Recent content by epsilon

I am currently reading around about squeezed light. I understand as far as the Second-Harmonic Generation (SHG) and Optical Parametric Amplifier (OPA) work, however I do not understand why the signal and idler photons that are produced by the OPA are a squeezed state. All diagrams that I have...

I am having some difficulty understanding the Pound-Drever-Hall frequency stabilisation technique, when locking a laser to a stable cavity. As far as I understand: We emit the laser frequency, f0. This signal is modulated with sideband frequencies, ± fm. This is fired towards the Fabry-Perot...

OK thank you! :-)

And so this is the Hubble parameter then? H = 1/a × da/dt

Question: Estimate the rate of continuous creation required to keep the density of the universe constant at 10-26kg/m3. Express your answer in protons/year/km3. Attempt: Assuming a spherical matter-dominated Friedmann universe, we know from solving the fluid equation that ρ ∝ 1/a3 (where ρ is...

Thank you, that was quite helpful (still slight uncertainty but better understanding now than before!)

I have been trying for hours to understand what is physically causing the interferometric rings to contract when the separation of the mirrors is reduced. From the equation: m\lambda = 2Lcos\theta, where m is the number of fringes, if we consider just one fringe at a fixed wavelength...

I also found that the MAC is easier to understand as the probability of a photoelectric absorption interaction per unit distance traveled into the material, for anyone else who is wondering!

I am currently trying to understand the mass attenuation coefficient (MAC) with regards to photoelectric absorption. Consider this graph: Why does this have a negative gradient? Why does the MAC decrease as the photon energy increases? From what I understand, the MAC is the rate of energy...

Thank you! This is why it wasn't making sense.

Thank you for your answer, you cleared up the misunderstanding that I had!

The part I understand: I understand that the spontaneous symmetry breaking of the Higgs produces the 'Mexican hat' potential, with two non-zero stable equilibria. I understand that as the Higgs is a complex field, there exists a phase component of the field. Under gauge transformations of...

I have actually solved this myself, but thought I would add the answer for anyone else that I wondering how to do it. Consider the ##\phi'(t')## part first. ##\frac{\partial}{\partial x}\phi'(t')## We need to have the denominator of the differentiation fraction to be the same function as the...

We have a function: ##\phi'(t',x')##. We want to find: ##\frac{\partial\phi'}{\partial x}##. I know that the answer is: ##\frac{\partial\phi'}{\partial x} = (\frac{\partial\phi'}{\partial t'} \cdot \frac{\partial t'}{\partial x}) + (\frac{\partial\phi'}{\partial x'} \cdot \frac{\partial...

Very good answer! Thank you!