High-capacity,long-distance underwater optical communication enables a global scale optical network covering orbit,land,and water.Underwater communication using photons as carriers has a high channel capacity;however,...High-capacity,long-distance underwater optical communication enables a global scale optical network covering orbit,land,and water.Underwater communication using photons as carriers has a high channel capacity;however,the light scattering and absorption of water lead to an inevitable huge channel loss,setting an insurmountable transmission distance for existing underwater optical communication technologies.Here,we experimentally demonstrate the photon-inter-correlation optical communication(PICOC)in air-water scenarios.We retrieve additional internal correlation resources from the sparse single-photon stream with high fidelity.We successfully realize the 105-m-long underwater optical communication against a total loss up to 120.1 d B using only a microwatt laser.The demonstrated underwater light attenuation is equivalent to the loss of 883-m-long Jerlov type I water,encouraging the practical air-water optical communication to connect deeper underwater worlds.展开更多
Nondeterministic-polynomial-time(NP)-complete problems are widely involved in various reallife scenarios but are still intractable in being solved efficiently on conventional computers.It is of great practical signifi...Nondeterministic-polynomial-time(NP)-complete problems are widely involved in various reallife scenarios but are still intractable in being solved efficiently on conventional computers.It is of great practical significance to construct versatile computing architectures that solve NP-complete problems with computational advantage.Here,we present a reconfigurable integrated photonic processor to efficiently solve a benchmark NP-complete problem,the subset sum problem.We show that in the case of successive primes,the photonic processor has genuinely surpassed electronic processors launched recently by taking advantage of the high propagation speed and vast parallelism of photons and state-of-the-art integrated photonic technology.Moreover,we are able to program the photonic processor to tackle different problem instances,relying on the tunable integrated modules,variable split junctions,which can be used to build a fully reconfigurable architecture potentially allowing 2^(N) configurations at most.Our experiments confirm the potential of the photonic processor as a versatile and efficient computing platform,suggesting a possible practical route to solving computationally hard problems at a large scale.展开更多
Squeezed light is a critical resource in quantum sensing and information processing. Due to the inherently weak optical nonlinearity and limited interaction volume, considerable pump power is typically needed to obtai...Squeezed light is a critical resource in quantum sensing and information processing. Due to the inherently weak optical nonlinearity and limited interaction volume, considerable pump power is typically needed to obtain efficient interactions to generate squeezed light in bulk crystals. Integrated photonics offers an elegant way to increase the nonlinearity by confining light strictly inside the waveguide. For the construction of large-scale quantum systems performing many-photon operations, it is essential to integrate various functional modules on a chip. However, fabrication imperfections and transmission cross talk may add unwanted diffraction and coupling to other photonic elements, reducing the quality of squeezing. Here, by introducing the topological phase, we experimentally demonstrate the topologically protected nonlinear process of four-wave mixing, enabling the generation of squeezed light on a silica chip. We measure the cross-correlations at different evolution distances for various topological sites and verify the nonclassical features with high fidelity. The squeezing parameters are measured to certify the protection of cavity-free, strongly squeezed states. The demonstration of topological protection for squeezed light on a chip brings new opportunities for quantum integrated photonics,opening novel approaches for the design of advanced multi-photon circuits.展开更多
Dynamic localization,which originates from the phenomena of particle evolution suppression under an externally applied AC electric field,has been simulated by suppressed light evolution in periodically curved photonic...Dynamic localization,which originates from the phenomena of particle evolution suppression under an externally applied AC electric field,has been simulated by suppressed light evolution in periodically curved photonic arrays.However,experimental studies on their quantitative dynamic transport properties and application for quantum information processing are rare.Here we fabricate one-dimensional and hexagonal two-dimensional arrays both with sinusoidal curvatures.We successfully observe the suppressed single-photon evolution patterns,and for the first time,to the best of our knowledge,measure the variances to study their transport properties.For onedimensional