Alejandro Somoza Marquez

Email: alejandro.somoza-marquez[at]uni-ulm.de
Tel: +49-731-50-22904
Room O25/411
Institute for Theoretical Physics
Ulm University
Albert-Einstein Allee 11
D-89081 Ulm, Germany

My Research Interests

Living beings, from photosynthesis to respiration perform an “orchestrated” dissipation which is crucial to their own autopoiseis. Incoming photons are first harvested by a set of chromophoric antennae in the form of molecular excitations that travel throughout the pigment-protein complex towards the reaction center (RC), where charge separation takes place. These electronic excitations are described by Frenkel excitons which rarely dissipate into the environment supplying a very high yield for light-to-charge conversion, typically above 95%. While coherence and delocalization seem to be the key ingredient to efficient energy transport, photosynthetic systems are highly disordered and noisy. Nevertheless, the interaction of the exciton with the bosonic environment is quite structured, probably finely-tuned by evolution pressure, and cannot be treated perturbatively. Understanding the underlying mechanisms of protection against decoherence requires the incorporation of nuclear motion at the same footing as the electronic degrees of freedom.

My research interest involves the investigation of new computational strategies for the efficient simulation of open quantum systems with strong vibronic features. My objective is to exploit quantum phenomenology in order to boost the power efficiency of organic photovoltaics. From charge separation to quantum transport and spectroscopy, my purpose is to uncover the key ingredients that determine the efficiency of both synthetic and natural light-harvesting systems. Once these design principles have been uncovered, they can be applied in the fabrication of a novel class of organic solar cells. Furthermore, I am interested in developing a consistent thermodynamic analysis of charge separation which incorporates the quantum aspects of this process.

From a foundations perspective, I am interested in microscopic formulations of the second law of thermodynamics, the mechanisms of decoherence and the boundaries between the realm of quantum mechanics and classical mechanics. Short lived quantum effects at room temperature constitute indeed an exciting playground to test these ideas.

My Publications

Probing ultrafast excitation energy transfer of the chlorosome with exciton–phonon variational dynamics
A. D. Somoza, L. C., K Sun and Y. Zhao
Phys. Chem. Chem. Phys., (2016)

Superradiance at the localization-delocalization crossover in tubular chlorosomes
R. A. Molina, E. Benito-Matías, A. D. Somoza, L. Chen, and Y. Zhao
Phys. Rev. E 93, 022414 (2016)

Optimal Energy Transfer in Light-Harvesting Systems
L. Chen, P. Shenai, F. Zheng, A. Somoza and Y. Zhao
Molecules, 20(8), 15224-15272 (2015)