{"id":1136,"date":"2012-10-09T11:04:33","date_gmt":"2012-10-09T16:04:33","guid":{"rendered":"https:\/\/scottaaronson.blog\/?p=1136"},"modified":"2016-12-10T04:25:13","modified_gmt":"2016-12-10T09:25:13","slug":"quantum-computing-in-the-newz","status":"publish","type":"post","link":"https:\/\/scottaaronson.blog\/?p=1136","title":{"rendered":"Quantum computing in the newz"},"content":{"rendered":"

Update (10\/10).<\/strong><\/span> \u00a0In case anyone is interested, here’s a comment<\/a> I posted over at Cosmic Variance, responding to a question about the relevance of Haroche and Wineland’s work for the interpretation of quantum mechanics.<\/p>\n

The experiments of Haroche and Wineland, phenomenal as they are, have zero implications one way or the other for the MWI\/Copenhagen debate (nor, for that matter, for third-party candidates like Bohm\u00a0\ud83d\ude42 ). In other words, while doing these experiments is a tremendous challenge requiring lots of new ideas, no sane proponent of\u00a0any<\/em>\u00a0interpretation would have made predictions for their outcomes other than the ones that were observed. To do an experiment about which the proponents of different interpretations might\u00a0conceivably<\/em>\u00a0diverge, it would be necessary to try to demonstrate quantum interference in a much,\u00a0much<\/em>\u00a0larger system \u2014 for example, a brain or an artificially-intelligent quantum computer. And even then, the different interpretations arguably don\u2019t make differing predictions about what the published\u00a0results<\/em>\u00a0of such an experiment would be. If they differ at all, it\u2019s in what they claim, or refuse to claim, about the experiences of the\u00a0subject<\/em>\u00a0of the experiment, while the experiment is underway. But if quantum mechanics is right, then the subject would necessarily have\u00a0forgotten<\/em>\u00a0those experiences by the end of the experiment \u2014 since otherwise, no interference could be observed!<\/p>\n

So, yeah, barring any change to the framework of quantum mechanics itself, it seems likely that people will be arguing about its interpretation forever. Sorry about that.\u00a0\ud83d\ude42<\/p><\/blockquote>\n

\n

Where is<\/strong> he? \u00a0So many wild claims being leveled, so many opportunities to set the record straight, and yet he completely fails to respond. \u00a0Where’s the passion he showed just four years ago? \u00a0Doesn’t he realize that having the facts on his side isn’t enough, has never been enough? \u00a0It’s as if his mind is off somewhere else, or as if he’s tired of his role as a public communicator and no longer feels like performing it. \u00a0Is his silence part of some devious master plan? \u00a0Is he simply suffering from a lack of oxygen in the brain? \u00a0What’s going on?<\/em><\/p>\n

Yeah, yeah, I know. \u00a0I should blog more. \u00a0I’ll have more coming soon, but for now, two big announcements related to quantum computing.<\/p>\n

Today the 2012 Nobel Prize in Physics<\/a> was awarded jointly to Serge Haroche and David Wineland, for “for ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems.”<\/em>\u00a0 I’m not very familiar with Haroche’s work, but I’ve known of Wineland for a long time as possibly the top quantum computing experimentalist in the business, setting one record after another in trapped-ion experiments. \u00a0In awarding this prize, the Swedes have recognized the phenomenal advances in atomic, molecular, and optical physics that have already happened<\/em>\u00a0over the last two decades, largely motivated by the goal of building a scalable quantum computer (along with other, not entirely unrelated goals, like more accurate atomic clocks). \u00a0In so doing, they’ve given what’s arguably the first-ever “Nobel Prize for quantum computing research,” without\u00a0violating their policy to reward only work that’s been directly confirmed by experiment. \u00a0Huge congratulations to Haroche and Wineland!!<\/p>\n

In other quantum computing developments: yes, I’m aware of the latest news from D-Wave<\/a>, which includes millions of dollars in new funding from Jeff Bezos (the founder of Amazon.com<\/a>, recipients of a large fraction of my salary). \u00a0Despite having officially retired<\/a> as Chief D-Wave Skeptic, I posted a comment<\/a> on Tom Simonite’s article in MIT Technology Review<\/em>, and also sent the following email to a journalist.<\/p>\n

