{"id":147234,"date":"2013-09-27T15:14:27","date_gmt":"2013-09-27T19:14:27","guid":{"rendered":"\/gazette\/?p=147234"},"modified":"2018-11-13T15:56:16","modified_gmt":"2018-11-13T20:56:16","slug":"seeing-light-in-a-new-way","status":"publish","type":"post","link":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/","title":{"rendered":"Seeing light in a new way"},"content":{"rendered":"\n\t
\"\"

\u201cIt\u2019s not an inapt analogy to compare this to light sabers," says Professor Mikhail Lukin when describing the creation of photonic molecules. "When these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d <\/p>

File photo by Kris Snibbe\/Harvard Staff Photographer<\/p><\/figcaption><\/figure>\n\n\t

\n\t\t\t\n\t\t\tScience & Tech\t\t<\/a>\n\t\t\n\t\t

\n\t\tSeeing light in a new way\t<\/h1>\n\n\t\n\t\t\t<\/div>\n\t\t\n\t
\n\t\t
\n\t\t\t
\n\t\t\t\t\t

\n\t\tPeter Reuell\t<\/p>\n\t\t\t

\n\t\t\tHarvard Staff Writer\t\t<\/p>\n\t\t\t\t\t<\/address>\n\t\t<\/div>\n\n\t\t

\n\t\t\tScientists coax photons to bind into molecules for first time\t\t<\/h2>\n\t\t\n<\/header>\n\n\n\n
\n\n\n\t\t

Scientists from Harvard University and the Massachusetts Institute of Technology (MIT) are challenging the conventional wisdom about light, and they didn\u2019t need to go to a galaxy far, far away to do it.<\/p>\n

Working with colleagues at the Harvard-MIT Center for Ultracold Atoms<\/a>, a group led by Harvard Professor of Physics Mikhail Lukin<\/a> and MIT Professor of Physics Vladan Vuletic managed to coax photons into binding together to form molecules \u2014 a state of matter that until recently had been purely theoretical. The work is described in a Sept. 25 paper in Nature.<\/p>\n

The discovery, Lukin said, runs contrary to decades of accepted wisdom about the nature of light.\u00a0 Photons have long been described as massless particles that don\u2019t interact with each other. Shine two laser beams at each other, he said, and they simply pass through one another.<\/p>\n

Photonic molecules, however, behave less like traditional lasers and more like something you might find in science fiction: the light saber.<\/p>\n

\u201cMost of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other,\u201d Lukin said. \u201cWhat we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn\u2019t been observed.<\/p>\n

\u201cIt\u2019s not an inapt analogy to compare this to light sabers,\u201d Lukin said. \u201cWhen these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d<\/p>\n

To get the normally massless photons to bind to each other, Lukin and his colleagues, including Harvard postdoctoral fellow Ofer Firstenberg, former Harvard doctoral student Alexey Gorshkov, and MIT graduate students Thibault Peyronel and Qiu Liang, couldn\u2019t rely on something like the Force<\/a>. They instead turned to a set of extreme conditions.<\/p>\n

Researchers began by pumping rubidium atoms into a vacuum chamber, then used lasers to cool the cloud of atoms to just a few degrees above absolute zero. Using extremely weak laser pulses, they fired single photons into the cloud of atoms.<\/p>\n

As the photons enter the cloud, Lukin said, their energy excites atoms along its path, causing the photons to slow dramatically. As the photons move through the cloud, that energy is handed off from atom to atom, and eventually exits the cloud with the photon.<\/p>\n

\u201cWhen the photon exits the medium, its identity is preserved,\u201d Lukin said. \u201cIt\u2019s the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together. But when it exits, it\u2019s still light. The process that takes place is the same. It\u2019s just a bit more extreme. The light is slowed considerably, and a lot more energy is given away than during refraction.\u201d<\/p>\n

When Lukin and his colleagues fired two photons into the cloud, they were surprised to see them exit as a single molecule.<\/p>\n

The reason they form the never-before-seen molecules? \u00a0It\u2019s an effect called a Rydberg blockade, Lukin said, which means that when an atom is excited, nearby atoms cannot be excited to the same degree. In practice, the effect means that as two photons enter the atomic cloud, the first excites an atom, but it must move forward before the second photon can excite nearby atoms.<\/p>\n

The result, he said, is that the two photons push and pull each other through the cloud as their energy is handed off from one atom to the next.<\/p>\n

\u201cIt\u2019s a photonic interaction that\u2019s mediated by the atomic interaction,\u201d Lukin said. \u201cThat makes these two photons behave like a molecule, and when they exit the medium they\u2019re much more likely to do so together than as single photons.\u201d<\/p>\n

While the effect is unusual, it has some practical applications.<\/p>\n

\u201cWe do this for fun, and because we\u2019re pushing the frontiers of science,\u201d Lukin said. \u201cBut it feeds into the bigger picture of what we\u2019re doing because photons remain the best possible means to carry quantum information. The handicap, though, has been that photons don\u2019t interact with each other.\u201d<\/p>\n

To build a quantum computer, he said, researchers need to build a system that can preserve quantum information and process it using quantum logic operations. The challenge, however, is that quantum logic requires interactions between individual quanta so that quantum systems can be switched to perform information processing.<\/p>\n

\u201cWhat we demonstrate with this process allows us to do that,\u201d Lukin said. \u201cBefore we make a useful, practical quantum switch or photonic logic gate, we have to improve the performance. So it\u2019s still at the proof-of-concept level, but this is an important step. The physical principles we\u2019ve established here are important.\u201d<\/p>\n

The system could even be useful in classical computing, Lukin said, considering the power-dissipation challenges that chip-makers face. A number of companies, including IBM, have worked to develop systems that rely on optical routers that convert light signals into electrical signals, but those systems face their own hurdles.<\/p>\n

Lukin also suggested that the system might one day even be used to create complex, 3-D structures, such as crystals, wholly out of light.<\/p>\n

\u201cWhat it will be useful for we don\u2019t know yet. But it\u2019s a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules\u2019 properties,\u201d he said.<\/p>\n\n\n<\/div>\n\n\t\t","protected":false},"excerpt":{"rendered":"

Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, Professor of Physics Mikhail Lukin and post-doctoral fellow Ofer Firstenberg have managed to coax photons into binding together to form molecules \u2014 a state of matter that, until recently, had been purely theoretical.<\/p>\n","protected":false},"author":105622744,"featured_media":147248,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"gz_ga_pageviews":15,"gz_ga_lastupdated":"2022-04-07 04:23","document_color_palette":"crimson","author":"Peter Reuell","affiliation":"Harvard Staff Writer","_category_override":"","_yoast_wpseo_primary_category":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1387],"tags":[5040,5043,12941,13050,13378,15359,16272,21213,21723,21727,22191,24120,24404,25205,25571,26119,26789,27327,27507,27508,27550,28500,29235],"gazette-formats":[],"series":[],"class_list":["post-147234","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-science-technology","tag-atom","tag-atomic-cloud","tag-faculty-of-arts-and-sciences","tag-fas","tag-firstenberg","tag-harvard","tag-harvard-mit-center-for-ultracold-atoms","tag-laser","tag-light","tag-light-saber","tag-lukin","tag-mikhail-lukin","tag-molecule","tag-nature","tag-news-hub","tag-ofer-firstenberg","tag-particle","tag-peter-reuell","tag-photon","tag-photonic-molecule","tag-physics","tag-quantum","tag-reuell"],"yoast_head":"\nSeeing light in a new way — Harvard Gazette<\/title>\n<meta name=\"description\" content=\"Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, Professor of Physics Mikhail Lukin and post-doctoral fellow Ofer Firstenberg have managed to coax photons into binding together to form molecules \u2014 a state of matter that, until recently, had been purely theoretical.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Seeing light in a new way — Harvard Gazette\" \/>\n<meta property=\"og:description\" content=\"Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, Professor of Physics Mikhail Lukin and post-doctoral fellow Ofer Firstenberg have managed to coax photons into binding together to form molecules \u2014 a state of matter that, until recently, had been purely theoretical.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/\" \/>\n<meta property=\"og:site_name\" content=\"Harvard Gazette\" \/>\n<meta property=\"article:published_time\" content=\"2013-09-27T19:14:27+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2018-11-13T20:56:16+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2013\/09\/lukin_605.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"605\" \/>\n\t<meta property=\"og:image:height\" content=\"403\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"harvardgazette\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/\"},\"author\":{\"name\":\"harvardgazette\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#\/schema\/person\/78d028cf624923e92682268709ffbc4b\"},\"headline\":\"Seeing light in a new way\",\"datePublished\":\"2013-09-27T19:14:27+00:00\",\"dateModified\":\"2018-11-13T20:56:16+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/\"},\"wordCount\":1029,\"publisher\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#organization\"},\"image\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg\",\"keywords\":[\"atom\",\"atomic cloud\",\"Faculty of Arts and Sciences\",\"FAS\",\"Firstenberg\",\"Harvard\",\"Harvard-MIT Center for Ultracold Atoms\",\"Laser\",\"light\",\"light saber\",\"Lukin\",\"Mikhail Lukin\",\"molecule\",\"Nature\",\"News Hub\",\"Ofer Firstenberg\",\"particle\",\"Peter Reuell\",\"photon\",\"photonic molecule\",\"Physics\",\"quantum\",\"Reuell\"],\"articleSection\":[\"Science & Tech\"],\"inLanguage\":\"en-US\",\"copyrightYear\":\"2013\",\"copyrightHolder\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#organization\"}},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/\",\"url\":\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/\",\"name\":\"Seeing light in a new way — Harvard Gazette\",\"isPartOf\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg\",\"datePublished\":\"2013-09-27T19:14:27+00:00\",\"dateModified\":\"2018-11-13T20:56:16+00:00\",\"description\":\"Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, Professor of Physics Mikhail Lukin and post-doctoral fellow Ofer Firstenberg have managed to coax photons into binding together to form molecules \u2014 a state of matter that, until recently, had been purely theoretical.\",\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#primaryimage\",\"url\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg\",\"contentUrl\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg\",\"width\":605,\"height\":403},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#website\",\"url\":\"https:\/\/news.harvard.edu\/gazette\/\",\"name\":\"Harvard Gazette\",\"description\":\"Official news from Harvard University covering innovation in teaching, learning, and research\",\"publisher\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/news.harvard.edu\/gazette\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#organization\",\"name\":\"The Harvard Gazette\",\"url\":\"https:\/\/news.harvard.edu\/gazette\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg\",\"contentUrl\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg\",\"width\":164,\"height\":64,\"caption\":\"The Harvard Gazette\"},\"image\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#\/schema\/logo\/image\/\"}},{\"@type\":\"Person\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#\/schema\/person\/78d028cf624923e92682268709ffbc4b\",\"name\":\"harvardgazette\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Seeing light in a new way — Harvard Gazette","description":"Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, Professor of Physics Mikhail Lukin and post-doctoral fellow Ofer Firstenberg have managed to coax photons into binding together to form molecules \u2014 a state of matter that, until recently, had been purely theoretical.