Huh Research Group
My theoretical chemistry research group is mainly working on quantum phenomena such as quantum coherence and entanglement in natural and artificial systems.
(i) The examples of former are photosynthetic light-harvesting complexes and olfaction (smell): The quantum particles like excitons (energy) and electrons are transferred in living systems to maintain the lives. Usually, the quantum transport problems are described in the "Open Quantum" picture, which separates the small quantum world to be explored from the remaining complex environments. My group develops the open quantum methods for dynamical molecular systems and applies them to various problems including synthetic materials.
(ii) Artificial quantum devices (quantum computer) can be designed to simulate or to compute dynamical systems like molecules. Quantum computers are expected to show the computational supremacy against the conventional machines, and the required techniques are being rapidly developed. However, there are not so many applications to be solved by quantum computers with full quantum benefits so far. In my group, we try to apply the quantum techniques to molecular problems, which would be the most demanding application field in quantum simulation.
We are also working on computational material science: lithium-ion battery electrode materials and electrolytes, and 1-D nanowire material design.
Quantum optical emulation of molecular vibronic spectroscopy using a trapped-ion device
Molecules are one of the most demanding quantum systems to be simulated by quantum computers due to their complexity and the emergent role of quantum nature. The recent theoretical proposal of Huh et al. (Nature Photon., 9, 615 (2015)) showed that a multi-photon network with a Gaussian input state can simulate a molecular spectroscopic process. Here, we present the first quantum device that generates a molecular spectroscopic signal with the phonons in a trapped ion system, using SO2 as an example. In order to perform reliable Gaussian sampling, we develop the essential experimental technology with phonons, which includes the phase-coherent manipulation of displacement, squeezing, and rotation operations with multiple modes in a single realization. The required quantum optical operations are implemented through Raman laser beams. The molecular spectroscopic signal is reconstructed from the collective projection measurements for the two-phonon-mode. Our experimental demonstration will pave the way to large-scale molecular quantum simulations, which are classically intractable, but would be easily verifiable by real molecular spectroscopy.