Hiding from the Environment: Decoherence-Free Subspaces

The efficiency of quantum computing relies on the fact that the behavior of quantum mechanical systems follows a different logic than the behavior of classical systems. However, it is in general difficult to find physical systems well decoupled from the environment, which might destroy their quantumness. An important task in quantum information science is therefore the engineering of systems with states hidden from the environment, which are known as decoherence-free states. Another task is finding efficient ways to manipulate them.