Integrated Calendar

The Large Hadron Collider (LHC) at CERN is the most powerful accelerator ever built. It provides an extremely rich environment to search for “physics beyond the standard model”. The ATLAS detector was designed to fully exploit the discovery potential of the LHC. The massive data collected by ATLAS lead to countless possible meas-urements - each having the potential of changing our understanding of particle physics. I will discuss conceptual as well as daily challenges addressed by experimental high energy physicists. Our search for lepton flavor violating Higgs decays and studies of advanced particle detectors will serve as examples for ongoing data analysis and prospects for instrumentation for future experiments, respectively.

Gaia is a space observatory which ESA has launched in December 2013. Its proclaimed mission is to study the origins and subsequent evolution of our Galaxy, the Milky Way. In order to attain its goals it is performing a survey of about a billion stars, allowing the construction of the most accurate three-dimensional map to date of the Galaxy. The talk will describe the Gaia space mission, its scientific context, and its expected impact, beyond its proclaimed mission. Specifically, it will look deeper into the prospects of detecting extrasolar transiting planets

Flying insects can perform a wide array of extreme aerial maneuvers with exquisite accuracy and robustness, outmaneuvering any man-made flying device. As a physical system, a flapping insect is strongly nonlinear with fast-growing mechanical instabilities that must be controlled to allow flight. Hence, similar to balancing a stick on one's fingertip, flapping flight is a delicate balancing act made possible only by ever-present, fast corrective actions. Understanding the underlying mechanisms of insect flight is a major challenge, since this graceful behavior is highly coupled to complex fluid flows and arises from the concerted operation of physiological functions across multiple length and time scales. As such, Insect flight research involves basic concepts from nonlinear dynamics, fluid mechanics, neurobiology and control theory, and has direct application to the development of small flapping robots.

Here we show how flies control their rotational degrees of freedom: yaw, pitch and roll. We focus on their body roll angle, which is unstable and most sensitive degree of freedom. We glue a magnet to each fly and apply a short magnetic pulse that rolls it in mid-air. Fast video shows that flies fully correct for perturbations of up to 100o within 30±7ms. The roll correction maneuver consists of a stroke-amplitude asymmetry that is well described by a linear PI controller. For more aggressive perturbations, we show evidence for nonlinear and hierarchical control mechanisms. Flies respond to roll perturbations within a single wing-beat, or 5ms, making this correction reflex one of the fastest in the animal kingdom.

The BCC phase of solid helium-4 has a gapped excitation mode, as revealed by inelastic neutron scattering experiments. This mode is unexpected, since BCC is a Bravais lattice and therefore acoustic modes are the only low-lying excitations expected in the harmonic solid. I will give a simple model for this new collective excitation based on the amplitude fluctuations of a quantum solid