Lecturer: Prof. Jonathan Dowling Affiliation: Hearne Institute for Theoretical Physics, Department of Physics & Astronomy, Louisiana State University Abstract: Quantum number-path entanglement is a resource for super-sensitive quantum metrology and in particular provides for sub-shot noise or even Heisenberg-limited sensitivity. However, such number-path entanglement has thought to have been resource intensive to create in the first place --- typically requiring either very strong nonlinearities, or nondeterministic preparation schemes with feed-forward, which are difficult to implement. Very recently, arising from the study of quantum random walks with multi-photon walkers, as well as the study of the computational complexity of passive linear optical interferometers fed with single-photon inputs, it has been shown that such passive linear optical devices generate a super- exponentially large amount of number-path entanglement. A logical question to ask is whether this entanglement may be exploited for quantum metrology. We answer that question here in the affirmative by showing that a simple, passive, linear- optical interferometer --- fed with only uncorrelated, single-photon inputs, coupled with simple, single- mode, disjoint photo- detection --- is capable of significantly beating the shot-noise limit. Our result implies a pathway forward to practical quantum metrology with readily available technology. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://hangouts.google.com/hangouts/_/mail.huji.ac.il/quantum?hceid=bWF...