I’m probably not a good person to comment on the “business” aspects of\u00a0D-Wave. \u00a0They’ve been extremely successful raising money in the past,\u00a0so it’s not surprising to me that they continue to be successful. \u00a0For\u00a0me, three crucial points to keep in mind are:<\/p>\n

(1) D-Wave still hasn’t demonstrated 2-qubit entanglement, which I see\u00a0as one of the non-negotiable “sanity checks” for scalable quantum\u00a0computing. \u00a0In other words: if you’re producing entanglement, then you\u00a0might or might not be getting quantum speedups, but if you’re not\u00a0producing entanglement, then our current understanding fails to\u00a0explain how you could possibly<\/em> be getting quantum speedups.<\/p>\n

(2) Unfortunately, the fact that D-Wave’s machine solves some\u00a0particular problem in some amount of time, and a specific classical\u00a0computer running (say) simulated annealing took more time, is not (by\u00a0itself) good evidence that D-Wave was achieving the speedup because<\/em> of\u00a0quantum effects. \u00a0Keep in mind that D-Wave has now spent ~$100 million\u00a0and ~10 years of effort on a highly-optimized, special-purpose computer\u00a0for solving one specific optimization problem. \u00a0So, as I like to put\u00a0it, quantum effects could be playing the role of “the stone in\u00a0a stone soup”: attracting interest, investment, talented people, etc. to build\u00a0a device that performs quite well at its specialized task, but not\u00a0ultimately because<\/em> of quantum coherence in that device.<\/p>\n

(3) The quantum algorithm on which D-Wave’s business model is\u00a0based — namely, the quantum adiabatic algorithm — has the property\u00a0that it “degrades gracefully” to classical simulated annealing when\u00a0the decoherence rate goes up. \u00a0This, fundamentally, is the thing that\u00a0makes it difficult to know what role, if any, quantum coherence is\u00a0playing in the performance of their device. \u00a0If they were trying to\u00a0use Shor’s algorithm to factor numbers, the situation would be much\u00a0more clear-cut: a decoherent version of Shor’s algorithm just gives\u00a0you random garbage. \u00a0But a decoherent version of the adiabatic\u00a0algorithm still gives you a pretty good (but now essentially\u00a0“classical”) algorithm, and that’s what makes it hard to understand\u00a0what’s going on here.<\/p>\n

As I’ve said before, I no longer feel like playing an adversarial\u00a0role. \u00a0I really, genuinely hope D-Wave succeeds. \u00a0But the burden is on\u00a0them to demonstrate that their device uses quantum effects to obtain a\u00a0speedup, and they still haven’t met that burden. \u00a0When and if the\u00a0situation changes, I’ll be happy to say so. \u00a0Until then, though, I\u00a0seem to have the unenviable task of repeating the same observation\u00a0over and over, for 6+ years, and confirming that, no, the latest sale,\u00a0VC round, announcement of another “application” (which, once again,\u00a0might or might not exploit quantum effects), etc., hasn’t\u00a0changed the truth of that observation.<\/p>\n

Best,
\nScott<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"

Update (10\/10). \u00a0In case anyone is interested, here’s a comment I posted over at Cosmic Variance, responding to a question about the relevance of Haroche and Wineland’s work for the interpretation of quantum mechanics. The experiments of Haroche and Wineland, phenomenal as they are, have zero implications one way or the other for the MWI\/Copenhagen […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"jetpack_seo_schema_type":"","_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"{title}\n\n{excerpt}\n\n{url}","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"_wpas_customize_per_network":false,"jetpack_post_was_ever_published":false},"categories":[4],"tags":[],"class_list":["post-1136","post","type-post","status-publish","format-standard","hentry","category-quantum"],"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=\/wp\/v2\/posts\/1136","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1136"}],"version-history":[{"count":5,"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=\/wp\/v2\/posts\/1136\/revisions"}],"predecessor-version":[{"id":3009,"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=\/wp\/v2\/posts\/1136\/revisions\/3009"}],"wp:attachment":[{"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1136"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1136"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scottaaronson.blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1136"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}