Microwave is widely used in present navigation system. It works well, yet it faces precision limit and other challenges. Quantum entanglement has been applied in various fields and resulted in quite remarkable improvement, especially in precision performance, as it can break quantum noise limit. Hence, we attempt to apply quantum entanglement to enhance merits of navigation system performed in microwave regime. This paper introduces principles of quantum microwave entanglement prepared by electro-opto-mechanical converters in detail, which is also adopted by quantum illumination. Meanwhile, a navigation scheme enhanced by quantum microwave entanglement is proposed. The working principles of the scheme, especially those of location, range finding and direction finding, are analyzed in detail. Besides, we compare navigation scheme of quantum microwave entanglement with present navigation scheme. It shows that navigation merits have been enhanced by quantum microwave entanglement, and it may be regarded as a candidate of new navigation method.
Microwave is widely used in present navigation system. It works well, yet it faces precision limit and other challenges. Quantum entanglement has been applied in various fields and resulted in quite remarkable improvement, especially in precision performance, as it can break quantum noise limit. Hence, we attempt to apply quantum entanglement to enhance merits of navigation system performed in microwave regime. This paper introduces principles of quantum microwave entanglement prepared by electro-opto-mechanical converters in detail, which is also adopted by quantum illumination. Meanwhile, a navigation scheme enhanced by quantum microwave entanglement is proposed. The working principles of the scheme, especially those of location, range finding and direction finding, are analyzed in detail. Besides, we compare navigation scheme of quantum microwave entanglement with present navigation scheme. It shows that navigation merits have been enhanced by quantum microwave entanglement, and it may be regarded as a candidate of new navigation method.
Microwave is widely used in present navigation system. It works well, yet it faces precision limit and other challenges. Quantum entanglement has been applied in various fields and resulted in quite remarkable improvements, especially in precision performance. Hence, we attempt to apply quantum entanglement to enhance merits of navigation system performed in microwave regime. This paper introduces principles of microwave-optical entanglement prepared by electro-opto-mechanical converters in detail. Meanwhile, a navigation ranging scheme exploiting this type of entanglement is proposed. The performance of the scheme is analyzed, and factors influencing entanglement feature and ranging feature are discussed. It shows that the ranging scheme has achieved quite precise results with help of microwave-optical entanglement, and it may be regarded as a promising candidate of new navigation ranging scheme.
Microwaves exhibit superior performance in free-space transmission compared to optical waves, primarily due to their ability to penetrate fog and experience lower losses in the Earth's atmosphere. Based on microwave-optical entanglement prepared by nano-cavity electro-opto-mechanic converters, we propose a scheme of a quantum positioning system using the distance-based positioning method. Principles of microwave-optical entanglement preparation and our QPS scheme are introduced in detail. The entanglement feature, system stability and positioning feature of the scheme are analyzed after simulations. Furthermore, we delve into the impact of key parameters, such as transmissivity and photon conversion efficiency, on positioning. Notably, the entanglement degrees for both microwave-optic entanglement at the transmitter and optic-optic entanglement at the receiver surpass one, affirming the efficiency of the scheme in preparing and maintaining entanglement. When transmissivity in beam-splitter models of both ground stations equals 0.5, our scheme achieves a minimal positioning error of 6.4×10-7m2 under ideal conditions. Additionally, we map out traces of a plane through continuous positioning using our scheme. These results demonstrate the theoretical efficiency and robustness of our proposed approach.
The cavity electro-opto-mechanical converter serves as a meticulously designed platform where hybrid entanglement, including microwave-optical entanglement, can be efficiently prepared. Leveraging microwave-optical entanglement, we propose a quantum synchronization protocol in this paper. This protocol utilizes the second-order coherence function of entanglement signals to determine the propagation time interval and time offset between two parties. Our results demonstrate that the entanglement feature is well-preserved throughout the entire process. Despite the transformation from microwave photodetection to convenient optical photodetection, the transmission superiority of microwaves in free-space is preserved. Under experimentally accessible parameter settings, we achieve a high synchronization precision of Δ τ =±2.704ps. It is theoretically proven that our quantum synchronization protocol holds promise as a viable candidate for future navigation synchronization systems.
