Seminars

In this talk, the exotic story of light matter interaction at the evel of one and even no atom is discussed. A single atom in free space can have significant effects on a single light beam producing e.g. sizeable phase shifts. Regarding the dynamics, a future goal is demonstrating time reversibility of spontaneous emission. But also without any atom, when studying empty space, there are intriguing concepts and future opportunities. [more]

Cold atom systems in optical lattices provide a promising platform for a wide variety of applications, ranging from quantum simulation to quantum metrology, due to their extremely high tunability and the ability to derive microscopic models under well-controlled approximations that give access to accurate descriptions. The proper characterization of those systems requires, in many scenarios, taking into account that they are subject to some dissipation sources, as dissipation can drastically modify the behaviour of the known phases of matter or even generate new ones. However, the description of open systems can quickly become numerically unaffordable. [more]

In this talk I will present an unpublished theory and experiment for two quantum nonlocality scenarios which generalise EPR-steering and Bell, respectively. in the sense of having weaker assumptions and thus more stringent experimental conditions. The first is to allow a finite amount of FTL communication of classical information in an EPR-steering scenario. The second relates to the recent theorem of Bruckner using "Wigner friends" in place of the determinism assumption in some formulations of Bell's theorem. [more]

[more]

The high flexibility of ultracold atoms allows for the design, control and thorough investigation of quantum matter. In this work we consider two one-dimensional Ramsey tunnel-coupled Bose gases and elaborate on its relation to the Prokrovsky-Talapov model. Further, we study the ground state with variational wave-functions and explore the experimental relevant finite system size effects. Finally, we discuss possible quench protocols in order to study the non-equilibrium evolution of the Pokrovsky-Talapov model and predict experimental relevant quantities such as the phase and the density. [more]