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Certifying Quantum Temporal Correlation via Randomized Measurements: Theory and Experiment
Hongfeng Liu1, Zhenhuan Liu2, Shu Chen2
1Southern University of Science and Technology, Department of Physics, Shenzhen 518055, China.
Physical Review Letters
|February 14, 2025
Summary
We present an efficient method to detect temporal quantum correlations using the pseudo-density operator (PDO). This approach uses randomized measurements, requiring fewer resources than traditional tomography for quantum systems.
Area of Science:
- Quantum Information Science
- Quantum Foundations
- Quantum Measurement
Background:
- Temporal quantum correlations are certified by pseudo-density operators (PDOs), with negative eigenvalues indicating their presence.
- Conventional PDO tomography is resource-intensive, requiring exponential resources and involving redundant information.
Purpose of the Study:
- To develop an efficient protocol for detecting temporal quantum correlations.
- To reduce the resource requirements for identifying quantum temporal correlations.
Main Methods:
- Virtually preparing the PDO within a single time slice.
- Estimating second-order moments using randomized measurements.
- Sample complexity analysis to determine measurement requirements.
Main Results:
- The developed protocol requires only a constant number of measurement bases.
- Runtime complexity remains constant regardless of the number of qubits, ideal for ensemble measurements.
- Experimental validation on a nuclear magnetic resonance platform confirmed theoretical predictions.
Conclusions:
- The proposed protocol offers an efficient and resource-saving method for certifying temporal quantum correlations.
- This technique is advantageous for quantum systems, particularly those employing ensemble average measurements.
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