Article
Optics
Shaoping Shi, Yajun Wang, Long Tian, Wei Li, Yimiao Wu, Qingwei Wang, Yaohui Zheng, Kunchi Peng
Summary: This article presents a fully connected continuous-variable quantum teleportation network architecture, where a squeezed state of light distributes entangled sideband modes to each communication link, offering potential for various tasks of quantum information processing.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
Mingjian He, Robert Malaney, Ryan Aguinaldo
Summary: In this paper, a nondeterministic teleportation protocol combining a Gaussian CV resource state with a modified Bell state measurement is presented, which significantly improves the fidelity of DV-qubits over a wide range of channel losses. Furthermore, the use of non-Gaussian operations on the CV resource state is shown to achieve near unity fidelity for any channel loss.
Article
Quantum Science & Technology
Lydia A. Kanari-Naish, Jack Clarke, Sofia Qvarfort, Michael R. Vanner
Summary: Cavity quantum optomechanics is a new platform for quantum science and technology that has various applications. This work introduces a pulsed approach to generate and verify non-Gaussian states of motion using the nonlinearity of the radiation-pressure interaction and photon-counting measurements. The authors also propose a protocol to measure the quadrature moments of the two mechanical oscillators using pulsed interactions, allowing for experimental characterization of bipartite mechanical quantum states. This scheme provides a new avenue for quantum experiments with entangled mechanical oscillators and has significant potential for quantum-information and sensing applications, as well as studying the quantum-to-classical transition.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Quantum Science & Technology
Ming Li, Yan-Lei Zhang, Xin-Biao Xu, Chun-Hua Dong, Guang-Can Guo, Chang-Ling Zou
Summary: This study explores the continuous-variable quantum entanglement of dissipative Kerr soliton combs in microresonators, uncovering two distinct features: entanglement of comb lines at the spectral edge and diminished entanglement at the center of the spectrum.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Optics
Olena Kovalenko, Vladyslav C. Usenko, Radim Filip
Summary: Two-mode squeezed states are scalable and robust entanglement resources for quantum information protocols;
Optimizing initial squeezing, relative phase, and linear coupling can reduce the degradation of Gaussian entanglement in the presence of crosstalk;
Compensating crosstalk through mode interference improves the efficiency of using multimode continuous-variable photonic entanglement in quantum networks.
Article
Optics
Maria Poxleitner, Haye Hinrichsen
Summary: Inspired by a previously introduced non-Gaussian two-parametric continuous-variable analog of an isotropic state, the study proposes a simple yet interesting Gaussian analog of an isotropic state with a correlation structure controlled by a mixing probability. Different from conventional isotropic states, the Gaussian version here is defined by a convex combination of covariance matrices and exhibits a finite threshold for entanglement in the parameter space, similar to the finite-dimensional two-qubit isotropic state.
Article
Quantum Science & Technology
Bingzhi Zhang, Quntao Zhuang
Summary: The text discusses the importance and dynamic evolution of entanglement in continuous-variable quantum networks, identifying squeezing as the key source of entanglement generation and predicting a surprising linear superposition law in the entanglement growth.
NPJ QUANTUM INFORMATION
(2021)
Article
Optics
Ayan Patra, Rivu Gupta, Saptarshi Roy, Aditi Sen(De)
Summary: In this study, the concept of fidelity deviation is introduced in continuous-variable quantum teleportation, allowing better characterization of CV states by considering both fidelity and fidelity deviation. The performance of the teleportation protocol is also explored in different input scenarios, and the effects of noise on average fidelity and fidelity deviation are investigated.
Article
Optics
Kowsar Al-Sadat Mousavitaha, Ozgur E. Mustecaplioglu, Esfandyar Faizi
Summary: This paper discusses a generalized micromaser setting, where a high-quality cavity is pumped by a beam of three-level atoms. The atoms are assumed to carry quantum coherence between their excited state doublet and are used to produce quantum entanglement between right-handed circular and left-handed circular polarized photons in the cavity.