Based on the characteristics of superposition, entanglement, non-locality and non-clonality of quantum mechanics, quantum information science can break through the physical limits of classical information and open up a new information processing function different from classical electromagnetic application methods. Due to the advantages of high-energy single photon in practical applications, the research and application of optical quantum information technology dominates the development of current quantum information technology. However, the free-space transmission of light waves is greatly affected by weather conditions and atmospheric particles. Comparing with other wave bands, classical microwave signal shows good penetration ability when transmitting in free space. By introducing quantum mechanics, microwave signal also exhibits non-classical merits. As quantum microwave signal inherits both classical transmission performance and quantum non-classical features, it can be utilized as a significant signal source for diverse applications in microwave domain, such as quantum communication, quantum navigation and quantum radar, which are based on quantum technologies in large scale and dynamic free space transmission. There are three main experimental platforms on which quantum microwave is studied and produced. They are cavity quantum electrodynamics(C-QED) system, circuit quantum electrodynamics(c-QED) system, and cavity electro-opto-mechanical(EOM) system, involving with several nonlinear effects such as Kerr effect, Casimir effect, three-wave mixing, etc. In this paper, the setups of these platforms and the preparation principles are introduced. Meanwhile, the preparation principles and methods of microwave single photon, entangled microwave photons, squeezed microwave fields and entangled microwave fields are summarized and analyzed in detail from three aspects. The present status of experimental progress in the relevant fields are summarized and listed as well. Besides, key problems in the application of quantum navigation in free space utilizing quantum microwave are probed. Among them, the most pressing ones are preparation ability, decoherence in transmission and detection of entangled quantum microwave signals, which are also discussed and analyzed in this paper. Finally, we look forward to the future development of quantum microwave technology. It mainly consists of manufacturing microwave detectors with high efficiency, designing thermal photon filters, and developing suitable antennas. We hope that this study can provide useful reference for scholars who are engaged in or interested in research related to quantum microwave technologies.
A quantum ranging scheme based on dual-path entangled microwaves and coherent detection is proposed to avoid the difficulties of low security, limited precision in traditional radio navigation ranging schemes, being sensitive to multipath effect and the poor performance of existing quantum ranging schemes in current navigation systems. Based on the characteristic that orthogonal quadrature of dual-path entangled microwaves has the largest cross-correlation when the two signals are synchronized, coherent detection is used to get the reference electromagnetic information and calculate the time delay. Based on the principle of pseudo code acquisition and tracking of satellite navigation receiver, a synchronization scheme of time delay is designed, which can acquire the accurate distance ranging. Simulated analysis is implemented in precision and anti- interference, which provide theoretical support for application of dual-path entangled microwaves and a new type of quantum navigation position technology.
A scheme of parametrically enhanced cavity electro-opto-mechanical converter is proposed in this paper, which utilizes Josephson parametric amplifier and optical parametric amplifier. Basic principles of typical cavity electro-opto-mechanical converter and parametrically enhanced version are introduced briefly. We have probed the squeezing and microwave-optical entanglement performance of the scheme with one or both of the amplifiers. The Wigner distribution of the optical output is obtained to analyze the squeezing effect. Meanwhile, quadrature variances and time domain waveforms of output signals are compared and discussed. The results show that microwave-optical entanglement has been enhanced via nonlinear parametric effects no matter when there is one or two amplifiers. However, single mode squeezing only occurs in the cavity which the amplifier is placed in, and this squeezing effect would not transmit to another cavity which hasn’t been amplified. When both amplifiers are introduced simultaneously, each output of cavity electro-opto-mechanical converter is squeezed independently. Our research provides another way to prepare squeezed microwave or optical signal and proves that microwave-optical entanglement can be well enhanced by introducing parametric amplifiers.