UMR 5672

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Soutenance d'Irénée Frérot

Quantum statistical approach to quantum correlations
When Oct 09, 2017
from 02:00 PM to 04:00 PM
Where Salle Fontaine (place de l'École)
Attendees Irénée Frérot
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Physical quantities in any system can fluctuate for two reasons: an uncertainty on the state of the system (due for instance to the presence of thermal noise), and an intrinsic quantum uncertainty (stemming from the superposition principle). We will show that quantum superpositions, which give rise to interference effects, manifest themselves as enhanced fluctuations with respect to the predictions of classical physics. Focusing on equilibrium systems, we will show how thermal and quantum uncertainties my be separated. Discussing the example of the Ising model, we will show that the "quantum variance" is especially suited to highlight the peculiar role of quantum fluctuations at phase transitions (be them of thermal of quantum nature). As a consequence of the exceptional quantum coherence which develops close to quantum critical points, we will finally anticipate an intriguing phenomenon of critical suppression of certain fluctuations (or "squeezing"), thereby opening novel perspectives for interferometric measurements limited by the quantum projection noise.