Article
Optics
Yuan-Yuan Zhao, Chao Zhang, Shuming Cheng, Xinhui LI, Yu Guo, Bi-Heng Liu, Huan-Yu Ku, Shin-Liang Chen, Qiaoyan Wen, Yun-Feng Huang, Guo-Yong Xiang, Chuan-Feng LI, Guang-Can Guo
Summary: This work proposes and experimentally demonstrates a device-independent protocol for certifying the presence of entanglement based on Einstein-Podolsky-Rosen (EPR) steering. The protocol is able to verify all bipartite EPR-steerable states by taking advantage of a measurement-device-independent technique and self-testing. This work provides further insight into quantum physics and could facilitate the realistic implementation of secure quantum information processing tasks.
Article
Physics, Multidisciplinary
Barbara Soda, Vivishek Sudhir, Achim Kempf
Summary: In addition to the Unruh effect, acceleration can induce transparency and stimulated Unruh effect in the quantum theory of the light-matter interaction. These new phenomena have the potential to be observed experimentally.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Ya-Dong Wu, Ge Bai, Giulio Chiribella, Nana Liu
Summary: Continuous-variable quantum information, encoded into infinite-dimensional quantum systems, is a promising platform for many quantum information protocols. It is essential to have reliable protocols for verifying multimode continuous-variable entangled states and devices, particularly in realistic scenarios where identical and independent operations cannot be guaranteed. This letter proposes the first set of protocols for verifying such states and devices in non-i.i.d scenarios, applicable to various types of quantum states and operations.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
C. Greganti, T. F. Demarie, M. Ringbauer, J. A. Jones, V Saggio, I. Alonso Calafell, L. A. Rozema, A. Erhard, M. Meth, L. Postler, R. Stricker, P. Schindler, R. Blatt, T. Monz, P. Walther, J. F. Fitzsimons
Summary: The study introduces a cross-verification technique that utilizes the principles of quantum computation for checking the results of quantum computers. Through consistency checks of different quantum circuits, the technique enables verification of quantum computations between independent devices and within a single device.
Article
Quantum Science & Technology
Ye-Chao Liu, Yinfei Li, Jiangwei Shang, Xiangdong Zhang
Summary: Quantum state verification (QSV) is the task of verifying the desired target state of a quantum device using local measurements only. Despite efficient verification protocols for certain types of entangled states, designing the verification protocol for arbitrary entangled states remains an open problem. This study presents a systematic strategy by considering the locality of choice-independent measurement protocols and demonstrates the superiority of the method using standard Pauli projections to attain better QSV strategies. The framework can also be extended to other tasks such as entanglement witnesses and parameter estimation.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Physics, Multidisciplinary
Yong Yu, Peng-Fei Sun, Yu-Zhe Zhang, Bing Bai, Yu-Qiang Fang, Xi-Yu Luo, Zi-Ye An, Jun Li, Jun Zhang, Feihu Xu, Xiao-Hui Bao, Jian-Wei Pan
Summary: In this experiment, an atomic-ensemble quantum memory was verified using a measurement-device-independent scheme. A single photon was stored in one atomic ensemble and later retrieved for interference with a second photon for a joint Bell-state measurement. By evaluating correlations between random states and BSM results, the memory's ability to preserve entanglement was confirmed.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
Yong'an Liu, Lizhi Sheng, Hui Zhao, Jinshou Tian, Baosheng Zhao
Summary: A visible light photon-counting imaging detector was developed for weak light intensities, showing promising performance in photon-counting radars and biofluorescence imaging applications. The detector had a quantum efficiency of 13.4% (@532 nm) and spatial resolution better than 100 µm, with preliminary imaging results obtained for real objects.
JOURNAL OF MODERN OPTICS
(2021)
Article
Optics
Kai Sun, Zi-Jian Zhang, Fei Meng, Bin Cheng, Zhu Cao, Jin-Shi Xu, Man-Hong Yung, Chuan-Feng Li, Guang-Can Guo
Summary: In this study, an efficient method for simplifying the verification of group non-membership is proposed and experimentally demonstrated, validating its effectiveness by observing a significant probability gap and providing a potential foundation for constructing more quantum protocols based on near-term quantum devices.
