Directly Estimating Mixed-State Entanglement with Bell Measurement Assistance

Fuente: arXiv
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Main Authors: Li, Gong-Chu, Chen, Lei, Zhang, Si-Qi, Hong, Xu-Song, Zhou, You, Chen, Geng, Li, Chuan-Feng, Guo, Guang-Can
Format: Preprint
Published: 2024
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_version_ 1866910515520864256
author Li, Gong-Chu
Chen, Lei
Zhang, Si-Qi
Hong, Xu-Song
Zhou, You
Chen, Geng
Li, Chuan-Feng
Guo, Guang-Can
author_facet Li, Gong-Chu
Chen, Lei
Zhang, Si-Qi
Hong, Xu-Song
Zhou, You
Chen, Geng
Li, Chuan-Feng
Guo, Guang-Can
contents Entanglement plays a fundamental role in quantum physics and information processing. Here, we develop an unbiased estimator for mixed-state entanglement in the few-shot scenario and directly estimate it using random unitary evolution in a photonic system. As a supplement to traditional projective measurements, we incorporate Bell measurements on qubit-pairs, enriching the previous randomized measurement scheme, which is no-go in this task with only local unitary evolution. The scheme is scalable to n-qubits via Bell measurements on qubit-pairs. The estimator can be derived directly from a few consecutive outcomes while exhibiting greater robustness to system errors and noise compared to schemes based on shadow estimation. We find that, under a fixed measurement resource, the way with more versatile measurement settings with fewer repeats per setting is more efficient. Our protocol and demonstration advance the direct characterization of quantum states in practice.
format Preprint
id arxiv_https___arxiv_org_abs_2405_20696
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Directly Estimating Mixed-State Entanglement with Bell Measurement Assistance
Li, Gong-Chu
Chen, Lei
Zhang, Si-Qi
Hong, Xu-Song
Zhou, You
Chen, Geng
Li, Chuan-Feng
Guo, Guang-Can
Quantum Physics
Entanglement plays a fundamental role in quantum physics and information processing. Here, we develop an unbiased estimator for mixed-state entanglement in the few-shot scenario and directly estimate it using random unitary evolution in a photonic system. As a supplement to traditional projective measurements, we incorporate Bell measurements on qubit-pairs, enriching the previous randomized measurement scheme, which is no-go in this task with only local unitary evolution. The scheme is scalable to n-qubits via Bell measurements on qubit-pairs. The estimator can be derived directly from a few consecutive outcomes while exhibiting greater robustness to system errors and noise compared to schemes based on shadow estimation. We find that, under a fixed measurement resource, the way with more versatile measurement settings with fewer repeats per setting is more efficient. Our protocol and demonstration advance the direct characterization of quantum states in practice.
title Directly Estimating Mixed-State Entanglement with Bell Measurement Assistance
topic Quantum Physics
url https://arxiv.org/abs/2405.20696