"Cooperative effects in quantum transport: Cooperative Shielding"

Dear All,

Mathematical Soft Matter Unit (Fried Unit) would like to invite you to a Seminar by Professor Luca Celardo from Università Cattolica del Sacro Cuore (Brescia, Itay)

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Date: Monday, February 8th, 2016
Time: 14:00-15:00
Venue: C016, LevelC, Lab 1
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Speaker:
Professor Luca Celardo
Assistant Professor
Department of Mathematics and Physics
Università Cattolica del Sacro Cuore

Title:
Cooperative effects in quantum transport: Cooperative Shielding

Abstract:
Cooperative effects in quantum systems are at the center of interest in many systems in physics such as cold atomic clouds, light-harvesting systems, trapped ions and strongly correlated materials. Cooperative quantum effects are at the heart of Superradiance and Supertransfer, producing enhanced energy transport efficiency and robustness to noise.
In the first part of the talk we will review the role of cooperativity in different physical systems, focusing on natural light-harvesting complexes.
The second part of the talk will be devoted to discuss the interplay of cooperativity and noise in systems with long-range interaction (many body spin systems and tight binding models). The main focus will be on a novel cooperative effect which we named Cooperative Shielding.
Contrary to the common expectation that long-range interaction should necessarily induce an instantaneous spread of information in the thermodynamic limit, we show that, as the system size increases, the dynamics can actually become more confined into invariant subspaces. In such subspaces, the dynamics is determined by an emergent Hamiltonian which contains only short range interactions. This implies that the dynamics is effectively shielded from long-range interaction, that is, it occurs as if that interaction was absent. Shielding is a cooperative effect, because the time over which it is effective diverges with system size. This shielding phenomenon can be related to the quantum Zeno effect. The latter refers to the confinement of the dynamics into invariant subspaces of a system under "continuous measurement". This implies that long-range interaction plays a role similar to a measuring apparatus.

Bio:
Luca Celardo is Assistant Professor in Condensed Matter Theory at the Department of Mathematics and Physics of Università Cattolica del Sacro Cuore (Brescia, Itay), where he leads the Open Quantum System and Quantum Biology group.
After receiving his PhD at the University of Milan, he held postdoctoral positions at Los Alamos National Laboratories, Benemérita Universidad Autonoma de Puebla, and Tulane University.