18,740 research outputs found
Low-frequency active noise control of an underwater large-scale structure with distributed giant magnetostrictive actuators
A light and thin underwater large-plate active acoustic structure is developed that satisfies the particular requirements of high pressure resilience, low frequency and high efficiency encountered in underwater work environments. A low-frequency miniaturized active control unit, with a thickness of less than 50 mm, is designed using giant magnetostrictive material (GMM). The noise reduction performance is measured with an active control system based on a multi-channel adaptive filter. The active control system is developed within a LabVIEW environment and can achieve significant levels of noise reduction within time intervals of less than one second achieving absorption coefficients far exceeding 0.8 even under high pressures. The new active-control system incorporates hardware and software components and represents a novel technology for low-frequency underwater noise reduction
Correcting low-frequency noise with continuous measurement
Low-frequency noise presents a serious source of decoherence in solid-state
qubits. When combined with a continuous weak measurement of the eigenstates,
the low-frequency noise induces a second-order relaxation between the qubit
states. Here we show that the relaxation provides a unique approach to
calibrate the low-frequency noise in the time-domain. By encoding one qubit
with two physical qubits that are alternatively calibrated, quantum logic gates
with high fidelity can be performed.Comment: 10 pages, 3 figures, submitte
Low-Frequency Noise Phenomena in Switched MOSFETs
In small-area MOSFETs widely used in analog and RF circuit design, low-frequency (LF) noise behavior is increasingly dominated by single-electron effects. In this paper, the authors review the limitations of current compact noise models which do not model such single-electron effects. The authors present measurement results that illustrate typical LF noise behavior in small-area MOSFETs, and a model based on Shockley-Read-Hall statistics to explain the behavior. Finally, the authors treat practical examples that illustrate the relevance of these effects to analog circuit design. To the analog circuit designer, awareness of these single-electron noise phenomena is crucial if optimal circuits are to be designed, especially since the effects can aid in low-noise circuit design if used properly, while they may be detrimental to performance if inadvertently applie
Low-frequency noise impact on CMOS image sensors
CMOS image sensors are nowadays extensively used in imaging applications even for high-end applications. This is really possible thanks to a reduction of noise obtained, among others, by Correlated Double Sampling (CDS) readout. Random Telegraph Signal (RTS) noise has thus become an issue for low light level applications especially in the context of downscaling transistor size. This paper describes the analysis of in-pixel source follower transistor RTS noise filtering by CDS circuit. The measurement of a non Gaussian distribution with a positive skew of image sensor output noise is analysed. Impact of dimensions (W and L) of the in-pixel source follower is demonstrated. Circuit to circuit pixel output noise dispersion on 12 circuits coming from 3 different wafers is also analysed and weak dispersion is seen
Low frequency noise in chemical vapor deposited MoS2
Inherent low frequency noise is a ubiquitous phenomenon, which limits
operation and performance of electronic devices and circuits. This limiting
factor is very important for nanoscale electronic devices, such as 2D
semiconductor devices. In this work, low frequency noise in high mobility
single crystal MoS2 grown by chemical vapor deposition (CVD) is investigated.
The measured low frequency noise follows an empirical formulation of mobility
fluctuations with Hooge' s parameter ranging between 1.44E-3 and 3.51E-2. Small
variation of Hooge's parameter suggests superior material uniformity and
processing control of CVD grown MoS2 devices than reported single-layer MoS2
FET. The extracted Hooge's parameter is one order of magnitude lower than CVD
grown graphene. The Hooge's parameter shows an inverse relationship with the
field mobility
Decoherence in qubits due to low-frequency noise
The efficiency of the future devices for quantum information processing is
limited mostly by the finite decoherence rates of the qubits. Recently a
substantial progress was achieved in enhancing the time, which a solid-state
qubit demonstrates a coherent dynamics. This progress is based mostly on a
successful isolation of the qubits from external decoherence sources. Under
these conditions the material-inherent sources of noise start to play a crucial
role. In most cases the noise that quantum device demonstrate has 1/f spectrum.
This suggests that the environment that destroys the phase coherence of the
qubit can be thought of as a system of two-state fluctuators, which experience
random hops between their states. In this short review we discuss the current
state of the theory of the decoherence due to the qubit interaction with the
fluctuators. We describe the effect of such an environment on different
protocols of the qubit manipulations - free induction and echo signal. It turns
out that in many important cases the noise produced by the fluctuators is
non-Gaussian. Consequently the results of the interaction of the qubit with the
fluctuators are not determined by the pair correlation function only.
We describe the effect of the fluctuators using so-called spin-fluctuator
model. Being quite realistic this model allows one to evaluate the qubit
dynamics in the presence of one fluctuator exactly. This solution is found, and
its features, including non-Gaussian effects are analyzed in details. We extend
this consideration for the systems of large number of fluctuators, which
interact with the qubit and lead to the 1/f noise. We discuss existing
experiments on the Josephson qubit manipulation and try to identify
non-Gaussian behavior.Comment: 25 pages, 7 figure
Low-frequency noise reduction of spacecraft structures
Low frequency noise reduction of spacecraft structure
Dephasing of qubits by transverse low-frequency noise
We analyze the dissipative dynamics of a two-level quantum system subject to
low-frequency, e.g. 1/f noise, motivated by recent experiments with
superconducting quantum circuits. We show that the effect of transverse linear
coupling of the system to low-frequency noise is equivalent to that of
quadratic longitudinal coupling. We further find the decay law of quantum
coherent oscillations under the influence of both low- and high-frequency
fluctuations, in particular, for the case of comparable rates of relaxation and
pure dephasing
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