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/","og_locale":"en_US","og_type":"article","og_title":"Seeing light in a new way — Harvard Gazette","og_description":"Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, Professor of Physics Mikhail Lukin and post-doctoral fellow Ofer Firstenberg have managed to coax photons into binding together to form molecules \u2014 a state of matter that, until recently, had been purely theoretical.","og_url":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/","og_site_name":"Harvard Gazette","article_published_time":"2013-09-27T19:14:27+00:00","article_modified_time":"2018-11-13T20:56:16+00:00","og_image":[{"width":605,"height":403,"url":"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2013\/09\/lukin_605.jpg","type":"image\/jpeg"}],"author":"harvardgazette","twitter_card":"summary_large_image","schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#article","isPartOf":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/"},"author":{"name":"harvardgazette","@id":"https:\/\/news.harvard.edu\/gazette\/#\/schema\/person\/78d028cf624923e92682268709ffbc4b"},"headline":"Seeing light in a new way","datePublished":"2013-09-27T19:14:27+00:00","dateModified":"2018-11-13T20:56:16+00:00","mainEntityOfPage":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/"},"wordCount":1029,"publisher":{"@id":"https:\/\/news.harvard.edu\/gazette\/#organization"},"image":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#primaryimage"},"thumbnailUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg","keywords":["atom","atomic cloud","Faculty of Arts and Sciences","FAS","Firstenberg","Harvard","Harvard-MIT Center for Ultracold Atoms","Laser","light","light saber","Lukin","Mikhail Lukin","molecule","Nature","News Hub","Ofer Firstenberg","particle","Peter Reuell","photon","photonic molecule","Physics","quantum","Reuell"],"articleSection":["Science & Tech"],"inLanguage":"en-US","copyrightYear":"2013","copyrightHolder":{"@id":"https:\/\/news.harvard.edu\/gazette\/#organization"}},{"@type":"WebPage","@id":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/","url":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/","name":"Seeing light in a new way — Harvard Gazette","isPartOf":{"@id":"https:\/\/news.harvard.edu\/gazette\/#website"},"primaryImageOfPage":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#primaryimage"},"image":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#primaryimage"},"thumbnailUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg","datePublished":"2013-09-27T19:14:27+00:00","dateModified":"2018-11-13T20:56:16+00:00","description":"Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, Professor of Physics Mikhail Lukin and post-doctoral fellow Ofer Firstenberg have managed to coax photons into binding together to form molecules \u2014 a state of matter that, until recently, had been purely theoretical.","inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/#primaryimage","url":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg","contentUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg","width":605,"height":403},{"@type":"WebSite","@id":"https:\/\/news.harvard.edu\/gazette\/#website","url":"https:\/\/news.harvard.edu\/gazette\/","name":"Harvard Gazette","description":"Official news from Harvard University covering innovation in teaching, learning, and research","publisher":{"@id":"https:\/\/news.harvard.edu\/gazette\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/news.harvard.edu\/gazette\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/news.harvard.edu\/gazette\/#organization","name":"The Harvard Gazette","url":"https:\/\/news.harvard.edu\/gazette\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/news.harvard.edu\/gazette\/#\/schema\/logo\/image\/","url":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg","contentUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg","width":164,"height":64,"caption":"The Harvard Gazette"},"image":{"@id":"https:\/\/news.harvard.edu\/gazette\/#\/schema\/logo\/image\/"}},{"@type":"Person","@id":"https:\/\/news.harvard.edu\/gazette\/#\/schema\/person\/78d028cf624923e92682268709ffbc4b","name":"harvardgazette"}]}},"parsely":{"version":"1.1.0","canonical_url":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/","smart_links":{"inbound":0,"outbound":0},"traffic_boost_suggestions_count":0,"meta":{"@context":"https:\/\/schema.org","@type":"NewsArticle","headline":"Seeing light in a new way","url":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/","mainEntityOfPage":{"@type":"WebPage","@id":"https:\/\/news.harvard.edu\/gazette\/story\/2013\/09\/seeing-light-in-a-new-way\/"},"thumbnailUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg?w=150","image":{"@type":"ImageObject","url":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg"},"articleSection":"Science & Tech","author":[{"@type":"Person","name":"harvardgazette"}],"creator":["harvardgazette"],"publisher":{"@type":"Organization","name":"Harvard Gazette","logo":"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg"},"keywords":["atom","atomic cloud","faculty of arts and sciences","fas","firstenberg","harvard","harvard-mit center for ultracold atoms","laser","light","light saber","lukin","mikhail lukin","molecule","nature","news hub","ofer firstenberg","particle","peter reuell","photon","photonic molecule","physics","quantum","reuell"],"dateCreated":"2013-09-27T19:14:27Z","datePublished":"2013-09-27T19:14:27Z","dateModified":"2018-11-13T20:56:16Z"},"rendered":"<script type=\"application\/ld+json\" class=\"wp-parsely-metadata\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@type\":\"NewsArticle\",\"headline\":\"Seeing light in a new way\",\"url\":\"https:\\\/\\\/news.harvard.edu\\\/gazette\\\/story\\\/2013\\\/09\\\/seeing-light-in-a-new-way\\\/\",\"mainEntityOfPage\":{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/news.harvard.edu\\\/gazette\\\/story\\\/2013\\\/09\\\/seeing-light-in-a-new-way\\\/\"},\"thumbnailUrl\":\"https:\\\/\\\/news.harvard.edu\\\/wp-content\\\/uploads\\\/2013\\\/09\\\/lukin_605.jpg?w=150\",\"image\":{\"@type\":\"ImageObject\",\"url\":\"https:\\\/\\\/news.harvard.edu\\\/wp-content\\\/uploads\\\/2013\\\/09\\\/lukin_605.jpg\"},\"articleSection\":\"Science & Tech\",\"author\":[{\"@type\":\"Person\",\"name\":\"harvardgazette\"}],\"creator\":[\"harvardgazette\"],\"publisher\":{\"@type\":\"Organization\",\"name\":\"Harvard Gazette\",\"logo\":\"https:\\\/\\\/news.harvard.edu\\\/gazette\\\/wp-content\\\/uploads\\\/2023\\\/12\\\/Harvard_Gazette_logo.svg\"},\"keywords\":[\"atom\",\"atomic cloud\",\"faculty of arts and sciences\",\"fas\",\"firstenberg\",\"harvard\",\"harvard-mit center for ultracold atoms\",\"laser\",\"light\",\"light saber\",\"lukin\",\"mikhail lukin\",\"molecule\",\"nature\",\"news hub\",\"ofer firstenberg\",\"particle\",\"peter reuell\",\"photon\",\"photonic molecule\",\"physics\",\"quantum\",\"reuell\"],\"dateCreated\":\"2013-09-27T19:14:27Z\",\"datePublished\":\"2013-09-27T19:14:27Z\",\"dateModified\":\"2018-11-13T20:56:16Z\"}<\/script>","tracker_url":"https:\/\/cdn.parsely.com\/keys\/news.harvard.edu\/p.js"},"jetpack_featured_media_url":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2013\/09\/lukin_605.jpg","has_blocks":true,"block_data":{"0":{"blockName":"harvard-gazette\/article-header","attrs":{"blockColorPalette":"","coloredHeading":"","creditText":"File photo by Kris Snibbe\/Harvard Staff Photographer","displayDetails":"","displayTitle":"","categoryId":1387,"mediaAlt":"","mediaCaption":"\u201cIt\u2019s not an inapt analogy to compare this to light sabers,\" says Professor Mikhail Lukin when describing the creation of photonic molecules. \"When these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d ","mediaId":147248,"mediaSize":"full","mediaType":"image","mediaUrl":"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2013\/09\/lukin_605.jpg","poster":"","title":"Seeing light in a new way","subheading":"Scientists coax photons to bind into molecules for first time","centeredImage":true,"className":"is-style-full-width-text-below","mediaHeight":403,"mediaWidth":605,"backgroundFixed":false,"backgroundTone":"light","coloredBackground":false,"displayOverlay":true,"fadeInText":false,"isAmbient":false,"mediaLength":"","mediaPosition":"","posterText":"","titleAbove":false,"useUncroppedImage":false,"lock":[],"metadata":[]},"innerBlocks":[],"innerHTML":"<figure class=\"wp-block-image\"><img alt=\"\" height=\"403\" loading=\"eager\" src=\"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2013\/09\/lukin_605.jpg\" width=\"605\"\/><figcaption class=\"wp-element-caption\"><p class=\"wp-element-caption--caption\">\u201cIt\u2019s not an inapt analogy to compare this to light sabers," says Professor Mikhail Lukin when describing the creation of photonic molecules. "When these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d <\/p><p class=\"wp-element-caption--credit\">File photo by Kris Snibbe\/Harvard Staff Photographer<\/p><\/figcaption><\/figure>\n","innerContent":["<figure class=\"wp-block-image\"><img alt=\"\" height=\"403\" loading=\"eager\" src=\"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2013\/09\/lukin_605.jpg\" width=\"605\"\/><figcaption class=\"wp-element-caption\"><p class=\"wp-element-caption--caption\">\u201cIt\u2019s not an inapt analogy to compare this to light sabers," says Professor Mikhail Lukin when describing the creation of photonic molecules. "When these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d <\/p><p class=\"wp-element-caption--credit\">File photo by Kris Snibbe\/Harvard Staff Photographer<\/p><\/figcaption><\/figure>\n"],"rendered":"<header\n\tclass=\"wp-block-harvard-gazette-article-header alignfull article-header is-style-full-width-text-below centered-image\"\n\tstyle=\" \"\n>\n\t<figure class=\"wp-block-image\"><img alt=\"\" height=\"403\" loading=\"eager\" src=\"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2013\/09\/lukin_605.jpg\" width=\"605\"\/><figcaption class=\"wp-element-caption\"><p class=\"wp-element-caption--caption\">\u201cIt\u2019s not an inapt analogy to compare this to light sabers," says Professor Mikhail Lukin when describing the creation of photonic molecules. "When these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d <\/p><p class=\"wp-element-caption--credit\">File photo by Kris Snibbe\/Harvard Staff Photographer<\/p><\/figcaption><\/figure>\n\n\t<div class=\"article-header__content\">\n\t\t\t<a\n\t\t\tclass=\"article-header__category\"\n\t\t\thref=\"https:\/\/news.harvard.edu\/gazette\/section\/science-technology\/\"\n\t\t>\n\t\t\tScience & Tech\t\t<\/a>\n\t\t\n\t\t<h1 class=\"article-header__title wp-block-heading \">\n\t\tSeeing light in a new way\t<\/h1>\n\n\t\n\t\t\t<\/div>\n\t\t\n\t<div class=\"article-header__meta\">\n\t\t<div class=\"wp-block-post-author\">\n\t\t\t<address class=\"wp-block-post-author__content\">\n\t\t\t\t\t<p class=\"author wp-block-post-author__name\">\n\t\tPeter Reuell\t<\/p>\n\t\t\t<p class=\"wp-block-post-author__byline\">\n\t\t\tHarvard Staff Writer\t\t<\/p>\n\t\t\t\t\t<\/address>\n\t\t<\/div>\n\n\t\t<time class=\"article-header__date\" datetime=\"2013-09-27\">\n\t\t\tSeptember 27, 2013\t\t<\/time>\n\n\t\t<span class=\"article-header__reading-time\">\n\t\t\t6 min read\t\t<\/span>\n\t<\/div>\n\n\t\n\t\t\t<h2 class=\"article-header__subheading wp-block-heading\">\n\t\t\tScientists coax photons to bind into molecules for first time\t\t<\/h2>\n\t\t\n<\/header>\n"},"2":{"blockName":"core\/group","attrs":{"templateLock":false,"metadata":{"name":"Article content"},"align":"wide","layout":{"type":"constrained","justifyContent":"center"},"tagName":"div","lock":[],"className":"","style":[],"backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","ariaLabel":"","anchor":""},"innerBlocks":[{"blockName":"core\/freeform","attrs":{"content":"","lock":[],"metadata":[]},"innerBlocks":[],"innerHTML":"\n\t\t<p>Scientists from Harvard University and the Massachusetts Institute of Technology (MIT) are challenging the conventional wisdom about light, and they didn\u2019t need to go to a galaxy far, far away to do it.<\/p>\n<p>Working with colleagues at the <a href=\"http:\/\/cuaweb.mit.edu\/\">Harvard-MIT Center for Ultracold Atoms<\/a>, a group led by Harvard Professor of Physics <a href=\"https:\/\/www.physics.harvard.edu\/people\/facpages\/lukin\">Mikhail Lukin<\/a> and MIT Professor of Physics Vladan Vuletic managed to coax photons into binding together to form molecules \u2014 a state of matter that until recently had been purely theoretical. The work is described in a Sept. 25 paper in Nature.<\/p>\n<p>The discovery, Lukin said, runs contrary to decades of accepted wisdom about the nature of light.\u00a0 Photons have long been described as massless particles that don\u2019t interact with each other. Shine two laser beams at each other, he said, and they simply pass through one another.<\/p>\n<p>Photonic molecules, however, behave less like traditional lasers and more like something you might find in science fiction: the light saber.<\/p>\n<p>\u201cMost of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other,\u201d Lukin said. \u201cWhat we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn\u2019t been observed.<\/p>\n<p>\u201cIt\u2019s not an inapt analogy to compare this to light sabers,\u201d Lukin said. \u201cWhen these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d<\/p>\n<p>To get the normally massless photons to bind to each other, Lukin and his colleagues, including Harvard postdoctoral fellow Ofer Firstenberg, former Harvard doctoral student Alexey Gorshkov, and MIT graduate students Thibault Peyronel and Qiu Liang, couldn\u2019t rely on something like <a href=\"http:\/\/scifi.about.com\/od\/starwarsglossaryandfaq\/a\/SWAR_glossary_the-force.htm\">the Force<\/a>. They instead turned to a set of extreme conditions.<\/p>\n<p>Researchers began by pumping rubidium atoms into a vacuum chamber, then used lasers to cool the cloud of atoms to just a few degrees above absolute zero. Using extremely weak laser pulses, they fired single photons into the cloud of atoms.<\/p>\n<p>As the photons enter the cloud, Lukin said, their energy excites atoms along its path, causing the photons to slow dramatically. As the photons move through the cloud, that energy is handed off from atom to atom, and eventually exits the cloud with the photon.<\/p>\n<p>\u201cWhen the photon exits the medium, its identity is preserved,\u201d Lukin said. \u201cIt\u2019s the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together. But when it exits, it\u2019s still light. The process that takes place is the same. It\u2019s just a bit more extreme. The light is slowed considerably, and a lot more energy is given away than during refraction.