{"id":1108,"date":"2017-06-14T09:55:59","date_gmt":"2017-06-14T07:55:59","guid":{"rendered":"https:\/\/webs.uab.cat\/giq\/seminar\/adaptive-phase-estimation-with-two-mode-squeezed-vacuum-and-parity-measurement\/"},"modified":"2017-06-14T09:55:59","modified_gmt":"2017-06-14T07:55:59","slug":"adaptive-phase-estimation-with-two-mode-squeezed-vacuum-and-parity-measurement","status":"publish","type":"seminar","link":"https:\/\/webs.uab.cat\/giq\/seminar\/adaptive-phase-estimation-with-two-mode-squeezed-vacuum-and-parity-measurement\/","title":{"rendered":"Adaptive phase estimation with two-mode squeezed-vacuum and parity measurement"},"content":{"rendered":"<div>A proposed phase-estimation protocol based on measuring the parity of a two-mode&nbsp;squeezed&nbsp;vacuum&nbsp;state at the output of a Mach-Zehnder interferometer shows that the Cramer-Rao sensitivity&nbsp;is sub-Heisenberg&nbsp;[Phys. Rev. Lett. 104, 103602 (2010)].&nbsp;However, these measurements are problematic,&nbsp;making it unclear if this sensitivity can be obtained with a finite number of measurements. This sensitivity is only for phase near zero, and in this region there is a problem with ambiguity because measurements cannot distinguish the sign of the phase. Here, we consider a finite&nbsp;number of parity measurements, and show that an adaptive technique gives a highly accurate phase estimate regardless of the phase. We show that the Heisenberg limit is reachable, where the number of trials needed for a mean photon number of 1 is approximately 100. We show that the Cramer-Rao sensitivity can be achieved approximately, and the estimation is unambiguous in the interval (-pi\/2, pi\/2).&nbsp;<\/div>\n<p><strong>Z. Huang, K.R. Motes, P.M. Anisimov, J.P. Dowling, D.W. Berry,&nbsp;Physical Review A 95 (5), 053837<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A proposed phase-estimation protocol based on measuring the parity of a two-mode&nbsp;squeezed&nbsp;vacuum&nbsp;state at the output of a Mach-Zehnder interferometer shows that the Cramer-Rao sensitivity&nbsp;is sub-Heisenberg&nbsp;[Phys. Rev. Lett. 104, 103602 (2010)].&nbsp;However, these measurements are problematic,&nbsp;making it unclear if this sensitivity can be obtained with a finite number of measurements. This sensitivity is only for phase near [&hellip;]<\/p>\n","protected":false},"author":20,"featured_media":0,"template":"","class_list":["post-1108","seminar","type-seminar","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/seminar\/1108","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/seminar"}],"about":[{"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/types\/seminar"}],"author":[{"embeddable":true,"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/users\/20"}],"wp:attachment":[{"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/media?parent=1108"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}