Recent content by Cedric Chia

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    A Understand Polaron Transformation in Quantum Optics: Wilson-Rae, Imamoğlu

    I'm trying to understand the so-called polaron transformation as frequently encountered in quantum optics. Take the following paper as example: "Quantum dot cavity-QED in the presence of strong electron-phonon interactions" by I. Wilson-Rae and A. Imamoğlu. We have the spin-phonon model with...
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    A Physical explanation of time-correlation function and spectrum

    From my reading of several quantum optics textbooks and spectroscopy texbooks, the emission and absorption spectrum of an atom or molecule are always given in terms of the time-correlation function, for example the emission spectrum of a two level atom is given by: $$...
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    A Absorption and emission spectrum in quantum optics

    The emission spectrum or resonance fluorescence for a quantum dot, atom or defect center are discussed in many quantum optics textbook, for example see "Quantum Optics" by Marlan O. Scully and M. Suhail Zubairy Chapter 10 , "Quantum Optics" by D. F. Walls and Gerard J. Milburn Chapter 10 and...
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    Parameterize Radial Vector of Electric Field due to Spherical Shell

    Thank you! You really made my day! I'm using the Griffiths Textbook but never thought of using vector addition on "curly-r / script-r" $$\text{script r} = \vec{r}-\vec{r'}$$ where $$\text{script r}:=\text{the vector starts at source charges (the sphere) and ends at point z}$$...
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    Parameterize Radial Vector of Electric Field due to Spherical Shell

    Thank you for your help but I'm actually looking for an alternative solution. For example: When finding electric field distance z perpendicular above the mid point of a line segment, we usually parameterize: $$\vec{r}=<-x,0,z>$$ in order to get from any point on the line segment to the point...
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    Parameterize Radial Vector of Electric Field due to Spherical Shell

    Homework statement: Find the electric field a distance z from the center of a spherical shell of radius R that carries a uniform charge density σ. Relevant Equations: Gauss' Law $$\vec{E}=k\int\frac{\sigma}{r^2}\hat{r}da$$ My Attempt: By using the spherical symmetry, it is fairly obvious...
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    I Expected value of 2^X and 2^-X

    For the following distributions find $$E[2^X]$$ and $$E[2^{-X}]$$ if finite. In each case,clearly state for what values of the parameter the expectation is finite. (a) $$X\sim Geom(p)$$ (b) $$X\sim Pois(\lambda)$$ My attempt: Using LOTUS and $$E[X]=\sum_{k=0}^{\infty}kP(X=k)=\frac{1-p}{p}$$...
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    What will the phasor diagram of this LCR circuit looks like?

    I know the current of capacitor and inductor must be parallel but pointing in opposite direction due to the fact they are connected in parallel thus having same voltage (please see attached screenshots). The current of resistor will simply be the sum of these two vectors, but what about its...
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    I Confusion on binding energy and ionization energy.

    For a single electron system, it's binding energy would just be -RZ2/n2 (where R = 13.606(eV) ). But when we're talking about multielectron system, it's binding energy would become -RZeff2/n2 (since there will be shielding effect due to the inner elecrons, where we need to figure out the Zeff...
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    I Confusion on binding energy and ionization energy.

    1) I know that the binding energy is the energy that holds a nucleus together ( which equals to the mass defect E = mc2 ). But what does it mean when we are talking about binding energy of an electron ( eg. binding energy = -Z2R/n2 ? ). Some website saying that " binding energy = - ionization...
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    Observing galaxies: area of sky would I need to survey

    thank you very much, you are very helpful
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    Observing galaxies: area of sky would I need to survey

    I think that would be (volume I need to observe) / (total sphere volume) = (10000) / (4188790) = 2.39⋅10-3
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    Observing galaxies: area of sky would I need to survey

    Thank you for the quick reply, the total volume of the sphere is 4188790 Mpc3 ("which indicates the volume of sky I could possibly observed is 4/3⋅π⋅d3 = 4188790 Mpc3") and the volume I need to view is 10000Mpc3 ("thus V=10000Mpc3, which is the volume I need to observed to find 100...
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    Observing galaxies: area of sky would I need to survey

    How can I find solid angle relative to the 10000MPc3?
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    Observing galaxies: area of sky would I need to survey

    Homework Statement Given that there are 10-2 Ellipticals per Mpc3 and my garden telescope can reach to 14 mag. How large an area of sky would I need to survey to find 100 Elliptical galaxies ? (assume the typical absolute magnitude for an Elliptical galaxy is -21 mag).Homework Equations...
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