Article
Multidisciplinary Sciences
William P. Livingston, Machiel S. Blok, Emmanuel Flurin, Justin Dressel, Andrew N. Jordan, Irfan Siddiqi
Summary: Continuous quantum error correction using direct parity measurements in a resource-efficient manner is demonstrated, achieving high detection efficiency and increasing the relaxation time of protected logical qubits.
NATURE COMMUNICATIONS
(2022)
Article
Optics
Dengke Qu, Kunkun Wang, Lei Xiao, Xiang Zhan, Peng Xue
Summary: Uncertainty relations are foundational principles in quantum physics, with preparation uncertainty being a key aspect. Unitary operators play a fundamental role in quantum theory, governing the evolution of both closed and open quantum systems. Understanding and quantifying uncertainty relations for unitary operators is crucial, and experimental investigations have shown agreement with theoretical predictions.
Article
Physics, Multidisciplinary
Liang Huang, Xue-Mei Gu, Yang-Fan Jiang, Dian Wu, Bing Bai, Ming-Cheng Chen, Qi-Chao Sun, Jun Zhang, Sixia Yu, Qiang Zhang, Chao-Yang Lu, Jian-Wei Pan
Summary: Nonlocality is a counterintuitive feature of nature that defies classical intuition. Recent investigations show that our physical world's nonlocality is at least tripartite, meaning that genuine tripartite nonlocal correlations cannot be replicated by any causal theory involving bipartite nonclassical resources and unlimited shared randomness. This study experimentally demonstrates genuine tripartite nonlocality in a network under strict locality constraints, using fair sampling assumption and postselection.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Robert Starek, Michal Micuda, Michal Kolar, Radim Filip, Jaromir Fiurasek
Summary: In this study, conditional enhancement of overall coherence of quantum states was investigated through probabilistic quantum operations that utilize a quantum filter diagonal in the basis of incoherent states. Optimal filters were identified to maximize output coherence for a given probability of successful filtering. Through a proof-of-principle experiment with linear optics, the performance of the studied quantum filters was verified and optimal quantum coherence enhancement by quantum filtering was observed.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
Article
Optics
Na Wang, Meihong Wang, Caixing Tian, Xiaowei Deng, Xiaolong Su
Summary: This article demonstrates the quantum steering swapping of Gaussian entangled states in a lossy channel and achieves the steerability of a new Gaussian state located in distant nodes by choosing the optimum gains in classical channels. This work is of great importance for the applications of quantum steering in asymmetric quantum information processing.
LASER & PHOTONICS REVIEWS
(2023)
Article
Multidisciplinary Sciences
Huili Zhang, Si Jiang, Xin Wang, Wengang Zhang, Xianzhi Huang, Xiaolong Ouyang, Yefei Yu, Yanqing Liu, Dong-Ling Deng, L-M Duan
Summary: This study demonstrates the vulnerability of machine learning techniques in classifying phases of matter through experimental tests, highlighting the need for further investigation in this area.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Huan Cao, Marc-Olivier Renou, Chao Zhang, Gaël Masse, Xavier Coiteux-Roy, Bi-Heng Liu, Yun-Feng Huang, Chuan-Feng Li, Guang-Can Guo, Elie Wolfe
Summary: Quantum theory predicts the existence of genuinely tripartite-entangled states that cannot be obtained from local operations and unlimited shared randomness. Researchers have experimentally verified these tripartite correlations and proposed a new method for falsifying causal theories limited to bipartite nonclassical resources. The validity of this method has been demonstrated through experiments.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Federico Centrone, Niraj Kumar, Eleni Diamanti, Iordanis Kerenidis
Summary: This research demonstrates a quantum computational advantage in an prover-verifier interactive setting for verifying an NP-complete problem, where the verifier only has limited information available for verification, efficiently performed using a linear optical implementation. By using coherent states, the study shows a quantum advantage in verifying the solution to an NP-complete problem with only partial information available.
NATURE COMMUNICATIONS
(2021)
Article
Quantum Science & Technology
G. S. Thekkadath, S. Sempere-Llagostera, B. A. Bell, R. B. Patel, M. S. Kim, I. A. Walmsley
Summary: This paper presents a GBS machine that achieves displacement by injecting a laser beam and a two-mode squeezed vacuum state. The study shows that the machine has the ability to reconstruct multimode Gaussian state and reduce computational complexity.
