{"id":313076,"date":"2025-11-25T16:33:08","date_gmt":"2025-11-25T16:33:08","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/313076\/"},"modified":"2025-11-25T16:33:08","modified_gmt":"2025-11-25T16:33:08","slug":"particle-physicists-detect-magic-at-the-large-hadron-collider","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/313076\/","title":{"rendered":"Particle Physicists Detect \u2018Magic\u2019 at the Large Hadron Collider"},"content":{"rendered":"

Quantum information researchers began looking for ways to generate and enhance magic in quantum systems. This caught the attention of a few particle physicists \u2014 including Martin and Chris White \u2014 who wondered how magic appears in systems of elementary particles. \u201cWe thought, the LHC is a quantum system. Top quarks are a quantum system. Can we look at that system and just see if it\u2019s magic or not?\u201d Chris White said.<\/p>\n

They proposed a way<\/a> to do so in late 2024. The paper is their first collaboration. \u201cI found it really quite emotional when it was released. We wanted to work together for many years,\u201d Martin White said.<\/p>\n

When Demina met the brothers at a conference, they inspired her to bring the proposal to her group at CMS. \u201cThey are identical twins, and one works in the U.K., and the other one works in Australia. They were moved very far apart, but are still in an entangled state,\u201d she mused.<\/p>\n

To glean the magic of top quarks, CMS analyzed a huge bank of collision data, tallying the spins of top quark pairs that flew off in all different directions. Doing this allowed the team to fill out a so-called spin correlation matrix, a complete description of the correlations between the particles\u2019 spins in the x, y, and z directions. From this matrix, physicists calculate magic.<\/p>\n

\"A <\/p>\n

Regina Demina led the analysis for the CMS experiment\u2019s recent measurement of magic at the Large Hadron Collider.<\/p>\n

Courtesy of Regina Demina<\/p>\n

The entangled quark pairs did indeed have magic. CMS\u2019s measurement marked the entry of the once-niche quantum computing concept into the realm of particle physics.<\/p>\n

The main point of studying magic is to potentially improve quantum computers rather than reveal new insights about elementary particles. But the sensitive methods developed for doing such a detailed measurement led to something unexpected: The physicists observed that the top quark and anti-top quark were sometimes extra-entangled. In these cases, the quarks were binding strongly to form a single particle, an elusive state called toponium. Toponium was predicted in 1990 but \u201cwas thought to be a too-subtle effect\u201d for a collider such as the LHC to see, said Marcel Vos<\/a>, a leader of the top quark research group at ATLAS.<\/p>\n

CMS and ATLAS posted their measurements of toponium in March<\/a> and July<\/a>, respectively. \u201cThat\u2019s our first tangible spin-off from all this,\u201d Vos said.<\/p>\n

Threads To Pull<\/p>\n

What some physicists find exciting about the new overlap between particle physics and quantum information theory is the chance to use the LHC to probe subtle questions about entanglement.<\/p>\n

For instance: \u201cWhat happens to your entangled system after the top quark decays? Will the daughters of the top quark still be entangled with the anti-top quark?\u201d Vos asked. \u201cQuantum field theory says they should be, but no one\u2019s ever tested it.\u201d<\/p>\n

The experiments might also offer new insights about the quantum-to-classical transition \u2014 how a quantum object goes from an uncertain state to a single definite state. This famously happens when a quantum object is measured, but in this case, the mystery crops up when the top quark decays into lighter particles. Initially, the quark is in an uncertain state of both possible spin directions at once. When it decays, the quark appears to choose one spin direction, and the particles it generates travel in certain directions based on that choice of spin. It\u2019s as if the top quark is forced to \u201cmeasure\u201d its own spin during its decay. \u201cMathematically, it\u2019s an equivalent process to making a measurement,\u201d Barr said. That gives physicists a fresh angle on the quantum-to-classical transition.<\/p>\n

Demina hopes to probe questions about time. \u201cThere is a certain theory that suggests that time is not a fundamental property of nature, but it is an emergent property,\u201d she said. One famous mechanism for how this can work was described by Don Page and William Wootters<\/a> in 1983. They argued that the universe as a whole may be timeless and unchanging, while observers inside the universe can perceive temporal evolution. This perception arises because various possible spatial configurations are entangled with the spatial configurations of an object with some periodic pattern, like the hands of a clock. The effect was demonstrated<\/a> with photons in 2013. \u201cMy dream is to perform this experiment in a system of elementary particles, to demonstrate the Page-Wootters mechanism,\u201d Demina said.<\/p>\n

Others have raised concerns that these top quark experiments cannot reliably test quantum mechanics at all. Herbert Dreiner, a physicist from the University of Bonn in Germany, argued in two recent<\/a> preprints<\/a> that the approach is circular: To measure entanglement, you need to relate the angular motion of the outgoing decay products to the top and anti-top quarks\u2019 spins. But \u201cin order to translate one into the other, you have to use some theory,\u201d Dreiner said. \u201cAnd if you\u2019re using quantum mechanics, you can\u2019t test for quantum mechanics.\u201d<\/p>\n

That debate is ongoing. To some, this whole line of experimentation is a sign that, after 17 years of collision experiments at the LHC, new goals are needed. \u201cThere is a sense that you\u2019re always looking for new things to do,\u201d Martin White said.<\/p>\n

\u201cThere is a lot of skepticism,\u201d Vos said. Still, \u201cyou start pulling on the thread, and you don\u2019t know what you\u2019re going to come up with.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"Quantum information researchers began looking for ways to generate and enhance magic in quantum systems. This caught the…\n","protected":false},"author":2,"featured_media":313077,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[49],"tags":[199,79],"class_list":{"0":"post-313076","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-physics","9":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/313076","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=313076"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/313076\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/313077"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=313076"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=313076"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=313076"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}