Exceptional CMSP Seminar IN PERSON (Atomistic Simulation Seminar Series): TOMORROW 6 April at 2:00PM in Euler LH, Prof. Andrea Marini

[CMSP Seminars Secretariat]

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Atomistic Simulation Webinar Series
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IN PERSON_

+ Zoom 
(https://zoom.us/meeting/register/tJEvc-CoqD8oEtLsljE4oWZtfWNP49uw_Xnk)


** * * TOMORROW Wednesday, 6 April 2022 at 2:00PM*****in Euler Lecture 
Hall (LB)** * **

Speaker:*Prof. Andrea Marini *(FLASHit, ISM, CNR)


Title:***Photo-induced phase-transitions and coherent phenomena in 
realistic materials: an ab-initio Many-Body approach
*

_Abstract_:
It is widely known that a monochromatic electro-magnetic wave can travel 
forever without losing information. It is similarly common knowledge 
among experimentalists that after a material has been photo-excited an 
additional, induced, electric field gets super-imposed to the external 
probe. This field is generated by the electronic charge oscillations. 
The key point is that this induced field appears only after the 
excitation. The system, at rest, is not able to produce it.

What makes the electrons to oscillate in phase and produce a macroscopic 
field is coherence?

In this talk I will discuss the role of coherence in out-of-equilibrium 
phenomena. I will describe some particularly striking examples of how a 
photo-excited material can reveal coherent phenomena like: magnetic 
phase transitions, coherent phonon oscillations and the formation of a 
spontaneous excitonic condensate.

I will also discuss the peculiarities of these phenomena taking the 
equilibrium perspective. From which it will appear evident that the 
system reacts is non-perturbative. A dynamics extremely challenging to 
describe theoretically.

The final message of my talk will be that concepts taken from the 
equilibrium regime are, often inadequate to describe out-of-equilibrium 
systems. A striking example will be the Exciton. Can we really say that 
excitons exist as real population of bound electron-hole pairs?

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CMSP Seminars support:OnlineCMSP at ictp.it  

CMSP, Condensed Matter & Statistical Physics Section
http://www.ictp.it/research/cmsp.aspx

The Abdus Salam International Centre for Theoretical Physics
https://www.ictp.it/

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