Theoretical breakthrough shows that time’s arrow can emerge naturally from how quantum parts become interconnected.

Chinese researchers have proposed a simple yet powerful theory to explain one of physics’ oldest puzzles: why time only moves forward and why travelling to the past remains impossible. Physicist Cai Qingyu and his team at Hainan University in southern China have developed a fresh explanation at the quantum level for why we cannot unscramble an egg or grow younger, even though the laws of physics perfectly allow time to go backwards. Unlike earlier theories, their framework does not rely on…

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  • Maeve@kbin.earth
    5·
    9 hours ago

    https://archive.ph/Qv2gl

    In a rare theoretical breakthrough, Cai and his team found that once particles interact and become linked through quantum correlations, those links cannot be undone, effectively locking in a forward direction of time. Senior theoretical physicist and member of the Chinese Academy of Sciences Sun Changpu, who was not involved in the study, praised the work as a significant step forward. The study offered deep insights into the fundamental connection between quantum and classical physics, “touching on one of the most profound questions in science”, Sun said, in a statement released by Hainan University. Cai and his team used correlation to measure how much information was being shared between different parts of the closed system as a way to track what was unfolding over time. The key result of the study was a mathematical no-go theorem proving that once these correlations form, there is no universal operation that can erase them, according to the paper. Just as entropy increases over time in classical systems, correlation always grows in the quantum world. Crucially, this growth is irreversible, offering a new internal explanation for why time moves forward, it said. According to the researchers, this insight offers a unifying explanation: growing correlations not only point to time’s direction in the quantum realm, but also help to explain why entropy increases and other phenomena in the classical world.