The principle is easy: one starter and one motor atom in a ring of laser
light - and a bit of fine tuning, in order to move always into the right direction.
The research group of the theoretical physicist Prof. Peter Hänggi from
the University
of Augsburg has invented a concept for the minimal version of an electric
motor, which gets on with only two atoms. The study has recently been published
in the renowned scientific journal Physical Review Letter.
An ordinary electric motor is based on the principle that mechanical work is
done by electrical energy. Hänggi and his co-authors Dr. Alexey Ponomarev
and Dr. Sergey Denisov now have transferred this principle into the nano world,
on the level of single atoms. „Since on that level the laws of classical
physics are not applicable, but those of quantum mechanics, the conversion of
electric energy into mechanical work is not a trivial challenge,” Hänggi
stresses.
The three physicists have met this challenge. They designed a magnetically
driven atomic quatum motor, by first “catching” two atoms in a ring
of laser ligth - one motor and one starter atom. This construction becomes a
motor, when motor and starter atom meet each other and interact via electro-magnetic
forces. The starter atom gives the motor atom a “kick”. “Since
there is no friction in this world, it is crucial to give the motor a moving
direction when it has been kicked off, in order to enable it to perform work
against an outer force”, explains Hänggi.
To keep the motor atom on its course, specifically tuned external electro-dynamic
forces are needed. “This ‘Tuning’, which avoids a false turn-over
of the motor atom in the ring, is the point”, emphasizes Hänggi.
He has also a technical term for it: “breaking of symmetry”. Speaking
of Tuning: What makes this smallest motor of the world superior to other motors:
“After switching off the electro-magnetic drive, it simply runs further
on, because there is no braking friction in its quantum world, which consists
only of two atoms.”
Posted August 3rd, 2009