\u201d<\/p>\n<p>When Lukin and his colleagues fired two photons into the cloud, they were surprised to see them exit as a single molecule.<\/p>\n<p>The reason they form the never-before-seen molecules? \u00a0It\u2019s an effect called a Rydberg blockade, Lukin said, which means that when an atom is excited, nearby atoms cannot be excited to the same degree. In practice, the effect means that as two photons enter the atomic cloud, the first excites an atom, but it must move forward before the second photon can excite nearby atoms.<\/p>\n<p>The result, he said, is that the two photons push and pull each other through the cloud as their energy is handed off from one atom to the next.<\/p>\n<p>\u201cIt\u2019s a photonic interaction that\u2019s mediated by the atomic interaction,\u201d Lukin said. \u201cThat makes these two photons behave like a molecule, and when they exit the medium they\u2019re much more likely to do so together than as single photons.\u201d<\/p>\n<p>While the effect is unusual, it has some practical applications.<\/p>\n<p>\u201cWe do this for fun, and because we\u2019re pushing the frontiers of science,\u201d Lukin said. \u201cBut it feeds into the bigger picture of what we\u2019re doing because photons remain the best possible means to carry quantum information. The handicap, though, has been that photons don\u2019t interact with each other.\u201d<\/p>\n<p>To build a quantum computer, he said, researchers need to build a system that can preserve quantum information and process it using quantum logic operations. The challenge, however, is that quantum logic requires interactions between individual quanta so that quantum systems can be switched to perform information processing.<\/p>\n<p>\u201cWhat we demonstrate with this process allows us to do that,\u201d Lukin said. \u201cBefore we make a useful, practical quantum switch or photonic logic gate, we have to improve the performance. So it\u2019s still at the proof-of-concept level, but this is an important step. The physical principles we\u2019ve established here are important.\u201d<\/p>\n<p>The system could even be useful in classical computing, Lukin said, considering the power-dissipation challenges that chip-makers face. A number of companies, including IBM, have worked to develop systems that rely on optical routers that convert light signals into electrical signals, but those systems face their own hurdles.<\/p>\n<p>Lukin also suggested that the system might one day even be used to create complex, 3-D structures, such as crystals, wholly out of light.<\/p>\n<p>\u201cWhat it will be useful for we don\u2019t know yet. But it\u2019s a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules\u2019 properties,\u201d he said.<\/p>\n","innerContent":["\n\t\t<p>Scientists from Harvard University and the Massachusetts Institute of Technology (MIT) are challenging the conventional wisdom about light, and they didn\u2019t need to go to a galaxy far, far away to do it.<\/p>\n<p>Working with colleagues at the <a href=\"http:\/\/cuaweb.mit.edu\/\">Harvard-MIT Center for Ultracold Atoms<\/a>, a group led by Harvard Professor of Physics <a href=\"https:\/\/www.physics.harvard.edu\/people\/facpages\/lukin\">Mikhail Lukin<\/a> and MIT Professor of Physics Vladan Vuletic managed to coax photons into binding together to form molecules \u2014 a state of matter that until recently had been purely theoretical. The work is described in a Sept. 25 paper in Nature.<\/p>\n<p>The discovery, Lukin said, runs contrary to decades of accepted wisdom about the nature of light.\u00a0 Photons have long been described as massless particles that don\u2019t interact with each other. Shine two laser beams at each other, he said, and they simply pass through one another.<\/p>\n<p>Photonic molecules, however, behave less like traditional lasers and more like something you might find in science fiction: the light saber.<\/p>\n<p>\u201cMost of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other,\u201d Lukin said. \u201cWhat we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn\u2019t been observed.<\/p>\n<p>\u201cIt\u2019s not an inapt analogy to compare this to light sabers,\u201d Lukin said. \u201cWhen these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d<\/p>\n<p>To get the normally massless photons to bind to each other, Lukin and his colleagues, including Harvard postdoctoral fellow Ofer Firstenberg, former Harvard doctoral student Alexey Gorshkov, and MIT graduate students Thibault Peyronel and Qiu Liang, couldn\u2019t rely on something like <a href=\"http:\/\/scifi.about.com\/od\/starwarsglossaryandfaq\/a\/SWAR_glossary_the-force.htm\">the Force<\/a>. They instead turned to a set of extreme conditions.<\/p>\n<p>Researchers began by pumping rubidium atoms into a vacuum chamber, then used lasers to cool the cloud of atoms to just a few degrees above absolute zero. Using extremely weak laser pulses, they fired single photons into the cloud of atoms.<\/p>\n<p>As the photons enter the cloud, Lukin said, their energy excites atoms along its path, causing the photons to slow dramatically. As the photons move through the cloud, that energy is handed off from atom to atom, and eventually exits the cloud with the photon.<\/p>\n<p>\u201cWhen the photon exits the medium, its identity is preserved,\u201d Lukin said. \u201cIt\u2019s the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together. But when it exits, it\u2019s still light. The process that takes place is the same. It\u2019s just a bit more extreme. The light is slowed considerably, and a lot more energy is given away than during refraction.\u201d<\/p>\n<p>When Lukin and his colleagues fired two photons into the cloud, they were surprised to see them exit as a single molecule.<\/p>\n<p>The reason they form the never-before-seen molecules? \u00a0It\u2019s an effect called a Rydberg blockade, Lukin said, which means that when an atom is excited, nearby atoms cannot be excited to the same degree. In practice, the effect means that as two photons enter the atomic cloud, the first excites an atom, but it must move forward before the second photon can excite nearby atoms.<\/p>\n<p>The result, he said, is that the two photons push and pull each other through the cloud as their energy is handed off from one atom to the next.<\/p>\n<p>\u201cIt\u2019s a photonic interaction that\u2019s mediated by the atomic interaction,\u201d Lukin said. \u201cThat makes these two photons behave like a molecule, and when they exit the medium they\u2019re much more likely to do so together than as single photons.\u201d<\/p>\n<p>While the effect is unusual, it has some practical applications.