OPTICS COMMUNICATIONS
(2023)
Article
Optics
Olena Kovalenko, Young-Sik Ra, Yin Cai, Vladyslav C. Usenko, Claude Fabre, Nicolas Treps, Radim Filip
Summary: Quantum key distribution using continuous variables offers high-speed, low-noise homodyne detection and can achieve secure key transmission over long distances. Increasing system clock rates and frequency-mode-multiplexing can further enhance the secret key rate.
PHOTONICS RESEARCH
(2021)
Article
Optics
Ian J. Tillman, Allison Rubenok, Saikat Guha, Kaushik P. Seshadreesan
Summary: In this study, we analyze a single-repeater-enhanced channel model with asymmetric half-channel losses to determine the optimal placements of the central repeater hub in a four-user hub-and-spoke network, aiming to enhance the rate of each entanglement flow.
Article
Optics
Goutam Misra, Ashok Kumar
Summary: This study theoretically investigates the multipartite continuous-variable quadrature entanglement generated by three symmetric cascaded nonlinear optical systems. Different continuous-variable entanglement criteria are used to characterize the entanglement. The results show that only a few bipartite combinations exhibit entanglement, while most tripartite combinations are entangled. Additionally, the negative partial transpose criterion can show entanglement in most cases.
Article
Optics
Qi-Ping Su, Tong Liu, Yu Zhang, Chui-Ping Yang
Summary: This paper presents a new method to generate hybrid maximally entangled states between continuous-variable qudits and discrete-variable qudits using superconducting cavities and cat states. The method is simple to operate, resulting in stable entangled states, and reduced decoherence effects from the qutrit.
Article
Optics
Konrad Schlichtholz, Bianka Woloncewicz, Marek Zukowski
Summary: This study focuses on bright emissions involving higher-order emissions of Greenberger-Horne-Zeilinger-entangled photons, which serve as a natural generalization of the squeezed vacuum. By using Pade approximation to overcome technical difficulties, the researchers are able to study the nonclassicality of the new bright generalized states. Violations of local realism and tailored entanglement indicators for this case are presented in the study.
Article
Physics, Multidisciplinary
B. Kuehn, W. Vogel, V Thiel, S. Merkouche, B. J. Smith
Summary: Measures of quantum properties are essential for understanding the differences between quantum and classical systems, and quantifying resources for quantum technologies. By comparing different filtered versions of the Glauber-Sudarshan P function, this study explores their ability to reveal nonclassical effects of light. It is shown that non-Gaussian filtered quasiprobabilities can uncover significant nonclassical effects even at low efficiencies.
PHYSICAL REVIEW LETTERS
(2021)
Article
Quantum Science & Technology
Seung-Woo Lee, Jaewan Kim, Hyunchul Nha
Summary: Quantum measurement plays multiple roles in quantum technology, including measurement-based quantum computation and protecting quantum information. Efforts have been made to find a balance between information gain and state disturbance, with the reversibility of quantum measurement being crucial for achieving information balance.
Article
Physics, Multidisciplinary
Jiyong Park
Summary: The study introduces a method for deriving a lower bound for a non-Gaussianity measure based on quantum relative entropy and demonstrates its effectiveness compared to previous methods. Additionally, the method is extended to measurements of multi-mode quantum states and finds application in non-Gaussian entanglement detection.
Article
Physics, Multidisciplinary
Jiyong Park
Summary: In this study, we derive accessible upper and lower bounds for quantum mutual information in continuous-variable quantum states. By observing certain functions of purities, we can bound the difference between quantum mutual information and its Gaussian reference. These bounds can be efficiently obtained by measuring purities and the covariance matrix without reconstructing the multimode quantum state. We also extend our approach to derive upper and lower bounds for the quantum total correlation of multimode quantum states and investigate the relations between the bounds for quantum mutual information and quantum conditional entropy.