arrays,the measured variances match both the analytical electric-field calculation and the quantum walk Hamiltonian engineering approach.For hexagonal arrays as anisotropic effective couplings in four directions are mutually dependent,the analytical approach suffers,whereas quantum walk conveniently incorporates all anisotropic coupling coefficients in the Hamiltonian and solves its exponential as a whole,yielding consistent variances with our experimental results.Furthermore,we implement a nearly complete localization to show that it can preserve both the initial injection and the wave packet after some evolution,acting as a memory of a flexible time scale in integrated photonics.We demonstrate a useful quantum simulation of dynamic localization for studying their anisotropic transport properties and a promising application of dynamic localization as a building block for quantum information processing in integrated photonics.展开更多
Quantum walks provide a speed-up in computational power for various quantum algorithms and serve as inspiration for the construction of complex graph representations.Many pioneering works have been dedicated to expand...Quantum walks provide a speed-up in computational power for various quantum algorithms and serve as inspiration for the construction of complex graph representations.Many pioneering works have been dedicated to expanding the experimental state space and the complexity of graphs.However,these experiments are mostly limited to small experimental scale,which do not reach a many-body level and fail to reflect the multi-particle quantum interference effects among non-adjacent modes.Here,we present a quantum walk with three photons on a two-dimensional triangular lattice,which is mapped to a 19×19×19 high-dimensional state space and constructs a complex graph with 6859 nodes and 45,486 edges.By utilizing the statistical signatures of the output combinations and incorporating machine learning techniques,we successfully validate the nonclassical properties of the experiment.Our implementation provides a paradigm for exponentially expanding the state space and graph complexity of quantum walks,paving the way for surmounting the classical regime in large-scale quantum simulations.展开更多
To realize a large-scale quantum network,both quantum memory and the interference of retrieved indistinguishable photons are essentially required to perform multi-photon synchronization and quantum-interference-mediat...To realize a large-scale quantum network,both quantum memory and the interference of retrieved indistinguishable photons are essentially required to perform multi-photon synchronization and quantum-interference-mediated entanglement swapping.Significant progress has been achieved in low-temperature and well-isolated systems.However,linking independent quantum memories at room temperature remain challenging.Here,we present an experimental demonstration of Hong–Ou–Mandel interference between single photons from two independent room-temperature quantum memories.We manage to simultaneously operate two such quantum memories and individually obtain a memory-built-in quantum correlation of Stokes and anti-Stokes photons by a far-off-resonance Duan–Lukin–Cirac–Zoller protocol.We also successfully enhance the Hong–Ou–Mandel interference rate up to about 15 times by increasing each photon rate,which is achieved by coordinating two quantum memories with a repeat-until-success fashion.We observe the visibility of quantum interference up to 75.0%without reduction of any background noise,well exceeding the classical limit of 50%.Our results,together with its straightforward,broadband,and room-temperature features,open up a promising way towards realizing large-scale quantum networks at ambient conditions.展开更多
基金National Key Research and Development Program of China(2019YFA0706302,2017YFA0303700,2019YFA0308700)National Natural Science Foundation of China(11690033,11761141014,11904229,61734005)+2 种基金Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Shanghai Municipal Education Commission(2017-01-07-00-02-E00049)Science and Technology Commission of Shanghai Municipality(17JC1400403)。
文摘High-capacity,long-distance underwater optical communication enables a global scale optical network covering orbit,land,and water.Underwater communication using photons as carriers has a high channel capacity;however,the light scattering and absorption of water lead to an inevitable huge channel loss,setting an insurmountable transmission distance for existing underwater optical communication technologies.Here,we experimentally demonstrate the photon-inter-correlation optical communication(PICOC)in air-water scenarios.We retrieve additional internal correlation resources from the sparse single-photon stream with high fidelity.We successfully realize the 105-m-long underwater optical communication against a total loss up to 120.1 d B using only a microwatt laser.The demonstrated underwater light attenuation is equivalent to the loss of 883-m-long Jerlov type I water,encouraging the practical air-water optical communication to connect deeper underwater worlds.
