Cavity Definition and 260 Threads

I think the answer for this may be straightforward, but I don't see anywhere that explains this from the scratch: A large resonant cavity with a small hole is used to approximate an ideal black body. I understand the conditions for the modes inside the cavity. But there are two points that...

I tried to use ##W = ε_0/2 \int E^2d\tau## for all space. So I find that ##E = \frac{(R^3 - b^3)\rho}{3ε_0r^2}## where ##\rho## is the charge denisty. So from here when I plug the equation I get something like $$W = \frac{(R^3 - b^3)^2\rho^2 4 \ pi}{18ε_0} \int_{?}^{\inf}1/r^2dr$$ Is this...

Hi. I'm having a hard time learning the physical realization of quantum computers. I got stuck with the section of optical cavity quantum eletrodynamics. There are some concepts I am not familiar with. I think I should read some introductory textbooks which cover cavity quantum electrodynamics...

I still did not understand this from my previous threads, what is the way to determine the instantaneous voltage across the cavity plates at any given moment, in a klystron I suppose the voltage would be proportional to the arriving electron bunch density which would determine the overall bunch...

I am currently studying this paper on quantum synchronization. The first page gives an introduction to synchronization and the basic setup of the ensembles in the cavity. My query is on the second page where the following statements are made. Can anyone see why the implication is that all...

I am currently studying quantum synchronization. I am reviewing a https://www.researchgate.net/publication/251232415_Quantum_Synchronization_of_Two_Ensembles_of_Atoms which describes quantum synchronization of two ensembles in a cavity. As such, I have a query regarding a cavity physics related...

Hi everyone I have some trouble understanding quantum physics. Here is a scan from the book from Eisberg and Resnick Here is how much I understand. This is radiation inside cubical cavity, λx/2 is distance from two nodes of component x of the radiation. Same goes for y and z components. In the...

Hi, my teacher showed us how we can derive de relation between spectral radiance and density of cavity (of a black hole), but I have a doubt. This is the equation of the energy that are coming from definited directions by the intervals of angles θ and Φ with frequency in a determined interval...

Homework Statement The laser cavity is formed by two mirrors separated by 15 cm. One of the mirrors has an ultra-high reflectivity and the output mirror has the much lower reflectivity of 99.5 %. How many photons are there in the cavity?[/B] The power of the laser is 1mW and the wavelength is...

If we start with a light mode in a perfect cavity, in a state such as ##1/2\hbar\omega_m + N\hbar\omega_m## , what happens if we introduce a small amount of roughness (something like 0.5% to 5% of ##\lambda_m##) ? Would it create a cluster of similar but non-degenerate discrete modes around the...

1. The problem statement, all variables and given/known date Homework Equations $$\delta v=\frac{c}{2nL} \:[1]$$ $$N=\frac{\Delta v}{\delta v}=\frac{2nL\Delta v}{c} \:[2]$$ The Attempt at a Solution I am having trouble with question 5, but have come to realize I think my cavity length is...

Homework Statement You have a conducting sphere that is in equilibrium, it has a cavity in it with positive charge +q. If you bring another charge +q2 near the outer edge of the conductor does the total surface charge on the wall of the cavity, q(int) change? There is an image attached that...

Homework Statement A spherical cavity is hollowed out of the interior of a neutral conducting sphere. At the center of the cavity is a point charge, of positive charge q. (picture attached) a)What is the total surface charge q(int) on the interior surface of the conductor (i.e., on the wall of...

Howdy, Say you've got two highly reflective mirrors forming a cavity. Some broadband light goes in, but only narrowband light comes out. Entropy is definitely decreased as far as the photons are concerned. Where does it go? This has been bugging me. I have a partial solution I was hoping you...

Suppose you have a spherical cavity, with a flow of a fluid ( in particular water), entering it from one side. What will happen to this flow? Will it create turbulences? Will speed increase? Will eventual waves entering the cavity be reflected, so creating waves with bigger amplitude? Suppose...

