- 标题
- 摘要
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- 实验方案
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Effects of scarring on quantum chaos in disordered quantum wells
摘要： The suppression of chaos in quantum reality is evident in quantum scars, i.e. in enhanced probability densities along classical periodic orbits. They provide opportunities in controlling quantum transport in nanoscale quantum systems. Here, we study energy level statistics of perturbed two-dimensional quantum systems exhibiting recently discovered, strong perturbation-induced quantum scarring. In particular, we focus on the effect of local perturbations and an external magnetic field on both the eigenvalue statistics and scarring. Energy spectra are analyzed to investigate the chaoticity of the quantum system in the context of the Bohigas–Giannoni–Schmidt conjecture. We find that in systems where strong perturbation-induced scars are present, the eigenvalue statistics are mostly mixed, i.e. between Wigner–Dyson and Poisson pictures in random matrix theory. However, we report interesting sensitivity of both the eigenvalue statistics to the perturbation strength, and analyze the physical mechanisms behind this effect.
关键词： quantum well,energy-level statistics,disorder,quantum scar,quantum chaos
更新于2025-09-19 17:15:36
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[IEEE NAECON 2018 - IEEE National Aerospace and Electronics Conference - Dayton, OH (2018.7.23-2018.7.26)] NAECON 2018 - IEEE National Aerospace and Electronics Conference - Multifunctional Radar and Communications Waveform Using Chaos
摘要： Multifunctional radar and communication systems possess advantages of lower cost and weight owing to sharing of hardware and antenna apertures. In addition, by using a joint waveform for both applications simultaneously, the occupied spectrum can be used very efficiently thereby guaranteeing a permanent availability of both functions. We propose a waveform implementation that utilizes properties from nonlinear dynamics and chaos to design a multifunctional waveform having the ability to adapt to varying operational and environmental considerations. In addition, use of a chaotic noise-like waveform has good low probability of intercept (LPI), low probability of detection (LPD), and anti-jam properties.
关键词： multifunctional RF systems,radar-communications coexistence,Chaos
更新于2025-09-19 17:15:36
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[ACM Press the 2nd International Conference - Las Vegas, NV, USA (2018.08.27-2018.08.29)] Proceedings of the 2nd International Conference on Vision, Image and Signal Processing - ICVISP 2018 - An Improved Pseudo-Random Number Generator Based on the Logistic Chaotic
摘要： The performance of the traditional one-dimensional Logistic chaotic pseudo-random number generator (PRNG) is analyzed. Furthermore, an improved algorithm for the statistical properties of the one-dimensional Logistic chaotic PRNG is proposed. Then, the paper demonstrates that the algorithm performed better than the traditional Logistic chaotic PRNG. The qualitative analysis and quantitative calculation prove that the randomness and uniformity of Logistic chaotic pseudo-random number are more advisable by the improved Logistic chaotic PRNG. Finally, the significance, the application in image encryption is discussed and tested in this paper.
关键词： Pseudo-random Number.,Topological Conjugate,Chaos,One-dimensional Logistic Mapping
更新于2025-09-19 17:15:36
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A new chaotic teaching learning based optimization for frequency reconfigurable antennas design
摘要： In this paper, a new chaotic teaching learning based optimization (CTLBO) is proposed. TLBO is a rather newly proposed population-based algorithm. This algorithm has no control parameters for the tuning and has a simple structure. We improve its performance by chaotic maps. First, the presented CTLBO is tested on nine unimodal/multimodal benchmark functions. Then, chaotic sequences are applied as vectors with different initial values for design of a frequency recon?gurable antenna (FRA) as a practical example. Comparisons of the performance of this algorithm with those of the basic TLBO, genetic algorithm and particle swarm optimization show the ability of this algorithm in design of FRAs in terms of faster convergence and better performance. A prototype of the optimized antenna with CTLBO algorithm is fabricated and the simulation and measurement results agree suitably.
关键词： Frequency recon?gurable antenna,Chaos theory,Teaching learning based optimization
更新于2025-09-19 17:15:36
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Reliability analysis and design of a single diode solar cell model using polynomial chaos and active subspace
摘要： In recent times, photovoltaic power systems are being used worldwide with a high rate of adoption as a source of clean energy. It is therefore important to study the impact of environmental uncertainties on the yielding power of these solar cells. This paper considers the problem of reliability analysis/design for the yield power in a single diode solar cell when there are uncertainties in the outdoor conditions (e.g. temperature, irradiance) with polynomial chaos and active subspace methods. With the polynomial chaos based surrogate modeling of the yield power, one can accurately and efficiently compute the mean and variance of the yielding power. Following this, reliability design is formulated as a bi-objective optimization problem involving (A) maximization of the mean power yield and (B) minimization of the power yield variation under temperature and irradiance uncertainties. The active subspace method is used to simplify the bi-objective formulation. It is found that utilizing the active subspace method can simplify the bi-objective nonlinear design problem to a bi-objective linear optimization one. Our simulation result shows that the bi-objective linear optimization problem results in a higher mean and lower variance in the maximum power point (MPP) than the direct non-linear design approach.