基金supported by the National Key R&D Program of China (Grants Nos. 2019YFA0308703, 2019YFA07063022017YFA0303700)+7 种基金the National Natural Science Foundation of China (NSFC)(Grant Nos. 62235012, 12104299,61734005, 11761141014, 11690033, 11904299, and 12304342)the Innovation Program for Quantum Science and Technology(Grant Nos. 2021ZD0301500 and 2021ZD0300700)the Science and Technology Commission of Shanghai Municipality(STCSM)(Grant Nos. 20JC1416300, 2019SHZDZX01,21ZR1432800, and 22QA1404600)the Shanghai Municipal Education Commission (SMEC)(Grant No. 2017-01-07-00-02-E00049)the China Postdoctoral Science Foundation (Grant Nos. 2022T150415, 2021M692094, and 2020M671091)the Startup Fund for Young Faculty at SJTU (SFYF at SJTU)additional support from a Shanghai Talent Programsupport from the Zhiyuan Innovative Research Center of Shanghai Jiao Tong University
文摘Nondeterministic-polynomial-time(NP)-complete problems are widely involved in various reallife scenarios but are still intractable in being solved efficiently on conventional computers.It is of great practical significance to construct versatile computing architectures that solve NP-complete problems with computational advantage.Here,we present a reconfigurable integrated photonic processor to efficiently solve a benchmark NP-complete problem,the subset sum problem.We show that in the case of successive primes,the photonic processor has genuinely surpassed electronic processors launched recently by taking advantage of the high propagation speed and vast parallelism of photons and state-of-the-art integrated photonic technology.Moreover,we are able to program the photonic processor to tackle different problem instances,relying on the tunable integrated modules,variable split junctions,which can be used to build a fully reconfigurable architecture potentially allowing 2^(N) configurations at most.Our experiments confirm the potential of the photonic processor as a versatile and efficient computing platform,suggesting a possible practical route to solving computationally hard problems at a large scale.
基金National Key R&D Program of China(2019YFA0308700, 2019YFA0706302, 2017YFA0303700)National Natural Science Foundation of China (NSFC)(11904229, 61734005, 11761141014, 11690033)+4 种基金Science and Technology Commission of Shanghai Municipality (STCSM)(20JC1416300, 2019SHZDZX01)Shanghai Municipal Education Commission (SMEC)(2017-01-07-00-02-E00049)China Postdoctoral Science Foundation (2020M671091)Australian Research Council (DE180100070)University of Technology Sydney Seed Fund。
文摘Squeezed light is a critical resource in quantum sensing and information processing. Due to the inherently weak optical nonlinearity and limited interaction volume, considerable pump power is typically needed to obtain efficient interactions to generate squeezed light in bulk crystals. Integrated photonics offers an elegant way to increase the nonlinearity by confining light strictly inside the waveguide. For the construction of large-scale quantum systems performing many-photon operations, it is essential to integrate various functional modules on a chip. However, fabrication imperfections and transmission cross talk may add unwanted diffraction and coupling to other photonic elements, reducing the quality of squeezing. Here, by introducing the topological phase, we experimentally demonstrate the topologically protected nonlinear process of four-wave mixing, enabling the generation of squeezed light on a silica chip. We measure the cross-correlations at different evolution distances for various topological sites and verify the nonclassical features with high fidelity. The squeezing parameters are measured to certify the protection of cavity-free, strongly squeezed states. The demonstration of topological protection for squeezed light on a chip brings new opportunities for quantum integrated photonics,opening novel approaches for the design of advanced multi-photon circuits.
基金National Natural Science Foundation of China(11690033,11761141014,11904229,61734005)National Key Research and Development Program of China(2017YFA0303700,2019YFA0308700,2019YFA0706302)+2 种基金Science and Technology Commission of Shanghai Municipality(STCSM)(21ZR1432800,20JC1416300,2019SHZDZX01)Shanghai Municipal Education Commission(SMEC)(2017-01-07-00-02-E00049)Shanghai talent program,Shanghai Jiao Tong University。
文摘Dynamic localization,which originates from the phenomena of particle evolution suppression under an externally applied AC electric field,has been simulated by suppressed light evolution in periodically curved photonic arrays.However,experimental studies on their quantitative dynamic transport properties and application for quantum information processing are rare.Here we fabricate one-dimensional and hexagonal two-dimensional arrays both with sinusoidal curvatures.We successfully observe the suppressed single-photon evolution patterns,and for the first time,to the best of our knowledge,measure the variances to study their transport properties.For onedimensional arrays,the measured variances match both the analytical electric-field calculation and the quantum walk Hamiltonian engineering approach.For hexagonal arrays as anisotropic effective couplings in four directions are mutually dependent,the analytical approach suffers,whereas quantum walk conveniently incorporates all anisotropic coupling coefficients in the Hamiltonian and solves its exponential as a whole,yielding consistent variances with our experimental results.Furthermore,we implement a nearly complete localization to show that it can preserve both the initial injection and the wave packet after some evolution,acting as a memory of a flexible time scale in integrated photonics.We demonstrate a useful quantum simulation of dynamic localization for studying their anisotropic transport properties and a promising application of dynamic localization as a building block for quantum information processing in integrated photonics.