PHOTONICS RESEARCH
(2021)
Review
Quantum Science & Technology
Joshua Morris, Valeria Saggio, Aleksandra Gocanin, Borivoje Dakic
Summary: As quantum technologies advance, verifying and estimating large entangled systems remains a major challenge in reliable quantum information processing. This review article presents novel techniques that overcome the limitations of current methods and can be applied to systems of arbitrary dimension.
ADVANCED QUANTUM TECHNOLOGIES
(2022)
Article
Engineering, Electrical & Electronic
Yifeng Xiong, Daryus Chandra, Soon Xin Ng, Lajos Hanzo
Summary: State-of-the-art noisy intermediate-scale quantum computers require low-complexity techniques for the mitigation of computational errors inflicted by quantum decoherence. Symmetry verification constitutes a class of quantum error mitigation (QEM) techniques. Inspired by the benefits of quantum switch in the quantum communication theory, we propose beneficial techniques for circuit-oriented symmetry verification that are capable of verifying the commutativity of quantum circuits without the knowledge of the quantum state. The applicability and implementational strategies of the proposed techniques are demonstrated by using practical quantum algorithms, including the quantum Fourier transform (QFT) and the quantum approximate optimization algorithm (QAOA).
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2023)
Article
Physics, Multidisciplinary
Peter Bierhorst, Jitendra Prakash
Summary: Based on new definitions, a multiparty behavior is considered genuinely multipartite nonlocal (GMNL) if it cannot be modeled by measurements on an underlying network of bipartite-only nonlocal resources, possibly supplemented with shared local resources. Different definitions allow or prohibit entangled measurements and superquantum behaviors on the bipartite resources. This paper categorizes the hierarchy of these new candidate definitions of GMNL in three-party quantum networks, revealing the connection to device-independent witnesses of network effects.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Saleh Rahimi-Keshari, Mohammad Mehboudi, Dario De Santis, Daniel Cavalcanti, Antonio Acin
Summary: Measurement incompatibility, a distinguishing property of quantum physics, is explored in this study using phase-space quasiprobability distributions. The research establishes a connection between nonclassicality and measurement incompatibility, particularly focusing on incompatibility-breaking channels for bosonic systems and Gaussian channels. Useful tools for investigating the effects of errors and imperfections on measurement incompatibility are provided, with the application of the approach illustrated on single-mode Gaussian channels.
Article
Multidisciplinary Sciences
Xi Chen, Bin Cheng, Zhaokai Li, Xinfang Nie, Nengkun Yu, Man-Hong Yung, Xinhua Peng
Summary: The study explores a cryptographic verification scheme for quantum cloud computing, finding that the NMR processor can be validated with 1.4% error using the scheme, while the IBM quantum cloud currently has a fidelity too low to pass the test.
Article
Physics, Multidisciplinary
Yu-Guang Yang, Xin-Long Lv, Shang Gao, Yi-Hua Zhou, Wei-Min Shi
Summary: This article presents a detector-device-independent (DDI) quantum key agreement (QKA) protocol based on single-photon Bell-state measurement. The protocol utilizes time-bin and path encoding to achieve complete Bell-state measurement, eliminating detector-side-channels. The proposed protocol satisfies the requirements for a secure QKA protocol and can be implemented using linear optical elements.
INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS
(2022)
Article
Optics
Xiaodong Zheng, Peiyu Zhang, Renyou Ge, Liangliang Lu, Guanglong He, Qi Chen, Fangchao Qu, Labao Zhang, Xinlun Cai, Yanqing Lu, Shining Zhu, Peiheng Wu, Xiao-Song Ma
Summary: Integrated photonics offers a way to miniaturize and enhance the performance of quantum key distribution (QKD) devices, with single-photon detectors being a key element. By integrating detectors onto photonic chips and utilizing time-bin encoded qubits and optimal Bell-state measurements, the key rate of measurement-device-independent QKD (MDI-QKD) can be increased, laying the foundation for a QKD network with untrusted relays.
