Quantum Precision Measurement Group

Welcome to the quantum precision measurement group at Key Lab of Quantum Information in University of Science and Technology of China (USTC). This group was established in Oct. 2010, and currently focuses on high precision measurement by harnessing quantum effects.

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Group News

Operational Resource Theory of Imaginarity

PostDoc K. D. Wu’s recent work “Operational Resource Theory of Imaginarity” has been published on Physical Review Letter. DOI: https://doi.org/10.1103/PhysRevLett.126.090401

Super-Heisenberg and Heisenberg Scalings Achieved Simultaneously in the Estimation of a Rotating Field

Associate researcher Z. B. Hou’s and research assistant Y. Jin’s work “Super-Heisenberg” and Heisenberg Scalings Achieved Simultaneously in the Estimation of a Rotating Field” has been published on Physical Review Letters.

Research interests

We mainly focus on experimental quantum metrology and related technologies and fundamental physics such as quantum tomography, quantum resource theory, Heisenberg’s uncertainty relations and quantum correlations, which are detailed below. Our experimental works are mainly performed with linear photonics and photon-atom integrated chips.

Heisenberg limited quantum metrology

Precision measurements are a major driving force of science and technology. The state-of-art traditional metrology has already reached its foundational ceiling, which is known as shot-noise limit. Fortunately, the next-generation quantum metrology, which utilizes quantum mechanical effects, such as superposition and entanglement, can increase the ceiling of precision up to Heisenberg limit. Although practical application scenarios involve many unknown parameters, general dynamics and noises, current studies mainly focus on the simplest single-parameter, commuting and noiseless cases such as phase estimation. To fill this gap between experimental studies and real application scenarios, we stand on the cutting edge of pushing experimental studies of quantum metrology towards multi-parameter [ 1], general non-commuting [ 2] and noisy cases.

Quantum tomography

Quantum tomography, characterizing the state of a quantum system, its evolution or measurement, is a starting point of many quantum information tasks. Precision and complexity are two main concerns of quantum tomography. Regarding to precision, we realized adaptive quantum tomography techniques [ 3] to achieve the quantum precision limit for individual measurements. To further improve the precision, we proposed and realized collective measurements using quantum walks, which achieved unprecedented precision and beat the precision limit of local measurements in quantum state tomography [ 4, 5]. Regarding to complexity of estimation algorithm, we proposed linear regression estimation and used parallel GPU programming to achieve full reconstruction of a 14-qubit state [ 5], the largest state ever fully reconstructed. We also experimentally self-guided tomography of a SU(2) operator to reduce the algorithm complexity of quantum process tomography [ 6]. Regarding to measurement complexity, we experimentally realized quantum process verification, which dramatically reduced the exponentially-increasing measurements to a polynomial growth of LOCC measurements.

Quantum resource theory

Quantum resource theory studies the transformation and conversion of information under certain constrains. The quantification and manipulation of various resources are of central interest in quantum information, quantum thermodynamics, and other fields of physics. Recently, resource theories have inspired rigorous studies on the long-standing notions of non-classicality in localized systems, where the development of coherence theory has become a fundamental task. Here, we focus on both theoretical and experimental investigation on manipulating and converting quantum resources. In particular, we experimentally study the task of manipulating coherence in quantum states, put forward a circuit for cyclic inter-converting coherence and quantum correlations, develop a new method detecting non-Markovianity based on coherence, and experimentally test the power of collective measurement in reducing measurement backaction.  

Group Member

Principal Investigators

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Xiang GuoYong

Professor of Physics

Quantum Optics, Quantum Information, Quantum Metrology, Quantum Measurement

Researchers

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Hou ZhiBo

Associate researcher

Quantum Information, Quantum Metrology, Quantum Tomography

Postdocs

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Wu KangDa

Postdoc

Quantum Information, Quantum resource theory

Grad Students

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He RenDong

Graduate student

Quantum Information

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Huang ChangJiang

Graduate student

Quantum machine learning

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Tang JunFeng

Graduate student

Quantum Tomography, Quantum Metrology

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Xu Lei

Graduate student

Quantum Information

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Zhang RuiQi

Graduate student

Quantum Tomography

Former Student

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Yin Qi

Former student

Quantum tomography

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Yuan Yuan

Former student

Quantum coherence

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Zhang ChenRui

Former student

Weak measurement

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Zhao Yuan Yuan

Former student

Quantum uncertainty principle

Publications

Quickly discover relevant content by filtering publications.

“Super-Heisenberg” and Heisenberg Scalings Achieved Simultaneously in the Estimation of a Rotating Field

The Heisenberg scaling, which scales as $N^{-1}$ in terms of the number of particles or $t^{-1}$ in terms of the evolution time, serves …

Zero–trade-off multiparameter quantum estimation via simultaneously saturating multiple Heisenberg uncertainty relations

Quantum estimation of a single parameter has been studied extensively. Practical applications, however, typically involve multiple …

Minimizing Backaction through Entangled Measurements

When an observable is measured on an evolving coherent quantum system twice, the first measurement generally alters the statistics of …

Minimal Tradeoff and Ultimate Precision Limit of Multiparameter Quantum Magnetometry under the Parallel Scheme

The precise measurement of a magnetic field is one of the most fundamental and important tasks in quantum metrology. Although extensive …

Operational Resource Theory of Imaginarity

Wave-particle duality is one of the basic features of quantum mechanics, giving rise to the use of complex numbers in describing states …

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