The Kavli Prize laurate lectures in Astrophysics
The Kavli Prize laurate lectures in Nanoscience
The Kavli Prize laurate lectures in Neuroscience
"Memory: Looking Back and Looking Forward"
Montreal Neurological Institute
In the early 1950's, the psychological study of a few neurosurgical patients (including the now well-known patient H.M.), all of whom exhibited a profound anterograde amnesia following bilateral damage to the medial structures of the temporal lobes, revealed the importance of the hippocampal region for autobiographical memory. In the ensuing search for a learning task that H.M. could master, a breakthrough came with the demonstration of spared motor learning, thus providing early evidence for the existence of multiple memory systems in the brain. Return to top
"Spatial Cells in the Hippocampal Formation"
University College London
The Hippocampal Formation contains several types of cells which code for different aspects of space: the animal's current location within the environment, its heading direction, the distance over which it travels in a particular direction, and the location of environmental boundaries. In my talk, I will summarise the properties of these cells and suggest how they contribute to the creation of a spatial map of the environment and its updating on the basis of new information. Return to top
"The Restless Brain"
Marcus E. Raichle
Washington University in St. Louis School of Medicine
Traditionally studies of brain function have focused on task-evoked responses. By their very nature such experiments tacitly encourage a reflexive view of brain function. While such an approach has been remarkably productive at all levels of neuroscience it ignores the alternative possibility that brain functions are mainly intrinsic involving information processing for interpreting, responding to and predicting environmental demands. I shall argue that the latter view best captures the essence of brain function, a position that accords well with the allocation of the brain’s energy resources. The nature of this intrinsic activity, which exhibits a surprising level of organization with dimensions of both space and time, is revealed in the ongoing activity of the brain. Understanding the nature of this intrinsic activity will require integrating knowledge from cognitive and systems neuroscience with cellular and molecular neuroscience where ion channels, receptors, components of signal transduction and metabolic pathways are all in a constant state of flux. The reward for doing so will be a much better understanding of human behavior in health and disease. Return to top
"Light, Metal and Tiny Holes"
Thomas W. Ebbesen
Université de Strasbourg
Materials structured on the nanometer scale can lead to improved and sometimes surprising properties. Metals are no exception to this rule. The presence of tiny holes in an opaque film can lead to a variety of unexpected optical properties such as strongly enhanced transmission and filtering. Such intriguing properties are due to the interaction of light with electronic resonances which can be controlled by structuring the metal at the subwavelength scale. It opens exciting new possibilities ranging from subwavelength optics and opto-electronics to molecular sensing and biophysics. Return to top
"Optical microscopy: the resolution revolution"
Stefan W. Hell
Max Planck Institute for Biophysical Chemistry
Throughout the 20th century it was widely accepted that a light microscope relying on conventional optical lenses cannot discern details that are much finer than about half the wavelength of light (200-400 nm), due to diffraction. However, in the 1990s, the viability to overcome the diffraction barrier was realized and microscopy concepts defined, that can resolve fluorescent features down to molecular dimensions. In this lecture, I will discuss the simple yet powerful principles that allow neutralizing the limiting role of diffraction. In a nutshell, feature molecules residing closer than the diffraction barrier are transferred to different (quantum) states, usually a bright fluorescent state and a dark state, so that they become discernible for a brief period of detection. Thus, the resolution-limiting role of diffraction is overcome, and the interior of transparent samples, such as living cells and tissues, can be imaged at the nanoscale. Return to top
"Controlling Light on the Nanoscale: How to See Really Small Things and How to Make Large Objects Invisible"
Sir John B. Pendry
Imperial College London
In many ways light and nanoscience do not mix well. By convention light can be focussed to a spot no smaller than about a micron whereas nano structures by definition are three orders of magnitude smaller in scale. However recent theoretical advances show how to control light at the nanoscale, provided we can find the correct materials for our devices. I shall describe these new theories, and how they enable us to concentrate light to better than a nanometre. In this way light can detect single molecules, and the huge concentrations of optical energy can force photons to interact with one another which they normally do not do. Return to top
"Inflationary Cosmology: Is Our Universe Part of a Multiverse?"
Massachusetts Institute of Technology
I will begin by explaining the basics of how inflation works, emphasizing how inflation can account for a number of features of the observed universe. An interesting feature of inflation is that almost all versions of it lead to eternal inflation: once inflation starts, it goes on forever, producing a "multiverse" of "pocket universes," one of which would be our universe. The multiverse idea is speculative, but I will explain why I believe it should be taken seriously. Return to top
Andrei D. Linde
Inflationary theory offers a simple and unique solution to many complicated cosmological problems. Since the time when it was first introduced, this theory evolved from an exciting but incomplete scenario to a general cosmological paradigm describing the origin of the universe and formation of its large-scale structure. In addition to explaining many features of our world which still do not have any alternative explanation, inflationary theory made many predictions which have been already confirmed by cosmological observations. In this talk I will particularly emphasize recent developments of inflationary theory based on supergravity and string theory. This will naturally lead to a discussion of the theory of inflationary multiverse and the string theory landscape. These new developments suggest that on a very large scale, much greater than what we can see now, the world may look totally different. Instead of being a single spherically symmetric balloon, our universe may look as a "multiverse", a collection of many different exponentially large parts ("universes") with different laws of physics operating in each of them. This changes the standard views on the universe and on our own place in the world. Return to top
"Discovery and investigation of a New Epoch in the Past of Our Universe"
Alexei A. Starobinsky
Landau Institute for Theoretical Physics
Now, after numerous confirmations of predictions of the inflationary scenario, both in general and for some of its simplest realizations, we can say with confidence that a new era in the history of our Universe has been discovered that preceded the hot radiation dominated stage, usually dubbed the Big Bang. This epoch was very beautiful from the aesthetic point of view: it was almost maximally symmetric with respect to properties of both space-time and quantum fields in it, up to its metastability and unavoidable quantum fluctuations due to the Heisenberg uncertainty principle. Still this epoch was an intermediate attractor for field equations, so it was not unnatural. Second, all concrete inflationary models lead to unambiguous predictions parameterized by a few number of constants. This makes them falsifiable, and many of them have already been refuted by observations. On the other hand, a number of simple models including some pioneer one-parameter ones proposed more than 30 years ago have remained in agreement with all observational data up to recent few months. However, nature need not be so simple and more than one phenomenological constant may be needed to describe inflation, with additional parameters reflecting different physical processes which might occur during it. I discuss the present situation and subtleties regarding search for the primordial gravitational wave background generated during inflation which was the first prediction of its observational consequences made in 1979. As a whole, now the conceptual transition occurs from proving the inflationary paradigm in general and testing some of its simplest models to applying it for investigation of particle physics at super-high energies and of the actual history of the Universe in the remote past using observational data. Return to top