Questions tagged [noise]
The noise tag has no summary.
300 questions
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Power spectral density of a laser's frequency noise
I am a bit confused about what power spectral density (PSD) is in the context of a laser. In particular, I came across this paper. In Fig. 1 they show PSD vs frequency. As far as I understand, PSD is ...
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Does the anomalous skin effect lead to increased noise at high frequencies?
I was recently reading about the anomalous skin effect, wherein the models governing the skin effect behaviour break down as the frequency gets high enough for the skin depth to approach or fall below ...
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Characterization of Markovianity, Gaussianity, and color for noise processes
Consider a noise process $\xi(t)$ that has some statistics in time. There are various ways to characterize such a process, 3 being Markovianity (independence from history), Gaussianity (Gaussian ...
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Fluctuating electric field or Johnson noise inside a cavity
I have read that "power is dissipated by the thermal motion of electrons in an imperfect conductor, and these fluctuating currents imply the presence of fluctuating electromagnetic fields in the ...
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The response of a linear quantum amplifier to broadband signals
I have been studying related knowledge of quantum linear amplifier noise limit recently, and the main reference material is Caves' literature. In this paper, the author uses equations (4.5, 4.40a, 4....
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What is the maximum possible noise level on Earth and what would be its consequences? [duplicate]
The theoretical situation described here comes from the SCP-498 page. SCP-498 is a theoretical device. It is an alarm clock that is triggered every 11 minutes, and creates a noise of 30dB. Until ...
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Can shot noise in a multi-species system always be expressed in terms of a Fano factor?
Consider a simple model of a two-species system of charge carriers $c$ and $d$ (say, both fermionic, with potentially different masses and dispersions but the same charge). Can the shot noise of such ...
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Linewidth dependence on dipole moment, is it linear or quadratic?
I am trying to calculate the linewidth of a two-level system because of charge noise. I have modeled the charge noise in two ways. I mean, both kinds deal with the correlation of the electric field. ...
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Long time behavior of noise process with flat spectral density and upper cutoff frequency
From this question we find that given a noisy process $x(t)$ with known spectral density $S_x(\omega)$, the mean square displacement is $$ \langle x(t)^2 \rangle = t^2 \int_0^\infty S_\dot{x}(\omega) \...
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Noise in gravitational wave detections
I'm reading a paper (https://doi.org/10.1103/PhysRevD.49.2658) in order to understand the use of Fisher Matrix in gravitational wave detection. I'm a bit confused with the assumptions they do about ...
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Shot noise limited detection
can somebody please explain the significance of shot noise limit? I am trying to understand why and how shot noise degrades image quality, for e.g., while imaging weakly scattering specimens using an ...
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In hetero- homodyne detection, what does it mean to operate at the Quantum Shot Noise limit?
I am an electrical engineering by trade, working on the analogue part (Transmitter & Receiver) of a quantum optical communication channel. By this, I mean I have not much experience on things ...
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What is the correlation between Brownian noise's low frequency components and the actual movement of particles?
I do have some crude training in mathematics, but I'm not a physicist or engineer. So I'd appreciate a simple not too technical explanation. I conceptually understand how hitting a piece of wood will ...
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Using the functional derivative and delta function for proving The Fokker-Planck Equation
I am reading "Lectures on Phase Transitions" by Nigel Goldenfeld, specifically Chapter 8, where the Fokker-Planck equation is derived. I found the following part of the proof, but there are ...
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Method of inserting random numbers in the numerical calculation of mean-squared displacement for brownian particle
I am trying to plot Mean-Squared-Displacement for a passive Brownian particle. For that I'm using the discretized over-damped version of the Langevin equation as: $$x(i+1)=x(i)+\sqrt{\frac{2.k_BT.\...