Article
Optics
Min Wei, Chun-Hui Zhang, Jian Li, Jia-Li Zhu, Qin Wang
Summary: Tomography is a beneficial technique in quantum information and quantum optics, and in this study, the authors conducted the first experimental demonstration of tomography-based quantum key distribution (TB-QKD). They compared it with reference-frame-independent QKD (RFI-QKD) and showed that TB-QKD outperformed RFI-QKD in certain channels.
Article
Quantum Science & Technology
Abhinav Anand, Jonathan Romero, Matthias Degroote, Alan Aspuru-Guzik
Summary: The paper discusses the potential advantage of machine learning in quantum computers and its robustness in the presence of noise, as well as investigates the impact of training time on the algorithm's performance. The results provide a foundation for experimental exploration of different quantum machine learning algorithms on noisy intermediate-scale quantum devices.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
Article
Physics, Multidisciplinary
Min Wang, Wei Zhang, Jianxing Guo, Xiaotian Song, Guilu Long
Summary: Quantum secure direct communication (QSDC) provides a practical method for secure and reliable information transmission in quantum networks. However, the lack of quantum relays hampers the practicality of quantum networks. To overcome this limitation, this study proposes a solution to encrypt messages with classical cryptography between intermediate nodes and transmit encrypted quantum messages using QSDC. The experimental demonstration shows the feasibility of constructing a large-scale quantum network in the future, with the relay supporting a QSDC communication rate of 2.5 kb/s within a 4 ms time delay.
Article
Optics
Maolin Luo, Xiaoqian Zhang, Xiaoqi Zhou
Summary: This paper demonstrates a proof-of-principle optical experiment to implement the quantum gate verification (QGV) scheme. The experimental results show that the QGV method can achieve the same results as the standard quantum process tomography method with fewer samples when evaluating the single-qubit quantum gates.
Article
Quantum Science & Technology
Yunlong Wang, Shihao Ru, Feiran Wang, Pei Zhang, Fuli Li
Summary: In this work, experimental demonstrations of four-dimensional X gate and controlled quantum gates based on orbital-angular-momentum and polarization degree of freedom of single photons, respectively, are presented. These results are important for achieving arbitrary high-dimensional quantum circuits, as well as for high-dimensional quantum communication and computation.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Optics
Shuang-Lin Li, Hai-Lin Yong, Yu-Huai Li, Kui-Xing Yang, Hao-Bin Fu, Hui Liu, Hao Liang, Ji-Gang Ren, Yuan Cao, Juan Yin, Cheng-Zhi Peng, Jian-Wei Pan
Summary: This study reports an experimental demonstration of Hong-Ou-Mandel interference with photons transmitted by free-space channels. The results show that the quantum property of photons remains even after transmission through unstable free-space channels, indicating the feasibility of free-space-based quantum interference in quantum information processing.
Article
Physics, Multidisciplinary
Daniel Llewellyn, Yunhong Ding, Imad I. Faruque, Stefano Paesani, Davide Bacco, Raffaele Santagati, Yan-Jun Qian, Yan Li, Yun-Feng Xiao, Marcus Huber, Mehul Malik, Gary F. Sinclair, Xiaoqi Zhou, Karsten Rottwitt, Jeremy L. O'Brien, John G. Rarity, Qihuang Gong, Leif K. Oxenlowe, Jianwei Wang, Mark G. Thompson
Article
Optics
Tianfeng Feng, Changliang Ren, Qin Feng, Maolin Luo, Xiaogang Qiang, Jing-Ling Chen, Xiaoqi Zhou
Summary: The study formulates the original EPR steering paradox into a contradictory equality, conducts experimental tests in a two-qubit scenario, and confirms that the experimental results coincide with theoretical predictions.
PHOTONICS RESEARCH
(2021)
Article
Physics, Multidisciplinary
Xiaoqian Zhang, Maolin Luo, Zhaodi Wen, Qin Feng, Shengshi Pang, Weiqi Luo, Xiaoqi Zhou
Summary: The study introduces a machine-learning-based method for evaluating quantum state fidelity, which is more flexible and efficient compared to other methods. This approach is applicable to arbitrary quantum states and can achieve high-precision fidelity prediction with fewer measurement settings.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Yang Qian, Zhijin Guan, Shenggen Zheng, Shiguang Feng
Summary: To implement a quantum circuit on an NISQ device, it needs to be transformed into an equivalent circuit that meets the device's connectivity constraints. This study proposes an algorithm based on quantum gate timing weights for subgraph isomorphism, providing a better initial mapping for a specific two-dimensional quantum architecture. Additionally, a heuristic swap sequence selection optimization algorithm is introduced to reduce the number of SWAP gates and optimize the circuit transformation. Experimental results demonstrate the effectiveness of the proposed algorithm, with a maximum optimization rate of 43.51% and an average optimization rate of 13.51%, outperforming existing methods.
