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An atomic clock doesn\u2019t have hands. It measures time by counting how often light pulses<\/a> at the exact frequency that a specific atom naturally absorbs.<\/p>\n Shine a tuned laser at a single ion, and the atom either absorbs the light or doesn\u2019t. The laser locks onto that frequency. The ticks come at hundreds of trillions per second \u2013 steady, year after year.<\/p>\n The best of these machines now drift by less than a second over the age of the universe. They underpin GPS, network synchronization, and a growing body of fundamental physics research.<\/p>\n A 2022 experiment at JILA in Colorado detected differences in clock rates across about 0.04 inches (1 millimeter) of vertical separation \u2013 roughly the width of a pencil tip.<\/p>\n Where Einstein steps in<\/p>\n That pencil-tip measurement is a relativity story. Einstein\u2019s general relativity says clocks run slower deeper in a gravitational well, an effect called time dilation<\/a>.<\/p>\n Raise a clock higher, and it ticks a little faster. Move it through space faster, and it ticks a little slower. Both effects have been observed repeatedly, with atomic clocks making the measurements.<\/p>\n Yet the theories used to explain these results treat time itself as a single, smooth parameter in the background. The clock is quantum. What it measures is not.<\/p>\n When time becomes quantum<\/p>\n Quantum mechanics is full of objects that refuse to commit. An electron sits in two energy levels at once; an atom occupies two locations at once. The condition has a name: quantum superposition<\/a>.<\/p>\n No one has yet observed time itself behaving this way. But if a quantum object can exist in a superposition of motions, relativity says each motion carries its own rate of time.<\/p>\n So the object\u2019s \u201cproper time\u201d \u2013 the time read by a clock traveling along with it \u2013 should also exist in superposition. In other words, different flows of time could be layered onto the same atom.<\/p>\n Quantum behavior in a clock<\/p>\n Associate Professor Joshua Foo of Kyushu University<\/a> in Fukuoka, Japan, was one of the lead authors of the paper, which explains how this quantum effect could register in a real clock.<\/p>\n The core prediction is that, in a clock precise enough to detect the effect, the atom\u2019s movement becomes entangled with the energy state the clock is tracking. Motion and energy become linked.<\/p>\n If that happens, the clock\u2019s own quantum interference becomes slightly distorted \u2013 a signal that existing measurement tools should be sensitive enough to detect.<\/p>\n \u201cWe found that the atomic clock\u2019s motion becomes \u2018entangled\u2019 with its internal energy. The signature of this entanglement is that the clock itself loses some of its quantum properties, which can be detected using modern techniques,\u201d said Foo.<\/p>\n The team also worked out how to make the signal louder. Today\u2019s trapped ions<\/a> sit inside electromagnetic cages and are cooled to within a whisker of absolute zero, where their residual motion must be described in quantum terms.<\/p>\n Preparing the ion in a squeezed state \u2013 pinning down its location at the cost of making its speed less predictable \u2013 amplifies the predicted effect by a factor of 100 to 1,000.<\/p>\n A leap of that size could open real experimental opportunities. Existing research on next-generation optical clocks has already incorporated squeezed states into the toolkit.<\/p>\n Building the quantum clock<\/p>\n For now, this remains a theoretical proposal. The required hardware already exists in principle \u2013 laboratories already build optical ion clocks using single charged atoms.<\/p>\n Aluminum and ytterbium<\/a> \u2013 a dense, silvery metal \u2013 are the two most common choices. Both can be cooled to near absolute zero and trapped with lasers precise enough to detect the effect the researchers predict.<\/p>\n What\u2019s still missing is a unified experimental protocol: the right degree of squeezing, the right interrogation method, and conditions clean enough to pull the signature out of the noise.<\/p>\n \u201cNaturally, bringing our theoretical model to reality is the big next step, and developing a detailed experiment that accounts for real-world unpredictability will give us further insight into our model,\u201d said Foo.<\/p>\n The future of quantum time<\/p>\n Physics has spent a century chasing the meeting point between relativity and quantum mechanics. Time has remained one of the deepest sticking points.<\/p>\n Until this study, no one had outlined a near-term experimental path to test whether time itself follows quantum rules. The new framework provides one.<\/p>\n If a clock built along these lines eventually shows the predicted entanglement<\/a> signature, it would mark the first observation of proper time existing in superposition.<\/p>\n That outcome would open the door to a regime where the smooth flow of time bends under quantum mechanics. The same techniques could then probe an even thornier question: the quantum side of gravity.<\/p>\n The study is published in Physical Review Letters<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"Every GPS satellite carries a correction baked into its software. Einstein\u2019s relativity says clocks tick faster in weaker…\n","protected":false},"author":2,"featured_media":654781,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[49],"tags":[199,79],"class_list":["post-654780","post","type-post","status-publish","format-standard","has-post-thumbnail","category-physics","tag-physics","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/654780","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=654780"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/654780\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/654781"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=654780"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=654780"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=654780"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Pictures](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/05\/atomic-clock_quantum-superposition-of-time_Kyushu-U_1s.webp\")
<\/a>Pictures of the components used in making an atomic clock. The ion trap (left image) holds the clock in place. The optical\/laser apparatus (right images) measures the clock\u2019s frequency. Credit: Kyushu University\/Colorado State University\/Christian Sanner. Click image to enlarge.Boosting the clock signal<\/p>\n