LB12021ER
Cells, cancer and rare events
Enormous strides have been made towards understanding the molecular and
genetic origins of cancers. At the same time something of a mystery
remains in the incidence rate of lung cancer in ex-smokers. Detailed
analysis of the dynamics suggests that part of the mechanism at least
may have nothing to do with genetic changes in DNA. In this paper a
possible mechanism is examined, which the author terms "homeostatic
metastability". The idea is that the clinical appearance of cancer may
be a random, rare event arising from the collective behaviour of the
cells, a bit like the way bubbles appear in a fizzy drink or ice
crystals nucleate in supercooled water. At the moment, homeostatic
metastability remains an intriguing possibilitity, put forward as a
hypothesis to be supported or knocked down by experimental evidence. If
it should prove to be a factor in cancer though, it opens up interesting
possibilities for novel treatment regimes.
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LG12379
First Bose-Einstein condensate of an alkaline earth element - Matter wave
meets optical atom clock
Bose-Einstein condensates (BECs) as a source of coherent matter waves have
been used in the past years for a variety of measurements in fundamental
quantum mechanics as well as a model system for solid state physics and
for quantum information. Most BECs are made from alkaline atoms sharing
one disadvantage: For optical transitions they have a broad line width
i.e. they can be excited not only by a single frequency but by frequencies
in a range of several megahertz. The energy uncertainty related to this
line width is large compared to typical energy scales in a BEC as
temperature, photon recoil, chemical potential, or trap level spacing.
For the first time, a BEC of alkaline earth atoms has been produced. The super-narrow intercombination lines of this class of atoms allow optical excitation
with high precision and make them candidates for optical clocks. Combining
this feature with the coherent matter wave of a BEC does not only promise
new measurements on matter light interaction but can also be used for
precision spectroscopy of the properties of a condensate or for new
interferometric sensors for various kinds of forces, e.g. gravity.