关键词： Polynomial chaos,Single diode solar cell,Active subspace,Reliability,Multi-objective optimization
更新于2025-09-19 17:13:59
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Dynamic channel selection in wireless communications via a multi-armed bandit algorithm using laser chaos time series
摘要： Dynamic channel selection is among the most important wireless communication elements in dynamically changing electromagnetic environments wherein, a user can experience improved communication quality by choosing a better channel. Multi-armed bandit (MAB) algorithms are a promising approach that resolve the trade-off between channel exploration and exploitation of enhanced communication quality. Ultrafast solution of MAB problems has been demonstrated by utilizing chaotically oscillating time series generated by semiconductor lasers. in this study, we experimentally demonstrate a MAB algorithm incorporating laser chaos time series in a wireless local area network (WLAN). Autonomous and adaptive dynamic channel selection is successfully demonstrated in an IEEE802.11a-based, four-channel WLAN. Although the laser chaos time series is arranged prior to the WLAN experiments, the results confirm the usefulness of ultrafast chaotic sequences for real wireless applications. In addition, we numerically examine the underlying adaptation mechanism of the significantly simplified MAB algorithm implemented in the present study compared with the previously reported chaos-based decision makers. This study provides a first step toward the application of ultrafast chaotic lasers for future high-performance wireless communication networks.
关键词： WLAN,IEEE802.11a,laser chaos time series,wireless communications,multi-armed bandit algorithm,Dynamic channel selection
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC) - Macao, Macao (2019.12.1-2019.12.4)] 2019 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC) - A Novel Cost-Effective AC-DC Power Supply for Indoor LED Lighting Applications
摘要： Differential-chaos-shift-keying cooperative communication (DCSK-CC) has attracted a great deal of attention in the past five years, because it can overcome the negative effect of wireless multipath fading. However, the conventional DCSK-CC system suffers from a major disadvantage of low data rate due to the resource consumption in cooperation. To address the issue, this paper proposes an efficient cooperative scheme, called partial-sequence CC (PS-CC) scheme, for the DCSK-CC system. In the PS-CC framework, the source and relays only transmit a partial chaotic sequence corresponding to one bit to the destination, while consuming the same transmission energy as DCSK-CC. To validate the feasibility of the DCSK PS-CC system, this paper carries out the error performance, diversity order, and data rate analyses under different cooperative conditions over multipath fading channels. Both numerical and simulated results show that the proposed PS-CC system outperforms the DCSK-based non-cooperative system and DCSK-CC systems over the range of signal-to-noise ratio under study. Moreover, the proposed system can enhance data rate and reduce the computational overhead of the relays as compared with the DCSK-CC system. In addition, it will be demonstrated that the DCSK PS-CC system preserves its advantages in typical ultra-wideband (UWB) channels. Overall, the PS-CC appears to be a desirable cooperative scheme for those applications featured by high-data-rate, low-power, and low-complexity, such as wireless sensor networks using the transmitted reference UWB technique.
关键词： multipath Rayleigh fading channel,partial-sequence cooperative communication (PS-CC),differential chaos shift keying (DCSK),User cooperation
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Topological Model of Laser Emission Parameters Research
摘要： The research paper presents a model for studying both the parameters and dynamics of laser light as a nonlinear dynamic system. The model provides for the measurement of the values of physical quantities by non-linear metrology methods and the analysis of the research findings with topological tools. The model is based on the assumption of interval values of the measured values and the possibility of changing the stationary dynamics into the random one. The model contains an experiment scheme and a procedure for evaluating measurement results. The peculiarity of the model lies in its systemic approach and suitability for measuring and researching stationary and chaotic modes. The model provides for the measurement of the emission parameter values intervals in various modes, of their stability values and time series prediction. Classification of the system dynamics is performed using the fractal dimension. The model can be used both to ensure the stability of the laser light parameters, and to obtain and control random emission.
关键词： chaos,fractal dimension,laser emission parameters stability
更新于2025-09-19 17:13:59
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Study of Chaos Control of a Dual-Ring Erbium-Doped Fiber Laser Using Parameter Method
摘要： This paper aims to study single-parameter and dual-parameter chaos control of a dual-ring erbium-doped fiber laser. We present the control model to pressure chaotic behavior of the laser to a periodic state or multi-periodic states by introducing a periodic mutational signal to adjust the losses of dual ring. When the loss of single ring is shifted between two different levels, the laser behaviors can be deduced to two single-period states, while two rings can emit cyclic pulses. We find a control-locking regime and discuss its frequency characteristic of the laser. When another signal is taken to control to perform on the loss, the laser can be deduced to show a period-2 state, a period-3 state, period-4 state and other multi-periodic states. And we find dual-dynamic controlled regimes, in which, one ring of the laser can be produced to show a periodic state while another ring presents a period-3 state. We find also a dual-period regime or a period-4 regime. When both the losses of dual ring are adjusted by shifting between different levels, the laser can produce a period-4, a period-6 and other multi-periodic states. The result indicates that chaos control of a dual-ring erbium-doped fiber laser can be realized using the single-parameter and dual-parameter methods.
关键词： chaos,control,laser
更新于2025-09-19 17:13:59
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Routes to Chaos of a Semiconductor Laser Subjected to External Optical Feedback: A Review
摘要： This paper reviews experimental investigations of the route to chaos of a semiconductor laser subjected to optical feedback from a distant reflector. When the laser is biased close to threshold, as the feedback strength is increased, an alternation between stable continuous wave (CW) behavior and irregular, chaotic fluctuations, involving numerous external-cavity modes, is observed. CW operation occurs on an external-cavity mode whose optical frequency is significantly lower than that of the solitary laser. The scenario is significantly different for larger currents as the feedback level is increased. At low feedback, the laser displays periodic or quasiperiodic behavior, mostly around external-cavity modes whose frequency is slightly larger than that of the solitary laser. As the feedback level increases, the RF and optical frequencies involved progressively lock until complete locking is achieved in a mixed external-cavity mode state. In this regime, the optical intensity and voltage oscillate at a frequency that is also equal to the optical frequency spacing between the modes participating in the dynamics. For even higher feedback, the locking cannot be maintained and the laser displays fully developed coherence collapse.
关键词： chaos,nonlinear dynamics,semiconductor laser,bifurcations,optical feedback
更新于2025-09-19 17:13:59