On May 9th, it was learned from the University of Science and Technology of China that a team led by academician Guo Guangcan, including Li Chuanfeng and Chen Geng, collaborated with their peers to achieve quantum precision measurement beyond the Heisenberg limit using quantum uncertainty causal order.
The research results have been published in the international journal “Nature Physics”.
Quantum precision measurement is committed to applying the principles of quantum mechanics to various measurement tasks in order to achieve measurement accuracy beyond classical limits. The Heisenberg limit is considered the ultimate limit that can be achieved using quantum methods and resources.
Previously, there were some works internationally claiming to have surpassed the Heisenberg limit. However, these works utilized nonlinear effects or included time-dependent Hamiltonians, which caused extensive discussions and were ultimately theoretically proven to still follow the Heisenberg limit when defined with energy equivalence as a normalization resource.
The researchers have designed a new hybrid quantum device, which uses a discrete quantum bit to control the evolution timing of two groups of continuous variables in photons. The experiment achieved uncertain causal order and thus realized precise measurement of geometric phase beyond the Heisenberg limit generated by evolution.
The experiment uses a single photon as a probe, and there is no interaction between photons. The energy required for a single measurement does not exceed the energy of a single photon, thus achieving the first experimental work that surpasses the Heisenberg limit under normalized resource definition.
Researchers stated that this experimental result has important implications for understanding uncertain causal order and quantum precision measurement.
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