  Hyperentanglement, defined as the simultaneous entanglement in several
independent degrees of freedom (DOFs) of a quantum system, is a fascinating
resource in quantum information processing with its outstanding merits. Here we
propose heralded hyperentanglement concentration protocols (hyper-ECPs) to
concentrate an unknown partially less polarization-spatial hyperentangled Bell
state with available linear optics and common single-photon detectors. By
introducing time-delay DOFs, the schemes are highly efficient in that the
success of the scheme can be accurately heralded by the detection signatures,
and postselection techniques or photon-number-resolving detectors, necessary
for previous experiments, are not required. Additionally, our linear optical
architectures allow certain states, where concentration fails, to be
recyclable, and a trick makes the success probabilities of our schemes higher
than those of previous linear optical hyper-ECPs.