基金supported by the National Key R&D Program of China(Grants No.2019YFA0308703,No.2019YFA0706302,and No.2017YFA0303700)National Natural Science Foundation of China(NSFC)(Grants No.62235012,No.11904299,No.61734005,No.11761141014,and No.11690033,No.12104299,and No.12304342)+4 种基金Innovation Program for Quantum Science and Technology(Grants No.2021ZD0301500,and No.2021ZD0300700)Science and Technology Commission of Shanghai Municipality(STCSM)(Grants No.20JC1416300,No.2019SHZDZX01,No.21ZR1432800,and No.22QA1404600)Shanghai Municipal Education Commission(SMEC)(Grants No.2017-01-07-00-02-E00049)China Postdoctoral Science Foundation(Grants No.2020M671091,No.2021M692094,No.2022T150415)support from a Shanghai talent program and support from Zhiyuan Innovative Research Center of Shanghai Jiao Tong University.
文摘Quantum walks provide a speed-up in computational power for various quantum algorithms and serve as inspiration for the construction of complex graph representations.Many pioneering works have been dedicated to expanding the experimental state space and the complexity of graphs.However,these experiments are mostly limited to small experimental scale,which do not reach a many-body level and fail to reflect the multi-particle quantum interference effects among non-adjacent modes.Here,we present a quantum walk with three photons on a two-dimensional triangular lattice,which is mapped to a 19×19×19 high-dimensional state space and constructs a complex graph with 6859 nodes and 45,486 edges.By utilizing the statistical signatures of the output combinations and incorporating machine learning techniques,we successfully validate the nonclassical properties of the experiment.Our implementation provides a paradigm for exponentially expanding the state space and graph complexity of quantum walks,paving the way for surmounting the classical regime in large-scale quantum simulations.
基金National Key Research and Development Program of China(2019YFA0706302,2019YFA0308700,2017YFA0303700)National Natural Science Foundation of China(NSFC)(11904229,61734005,11761141014,11690033)+4 种基金Science and Technology Commission of Shanghai Municipality(STCSM)(20JC1416300,2019SHZDZX01)Shanghai Municipal Education Commission(SMEC)(2017-01-07-00-02-E00049)China Postdoctoral Science Foundation(2020M671091)Shanghai Talent ProgramZhiyuan Innovative Research Center of Shanghai Jiao Tong University.
文摘To realize a large-scale quantum network,both quantum memory and the interference of retrieved indistinguishable photons are essentially required to perform multi-photon synchronization and quantum-interference-mediated entanglement swapping.Significant progress has been achieved in low-temperature and well-isolated systems.However,linking independent quantum memories at room temperature remain challenging.Here,we present an experimental demonstration of Hong–Ou–Mandel interference between single photons from two independent room-temperature quantum memories.We manage to simultaneously operate two such quantum memories and individually obtain a memory-built-in quantum correlation of Stokes and anti-Stokes photons by a far-off-resonance Duan–Lukin–Cirac–Zoller protocol.We also successfully enhance the Hong–Ou–Mandel interference rate up to about 15 times by increasing each photon rate,which is achieved by coordinating two quantum memories with a repeat-until-success fashion.We observe the visibility of quantum interference up to 75.0%without reduction of any background noise,well exceeding the classical limit of 50%.Our results,together with its straightforward,broadband,and room-temperature features,open up a promising way towards realizing large-scale quantum networks at ambient conditions.
