04-29-12, 07:14 PM #1
Adjustable Magnetic Field Can Create Several New Phases Of Atomtronic Matter
A new study* shows how a simple "joystick" consisting of an adjustable magnetic field can create several new phases of atomtronic matter, several of them never seen before. Charles Clark, Co-Director of the Joint Quantum Institute** reported the results at the meeting of the American Association for the Advancement of Science (AAAS) in Vancouver on February 18, 2012.***
One of the attractions of atomtronics is that the properties of electrons moving through solid state materials can often be mimicked using atoms operating under highly controlled circumstances. Why not just study electrons directly? Because in atomtronics the forces among the atoms can be controlled; you can't do that as well with electrons in solids. That is, atoms can be induced to interact via a force that can be dialed up or down, exploiting the large magnetic dipole moment of some atoms, such as dysprosium-161.
Clark will describe theoretical work carried out with colleagues at George Mason University, the University of Hamburg, Germany and the University of California, Riverside. Together they have studied what happens when ultracold highly magnetic atoms are held in an optical lattice and subjected to an external magnetic field, which can be steered in various directions. This field tugs on the atom-sized magnets and, along with the direction of the field itself, leave the atoms standing upright or pulled over on their sides at various inclinations described in the figure by the angles phi and theta. In this way, the researcher can tune the interaction---force on demand.
The atoms don't just stay put as they are being jerked around. They disport themselves into patterns. Each pattern can be considered a different phase of atomtronic matter. And just as water molecules can exist in phases---ice, water, steam---depending on how a joystick that controls temperature and pressure is deployed, so the magnetic atoms sort themselves into numerous phases depending on the magnetic joystick controlling the strength and orientation of the applied magnetic field.
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