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Seminari  

Il Dipartimento di Fisica ospita Seminari di Dipartimento, Seminari organizzati dai gruppi di ricerca, e Physics Colloquia organizzati dalla Scuola di Dottorato.

I Seminari vengono inseriti nel Calendario.

Di seguito gli eventuali Seminari in programma nel mese in corso:

Seminari  
31/01/2019 Ore 12:30 - 16:30

Quantum Mechanical Methods for Spectroscopic Calculations of High Dimensional Molecular Systems

31/1/2019 12:30
Dip. di Fisica. Aula Caldirola.
Quantum Mechanical Methods for Spectroscopic Calculations of High Dimensional Molecular Systems
Dr. MICHELE CEOTTO

Affiliation: Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi 19, 20133 Milano, Italy


"I will present some novel semiclassical methods for spectroscopic calculations. These approaches can be employed for spectroscopic calculations of gas-phase molecular and supramolecular systems up to hundreds of degrees of freedom, as well as to condensed phase systems. Some methods are based on a “divide-and-conquer” approach, where the full dimensional spectra are obtained as a composition of several lower dimensional ones. Others exploit hierarchically the different levels of accuracy of different semiclassical propagators.
All methods are amenable to ab initio molecular dynamics simulations.

References
1. M. Micciarelli, R. Conte, J. Suarez, and M. Ceotto, JCP 149, 064115 (2018);
2. M. Buchholz, F. Grossmann, and M. Ceotto, JCP 148, 114107 (2018);
3. G. Di Liberto, R. Conte, and M. Ceotto, JCP 148, 104302 (2018);
4. G. Di Liberto, R. Conte, and M. Ceotto, JCP 148, 014307 (2018);
5. M. Buchholz, F. Grossmann, and M. Ceotto, JCP 147, 164110 (2017);
6. M. Ceotto, G. Di Liberto, and R. Conte, PRL 119, 010401 (2017);
7. F. Gabas, R. Conte, and M. Ceotto, JCTC 13, 2378-2388 (2017);
8. G. Di Liberto, M. Ceotto, JCP 145, 144107 (2016);
9. M. Buchholz, F. Grossmann, M. Ceotto, JCP 144, 094102 (2016);"

Stefano Zapperi    stefano.zapperi@unimi.it

17/01/2019 Ore 15:00 - 19:00

Weak field and full GR cosmological simulations

17/1/2019 ore 15:00
Dip. Fisica, Aula Consiglio
Weak field and full GR cosmological simulations    
Dr. Marco Bruni
Università di Portsmouth (UK)

"In this talk I will describe progresses in considering GR effects in the dynamics of structure formation. First I will present results of a nonlinear post-Friedman
approximation, a kind of post-Newtonian formalism.
Then I will focus on recent fully nonlinear numerical relativity simulations. Numerical relativity is a fundamental tool in the modelling of gravitational waves sources, but its application to cosmology is in its infancy. As more interdisciplinary work between the gravitational waves and the cosmology communities will develop, in the next few years numerical relativity may become a fundamental tool for understanding the extent to which we can trust standard newtonian N-body simulations on the largest scales. First results of simulations representing the full GR nonlinear evolution of initial perturbations in a Einstein de Sitter background are:
1) back-reaction effects on the overall expansion of the model are very small;
2) voids expansion rate is significantly higher than that of the background;
3) over-densities can reach turn-around much earlier than predicted by the standard top-hat model.
To establish the significance of these
results is the goal of future work.

http://www0.mi.infn.it/~sleoni/TEMP/Bruni-17-1-19.pdf

silvia leoni    silvia.leoni@mi.infn.it

08/01/2019 Ore 11:00 - 14:00

Solutions of the many-­electron problem in materials: recent advances from quantum Monte Carlo

8/1/2019 ore 11:00   Dip. di Fisica. Aula Caldirola
Solutions of the many-­electron problem in materials: recent advances from quantum Monte Carlo
Mario Motta    Caltech, Pasadena, California, USA

One of the grand challenges in physics and chemistry is the accurate treatment of interacting many-electron systems. This is difficult because of the combinatorial growth of the dimension of the Hilbert space involved with system size, along with the high degree of entanglement produced by the combination of Fermi statistics and electron-electron interactions. Recently, significant advances have been achieved by a combination of methodological developments and powerful computational resources, which are leading to the solution of increasingly more complex and relevant problems. I will give an overview of some of these advances and will briefly discuss a computational framework that played an important role in them, the auxiliary-field quantum Monte Carlo (AFQMC) method. I will present the theoretical foundations of this method, and recently developed algorithms to compute important observables like density matrices and forces within AFQMC

Davide Galli    davide.galli@unimi.it

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