{"117741":{"#nid":"117741","#data":{"type":"news","title":"Researchers Develop Blueprint for Nuclear Clock Accurate Over Billions of Years","body":[{"value":"\u003Cp\u003EA clock accurate to within a tenth of a second over 14 billion years -- the age of the universe -- is the goal of research being reported this week by scientists from three different institutions. To be published in the journal \u003Cem\u003EPhysical Review Letters\u003C\/em\u003E, the research provides the blueprint for a nuclear clock that would get its extreme accuracy from the nucleus of a single thorium ion.\u003C\/p\u003E\u003Cp\u003ESuch a clock could be useful for certain forms of secure communication -- and perhaps of greater interest -- for studying the fundamental theories of physics. A nuclear clock could be as much as one hundred times more accurate than current atomic clocks, which now serve as the basis for the global positioning system (GPS) and a broad range of important measurements.\u003C\/p\u003E\u003Cp\u003E\u0022If you give people a better clock, they will use it,\u0022 said Alex Kuzmich, a professor in the \u003Ca href=\u0022http:\/\/www.physics.gatech.edu\u0022\u003ESchool of Physics\u003C\/a\u003E at the Georgia Institute of Technology and one of the paper\u0027s co-authors. \u0022For most applications, the atomic clocks we have are precise enough. But there are other applications where having a better clock would provide a real advantage.\u0022\u003C\/p\u003E\u003Cp\u003EIn addition to the Georgia Tech physicists, researchers in the School of Physics at the University of New South Wales in Australia and at the Department of Physics at the University of Nevada also contributed to the study. The research has been supported by the Office of Naval Research, the National Science Foundation and the Gordon Godfrey fellowship.\u003C\/p\u003E\u003Cp\u003EEarly clocks used a swinging pendulum to provide the oscillations needed to track time. In modern clocks, quartz crystals provide high-frequency oscillations that act like a tuning fork, replacing the old-fashioned pendulum. Atomic clocks derive their accuracy from laser-induced oscillations of electrons in atoms. However, these electrons can be affected by magnetic and electrical fields, allowing atomic clocks to drift ever so slightly -- about four seconds in the lifetime of the universe.\u003C\/p\u003E\u003Cp\u003EBecause neutrons are much heavier than electrons and densely packed into the atomic nucleus, they are less susceptible to these perturbations than the electrons. A nuclear clock should therefore be less affected by environmental factors than its atomic cousin.\u003C\/p\u003E\u003Cp\u003E\u0022In our paper, we show that by using lasers to orient the electrons in a very specific way, we can use the neutron of an atomic nucleus as the clock pendulum,\u0022 said Corey Campbell, a research scientist in the Kuzmich laboratory and the paper\u0027s first author. \u0022Because the neutron is held so tightly to the nucleus, its oscillation rate is almost completely unaffected by any external perturbations.\u0022\u003C\/p\u003E\u003Cp\u003ETo create the oscillations, the researchers plan to use a laser operating at petahertz frequencies -- 10 (15)\u0026nbsp;oscillations per second -- to boost the nucleus of a thorium 229 ion into a higher energy state. Tuning a laser to create these higher energy states would allow scientists to set its frequency very precisely, and that frequency would be used to keep time instead of the tick of a clock or the swing of a pendulum.\u003C\/p\u003E\u003Cp\u003EThe nuclear clock ion will need to be maintained at a very low temperature -- tens of microkelvins -- to keep it still. To produce and maintain such temperatures, physicists normally use laser cooling. But for this system, that would pose a problem because laser light is also used to create the timekeeping oscillations.\u003C\/p\u003E\u003Cp\u003ETo solve that problem, the researchers include a single thorium 232 ion with the thorium 229 ion that will be used for timekeeping. The heavier ion is affected by a different wavelength than the thorium 229. The researchers can then cool the heavier ion, which lowers the temperature of the clock ion without affecting the oscillations.\u003C\/p\u003E\u003Cp\u003E\u0022The cooling ion acts as a refrigerator, keeping the clock ion very still,\u0022 said Alexander Radnaev, a graduate research assistant in the Kuzmich lab. \u0022This is necessary to interrogate the clock ion for very long and to make a very accurate clock that will provide the next level of performance.\u0022\u003C\/p\u003E\u003Cp\u003ECalculations suggest that a nuclear clock could be accurate to 10 (-19), compared to 10 (-17) for the best atomic clock.