Friday, July 31, 2009

It has to do with the first sovereign emperor of China and an ancient army of the dead.

Raiders of the lost dimension

03 Jun

Posted by Jason as Science

terracotta.jpgThe good folks at the National high magnetic field lab have been up to some interesting stuff. See these guys?

They are covered in a pigment called Han purple that was painted on them when they were created over 2000 years ago. For whatever reason the researchers were studying this substance, and well, let’s see a quote from the article.

“They observed that at high magnetic fields (above 23 tesla) and temperatures between 1 and 3 degrees Kelvin (approximately -460 degrees Fahrenheit), the magnetic waves in three-dimensional crystals of Han purple “exist” in a three-dimensional world as per conventional wisdom. However, below those temperatures, near the quantum limit, one of the dimensions is no longer accessible, with the unexpected consequence that magnetic ripples propagate in only two dimensions. (Kelvin is the temperature scale used by scientists; zero degrees Kelvin is absolute zero, a temperature so low it is experimentally unreachable.)

The magnetic waves in the pigment exist in a unique state of matter called a Bose Einstein condensate (BEC), so named for its theoretical postulation by Satyendra Nath Bose and Albert Einstein. In the BEC state, the individual waves (associated with magnetism from pairs of copper atoms in BaCuSi2O6) lose their identities and condense into one giant wave of undulating magnetism. As the temperature is lowered, this magnetic wave becomes sensitive to vertical arrangement of individual copper layers, which are shifted relative to each other – a phenomenon known as “geometrical frustration.” This makes it difficult for the magnetic wave to exist in the third up-down dimension any longer, and leads to a change to a two-dimensional wave, in very much the same way as ripples are confined to the surface of a pond. The theoretical framework that leads to this interpretation was provided by Cristian Batista at LANL.”

What are the practicle implications for this? I have no idea, those warriors are awesome looking though.