Stephen D. Bartlett

TL;DR: This paper reviews the role of reference framesmore and superselection rules in the theory of quantum-information processing and finds that quantum unspeakable information becomes a new kind of resource that can be manipulated, depleted, quantified, etc.

TL;DR: Two tomography schemes that scale much more favourably than direct tomography with system size are presented, one of them requires unitary operations on a constant number of subsystems, whereas the other requires only local measurements together with more elaborate post-processing.

TL;DR: This work generalizes Kitaev’s phase estimation algorithm using adaptive measurement theory to achieve a standard deviation scaling at the Heisenberg limit, representing a drastic reduction in the complexity of achieving quantum-enhanced measurement precision.

TL;DR: It is obtained that any quantum process that begins with unentangled Gaussian states, performs only transformations generated by Hamiltonians that are quadratic in the canonical operators, and involves only measurements of canonical operators and suitable operations conditioned on these measurements can be simulated efficiently on a classical computer.

TL;DR: It is shown experimentally and theoretically that qutrits with even a small amount of decoherence cannot offer increased security over qubits, and model the sensitivity of this to mixture shows that this cannot be done.