Seminare

In this talk, we describe some of the unusual optical properties of materials, known as epsilon-near-zero (ENZ) materials, for which the dielectric permittivity is very small. We describe some of the unusual geometrical optical properties of such materials and present theoretical predictions of how fundamental radiative properties are modified under such conditions. We also describe some of the nonlinear optical properties of these materials. Recent work has shown that optical materials can display an extremely large optical nonlinear response in their ENZ spectral region. [mehr]

Atomic Bose-Einstein condensates (BECs) are highly controllable isolated quantum systems with long coherence times, and offer applications in metrology and quantum information processing. We experimentally prepare two-component Rubidium-87 BECs, consisting of a few hundred atoms, on an atom-chip. Using state-selective potentials to tune the collisional interactions (one-axis twisting dynamics), we prepare many-particle non-classical states. After a time-of-flight expansion, high-resolution images allows us to access sub-regions of the atomic density distribution of various shapes and measure the spin correlations between them. [mehr]

This talk is devoted to modern methods of laser spectroscopy, with the special focus on applications that require extreme ultraviolet (XUV) radiation and extreme resolution. [mehr]

Linking remote quantum systems promises a host of new applications, ranging from distributed quantum computing to entanglement enhanced telescopes. Long distance quantum networks will require many nodes consisting of interfaces between local quantum memories and optical photons. While there are many contenders for these quantum nodes, nanophotonic implementations are particularly attractive: Once a single system works, it can be reproduced many times at minimal marginal costs. [mehr]

In quanum information theory, the von Neumann entropy usually arises in i.i.d settings, while single-shot settings are commonly characterized by (smoothed) Renyi entropies. I discuss new results that give single-shot interpretations to the von Neumann entropy under appropriate conditions. [mehr]