PhysOrg.com) -- "The concept of matter waves is at the heart of quantum mechanics," Oliver Morsch tells PhysOrg.com. "At the beginning of the last century, scientists discovered that solid particles could exhibit properties of waves, such as interference and diffraction. Until then, it was assumed that only light behaved as a wave. But in the quantum world everything is basically a wave."


Morsch is part of a group of scientists, including Alessandro Zenesini, Hans Lignier, Donatella Ciampini and Ennio Arimondo, at the University of Pisa in Italy. The group has discovered a way to more efficiently control matter waves in a setup that simulates a solid state system. "Once you have control over a quantum system," Morsch explains, "you can learn any number of things, especially from a fundamental point of view. Additionally, it is worth noting that almost all of our modern technology is related in some way to quantum mechanical principles." The group's technique is described in Physical Review Letters: "Coherent Control of Dressed Matter Waves."

In order to control the matter waves, Morsch and his colleagues created an optical lattice. "We, in effect, create a light crystal," Morsch says. "It's not a true solid, but it mimics the crystal lattice of a solid. It provides us with a sort of model system for solid state applications, allowing us to perform experiments without being bound by the naturally given physical properties of a solid." Once the lattice is created, using lasers and mirrors, the Pisa University group shook the mirrors - and hence the optical lattice - to create a phenomenon known as dynamic localization.

"It's very counter-intuitive," Morsch says of dynamic localization. "Before we shake the lattice, atoms move freely throughout by quantum tunneling. However, once we apply the shaking, they stop moving. For certain values, we can make sure that atoms stay put in one lattice site. We can also create a quantum phase transition so that the system changes its bulk properties when you change a parameter. In our experiment, we create a phase transition by shaking. That is our control over the matter waves."