  Quantum correlations in an entangled many-body system are capable of storing
information. Even when the information is injected by a local unitary operation
to the system, the entanglement delocalizes it. In a recent study on
multiple-qubit systems, it is shown that a virtual qubit defined in the
correlation space plays a role of perfect storage of delocalized information,
which is called a quantum information capsule (QIC). In order to enhance the
capacity of quantum information storage, it is crucial to formulate the cases
for multiple-qudit systems and continuous-variable (CV) systems. We
analytically prove that it is possible to construct a QIC for general write
operations of the systems. It turns out that the extension to quantum field
theory is achievable. For Gaussian states, we explicitly construct a QIC for
shift write operations. We analyze the time-evolution of QIC in a CV system to
demonstrate the diffusion of information in entangled pure states.