Article
Physics, Multidisciplinary
Ji Chu, Xiaoyu He, Yuxuan Zhou, Jiahao Yuan, Libo Zhang, Qihao Guo, Yongju Hai, Zhikun Han, Chang-Kang Hu, Wenhui Huang, Hao Jia, Dawei Jiao, Sai Li, Yang Liu, Zhongchu Ni, Lifu Nie, Xianchuang Pan, Jiawei Qiu, Weiwei Wei, Wuerkaixi Nuerbolati, Zusheng Yang, Jiajian Zhang, Zhida Zhang, Wanjing Zou, Yuanzhen Chen, Xiaowei Deng, Xiuhao Deng, Ling Hu, Jian Li, Song Liu, Yao Lu, Jingjing Niu, Dian Tan, Yuan Xu, Tongxing Yan, Youpeng Zhong, Fei Yan, Xiaoming Sun, Dapeng Yu
Summary: Translating high-level global operations into hardware-native logic gates, known as quantum compiling, is crucial for implementing quantum algorithms on realistic devices. By optimizing compilation and demonstrating low-depth synthesis of quantum logic gates on a superconducting quantum processor, the efficiency of near-term quantum computers can be substantially improved, enabling more meaningful quantum applications on noisy devices.
Article
Optics
Woochang Shin, Changsuk Noh, Jiyong Park
Summary: We derive quantum Renyi-2 entropy power inequalities for Gaussian operations and show that they generalize known quantum von Neumann entropy power inequalities for Gaussian states. However, they do not hold for non-Gaussian states. We also derive quantum Renyi-2 entropy power inequalities that provide lower bounds for Gaussian operations for any state. The inequality for the squeezing operation has applications in the generation and detection of quantum entanglement.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Wentao Chen, Yao Lu, Shuaining Zhang, Kuan Zhang, Guanhao Huang, Mu Qiao, Xiaolu Su, Jialiang Zhang, Jing-Ning Zhang, Leonardo Banchi, M. S. Kim, Kihwan Kim
Summary: A minimal-loss programmable phononic network is demonstrated, which can deterministically prepare and detect any phononic state. The network can be extended to reveal quantum advantage and has high reconstruction fidelities for both single- and two-phonon states.
Article
Optics
Jaehak Lee, Jiyong Park, Jaewan Kim, M. S. Kim, Hyunchul Nha
Summary: Homodyne measurement is a crucial tool for addressing continuous variables in bosonic quantum systems. However, the use of a strong coherent local oscillator is not readily available for massive quantum systems like a Bose-Einstein condensate, making it necessary to establish a practical framework that includes the effects of nonideal local oscillators. We develop entanglement criteria beyond a Gaussian regime for realistic homodyne measurement, which do not require assumptions on the state of local oscillators.
Article
Physics, Multidisciplinary
Jaehak Lee, Kyunghyun Baek, Jiyong Park, Jaewan Kim, Hyunchul Nha
Summary: This paper investigates how to protect quantum resources from noise and identifies the fundamental limitations on concentrating and preserving these resources. By studying the properties of resource measures and the application of correlated input states, it reveals how to manipulate quantum resources more effectively.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Multidisciplinary
Jiyong Park, Jaehak Lee, Hyunchul Nha
Summary: By establishing a framework of nonclassicality in phase space, we comprehensively address the characterization of nonclassical states and effectively detect all nonclassical Gaussian and non-Gaussian states. Importantly, our method provides an experimentally accessible lower bound for a nonclassicality measure and can be adapted for practical tests looking into the particle and wave nature of bosonic systems.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Optics
Jiyong Park, Jaehak Lee, Kyunghyun Baek, Hyunchul Nha
Summary: The study proposes a non-Gaussianity measure for a multimode quantum state based on the negentropy of quadrature distributions, which satisfies ideal properties such as faithfulness, invariance under Gaussian unitary operations, and monotonicity under Gaussian channels. A quantitative relation is found between this measure and previously proposed non-Gaussianity measures, allowing for estimation through homodyne detection without the need for full quantum-state tomography.