TY - JOUR
T1 - Hard limits on the postselectability of optical graph states
AU - Adcock, Jeremy C.
AU - Morley-Short, Sam
AU - Silverstone, Joshua W.
AU - Thompson, Mark G.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Coherent control of large entangled graph states enables a wide variety of quantum information processing tasks, including error-corrected quantum computation. The linear optical approach offers excellent control and coherence, but today most photon sources and entangling gates—required for the construction of large graph states—are probabilistic and rely on postselection. In this work, we provide proofs and heuristics to aid experimental design using postselection. We introduce a versatile design rule for postselectable experiments: drawn as a graph, with qubit as vertices and gates and photon-pair sources as edges, an experiment may only contain cycles with an odd number of sources. We analyse experiments that use photons from postselected photon-pair sources, and lower bound the number of accessible classes of graph state entanglement in the non-degenerate case—graph state entanglement classes that contain a tree are are always accessible. The proportion of graph states accessible by postselection shrinks rapidly, however. We list accessible classes for various resource states up to 9 qubits. Finally, we apply these methods to near-term multi-photon experiments.
AB - Coherent control of large entangled graph states enables a wide variety of quantum information processing tasks, including error-corrected quantum computation. The linear optical approach offers excellent control and coherence, but today most photon sources and entangling gates—required for the construction of large graph states—are probabilistic and rely on postselection. In this work, we provide proofs and heuristics to aid experimental design using postselection. We introduce a versatile design rule for postselectable experiments: drawn as a graph, with qubit as vertices and gates and photon-pair sources as edges, an experiment may only contain cycles with an odd number of sources. We analyse experiments that use photons from postselected photon-pair sources, and lower bound the number of accessible classes of graph state entanglement in the non-degenerate case—graph state entanglement classes that contain a tree are are always accessible. The proportion of graph states accessible by postselection shrinks rapidly, however. We list accessible classes for various resource states up to 9 qubits. Finally, we apply these methods to near-term multi-photon experiments.
KW - entanglement
KW - graph states
KW - linear optical quantum computing
KW - numerical methods
KW - photon sources
KW - photonic experiment design
KW - postselection
UR - http://www.scopus.com/inward/record.url?scp=85060176157&partnerID=8YFLogxK
U2 - 10.1088/2058-9565/aae950
DO - 10.1088/2058-9565/aae950
M3 - Article (Academic Journal)
AN - SCOPUS:85060176157
SN - 2058-9565
VL - 4
JO - Quantum Science and Technology
JF - Quantum Science and Technology
IS - 1
M1 - 015010
ER -