Measurement<\/p>\n\n\n\n
Some issues regarding measurement in quantum circuits are to be noted<\/p>\n\n\n\n
here, which you can prove for yourself with some thought:<\/p>\n\n\n\n
1. Deferred measurement: when measurements are made in a circuit<\/p>\n\n\n\n
and after that further gates are implemented (whether controlled by the<\/p>\n\n\n\n
measurement or no), it can always be assumed that the measurement is<\/p>\n\n\n\n
made at the very end of the circuit. This is saying that measurement can<\/p>\n\n\n\n
always be assumed to have been deferred to the end of the computation<\/p>\n\n\n\n
without any e\ufb00ect on the results.<\/p>\n\n\n\n
2. Implicit measurement: any quantum wires that are left at the end<\/p>\n\n\n\n
of the circuit can be assumed to have been measured: their states will<\/p>\n\n\n\n
anyway have collapsed when other wires are measured for the purpose<\/p>\n\n\n\n
of readout.<\/p>\n\n\n\n
3. Irreversibility: quantum measurement is in general an irreversible pro-<\/p>\n\n\n\n
cess, and if included in a circuit, will make it irreversible. However, if<\/p>\n\n\n\n
the measurement reveals no information about the state being measured<\/p>\n\n\n\n
(refer for instance to the teleportation protocol of Example 7.2) then the<\/p>\n\n\n\n
circuit is still reversible!<\/p>\n\n\n\n
Many of the results in this chapter are discussed in the paper by Barenco<\/p>\n\n\n\n
et al. [3], and in the book by Mermin [48].<\/p>\n","protected":false},"excerpt":{"rendered":"
Measurement Some issues regarding measurement in quantum circuits are to be noted here, which you can prove for yourself with some thought: 1. Deferred measurement: when measurements are made in a circuit and after that further gates are implemented (whether controlled by the measurement or no), it can always be assumed that the measurement is […]<\/p>\n","protected":false},"author":1,"featured_media":4041,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[496],"tags":[],"class_list":["post-4078","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-quantum-gates-and-circuits"],"jetpack_featured_media_url":"https:\/\/workhouse.sweetdishy.com\/wp-content\/uploads\/2024\/09\/quantum-2.png","_links":{"self":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/4078","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/comments?post=4078"}],"version-history":[{"count":1,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/4078\/revisions"}],"predecessor-version":[{"id":4079,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/4078\/revisions\/4079"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media\/4041"}],"wp:attachment":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media?parent=4078"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/categories?post=4078"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/tags?post=4078"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}