Enhancement of vibrationally assisted energy transfer by proximity to exceptional points, probed by fluorescence-detected vibrational spectroscopy

Kavli Affiliate: Birgitta Whaley

| First 5 Authors: Zeng-Zhao Li, K. Birgitta Whaley, , ,

| Summary:

Emulation of energy transfer processes in natural systems on quantum
platforms can further our understanding of complex dynamics in nature. One
notable example is the demonstration of vibrationally assisted energy transfer
(VAET) on a trapped-ion quantum emulator, which offers insights for the
energetics of light harvesting. In this work, we expand the study of VAET
simulation with trapped ions to a non-Hermitian quantum system comprising a
$mathscr{PT}$-symmetric chromophore dimer weakly coupled to a vibrational
mode. We first characterize exceptional points (EPs) and non- Hermitian
features of the excitation energy transfer processes in the absence of the
vibration, finding a degenerate pair of second-order EPs. Exploring the
non-Hermitian dynamics of the whole system including vibrations, we find that
energy transfer accompanied by absorption of phonons from a vibrational mode
can be significantly enhanced near such a degenerate EP. Our calculations
reveal a unique spectral feature accompanying the coalescing of eigenstates and
eigenenergies that provides a novel approach to probe the degenerate EP by
fluorescence-detected vibrational spectroscopy. Enhancement of the VAET process
near the EP is found to be due to maximal favorability of phonon absorption at
the degenerate EP, enabling multiple simultaneous excitations. Our work on
improving VAET processes in non-Hermitian quantum systems paves the way for
leveraging non-Hermiticity in quantum dynamics related to excitation energy

| Search Query: ArXiv Query: search_query=au:”Birgitta Whaley”&id_list=&start=0&max_results=3

Read More