\u003C\/p\u003E\u003Cp\u003EBecause they operate in slightly different ways, atomic clocks and nuclear clocks could one day be used together to examine differences in physical constants. \u0022Some laws of physics may not be constant in time,\u0022 Kuzmich said. \u0022Developing better clocks is a good way to study this.\u0022\u003C\/p\u003E\u003Cp\u003EThough the research team believes it has now demonstrated the potential to make a nuclear clock -- which was first proposed in 2003 -- it will still be a while before they can produce a working one.\u003C\/p\u003E\u003Cp\u003EThe major challenge ahead is that the exact frequency of laser emissions needed to excite the thorium nucleus hasn\u0027t yet been determined, despite the efforts of many different research groups.\u003C\/p\u003E\u003Cp\u003E\u0022People have been looking for this for 30 years,\u0022 Campbell said. \u0022It\u0027s worse than looking for a needle in a haystack. It\u0027s more like looking for a needle in a million haystacks.\u0022\u003C\/p\u003E\u003Cp\u003EBut Kuzmich believes that problem will be solved, allowing physicists to move to the next generation of phenomenally accurate timekeepers.\u003C\/p\u003E\u003Cp\u003E\u0022Our research shows that building a nuclear clock in this way is both worthwhile and feasible,\u0022 he said. \u0022We now have the tools and plans needed to move forward in realizing this system.\u0022\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E75 Fifth Street, N.W., Suite 314\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAtlanta, Georgia \u0026nbsp;30308 \u0026nbsp;USA\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Precision of Nuclear Clock Depends on Single Atom of Thorium"}],"field_summary":[{"value":"\u003Cp\u003EA clock accurate to within a tenth of a second over 14 billion years \u2013 the age of the universe \u2013 is the goal of research being reported this week in the journal \u003Cem\u003EPhysical Review Letters. \u003C\/em\u003EThe research provides the blueprint for a nuclear clock based on a single thorium ion.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have developed plans for an ultra-precise nuclear clock accurate over billions of years."}],"uid":"27303","created_gmt":"2012-03-19 13:19:42","changed_gmt":"2016-10-08 03:11:52","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2012-03-19T00:00:00-04:00","iso_date":"2012-03-19T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"117691":{"id":"117691","type":"image","title":"Nuclear Clock - Overlapping Lasers","body":null,"created":"1449178256","gmt_created":"2015-12-03 21:30:56","changed":"1475894471","gmt_changed":"2016-10-08 02:41:11","alt":"Nuclear Clock - Overlapping Lasers","file":{"fid":"194267","name":"nuclear-clock29.jpg","image_path":"\/sites\/default\/files\/images\/nuclear-clock29_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/nuclear-clock29_0.jpg","mime":"image\/jpeg","size":1820202,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/nuclear-clock29_0.jpg?itok=F4Ghh9cw"}},"117721":{"id":"117721","type":"image","title":"Nuclear Clock - Ion Trap","body":null,"created":"1449178256","gmt_created":"2015-12-03 21:30:56","changed":"1475894736","gmt_changed":"2016-10-08 02:45:36","alt":"Nuclear Clock - Ion Trap","file":{"fid":"194270","name":"ion_trap.jpg","image_path":"\/sites\/default\/files\/images\/ion_trap_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/ion_trap_0.jpg","mime":"image\/jpeg","size":816189,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/ion_trap_0.jpg?itok=jCAiL5W0"}},"117731":{"id":"117731","type":"image","title":"Nuclear Clock - Containing Thorium Atoms","body":null,"created":"1449178256","gmt_created":"2015-12-03 21:30:56","changed":"1475894736","gmt_changed":"2016-10-08 02:45:36","alt":"Nuclear Clock - Containing Thorium Atoms","file":{"fid":"194271","name":"dsc04717.jpg","image_path":"\/sites\/default\/files\/images\/dsc04717_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/dsc04717_0.jpg","mime":"image\/jpeg","size":1257641,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/dsc04717_0.jpg?itok=rA55qWnj"}}},"media_ids":["117691","117721","117731"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"147","name":"Military Technology"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"24201","name":"Alex Kuzmich"},{"id":"27451","name":"atomic clock"},{"id":"27431","name":"nuclear clock"},{"id":"960","name":"physics"},{"id":"166937","name":"School of Physics"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39481","name":"National Security"}],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News \u0026amp; Publications Office\u003C\/p\u003E\u003Cp\u003E404-894-6986\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}