
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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