Integrated Calendar

We will discuss a procedure to construct N=1 (singular) Lagrangians describing some of the N=2 strongly coupled SCFTs believed to be non-Lagrangian. we will apply the same procedure to study some of the properties of a putatively new N=1 SCFT which otherwise does not have, at the moment, a description in terms of a Lagrangian.

Since the mid-nineties of the 20th century it became apparent that one of the centuries’ most important technological inventions, computers in general and many of their applications could possibly be further enormously enhanced by using operations based on quantum physics. This is timely since the classical roadmaps for the development of computational devices, commonly known as Moore’s law, will cease to be applicable within the next decade due to the ever smaller sizes of the electronic components that soon will enter the quantum physics realm. Computations, whether they happen in our heads or with any computational device, always rely on real physical processes, which are data input, data representation in a memory, data manipulation using algorithms and finally, the data output. Building a quantum computer then requires the implementation of quantum bits (qubits) as storage sites for quantum information, quantum registers and quantum gates for data handling and processing and the development of quantum algorithms.
In this talk, the basic functional principle of a quantum computer will be reviewed. It will be shown how strings of trapped ions can be used to build a quantum information processor and how basic computations can be performed using quantum techniques. In particular, the quan-tum way of doing computations will be illustrated by analog and digital quantum simulations, which reach from the simulation of quantum many-body spin systems over open quantum systems to the quantum simulation of a lattice gauge theory.

Most excitatory cells in layer 4 of the mouse somatosensory cortex are spiny stellate (SpSt) neurons, which receive nearly all their excitatory input from the thalamus and from other SpSt neurons in the same barrel. Because layer 4 is the key entrance point into the cortical circuit, we assume that SpSt neurons respond rapidly to sensory input. However, these cells are very small, and there are strong theoretical reasons to suspect that their compact morphology could impair their capacity to encode high input frequencies and thus hamper the temporal fidelity of cortical processing. We use whole-cell patch clamp to measure the temporal properties of asynchronous noise in SpSt cells as compared with the much larger layer 5 pyramidal (Pyr) cells, and characterize the capabilities of both cell types to encode high frequencies in a synaptically active-like environment. We find that individual SpSt cells indeed have a much narrower dynamic range than Pyr cells when probed with inputs on a background of identical noise characteristics. However, the synaptic dynamics in SpSt cells, as evidenced by the correlation time of asynchronous noise, is slower than in Pyr neurons, and the slower correlation time of the SpSt cells is associated with significant broadening of their dynamic range. We further show that this compensatory improvement in encoding bandwidth of sensory input depends on activation of potassium conductances, as it decreases when potassium channels are pharmacologically blocked.

Bacterial cells use large receptor arrays to detect chemical gradients in their environment. I will describe recent progress in understanding the signalling properties of these arrays and the direct impact that these structures have on chemotaxis behavior.