- 标题
- 摘要
- 关键词
- 实验方案
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A Quantum Image Watermarking Scheme Based on Two-Bit Superposition
摘要： Quantum watermarking technology protects copyright by embedding an invisible quantum signal in quantum multimedia data. This paper proposes a two-bit superposition method which embeds a watermark image (or secret information) into a carrier image. Firstly, the bit-plane is used to encrypt the watermark image. At the same time, the quantum expansion method is used to extend the watermark image to the same size with the carrier image, and then the image is encrypted through the Fibonacci scramble method again. Secondly, the first proposed method is the two bits of the watermark image which is embedded into the carrier image in accordance with the order of the high and lowest qubit, and the second proposed method which is the high bit of the watermark image is embedded to the lowest bit. Then the lowest bit of the watermark image is embedded in carrier image. Third, the watermark image is extracted through 1-CNOT and swap gates, and the watermark image is restored by inverse Fibonacci scramble, inverse expansion method and inverse bit-plane scramble method. Finally, for the validation of the proposed scheme, the signal-to-noise ratio (PSNR), the image histogram and the robustness of the two watermarking methods are analyzed.
关键词： Fibonacci scramble,Swap gates,Superposition,Robustness,Bit-plane scramble
更新于2025-09-23 15:23:52
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Deterministic quantum state transfer between remote atoms with photon-number superposition states
摘要： We propose a protocol for quantum networking based on deterministic quantum state transfer between distant memory nodes using photon-number superposition states (PNSS). In the suggested scheme, the quantum nodes are single atoms con?ned in high-?nesse optical cavities linked by photonic channels. The quantum information written in a superposition of atomic Zeeman states of sending system is faithfully mapped through cavity-assisted Raman scattering onto PNSS of linearly polarized cavity photons. The photons travel to the receiving cavity, where they are coherently absorbed with unit probability creating the same superposition state of the second atom, thus ensuring high-?delity transfer between distant nodes. We develop this approach at ?rst for photonic qubit and show that this superposition state is no less reliably protected against the propagation losses compared to the single-photon polarization states, whereas the limitation associated with the delivery of more than one photon does not affect the process ?delity. Then, by preserving the advantages of qubits, we extend the developed technique to the case of state transfer by photonic qutrit, which evidently possesses more information capacity. This reliable and ef?cient scheme promises also a successful distribution of entanglement over long distances in quantum networks.
关键词： photonic qutrit,photonic qubit,quantum networking,quantum state transfer,entanglement distribution,optical cavities,Raman scattering,photon-number superposition states
更新于2025-09-23 15:21:01
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Toward the laser control of electronic decoherence
摘要： Controlling electronic decoherence in molecules is an outstanding challenge in chemistry. Recent advances in the theory of electronic decoherence [B. Gu and I. Franco, J. Phys. Chem. Lett. 9, 773 (2018)] have demonstrated that it is possible to manipulate the rate of electronic coherence loss via control of the relative phase in the initial electronic superposition state. This control emerges when there are both relaxation and pure-dephasing channels for decoherence and applies to initially separable electron–nuclear states. In this paper, we demonstrate that (1) such an initial superposition state and the subsequent quantum control of electronic decoherence can be created via weak-field one-photon photoexcitation with few-cycle laser pulses of definite carrier envelope phase (CEP), provided the system is initially prepared in a separable electron–nuclear state. However, we also demonstrate that (2) when stationary molecular states (which are generally not separable) are considered, such one-photon laser control disappears. Remarkably, this happens even in situations in which the initially factorizable state is an excellent approximation to the stationary state with fidelity above 98.5%. The laser control that emerges for initially separable states is shown to arise because these states are superpositions of molecular eigenstates that open up CEP-controllable interference routes at the one-photon limit. Using these insights, we demonstrate that (3) the laser control of electronic decoherence from stationary states can be recovered by using a two-pulse control scheme, with the first pulse creating a vibronic superposition state and the second one inducing interference. This contribution advances a viable scheme for the laser control of electronic decoherence and exposes a surprising artifact that is introduced by widely used initially factorizable system-bath states in the field of open quantum systems.
关键词： electronic decoherence,few-cycle laser pulses,laser control,carrier envelope phase,vibronic superposition state,quantum control
更新于2025-09-23 15:21:01
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Superposition Construction of NB-QC-LDPC Codes for optical communication systems
摘要： In this paper, we consider the construction of NB-QC-LDPC code in the framework of superposition for optical communication systems. By maximizing the girth and reducing the number of g-cycles of the base cycle matrix, NB-QC-LDPC codes with good distributions could be constructed. Simulation results show that, with the same implementation cost, the constructed codes could achieve 0.1dB~0.4dB NCG in iterative decoding at the BER of 10^-4 when compared with the recent proposed codes.
