Correlated particles generation in non-equilibrium 1D gases

The COPANEQ (Correlated particles generation in non-equilibrium 1D gases) project aims at understanding how a one-dimensional quantum system prepared in a non-equilibrium state evolves. When atomic gases are cooled down to ultralow temperatures, they enter the quantum regime and behave like matterwaves. For example, they exhibit in this regime interferences, as waves of light do. However, in contrast to light, atoms are interacting which each other, which produces correlations between them. These correlations can affect the temporal evolution of the atomic quantum gas. Due to the spreading of correlations, the complexity of the atomic state increases dramatically with time, and therefore the computational resources necessary to calculate this state with a classical computer increase dramatically as well. The most efficient way to investigate how the correlations between atoms impact the dynamics of the quantum gas and which new correlations are generated during this dynamics is therefore to perform the experiment on the atoms. In the COPANEQ project, we will use an atomchip a few cm^2 large microfabricated device allowing precise and versatile generation of electromagnetic fields to trap atoms in an elongated geometry and manipulate their state. The particularity of our experiment is that we can prepare the atoms in an excited motional state, where their mean speed is zero but the distribution of individual velocities differs from the equilibrium state. Due to this non- equilibrium situation, we will trigger a dynamics during which correlations between the atoms velocities will be generated. In particular, we will investigate one situation where we expect the atoms to be emitted by pairs of entangled atoms. In this state the correlations can not be explained by a classical description, but only by quantum mechanics. While production of entangled states of light has been performed since decades and is now a mature technology having for instance applications in quantum cryptography, protocols for generation of pairwise entangled atoms are still to be developed, and The COPANEQ project is part of this effort.