2019-05-24
14:00 at HCP F 43.4

Past and future research: Extended broken symmetry, liquid crystals in DNA macromolecules and ellipsoidal particles at interfaces

Alberto Giacomo Orellana

Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy

In this seminar, I will briefly introduce my past research experiences and some ideas for future work. In the first part I will introduce the problem of static correlation in density functional theory, and how it affects simulations in real systems like ferredoxin. This problem can be dealt with an extended broken symmetry approach, assuming that the system follows an Heisenberg hamiltonian and using Clebsch-Gordan coefficients.

In the second part I will explain my master’s thesis work: it is well known in literature that double helix DNA macromolecule cannot exhibit smectic order, due to the self-assembly nature of stack interaction. Recent developments in DNA nanotecnology and DNA origamy allow to inhibit stack interaction and allow to create double helix hairpin with smectic order. In this framework, also particles with complex shapes can be created, for example the asymmetric duplex exhibiting new exotic mesophase. I studied these macromolecules from a computational point of view, using simple coarse-grained models and Monte Carlo simulations, trying to confirm experimental results. I also developed a new protocol based on thermodynamic integration that allows to compute the difference in free energy between two smectic metastable states, and that can be easily generalized in different contexts.

Finally, I will suggest some strategies that may be used in order to study ellipsoidal particles at interfaces, like maximum entropy principle with experimental datas for empirical potential optimization.