关键词： NCG,optical communication systems,girth,superposition,NB-QC-LDPC codes
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Ultrasonics Symposium (IUS) - Glasgow, United Kingdom (2019.10.6-2019.10.9)] 2019 IEEE International Ultrasonics Symposium (IUS) - CMUT with mechanically coupled plate actuators -Linearized electrostatic modeling
摘要： This paper derives an analytical model of the electrostatic transduction of a capacitive micromachined ultrasonic transducer (CMUT) with mechanically coupled plate actuators. The mass of the coupling geometry significantly affects the dynamic deflection shape of the plate actuators. As the electrostatic transduction of a CMUT depends on the distance between both electrodes of these capacitive systems, the static and dynamic deflection shapes are taken into account for the small signal electrostatic behavior. The analysis of the electrostatic lumped elements, varying with the bias voltage, reveals a dependence on the deflection shape. A comparison with finite element simulations shows good agreement with the analytical model.
关键词： CMUT,modeling,superposition,electrostatics
更新于2025-09-16 10:30:52
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Stress distribution characteristics of the optical fiber with multiple stress elements
摘要： The stress field in an optical fiber with one circular stress element is calculated theoretically. The stress field distribution for any optical fiber with multiple stress elements is derived based on the superposition theorem and the integration method. As is shown in this paper, the stress field in the core or in the region near core can be expressed by a formula with sine or cosine function. This result is important to reveal the coupling characteristics of the stress induced optical fiber with multiple stress elements when it is spun by an appropriate spinning rate.
关键词： Optical fiber,Multiple stress elements,Integration method,Stress field,Superposition theorem
更新于2025-09-11 14:15:04
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Evaluating Scattered Electromagnetic Field from Fractal Surface Using its Components
摘要： In this paper, a novel method is proposed to evaluate the scattered field from rough surfaces by decomposition-reconstitution. The extended boundary condition method (EBCM) is employed in conjunction with a Weierstrass Mandelbrot (WM) function for fractal surface profile and its components. WM function can be decomposed into a series of sinusoidal profile. The properties of the sinusoidal profile and WM function to be periodic and almost periodic allow the deriving respective amplitudes of the scattered Floquet modes. The superposition of scattered fields from each sinusoidal component is consistent with the scattered field from WM surface. The result has compared with AIEM in backscattering coefficients. Thus, by calculating the scattered information for each sinusoidal component of the rough surface, we can obtain the overall scattered field.
关键词： Fractal,Scattered field superposition,Rough surface decomposition,Extended Boundary Condition Method,Electromagnetic Scattering
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - High-Precision Magnetic Field Vector Measurement Based on the Quantum Coherent Superposition States
摘要： The high precision measurement of magnetic field vector based on quantum coherent superposition states due to the interaction of the atomic system with linearly polarized light and magnetic field is described. The coordinate systems are physically orthogonal, which defined by the directions of light polarization and propagation. Because the quantum beat signals resulted by the coherent superposition states are no longer affected by nonlinear Zeeman shift, the measurement has smaller systematic error. The method is suitable for the measurements of vector fields such as the Earth’s magnetic field.
关键词： magnetic field vector,Atomic magnetometer,quantum coherent superposition state,precision measurement,quantum beat technology
更新于2025-09-10 09:29:36
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An overview of the methods for deriving recurrence relations for T-matrix calculation
摘要： In this paper, we present a consistent analysis of the methods dealing with the derivation of recurrence relations for calculation of the T -matrix. Central and forward recurrence relations are obtained in the framework of the invariant embedding T -matrix method, the matrix Riccati equation method, and the superposition T -matrix method. The accuracies and e?ciencies of the central and forward recurrence schemes are analyzed, and some implementation issues related to the improvement of the numerical accuracy and to the problem of overcoming of over?ow errors are discussed.
关键词： recurrence relations,matrix Riccati equation,over?ow errors,invariant embedding,superposition T-matrix method,numerical accuracy,T-matrix
更新于2025-09-10 09:29:36
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Entanglement activation from quantum coherence and superposition
摘要： Quantum entanglement and coherence are two fundamental features of nature, arising from the superposition principle of quantum mechanics. While considered as puzzling phenomena in the early days of quantum theory, it is only very recently that entanglement and coherence have been recognized as resources for the emerging quantum technologies, including quantum metrology, quantum communication, and quantum computing. In this work we study the limitations for the interconversion between coherence and entanglement. We prove a fundamental no-go theorem, stating that a general resource theory of superposition does not allow for entanglement activation. By constructing a quantum controlled-NOT gate as a free operation, we experimentally show that such activation is possible within the more constrained framework of quantum coherence. By using recent results from coherence theory, we further show that the trace norm entanglement is not a strong entanglement monotone.
关键词： quantum technologies,entanglement activation,quantum entanglement,quantum coherence,trace norm entanglement,no-go theorem,superposition principle
更新于2025-09-09 09:28:46