Physical review. A/Physical review, A, Journal Year: 2023, Volume and Issue: 107(5)
Published: May 30, 2023
The authors investigate the dimensionality of photonic quantum entanglement distributed through a 10.2-km atmospheric link connecting building in center Vienna to distant laboratory Bisamberg. An atypical approach time-bin encoding was employed analyze data. results show that data cannot be explained by qubits alone, indicating presence high-dimensional system.
Language: Английский
Quantum Information Processing, Journal Year: 2021, Volume and Issue: 20(3)
Published: March 1, 2021
Language: Английский
Citations
47
Physical Review Applied, Journal Year: 2021, Volume and Issue: 15(3)
Published: March 1, 2021
High-dimensional entanglement promises to increase the information capacity of photons and is now routinely generated, exploiting spatiotemporal degrees freedom single photons. A curious feature these systems possibility certifying despite strong noise in data. We show that it also possible exploit this noisy high-dimensional for quantum key distribution by introducing a protocol uses multiple subspaces system simultaneously. Our can be used establish secret even extremely experimental conditions, where qubit protocols fail. To that, we analyze performance our models apply two most commonly sources entanglement: time bins spatial modes.
Language: Английский
Citations
45
Physical Review Letters, Journal Year: 2023, Volume and Issue: 130(5)
Published: Feb. 3, 2023
High-dimensional (HD) entanglement enables an encoding of more bits than in the two-dimensional case and promises to increase communication capacity over quantum channels improve robustness noise. In practice, however, one central challenges is devise efficient methods quantify HD explicitly. Full state tomography a standard technology obtain all information about state, but it becomes impractical because required measurements exponentially with dimension systems. Hence, highly anticipated that new method will be found for characterizing as few possible without introducing unwarranted assumptions. Here, we present demonstrate scan-free independent dimension, which only requires two characterization two-photon orbital angular momentum (OAM) entanglement. Taking Laguerre-Gaussian modes photons example, density matrices OAM entangled states are experimentally reconstructed very high fidelity. Our also generalized mixed results provide realistic approaches quantifying complex many scientific engineering fields such multiphoton systems process tomography.
Language: Английский
Citations
19
Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)
Published: Oct. 2, 2024
Language: Английский
Citations
8
Physical Review Letters, Journal Year: 2021, Volume and Issue: 127(11)
Published: Sept. 10, 2021
Entanglement-based quantum communication offers an increased level of security in practical secret shared key distribution. One the fundamental principles enabling this security---the fact that interfering with one photon will destroy entanglement and thus be detectable---is also greatest obstacle. Random encounters traveling photons, losses, technical imperfections make noise inevitable part any scheme, severely limiting distance, rate, environmental conditions which distribution can employed. Using photons entangled their spatial degree freedom, we show resistance high-dimensional indeed harnessed for schemes. We perform eight paths at various levels rates that, even after error correction privacy amplification, still exceed 1 bit per pair furthermore certify a secure would prohibit comparable qubit based schemes from working.
Language: Английский
Citations
38
Physical Review Letters, Journal Year: 2022, Volume and Issue: 128(25)
Published: June 21, 2022
We investigate entanglement detection when the local measurements only nearly correspond to those intended. This corresponds a scenario in which measurement devices are not perfectly controlled, but nevertheless operate with bounded inaccuracy. formalise this through an operational notion of inaccuracy that can be estimated directly lab. To demonstrate relevance approach, we show small magnitudes significantly compromise several renowned witnesses. For two arbitrary-dimensional systems, how compute tight corrections family standard witnesses due any given level also develop semidefinite programming methods bound correlations these scenarios.
Language: Английский
Citations
23
npj Quantum Information, Journal Year: 2023, Volume and Issue: 9(1)
Published: May 5, 2023
Entanglement distribution is at the heart of most quantum communication protocols. Inevitable loss photons along channels a major obstacle for distributing entangled over long distances, as no-cloning theorem forbids information to simply be amplified way done in classical communication. It therefore desirable every successfully transmitted photon pair carry much entanglement possible. Spontaneous parametric down-conversion (SPDC) creates multiple high-dimensional degrees freedom simultaneously, often referred hyper-entanglement. In this work, we use multicore fibre (MCF) show that energy-time and polarization can simultaneously cores, even maintaining path across cores. We verify fidelity ideal Bell state least 95$\%$ all freedom. Furthermore, because are created with center wavelength 1560 nm, our approach readily integrated into modern telecommunication infrastructure, thus paving high-rate key many other entanglement-based
Language: Английский
Citations
15
Physical Review Letters, Journal Year: 2023, Volume and Issue: 131(17)
Published: Oct. 25, 2023
We introduce two families of criteria for detecting and quantifying the entanglement a bipartite quantum state arbitrary local dimension. The first is based on measurements in mutually unbiased bases second equiangular measurements. Both give qualitative result terms state's dimension quantitative its fidelity with maximally entangled state. are universally applicable since no assumptions required. Moreover, experimenter can control trade-off between resource-efficiency noise-tolerance by selecting number performed. For paradigmatic noise models, we show that only small necessary to achieve nearly-optimal detection any global product projections scales linearly dimension, thus paving way quantification very high-dimensional entanglement.
Language: Английский
Citations
14
Advanced Quantum Technologies, Journal Year: 2024, Volume and Issue: 7(11)
Published: Aug. 20, 2024
Abstract A systematic analysis of the advantages and challenges associated with satellite‐based implementation high dimensional extended B92 (HD‐Ext‐B92) high‐dimensional BB84 (HD‐BB84) protocol is analyzed. The method used earlier for obtaining key rate HD‐Ext‐B92 modified here subsequently variations rate, probability distribution (PDR), quantum bit error (QBER) respect to dimension noise parameter a depolarizing channel studied using equation. Further, average (per pulse) zenith angle link length in different weather conditions day night considering extremely low are investigated elliptic beam approximation. effectiveness HD‐(extended) protocols creating links (both up‐link down‐link) established by appropriately modeling atmosphere analyzing variation rates transmittance (PDT). performed has revealed that higher dimensions, HD‐BB84 outperforms terms both tolerance. However, experiences more pronounced saturation QBER dimensions.
Language: Английский
Citations
6
Physical review. A/Physical review, A, Journal Year: 2024, Volume and Issue: 109(2)
Published: Feb. 20, 2024
Qudit, a high-dimensional quantum system, can provide larger Hilbert space, and it has been shown that the space remarkable advantages over smaller one in information processing. However, is great challenge to realize high-fidelity gates with qudits. Here we theoretically propose experimentally demonstrate four-dimensional (including generalized Pauli ${X}_{4}$ gate, ${Z}_{4}$ all of their integer powers) optical qudits based on polarization-spatial degree freedom single photon. Furthermore, also polarization-controlled eight-dimensional controlled-${X}_{4}$ gate its powers. The experimental results achieve both ultrahigh average fidelity $99.73%$ efficiency $99.47%$, which are above error threshold for fault-tolerant computation. Our work paves way large-scale computation polynomial resource cost.
Language: Английский
Citations
5