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Transition kinetics of impurity doped quantum dots under time-dependent confinement potential: role of noise
摘要： Present study endeavors to analyze the role of Gaussian white noise and fluctuating confinement potential on time-average excitation rate (TAER) of impurity doped quantum dot (QD). The TAER profiles are exhaustively monitored as a number of physical quantities are varied over a range with and without noise. Application of noise to the system takes place in two different pathways known as ‘additive’ and ‘multiplicative’. And the fluctuation of the confinement potential has been considered to be cosinusoidal and random which induces the excitation of ground state electronic population to the higher states. The TAER profiles comprise of features like steady increase/decrease, maximization, minimization and saturation. However, the specific characteristics of a particular profile depend on presence/absence of noise, the noise mode, the nature of fluctuating confinement potential and the identity of the physical quantity being varied. Production of large TAER of doped QD depends on noise-mode and nature of fluctuating confinement potential based on which the noise strength is required to be maintained in the vicinity of some typical values.
关键词： additive noise,Gaussian white noise,time-average excitation rate,impurity doped quantum dot,multiplicative noise,fluctuating confinement potential
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Spectrally-selective Photovoltaics via Photonic Band Engineering in Absorbing Media
摘要： Partial discharge (PD) detection has been proved as an effective tool for insulation condition monitoring of power equipment. The energy of PD pulses is valuable for studying the characteristics of PD activities. This paper proposes a method for estimating the energy of PD pulses in the presence of white noise and narrowband noise. First, a maximum likelihood (ML) estimator of the pulse energy is derived from the probability distribution of the energy spectral coefficients. To implement the ML method, the sampled data are divided into signal frames and noise frames. The noise frames are then utilized for extracting noise parameters using the 3F-C method. Eventually, these noise parameters are applied to the signal frames to find the ML estimate of the pulse energy. To verify the effectiveness of the proposed method, both simulated data and measured data have been processed using the proposed method and the conventional wavelet packet (WP) denoising method. Compared with the WP denoising method, the proposed method has a higher accuracy and is less susceptible to the lengths of the sampling time windows. The advantage of the method is more significant in unfavorable conditions where the signal-to-noise ratio is low and the accurate lengths of the PD pulses are difficult to determine.
关键词： white noise,maximum likelihood (ML) estimation,3F-C method,Partial discharge (PD),narrowband noise,energy estimation
更新于2025-09-23 15:21:01
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Dynamics of an open double quantum dot system via quantum measurement
摘要： We study the dynamics of a double quantum dot (DQD) system interacting with a Gaussian white noise (GWN) environment which is measured by a quantum point contact (QPC) device. With both the transverse and longitudinal noise taken into account, we utilize an effective method by adding an additional Bloch vector to calculate the cumulant generating functions of the electron transfer in the QPC detector based on the full counting statistics. We study the average detector current, Fano factor, and average waiting time of the electron transfer in the presence of decoherence effects of the DQD system caused by both the QPC and the GWN environment. It indicates that the decoherence effects arising from the QPC and the GWN environment have obviously different influences on the electron transfer detected by the QPC device in both short-time and long-time limits. It is shown that the measurement process would localize the electron in a DQD in a short time and that the distribution of the average current and Fano factor versus level displacement in long-time limit are broadened due to the interaction between the system and GWN environment, which provides a reliable method to explore the dynamical behavior of an open quantum system and to extract the characteristics of the environment by analyzing the detector outcome. Our results provide theoretical support for studies of quantum measurement in a semiconductor device affected by a fluctuant environment.
关键词： full counting statistics,Gaussian white noise,quantum point contact,double quantum dot,decoherence
更新于2025-09-23 15:21:01
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Analyzing role of relaxation time on second harmonic generation and optical dielectric function of impurity doped quantum dots under the aegis of noise
摘要： Present study monitors the influence of relaxation time (τ) on second harmonic generation (SHG) and total optical dielectric function (TODF) of impurity containing quantum dot (QD) under the stewardship of Gaussian white noise. Two distinct roadways viz. ‘additive’ and ‘multiplicative’ have been exploited for the entrance of noise to the system. Both in absence and presence of noise the SHG and TODF peak positions do not exhibit any shift with increase in τ. The SHG peak values display monotonic behavior with the variation of τ. However, the TODF peak values delicately depend on variation of τ being guided by the presence of noise and also on its mode of introduction. Presence of additive (multiplicative) noise causes enhancement (suppression) of SHG and TODF peak values as τ varies over a range. The findings appear to be crucial in the fabrication of QD-based opto-electronic devices where role of noise deserves to be properly addressed.
关键词： Quantum dot,Gaussian white noise,Impurity,Total optical dielectric function,Relaxation time,Second harmonic generation
更新于2025-09-23 15:21:01
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Generation of entangled states by a linear coupling coupler pumped in two modes induced by broadband laser
摘要： We research on a Kerr nonlinear coupler comprising two nonlinear oscillations linearly couple with each other. This coupler is pumped by external classical fields, which are supposed to be decomposed into two parts: a coherent part and a randomly fluctuating chaotic component (white noise). We can see that the quantum evolution of the pumped couplers is closed in a Hilbert space of two-qubit spanned by single-photon and vacuum states only. Hence, the pumped couplers can treat as a system of two-qubit. Analysis of time evolution of the quantum entanglement shows that maximally entangled states can be generated in the system and compare these results with that obtained previously by other authors.
关键词： quantum entanglement,Generation of entangled states,Bell-like states,white noise,Kerr nonlinear coupler
更新于2025-09-11 14:15:04
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Noise Analysis and Modeling in Visible Light Communication Using Allan Variance
摘要： Visible Light Communication (VLC) is a rising communication technology which uses Light-Emitting Diode (LED) luminaries for high-speed data transferring; however, the optical signal is usually degraded by the noise in the practical VLC system. In this article, Allan Variance is introduced for noise analysis and modeling in VLC for the first time, which provides an efficient method to measure different kinds of noise in the VLC systems. By applying Allan variance to analyze the signals collected from the real-world environment, both white noise and random walk are observed in the VLC systems. The observed white noise and random walk are also modeled by using the Allan variance. The noise analysis and modeling based on Allan variance provide a method to improve the performance of VLC.
关键词： Visible Light Communication (VLC),random walk,white noise,Allan Variance,time-correlated noise,photodiode
更新于2025-09-09 09:28:46