Julio Barreiro, Max Planck Institute of Quantum Optics & Ludwig Maximilian University of Munich, Germany
Abstract
Quantum simulations and applications of quantum information usually
have experimentally demanding requirements. I will show how these were
circumvented in several experiments with photons and ions by using
resources additional to the systems of interest. In particular, we
take advantage of other degrees of freedom and the environment, either
intrinsic or engineered, through dissipation and decoherence. As an
example, although full quantum dense coding is impossible with linear
optics, we realized it by using entanglement in an additional degree
of freedom of a pair of photons. Another challenging task is quantum
error correction. By dissipatively providing fresh ancillas to the
algorithm, a qubit was repetitively corrected for in three iterations
in a system of trapped ions. In the context of quantum simulations, an
auxiliary qubit was engineered as a controlled environment that
allowed us to demonstrate a toolbox for the simulation of open
systems. These and other experiments will be presented. Finally, I
will discuss how similar approaches can lead to an arbitrary many-body
simulator in a system of ultracold atoms in optical lattices.