{"id":1228,"date":"2021-02-17T17:33:21","date_gmt":"2021-02-17T15:33:21","guid":{"rendered":"https:\/\/webs.uab.cat\/giq\/seminar\/bosonic-data-hiding-power-of-linear-vs-non-linear-optics\/"},"modified":"2021-02-17T17:33:21","modified_gmt":"2021-02-17T15:33:21","slug":"bosonic-data-hiding-power-of-linear-vs-non-linear-optics","status":"publish","type":"seminar","link":"https:\/\/webs.uab.cat\/giq\/seminar\/bosonic-data-hiding-power-of-linear-vs-non-linear-optics\/","title":{"rendered":"Bosonic data hiding: power of linear vs non-linear optics"},"content":{"rendered":"<p><font face=\"monospace\">We show that the positivity of the Wigner function&nbsp;of Gaussian states and measurements provides an elegant way&nbsp;to bound the discriminating power of \u00ablinear optics\u00bb, which&nbsp;we formalise as Gaussian measurement operations augmented by&nbsp;classical (feed-forward) communication (GOCC). This allows&nbsp;us to reproduce and generalise the result of Takeoka and Sasaki&nbsp;[PRA 78:022320, 2008], which tightly characterises the GOCC&nbsp;norm distance of coherent states, separating it from the&nbsp;optimal distinguishability according to Helstrom&#8217;s theorem.<\/font><\/p>\n<p><font face=\"monospace\">Furthermore, invoking ideas from classical and quantum Shannon&nbsp;theory we show that there are states, each a probabilistic&nbsp;mixture of multi-mode coherent states, which are exponentially&nbsp;reliably discriminated in principle, but appear exponentially&nbsp;close judging from the output of GOCC measurements. In analogy&nbsp;to LOCC data hiding, which shows an irreversibility in the&nbsp;preparation and discrimination of states by the restricted&nbsp;class of local operations and classical communication (LOCC),&nbsp;we call the present effect GOCC data hiding.<\/font><\/p>\n<p><font face=\"monospace\">We also present general bounds in the opposite direction,&nbsp;guaranteeing a minimum of distinguishability under measurements with positive Wigner function, for any bounded-energy states&nbsp;that are Helstrom distinguishable. We conjecture that a similar&nbsp;bound holds for GOCC measurements.<\/font><\/p>\n","protected":false},"excerpt":{"rendered":"<p>We show that the positivity of the Wigner function&nbsp;of Gaussian states and measurements provides an elegant way&nbsp;to bound the discriminating power of \u00ablinear optics\u00bb, which&nbsp;we formalise as Gaussian measurement operations augmented by&nbsp;classical (feed-forward) communication (GOCC). This allows&nbsp;us to reproduce and generalise the result of Takeoka and Sasaki&nbsp;[PRA 78:022320, 2008], which tightly characterises the GOCC&nbsp;norm distance [&hellip;]<\/p>\n","protected":false},"author":20,"featured_media":0,"template":"","class_list":["post-1228","seminar","type-seminar","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/seminar\/1228","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=1228"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}