Seminare

In the quantum information literature, self-testing refers to the action of uniquely determining a quantum state based solely on the statistics of measurement outcomes and minimal assumptions. These quantum self-testing protocols are more stringent than well-known Bell tests. While violation of a Bell inequality for a bipartite system establishes that its quantum state is entangled, it cannot certify, for instance, that its quantum state is maximally entangled. We extend self-testing techniques to certification of quantum measurements in various physical settings. [mehr]

The microwave technology has been one of the important tools in fundamental physics since Rabi's pioneering work on hydrogen atoms. In this seminar, direct spectroscopy of positronium hyperfine structure with very high frequency microwaves, often referred to as millimeter or sub-THz waves, will be discussed. [mehr]

The primary phase of the light-molecule interaction is the photon energy absorption and deposition. Although the electron is much lighter than the nuclei, there is a strong electron-nuclear correlation for molecules exposed to strong laser fields. The photon energy deposits into the nuclei governs the succeeding dynamics and thus the fate of the molecules. [mehr]

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]