September 16 2015

21.09.2015:"Licht-Reflektionen" :Talk of J.-M. Raimond

Lecture series “Licht-Reflektionen” for the International Year of Light


Jean-Michel Raimond
Université Pierre et Marie Curie, Paris
Laboratoire Kastler Brossel, Collège de France ENS, CNRS, UPMC, Paris

Montag, 21. September 2015, 17:30 Uhr
Campus, Gebäude C6 4, Großer Hörsaal

Quantenforschung mit Atomen und Licht in Resonatoren –
Exploring the quantum with atoms and light in cavities

The fascinating properties of light have guided our first steps in the weird quantum
world. We have now acquired an in-depth understanding of the micro-world. It led to
many applications and to new experimental tools. In turn, these tools allow us to unveil
the most basic quantum phenomena, to realize the thought experiments repeatedly used
by the founding fathers to assess their interpretation of the newborn quantum theory.
We can also think of harnessing the quantum for radically new methods in information
transmission and processing.
Cavity quantum electrodynamics belongs to this very active trend. It deals with a single
atom interacting coherently with a few photons in a single field mode stored in a high
quality cavity, a modern equivalent of Einstein’s photon box. With circular Rydberg
atoms and superconducting cavities, we count the photons without losing them,
realizing an ideal measurement of the field intensity. We use this information in a
quantum feedback loop stabilizing the photon number against cavity losses. We also
prepare mesoscopic quantum superpositions, reminiscent of the famous Schrödinger
cat, and study their decoherence, shedding some light onto the quantum to classical

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