May
26
Teaser:

Superconducting circuitry can now be fabricated at the nanoscale by depositing suitable materials on to single molecules, such as DNA or carbon nanotubes. I shall discuss various themes that arise when superconductivity is explored in this new regime, including the thermal passage over and quantum tunneling through barriers by the superconducting condensate, as well as the hormetic impact that magnetism can have on nanosuperconductivity. I shall also describe circuits that realize nanoscale superconducting quantum interference devices, exploring their sensitivity to magnetic fields and spatial patterns of supercurrent. These features hint at possible uses of nanoscale superconducting...

May
05
Teaser:

X-ray science is undergoing one of its greatest revolutions to date with the construction of intense x-ray free electron lasers in Stanford, USA (LCLS), Hamburg, Germany (XFEL), and Harima Science Garden City, Japan (SCSS). These are vast, several-hundred-million dollar machines that will provide x-ray pulses that are many million times brighter than current sources. Similarly groundbreaking are the emerging attosecond light sources based on intense, pulsed lasers; they are relatively inexpensive laboratory-size instruments. These two emerging radiation sources will enable radically new research and have unnumbered potential applications in materials science, chemistry, biology, AMO,...

Mar
25
Teaser:

Twistor theory is now over 45 years old. In December 1963, I proposed the initial ideas of this scheme, based on complex-number geometry, which presents an alternative perspective to that of standard 4-dimensional space-time, for the basic arena in which (quantum) physics takes place. Over the succeeding years, there were numerous intriguing developments. But many of these were primarily mathematical, and there was little interest expressed by the physics community. Things changed rather dramatically, in December 2003, when E.Witten produced a 99-page article initiating the subject of “twistor-string theory” this providing a novel approach to high-energy scattering...

Mar
24
Teaser:

There is much impressive observational evidence, mainly from the cosmic microwave background (CMB), for an enormously hot and dense early stage of the universe referred to as the Big Bang. Observations of the CMB are now very detailed, but this very detail presents new puzzles of various kinds, one of the most blatant being an apparent paradox in relation to the second law of thermodynamics. The hypothesis of inflationary cosmology has long been argued to explain away some of these puzzles, but it does not resolve some key issues, including that raised by the second law. In this talk, I describe a quite different proposal, which posits a succession of universe aeons prior to our...

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