<\/p>\n<p>\u201cWe do this for fun, and because we\u2019re pushing the frontiers of science,\u201d Lukin said. \u201cBut it feeds into the bigger picture of what we\u2019re doing because photons remain the best possible means to carry quantum information. The handicap, though, has been that photons don\u2019t interact with each other.\u201d<\/p>\n<p>To build a quantum computer, he said, researchers need to build a system that can preserve quantum information and process it using quantum logic operations. The challenge, however, is that quantum logic requires interactions between individual quanta so that quantum systems can be switched to perform information processing.<\/p>\n<p>\u201cWhat we demonstrate with this process allows us to do that,\u201d Lukin said. \u201cBefore we make a useful, practical quantum switch or photonic logic gate, we have to improve the performance. So it\u2019s still at the proof-of-concept level, but this is an important step. The physical principles we\u2019ve established here are important.\u201d<\/p>\n<p>The system could even be useful in classical computing, Lukin said, considering the power-dissipation challenges that chip-makers face. A number of companies, including IBM, have worked to develop systems that rely on optical routers that convert light signals into electrical signals, but those systems face their own hurdles.<\/p>\n<p>Lukin also suggested that the system might one day even be used to create complex, 3-D structures, such as crystals, wholly out of light.<\/p>\n<p>\u201cWhat it will be useful for we don\u2019t know yet. But it\u2019s a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules\u2019 properties,\u201d he said.<\/p>\n"],"rendered":"\n\t\t<p>Scientists from Harvard University and the Massachusetts Institute of Technology (MIT) are challenging the conventional wisdom about light, and they didn\u2019t need to go to a galaxy far, far away to do it.<\/p>\n<p>Working with colleagues at the <a href=\"http:\/\/cuaweb.mit.edu\/\">Harvard-MIT Center for Ultracold Atoms<\/a>, a group led by Harvard Professor of Physics <a href=\"https:\/\/www.physics.harvard.edu\/people\/facpages\/lukin\">Mikhail Lukin<\/a> and MIT Professor of Physics Vladan Vuletic managed to coax photons into binding together to form molecules \u2014 a state of matter that until recently had been purely theoretical. The work is described in a Sept. 25 paper in Nature.<\/p>\n<p>The discovery, Lukin said, runs contrary to decades of accepted wisdom about the nature of light.\u00a0 Photons have long been described as massless particles that don\u2019t interact with each other. Shine two laser beams at each other, he said, and they simply pass through one another.<\/p>\n<p>Photonic molecules, however, behave less like traditional lasers and more like something you might find in science fiction: the light saber.<\/p>\n<p>\u201cMost of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other,\u201d Lukin said. \u201cWhat we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn\u2019t been observed.<\/p>\n<p>\u201cIt\u2019s not an inapt analogy to compare this to light sabers,\u201d Lukin said. \u201cWhen these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d<\/p>\n<p>To get the normally massless photons to bind to each other, Lukin and his colleagues, including Harvard postdoctoral fellow Ofer Firstenberg, former Harvard doctoral student Alexey Gorshkov, and MIT graduate students Thibault Peyronel and Qiu Liang, couldn\u2019t rely on something like <a href=\"http:\/\/scifi.about.com\/od\/starwarsglossaryandfaq\/a\/SWAR_glossary_the-force.htm\">the Force<\/a>. They instead turned to a set of extreme conditions.<\/p>\n<p>Researchers began by pumping rubidium atoms into a vacuum chamber, then used lasers to cool the cloud of atoms to just a few degrees above absolute zero. Using extremely weak laser pulses, they fired single photons into the cloud of atoms.<\/p>\n<p>As the photons enter the cloud, Lukin said, their energy excites atoms along its path, causing the photons to slow dramatically. As the photons move through the cloud, that energy is handed off from atom to atom, and eventually exits the cloud with the photon.<\/p>\n<p>\u201cWhen the photon exits the medium, its identity is preserved,\u201d Lukin said. \u201cIt\u2019s the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together. But when it exits, it\u2019s still light. The process that takes place is the same. It\u2019s just a bit more extreme. The light is slowed considerably, and a lot more energy is given away than during refraction.\u201d<\/p>\n<p>When Lukin and his colleagues fired two photons into the cloud, they were surprised to see them exit as a single molecule.<\/p>\n<p>The reason they form the never-before-seen molecules? \u00a0It\u2019s an effect called a Rydberg blockade, Lukin said, which means that when an atom is excited, nearby atoms cannot be excited to the same degree. In practice, the effect means that as two photons enter the atomic cloud, the first excites an atom, but it must move forward before the second photon can excite nearby atoms.<\/p>\n<p>The result, he said, is that the two photons push and pull each other through the cloud as their energy is handed off from one atom to the next.<\/p>\n<p>\u201cIt\u2019s a photonic interaction that\u2019s mediated by the atomic interaction,\u201d Lukin said. \u201cThat makes these two photons behave like a molecule, and when they exit the medium they\u2019re much more likely to do so together than as single photons.\u201d<\/p>\n<p>While the effect is unusual, it has some practical applications.<\/p>\n<p>\u201cWe do this for fun, and because we\u2019re pushing the frontiers of science,\u201d Lukin said. \u201cBut it feeds into the bigger picture of what we\u2019re doing because photons remain the best possible means to carry quantum information. The handicap, though, has been that photons don\u2019t interact with each other.\u201d<\/p>\n<p>To build a quantum computer, he said, researchers need to build a system that can preserve quantum information and process it using quantum logic operations. The challenge, however, is that quantum logic requires interactions between individual quanta so that quantum systems can be switched to perform information processing.<\/p>\n<p>\u201cWhat we demonstrate with this process allows us to do that,\u201d Lukin said. \u201cBefore we make a useful, practical quantum switch or photonic logic gate, we have to improve the performance. So it\u2019s still at the proof-of-concept level, but this is an important step. The physical principles we\u2019ve established here are important.\u201d<\/p>\n<p>The system could even be useful in classical computing, Lukin said, considering the power-dissipation challenges that chip-makers face. A number of companies, including IBM, have worked to develop systems that rely on optical routers that convert light signals into electrical signals, but those systems face their own hurdles.