Does the operation of a cylindrical microwave cavity resonator as described here, https://en.wikipedia.org/wiki/Microwave_cavity, depend on the speed of light being isotropic along the cylinder axis?

suppose there is a cavity inside a current carrying conductor.if anyone is inside the cavity he will be electrified or not?what's the explanation of this problem?

Dear all, I am looking for an introductory QED textbook (or quantum optics if not) that also covers QED cavity and Purcell effect in one of its chapters. I am not planning to extensively understand every single detail about QED cavity and Purcell effect since I am not a physicist and I don't...

I have a non conducting sphere with a charge ρ=A/r per uni vollume A is constant. suppose there is a cavity in the centre and within a particle of charge q. i want to find the E inside the sphere in respect with r. Homework EquationsThe Attempt at a Solution for radius equal of the cavity i get...

<< Mentor Note -- thread moved from the technical forums, so no Homework Help Template is shown >> Let's say you have a laser cavity with two mirrors at either end, one is considered 100% reflective, the other 99.9%, so that a wave beam is emitted through this lower reflectivity mirror. I know...

I have been trying to understand the role of a cavity as a black body radiator in the derivation of planks black body radiation law but it has left me with 5 main questions: 1. If an object is a perfect absorber it must also be a perfect emitter, meaning that (allowing for a cavity not being a...

I am learning about lasers and trying to clear up some blurry concepts in my head so I am not necessary using heavy math for description here so please bear with me. Let's take EM field in a rectangular box with walls that are perfect conductors (optical cavity). EM field distribution inside...

Homework EquationsThe Attempt at a Solution A)[/B] In the spherical cavity, let me have a Gaussian Spherical Surface around the center. Applying Gauss' s Law for dielectrics, ##\oint _S\vec D⋅ d \vec a = Q_{f_{en}} ## Due to the symmetry of the problem and ## Q_{f_{en}} =0## , ## \vec D = 0...

Hello friends. If i have a dieletric material ( w/ a hole) and apply an uniform eletric field on it, the eletric field in the hole will stay null ? Peace.

Homework Statement A uniform spherical charge density of radius R is centred at origin O. A spherical cavity of radius r and centre P is made. OP = D = R-r. If the electric field inside the cavity at position r is E(r), the correct statement is: 1)E is uniform, its magnitude is independent of r...

Consider the microwave cavity used in a particle accelerator to accelerate particle bunches. Before a bunch of particles enters the microwave cavity can we, if only in principle, quantum mechanically describe the state of the microwave cavity as a proper sum of microwave photon number states...

Hi , what happen if a half dipole linear antenna is placed inside an electric conducting resonant cavity? The cavity itself is the conductive ground of the half dipole antenna. How can I solve such problem in which the cavity works as resonant cavity and it is part of the antenna itself? Cheers...

Hello Guys How are you?? Today i was studying physiology Body temperature measurement and i saw in general and in normal conditions that the oral cavity temperature is lesser than rectal temperature but why the oral temperature is lesser than rectal temperature?? And what is the reason?

What if I replaced the half transparent mirror in a laser cavity with a 100% reflective mirror? -would all photons escape due to the quantum tunneling effect? -would the mirrors melt? Thanks :biggrin:

Homework Statement An isolated conductor has a net charge of +14.0 × 10- 6 C and a cavity with a particle of charge q = +4.30 × 10-6 C. What is the charge (a) on the cavity wall and (b) on the outer surface? Homework EquationsThe Attempt at a Solution So I understand that B is just adding the...

Hello, I would like to know how to calculate the negative energy density in the region between two Casimir plates, given a distance between two parallel plates. Thanks, much appreciated!

It is a simple arrangement. Imagine that we have an empty cubic box. Outside the box the electric potential is infinite. Imagine that you put an electric charge at the geomectric center of the box. What is the field around this charge? In other words, the tool I have to calculate the field...

Homework Statement Calculate the number of modes in a cubic cavity of length a=2.5 cm in the wavelength interval (λ1,λ2) where λ1=500 nm and λ2=501 nm. What's the total energy which radiates from the cavity if it's kept at a constant temperature of T=1500 K. Homework Equations I imagine these...

