BATH · A Probe for Environment Properties in Open Quantum Systems: Accessing Spectral Densities with Multi-Dimensional Coherent Spectroscopy
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2017-02-01 → 2019-01-31
- EU contribution
- €173,857
- Participants
- 1
- Scheme
- MSCA-IF-EF-ST
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Results in brief
A Probe for Environment Properties in Open Quantum Systems: Accessing Spectral Densities with Multi-Dimensional Coherent Spectroscopy
The excitation of matter by light underlies some of the most important human-made technologies, and processes in nature. The dynamics of the photoexcited state is modulated by the motion of the environment which can successfully steer it to a desired state, or alternatively destroy it before it can be converted to useful energy. The BATH project strives to recover the information on the system-bath interaction using two-dimensional electronic spectroscopy (2DES). This technique is the most sophisticated third-order time resolved technique providing detailed information on the dynamics of electronic excitation on a sub-20fs timescale. The work preferentially focuses on materials incorporating both plasmonic nanoparticles and molecular aggregates. From a fundamental standpoint they can exhibit quantum interferences, and have a complex dissipative environmental bath consisting of molecular vibrations, solvent motion and phonon modes of the lattice. In addition, many-body effects (e-e scattering) influence the early dynamics. From a practical standpoint, plasmon-based materials are candidates for quantum optics manipulations (cavity quantum electrodynamics, adiabatic passage methods, coherent population trapping) as well as photocatalysis (plasmon enhanced photochemistry). They are thus an ideal problem to answer fundamentally important questions with very realistic applications. The work is arranged into two mutually supporting directions. We carry out spectroscopy experiments (pump-probe, 2DES) on plasmon-based materials to reveal their dissipative mechanisms and identify the features of the 2DES spectrum which can be directly associated to system-bath couplings. We also develop the theory to understand the photoexcited dynamics using simple models that can be solved analytically, and carry out simulations of the 2DES experiment.
Data: CORDIS, © European Union
Project objective
The structures nature has built to harvest and use the light from the sun are full of ingenuity. Indeed, they are the product of millions of years of trial and error. A lot can be learnt from the structure and function of photosynthetic organisms to help guide humanity's effort to develop solar energy technologies. One of the frontiers in understanding the early stages of photosynthesis is the interaction of the excited chromophores with the environment, and in particular how energy is dissipated as the light-induced excitation migrates to the reaction center where it will produce a charge separated state. It has become evident that the details of the dissipation are crucial for an efficient transfer. Dissipation is characterized by the spectral density of the bath, but this information is difficult to extract experimentally. Current approaches (e.g. three pulse photon echo spectroscopy, fluorescence line narrowing) have several limitations such as the inability to predict the motion for short times where the non-Markovianity of the bath is most evident. In this work, we will develop descriptions of multidimensional spectroscopy which will map the spectral density as an experimental observable. For this we will work in the Non-equilibrium Green functions formalism, and apply partition ansatz for the bath such as the surrogate Hamitlonian to facilitate obtaining analytical expressions. Our formalism will be benchmarked against exact numerical methods by the use of entanglement and non-Markovianity witnesses. The application of our theory to natural systems will yield a picture of the most salient bath features in natural systems. These will be then compared to selected artificial systems.
Original text from CORDIS.
Participants
- LUNDS UNIVERSITET · LundCoordinatorSweden
Links
Data: CORDIS, © European Union