<\/p>\n<p>Lukin also suggested that the system might one day even be used to create complex, 3-D structures, such as crystals, wholly out of light.<\/p>\n<p>\u201cWhat it will be useful for we don\u2019t know yet. But it\u2019s a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules\u2019 properties,\u201d he said.<\/p>\n"}],"innerHTML":"\n<div class=\"wp-block-group alignwide\">\n\n\n\n<\/div>\n","innerContent":["\n<div class=\"wp-block-group alignwide\">\n\n","\n\n<\/div>\n"],"rendered":"\n<div class=\"wp-block-group alignwide has-global-padding is-content-justification-center is-layout-constrained wp-block-group-is-layout-constrained\">\n\n\n\t\t<p>Scientists from Harvard University and the Massachusetts Institute of Technology (MIT) are challenging the conventional wisdom about light, and they didn\u2019t need to go to a galaxy far, far away to do it.<\/p>\n<p>Working with colleagues at the <a href=\"http:\/\/cuaweb.mit.edu\/\">Harvard-MIT Center for Ultracold Atoms<\/a>, a group led by Harvard Professor of Physics <a href=\"https:\/\/www.physics.harvard.edu\/people\/facpages\/lukin\">Mikhail Lukin<\/a> and MIT Professor of Physics Vladan Vuletic managed to coax photons into binding together to form molecules \u2014 a state of matter that until recently had been purely theoretical. The work is described in a Sept. 25 paper in Nature.<\/p>\n<p>The discovery, Lukin said, runs contrary to decades of accepted wisdom about the nature of light.\u00a0 Photons have long been described as massless particles that don\u2019t interact with each other. Shine two laser beams at each other, he said, and they simply pass through one another.<\/p>\n<p>Photonic molecules, however, behave less like traditional lasers and more like something you might find in science fiction: the light saber.<\/p>\n<p>\u201cMost of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other,\u201d Lukin said. \u201cWhat we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn\u2019t been observed.<\/p>\n<p>\u201cIt\u2019s not an inapt analogy to compare this to light sabers,\u201d Lukin said. \u201cWhen these photons interact with each other, they\u2019re pushing against and deflecting each other. The physics of what\u2019s happening in these molecules is similar to what we see in the movies.\u201d<\/p>\n<p>To get the normally massless photons to bind to each other, Lukin and his colleagues, including Harvard postdoctoral fellow Ofer Firstenberg, former Harvard doctoral student Alexey Gorshkov, and MIT graduate students Thibault Peyronel and Qiu Liang, couldn\u2019t rely on something like <a href=\"http:\/\/scifi.about.com\/od\/starwarsglossaryandfaq\/a\/SWAR_glossary_the-force.htm\">the Force<\/a>. They instead turned to a set of extreme conditions.<\/p>\n<p>Researchers began by pumping rubidium atoms into a vacuum chamber, then used lasers to cool the cloud of atoms to just a few degrees above absolute zero. Using extremely weak laser pulses, they fired single photons into the cloud of atoms.<\/p>\n<p>As the photons enter the cloud, Lukin said, their energy excites atoms along its path, causing the photons to slow dramatically. As the photons move through the cloud, that energy is handed off from atom to atom, and eventually exits the cloud with the photon.<\/p>\n<p>\u201cWhen the photon exits the medium, its identity is preserved,\u201d Lukin said. \u201cIt\u2019s the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together. But when it exits, it\u2019s still light. The process that takes place is the same. It\u2019s just a bit more extreme. The light is slowed considerably, and a lot more energy is given away than during refraction.\u201d<\/p>\n<p>When Lukin and his colleagues fired two photons into the cloud, they were surprised to see them exit as a single molecule.<\/p>\n<p>The reason they form the never-before-seen molecules? \u00a0It\u2019s an effect called a Rydberg blockade, Lukin said, which means that when an atom is excited, nearby atoms cannot be excited to the same degree. In practice, the effect means that as two photons enter the atomic cloud, the first excites an atom, but it must move forward before the second photon can excite nearby atoms.<\/p>\n<p>The result, he said, is that the two photons push and pull each other through the cloud as their energy is handed off from one atom to the next.<\/p>\n<p>\u201cIt\u2019s a photonic interaction that\u2019s mediated by the atomic interaction,\u201d Lukin said. \u201cThat makes these two photons behave like a molecule, and when they exit the medium they\u2019re much more likely to do so together than as single photons.\u201d<\/p>\n<p>While the effect is unusual, it has some practical applications.<\/p>\n<p>\u201cWe do this for fun, and because we\u2019re pushing the frontiers of science,\u201d Lukin said. \u201cBut it feeds into the bigger picture of what we\u2019re doing because photons remain the best possible means to carry quantum information. The handicap, though, has been that photons don\u2019t interact with each other.\u201d<\/p>\n<p>To build a quantum computer, he said, researchers need to build a system that can preserve quantum information and process it using quantum logic operations. The challenge, however, is that quantum logic requires interactions between individual quanta so that quantum systems can be switched to perform information processing.<\/p>\n<p>\u201cWhat we demonstrate with this process allows us to do that,\u201d Lukin said. \u201cBefore we make a useful, practical quantum switch or photonic logic gate, we have to improve the performance. So it\u2019s still at the proof-of-concept level, but this is an important step. The physical principles we\u2019ve established here are important.\u201d<\/p>\n<p>The system could even be useful in classical computing, Lukin said, considering the power-dissipation challenges that chip-makers face. A number of companies, including IBM, have worked to develop systems that rely on optical routers that convert light signals into electrical signals, but those systems face their own hurdles.<\/p>\n<p>Lukin also suggested that the system might one day even be used to create complex, 3-D structures, such as crystals, wholly out of light.<\/p>\n<p>\u201cWhat it will be useful for we don\u2019t know yet. But it\u2019s a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules\u2019 properties,\u201d he said.