Homework Statement In the book "Quantum Optics" written by Scully and Zubairy, there is an equation (1.1.5). The equation is presented directly and not explained how to be deduced. The content is as follows. Homework Equations The Attempt at a Solution I know the solution should have the form...

Homework Statement A solid sphere of density ##ρ## and radius ##R## is centered at the origin. It has a spherical cavity in it that is of radius ##R/4## and which is centered at ##(R/2, 0, 0)##, i.e. a small sphere of material has been removed from the large sphere. What is the the center of...

Why is the probability of one-photon loss from a cavity in the time interval ##[t, t+\delta t]## is: ##\kappa \delta t\langle \psi(t)| \hat{a}^{\dagger}\hat{a} |\psi(t)\rangle## where ##\kappa## is the decay rate. It looks like the Fermi Golden rule but it's not exactly it.

Homework Statement Just having some trouble with a question about Fabry-Perot intereferometers. Here's the question: a) Consider a beam of light undergoing multiple reflections in a Fabry-Perot cavity between two surfaces, both with reflectance R, and with no absorption. Homework Equations...

NOTE: Other threads suggest solving it with Gauss' Law. I'd like to see an approach through direct integration, no full followthrough necessary.. 1. Homework Statement Consider a sphere with a uniform distribution of charge ρ (ro). Inside the sphere is a cavity (spherical). Calculate the...

Does anyone know if there's any q-switching technique that makes use of an unstable resonant cavity (or some kind of switching of the cavity between stable and unstable) to achieve the pulse output?

I want to build a Resonant Cavity to play with frequencies around 100-700 mhz. I'd like to try different shapes, so I was thinking in using a cheap malleable material like aluminum foil. Questions: - I think one layer of aluminum foil might be too thin.. If I paste a couple of layers will do...

In linear accelerators that use a disk loaded structure (traveling wave), how would you calculate the iris(disk hole) radius, cavity radius, and disk thickness according to the wavelength

In a linear accelerator that use cavities and microwaves or radio waves to accelerate particles, how would one find dimensions such as cavity openings, cavity size, length between cavities, etc.

First, sorry if something is not totally clear, I'm translating physics term the best I can! 1. Homework Statement A sphere or radius a of permittivity ε2 is placed in a dielectric ε1. Without the sphere, we would have E = E0. We want to find the solution to this problem when ε2 = 1...

bear with me, i know that this question has been asked many time , but i would like a definite answer, now, starting off the external charge density on the outer surface of sphere WILL be uniform by unique solution of Laplace equation and letting the sphere be huge, so, electric field due to...

hello, I am studying spontaneous decay of an atom in spherical cavity - but I am not getting any good book on that can anyone help me in this regard. thanks wasi

Homework Statement U = u(T)V; P=u(T)/3 a. Find (ds/dt)v and (ds/dv)T in terms of u. Ans. (ds/dt)v = 1/T[du/dt] and (ds/dv)T = 1/T[du/dv + P]...Correct b. Show that u(T) = Const*T^4 equate partials above and integrate...Correct c. Find a Relation between V and T during adiabatic compression or...

Assume that one builds a Casimir cavity in the traditional manner, with closely spaced walls. We know the Casimir Effect becomes more pronounced the closer the walls are spaced. Now, if one were to build six such Casimir cavities, and assemble them into a box, would the same effect be noticed...

If a conductor has a cavity in it and if a charge is placed in the cavity, then will the electric field inside it be zer

http://www.cengage.com/resource_uploads/static_resources/0534493394/4891/Ch03-WebAppendix01.pdf I've been doing some reading and I came across a mathematical step that is confusing me. Could someone explain to me how they get from equation 3.45 to equation 3.46 in the link that I have posted...

Hi, I'm Sungdae studying in Korea. In common, making a energy state in the photonic energy gap. but i don't know exactly what a different single-mode-cavity and 'single'-mode-cavity? Thanks