ADVANCED PHOTONICS
(2021)
Article
Optics
G. S. Thekkadath, S. Sempere-Llagostera, B. A. Bell, R. B. Patel, M. S. Kim, I. A. Walmsley
Summary: In this study, the discrimination of binary-phase-shifted coherent states at a telecom wavelength was successfully achieved using a photon-number-resolving detector, the transition-edge sensor, resulting in a bit error probability that exceeds the standard quantum limit by up to 7.7 dB. This improvement persists for signals containing up to approximately seven photons on average and can be achieved in a single shot, making the approach compatible with larger bandwidths.
Article
Quantum Science & Technology
David Drahi, Demid Sychev, Khurram K. Pirov, Ekaterina A. Sazhina, Valeriy A. Novikov, Ian A. Walmsley, A. Lvovsky
Summary: This paper focuses on the interconversion between the dual-rail and single-rail encodings of quantum information in optical qubits. The study demonstrates the necessity of completing the conversion between the three primary encodings of a qubit in the optical field to achieve cohesive quantum networks.
Article
Optics
Hang Li, Jian-Peng Dou, Xiao-Ling Pang, Tian-Huai Yang, Chao-Ni Zhang, Yuan Chen, Jia-Ming Li, Ian A. Walmsley, Xian-Min Jin
Summary: This paper reports the heralding quantum entanglement between two atomic ensembles at room temperature, demonstrating the existence of a single excitation delocalized in two atomic ensembles. The findings pave the way for constructing quantum networks and distributing entanglement across multiple remote nodes at ambient conditions.
Article
Quantum Science & Technology
T. J. Sturges, T. McDermott, A. Buraczewski, W. R. Clements, J. J. Renema, S. W. Nam, T. Gerrits, A. Lita, W. S. Kolthammer, A. Eckstein, I. A. Walmsley, M. Stobinska
Summary: Research has shown that utilizing higher-order Fock states for quantum simulations can effectively reveal topological matter, simulate non-linear systems, and elucidate a perfect quantum transfer mechanism.
NPJ QUANTUM INFORMATION
(2021)
Article
Optics
B. A. Bell, I. A. Walmsley
Summary: Quantum integrated photonics require large-scale linear optical circuitry with a universally programmable circuit to implement arbitrary unitary transformations. The Reck scheme achieves this using Mach-Zehnder interferometers, while the Clements scheme improves circuit depth efficiency.
Article
Optics
S. Sempere-Llagostera, G. S. Thekkadath, R. B. Patel, W. S. Kolthammer, I. A. Walmsley
Summary: In this study, we use the photon-number resolving capabilities of commercial superconducting nanowire single-photon detectors to improve the quality of single photons generated through nonlinear processes. Our results demonstrate the feasibility of enhancing the quality of heralded single-photon sources using readily available technology.
Article
Physics, Multidisciplinary
G. S. Thekkadath, B. A. Bell, R. B. Patel, M. S. Kim, I. A. Walmsley
Summary: The article presents a scheme for measuring the time-frequency structure of quantum light and demonstrates its effectiveness through experiments. The proposed method does not require phase stability, nonlinearities, or spectral shaping, making it a simple and practical way to measure the modal structure of quantum light.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Jacob F. F. Bulmer, Bryn A. Bell, Rachel S. Chadwick, Alex E. Jones, Diana Moise, Alessandro Rigazzi, Jan Thorbecke, Utz-Uwe Haus, Thomas Van Vaerenbergh, Raj B. Patel, Ian A. Walmsley, Anthony Laing
Summary: Identifying the boundary at which quantum machines provide a computational advantage over classical counterparts is crucial. Gaussian boson sampling (GBS), which involves measuring photons from a highly entangled Gaussian state, is a leading approach in pursuing quantum advantage. This paper presents faster classical GBS simulation methods and introduces an efficient distribution for classical sampling that passes various GBS validation methods.
Article
Optics
Bangshan Sun, Fyodor Morozko, Patrick S. Salter, Simon Moser, Zhikai Pong, Raj B. Patel, Ian A. Walmsley, Mohan Wang, Adir Hazan, Nicolas Barre, Alexander Jesacher, Julian Fells, Chao He, Aviad Katiyi, Zhen-Nan Tian, Alina Karabchevsky, Martin J. Booth
Summary: This paper reports a new method for femtosecond laser writing of optical-fiber-compatible glass waveguides, which enables high precision and low loss control of waveguide cross-sections. The fabricated waveguides show high refractive index contrast, low propagation loss, and low coupling loss, and they can operate across a broad range of wavelengths.
