Featured in EPN
Featuring in the latest issue of EPN:
A new spin on Earth’s deep mantle1
by J. Badro
‘Earth’s mantle is the largest distinct layer within the Earth, between the crust and the core. It accounts for roughly 2/3 of Earth’s mass and is composed mainly of dense iron-bearing silicates. Laboratory experiments have recently shown that iron in mantle minerals undergoes a high-spin to low-spin transition driven by pressure, occurring at mid to lowermost mantle depths. This introduces a paradigm shift in our understanding of the physics and chemistry of the deep Earth…’
Ratchets from the cold: Brownian motors with cold atoms in optical lattices2
by F. Renzoni
‘Brownian motors, or ratchets, are devices which ‘rectify’ Brownian motion, that is, they can generate a current of particles out of unbiased fluctuations. The present article reviews recent experimental realizations of ratchets employing cold atoms in optical lattices. This is quite an unusual system for a Brownian motor as there is not a real thermal bath, and both the periodic potential for the atoms and the fluctuations are determined by laser fields. Such a system has allowed us to explore a number of fundamental features of ratchets…’
The rediscovery of the ‘French Blue’ diamond3
by F. Farges, J. Vinson, J. J. Rehr & J.E. Post
‘Jean-Baptiste Tavernier (1605-1689), a French traveller, returned from India in 1668, with a large (115.16 carats) blue diamond from an unknown mine in India. After the King of France, Louis XIV (1638-1715), purchased the gem, it became the largest diamond of the French Crown Jewels. Alas, in September 1792, this very unique and large blue diamond was stolen along with other gems of the French Crown Jewels. Although most were eventually recovered, the ‘French Blue’ diamond never reappeared…’
