  Symmetry considerations are key towards our understanding of the fundamental
laws of Nature. The presence of a symmetry implies that a physical system is
invariant under specific transformations and this invariance may have deep
consequences. For instance, symmetry arguments state that a system will remain
in its initial state if incentives to actions are equally balanced. Here, we
apply this principle to a chain of qubits and show that it is possible to
engineer the symmetries of its Hamiltonian in order to keep quantum information
intrinsically protected from both relaxation and decoherence. We show that the
coherence properties of this system are strongly enhanced relative to those of
its individual components. Such a qubit chain can be realized using a simple
architecture consisting of a relatively small number of superconducting
Josephson junctions.