Article
Quantum Science & Technology
Minghua Pan, Taiping Xiong, Shenggen Zheng
Summary: This study partially agrees with the loss of quadratic speedup in Grover's search algorithm (GSA) when exposed to quantum noise and presents its findings. It examines different diagonalizable noises in GSA and observes a decrease in success probability and oscillation around 1/2 as the number of iterations increases. The results show that certain types of noise, such as bit flip and bit-phase flip noise, can improve the performance of GSA. The study also determines the noise threshold for bit-phase flip noise and demonstrates that GSA with this noise still outperforms its classical counterpart.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Astronomy & Astrophysics
Tianfeng Feng, Vlatko Vedral
Summary: The article proposes a criterion based on the logical contradictions of weak entanglement to enhance the sensitivity of signals caused by gravitationally induced entanglement. By utilizing the weak-value scenario and EPR steering, the authors prove the impossibility of simulating the amplified-weak-value phenomenon in a classical setting. Their approach can amplify gravitationally induced entanglement signals that were previously unobservable, depending on the magnitude of the weak value, and opens up possibilities for a more general weak entanglement criterion.
Article
Optics
Congxiu Li, Yaxin Wang, Tianfeng Feng, Zhihao Li, Changliang Ren, Xiaoqi Zhou
Summary: This study validates a direct measurement protocol that does not require ancillary pointers and can obtain the values of specific elements of a quantum state's density matrix with a small number of measurements. The experimental results deviate minimally from the ideal values, and this method has potential applications in various quantum information problems.
Article
Physics, Multidisciplinary
Minghua Pan, Haozhen Situ, Shenggen Zheng
Summary: This paper investigates the complementary relationship between coherence and the success probability in Grover search algorithm (GSA) by defining the normalization coherence N(C). The study confirms the stability of this relationship in different environments and demonstrates that manipulating complementary coherence can enhance the success probability, which is of great importance for quantum algorithm design in the NISQ era.
Article
Optics
Changliang Ren, Xiaowei Liu, Wenlin Hou, Tianfeng Feng, Xiaoqi Zhou
Summary: This study discusses the nonlocality sharing in a three-qubit system through multilateral sequential measurements. It is observed that all eight MABK inequalities can be violated simultaneously, leading to the nonlocality sharing based on the multiple violations of MABK inequality in the trilateral sequential measurements scenario. However, genuine nonlocality sharing based on the multiple violation of Svetlichny inequality can only be observed in the unilateral sequential measurements scenario. Compared to two-qubit cases, the nonlocality sharing in a three-qubit system exhibits more fruitful characteristics.
Article
Optics
Maolin Luo, Xiaoqian Zhang, Xiaoqi Zhou
Summary: This paper demonstrates a proof-of-principle optical experiment to implement the quantum gate verification (QGV) scheme. The experimental results show that the QGV method can achieve the same results as the standard quantum process tomography method with fewer samples when evaluating the single-qubit quantum gates.
Article
Optics
Tianfeng Feng, Changliang Ren, Xiaoqi Zhou
Summary: The proposed direct measurement scheme based on phase-shifting operations eliminates the need for ancillary pointers and requires estimating at most six expectation values of projective observables to determine any specific element of an unknown quantum density matrix. A concrete quantum circuit is provided for implementing this scheme for multiqubit states.
Article
Physics, Multidisciplinary
Xing Ze-Yu, Li Zhi-Hao, Feng Tian-Feng, Zhou Xiao-Qi
Summary: This paper proposes a high-speed calibration method in integrated photonics, which achieves exponential acceleration by linearly increasing calibration time with the number of cascades. The method involves calibrating phase shifters one by one via two-dimensional scanning, significantly reducing the calibration time and improving fidelity.
ACTA PHYSICA SINICA
(2021)
Article
Optics
Qin Feng, Tianfeng Feng, Yuling Tian, Maolin Luo, Xiaoqi Zhou