LIGHT-SCIENCE & APPLICATIONS
(2022)
Article
Physics, Multidisciplinary
S. Sempere-Llagostera, R. B. Patel, I. A. Walmsley, W. S. Kolthammer
Summary: Gaussian boson sampling is a concept in quantum computing that involves drawing samples from a nonclassical Gaussian state using photon-number resolving detectors. In this study, we experimentally implement Gaussian boson sampling using a time-bin encoded interferometer and find improvements in searching for dense subgraphs in a graph.
Article
Physics, Applied
S. E. Thomas, S. Sagona-Stophel, Z. Schofield, I. A. Walmsley, P. M. Ledingham
Summary: This paper reports a telecommunications wavelength- and bandwidth-compatible quantum memory, which enables efficient storage and on-demand retrieval of quantum optical states. It is an essential technology for future terrestrial-based quantum optical networking. The memory demonstrates a total internal efficiency of 20.90(1)% and a Doppler-limited storage time of 1.10(2) ns using the Off-Resonant Cascaded Absorption protocol in hot 87Rb vapor.
PHYSICAL REVIEW APPLIED
(2023)
Article
Multidisciplinary Sciences
F. H. B. Somhorst, R. van der Meer, M. Correa Anguita, R. Schadow, H. J. Snijders, M. de Goede, B. Kassenberg, P. Venderbosch, C. Taballione, J. P. Epping, H. H. van den Vlekkert, J. Timmerhuis, J. F. F. Bulmer, J. Lugani, I. A. Walmsley, P. W. H. Pinkse, J. Eisert, N. Walk, J. J. Renema
Summary: This study demonstrates that in a unitarily evolving system, single-mode measurements can converge to a thermal state using photons in an integrated optical interferometer. The resolution to the paradox between unitary evolution and the second law of thermodynamics is the recognition that the global unitary evolution of a multi-partite quantum state causes local subsystems to evolve towards maximum-entropy states. The experiment utilizes a programmable integrated quantum photonic processor to manipulate quantum states and shows the potential of photonic devices for simulating non-Gaussian states.
NATURE COMMUNICATIONS
(2023)
Proceedings Paper
Instruments & Instrumentation
Georg Enzian, Lars Freisem, John J. Price, Andreas O. Svela, Jack Clarke, Magdalena Szczykulska, Joshua Nunn, Ian Walmsley, Jonathan Silver, Leonardo Del Bino, Shuangyou Zhang, Pascal Del'Haye, Biveen Shajilal, Jiri Janousek, Ben C. Buchler, Ping Koy Lam, Michael R. Vanner
Summary: Research on backward Brillouin scattering in whispering-gallery-mode micro-resonators provides a promising avenue for both classical and quantum optomechanics applications. Our team, in collaboration with others, is utilizing this regime to prepare non-Gaussian motional states of the acoustic field. Recent experimental results include Brillouin optomechanical strong coupling, manipulation of thermal states by adding or subtracting single phonons, and phase-space tomography of non-Gaussian states generated by subtracting single or multiple phonons.
OPTICAL AND QUANTUM SENSING AND PRECISION METROLOGY II
(2022)
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
D. Main, T. M. Hird, S. Gao, E. Oguz, D. J. Saunders, I. A. Walmsley, P. M. Ledingham
Summary: Quantum memories play a crucial role in enabling large-scale quantum networks, requiring strict requirements such as storage time, retrieval efficiency, bandwidth, and scalability. On warm atomic vapor platforms, both on- and off-resonant ladder protocols show promise in combining efficient high-bandwidth operation with on-demand retrieval, though the storage time is limited by motion-induced dephasing from the broad velocity distribution of atoms. However, velocity selective optical pumping has been demonstrated here to overcome this decoherence mechanism, potentially increasing the achievable memory storage time for vapor memories.