<\/p>\n\n\n<\/div>\n"}},"jetpack-related-posts":[{"id":326934,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2021\/07\/harvard-led-physicists-create-256-qubit-programmable-quantum-simulator\/","url_meta":{"origin":147234,"position":0},"title":"Harvard-led physicists take big step in race to quantum computing","author":"Lian Parsons","date":"July 7, 2021","format":false,"excerpt":"A Harvard-led team has created a 256-qubit programmable quantum simulator that represents the cutting edge in the world-wide quantum race.","rel":"","context":"In "Science & Tech"","block_context":{"text":"Science & Tech","link":"https:\/\/news.harvard.edu\/gazette\/section\/science-technology\/"},"img":{"alt_text":"Dolev Bluvstein, Mikhail Lukin and Sepehr Ebadi.","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2021\/07\/052121_QS_1063.jpeg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2021\/07\/052121_QS_1063.jpeg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2021\/07\/052121_QS_1063.jpeg?resize=525%2C300 1.5x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2021\/07\/052121_QS_1063.jpeg?resize=700%2C400 2x"},"classes":[]},{"id":355876,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2023\/03\/mikhail-lukin-named-university-professor\/","url_meta":{"origin":147234,"position":1},"title":"Mikhail Lukin named University Professor","author":"harvardgazette","date":"March 23, 2023","format":false,"excerpt":"A pioneer and leader in quantum science and quantum computing, Mikhail Lukin will hold the Friedman University Professorship.","rel":"","context":"In "Campus & Community"","block_context":{"text":"Campus & Community","link":"https:\/\/news.harvard.edu\/gazette\/section\/campus-community\/"},"img":{"alt_text":"Mikhail Lukin.","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/03\/Lukin2500.jpeg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/03\/Lukin2500.jpeg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/03\/Lukin2500.jpeg?resize=525%2C300 1.5x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/03\/Lukin2500.jpeg?resize=700%2C400 2x"},"classes":[]},{"id":365336,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2023\/10\/self-correcting-quantum-computers-within-reach-error-correction-entanglement\/","url_meta":{"origin":147234,"position":2},"title":"Self-correcting quantum computers within reach?","author":"gazettebeckycoleman","date":"October 11, 2023","format":false,"excerpt":"Harvard team\u2019s method of reducing errors tackles a major barrier to scaling up technology.","rel":"","context":"In "Science & Tech"","block_context":{"text":"Science & Tech","link":"https:\/\/news.harvard.edu\/gazette\/section\/science-technology\/"},"img":{"alt_text":"Blue glowing quantum correlation.","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/10\/20231011_quatum-entanglment-scaled.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/10\/20231011_quatum-entanglment-scaled.jpg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/10\/20231011_quatum-entanglment-scaled.jpg?resize=525%2C300 1.5x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/10\/20231011_quatum-entanglment-scaled.jpg?resize=700%2C400 2x"},"classes":[]},{"id":367538,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2023\/12\/researchers-create-first-logical-quantum-processor\/","url_meta":{"origin":147234,"position":3},"title":"Researchers create first logical quantum processor","author":"harvardgazette","date":"December 8, 2023","format":false,"excerpt":"Key step toward reliable, game-changing quantum computing","rel":"","context":"In "Science & Tech"","block_context":{"text":"Science & Tech","link":"https:\/\/news.harvard.edu\/gazette\/section\/science-technology\/"},"img":{"alt_text":"Mikhail Lukin and including Dolev Bluvstein","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/112823_quantum_015.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/112823_quantum_015.jpg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/112823_quantum_015.jpg?resize=525%2C300 1.5x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/112823_quantum_015.jpg?resize=700%2C400 2x"},"classes":[]},{"id":333932,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2021\/12\/harvard-led-team-takes-step-in-quest-for-quantum-computing\/","url_meta":{"origin":147234,"position":4},"title":"Step in quest for quantum computing","author":"Lian Parsons","date":"December 2, 2021","format":false,"excerpt":"Harvard researchers observe a state of matter predicted and hunted for 50 years, but never previously observed.","rel":"","context":"In "Science & Tech"","block_context":{"text":"Science & Tech","link":"https:\/\/news.harvard.edu\/gazette\/section\/science-technology\/"},"img":{"alt_text":"Professor Mikhail Lukin (left) and Giulia Semeghini.","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2021\/10\/110121_Lukin_264.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2021\/10\/110121_Lukin_264.jpg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2021\/10\/110121_Lukin_264.jpg?resize=525%2C300 1.5x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2021\/10\/110121_Lukin_264.jpg?resize=700%2C400 2x"},"classes":[]},{"id":384881,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2024\/05\/glimpse-of-next-generation-internet\/","url_meta":{"origin":147234,"position":5},"title":"Glimpse of next-generation internet","author":"Anne Mannning","date":"May 15, 2024","format":false,"excerpt":"Physicists demo first metro-area quantum computer network in Boston","rel":"","context":"In "Science & Tech"","block_context":{"text":"Science & Tech","link":"https:\/\/news.harvard.edu\/gazette\/section\/science-technology\/"},"img":{"alt_text":"Mikhail Lukin (left) and Can Knaut stand near a quantum network node.","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2024\/05\/042324_Quantum_Network_Node_0062.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2024\/05\/042324_Quantum_Network_Node_0062.jpg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2024\/05\/042324_Quantum_Network_Node_0062.jpg?resize=525%2C300 1.5x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2024\/05\/042324_Quantum_Network_Node_0062.jpg?resize=700%2C400 2x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/posts\/147234","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/users\/105622744"}],"replies":[{"embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/comments?post=147234"}],"version-history":[{"count":1,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/posts\/147234\/revisions"}],"predecessor-version":[{"id":258621,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/posts\/147234\/revisions\/258621"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/media\/147248"}],"wp:attachment":[{"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/media?parent=147234"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/categories?post=147234"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/tags?post=147234"},{"taxonomy":"format","embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/gazette-formats?post=147234"},{"taxonomy":"series","embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/series?post=147234"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}