What is Casimir effect: Definition and 103 Discussions
In quantum field theory, the Casimir effect is a physical force acting on the macroscopic boundaries of a confined space which arises from the quantum fluctuations of the field. It is named after the Dutch physicist Hendrik Casimir, who predicted the effect for electromagnetic systems in 1948.
In the same year, Casimir together with Dirk Polder described a similar effect experienced by a neutral atom in the vicinity of a macroscopic interface which is referred to as Casimir–Polder force. Their result is a generalization of the London–van der Waals force and includes retardation due to the finite speed of light. Since the fundamental principles leading to the London–van der Waals force, the Casimir and the Casimir–Polder force, respectively, can be formulated on the same footing, the distinction in nomenclature nowadays serves a historical purpose mostly and usually refers to the different physical setups.
It was not until 1997 that a direct experiment by S. Lamoreaux quantitatively measured the Casimir force to within 5% of the value predicted by the theory.The Casimir effect can be understood by the idea that the presence of macroscopic material interfaces, such as conducting metals and dielectrics, alters the vacuum expectation value of the energy of the second-quantized electromagnetic field. Since the value of this energy depends on the shapes and positions of the materials, the Casimir effect manifests itself as a force between such objects.
Any medium supporting oscillations has an analogue of the Casimir effect. For example, beads on a string as well as plates submerged in turbulent water or gas illustrate the Casimir force.
In modern theoretical physics, the Casimir effect plays an important role in the chiral bag model of the nucleon; in applied physics it is significant in some aspects of emerging microtechnologies and nanotechnologies.
At the heart of this posting is the questions raised in this Nature article on the nature of death for BH visitors. (I'll call that visitor "Alice".)
Physics is still struggling with this question - and so am I.
Until recently, I was very impressed with the Equivalence Principle which confers...
When quantum chemistry computations are performed, different methods are used. Among the most popular are the density functional theory (DFT) methods. And it is known that the DFT approach usually underestimates the dispersion interaction, and to solve this problem, often empirical dispersion...
(note to mod: I changed the journal to a more reputable one that should fit the rules - please check if it's approved for you - thanks!)
Preface
Some of you may know this but a little while ago Garret Moddel, a professor at Boulder Colorado University, published a paper that described an...
Vacuum energy is predicted by Quantum Field Theory, and also independently corroborated by recent observations in cosmology involving accelerated expansion. More corroboration occurs in superconducting cuprates exhibiting quantum criticality, and in the Casimir effect
The island of Sardinia...
According to the dictionary, a "heuristic" is a tool to allow someone to figure out on her own the full explanation.
If I say that explanation A is a heuristic for a complicated concept B, shouldn't B be at least a close, even if incorrect, explanation?
Specifically, I have read (sorry about...
The Casimir effect is a small attractive force that acts between two close parallel uncharged conducting plates. That force is caused by quantum vacuum fluctuations of the electromagnetic field.
What is the cause of the fluctuations? Or, they are uncaused (random)? At least, what are the...
"In the example of Fig. 1, Maxwell’s equations allow field modes of arbitrarily large frequency both between the plates and outside them, and therefore the zero-point field energy is infinite when the plates are separated by a finite distance d as well as when they are infinitely far apart...
Also, I have heard from physicists that vacuum energy fluctuation (creation and destruction of virtual particles) violates energy conservation. The reason, they justify, is based on uncertainty principle (energy-time form of uncertainty principle), energy can exist and disappear for a very short...
Summary:: Any good english or german sources for Casimir effect, quantum fluctuations or zero point energy
Hello, fellow quantum physicists
I am currently writing a detailed physics script for my quantum physics project and I wanted to ask if you know some good internet sources on the theme of...
I have in mind a way to enable FTL travel. Is this way viable?
In the paper: "Weighing the vacuum with the Archimedes experiment"
we can see the dependency of the gravitational repulsion exerted by Casimir Vacuum on the energy between the plates. The force goes as E / c^2.
In the papers...
Quantum mechanics has argued for years that space is not a vacuum.
Arguments attempting to brush aside quantum mechanics vacuum theory claiming, it's 'just a quantum mathematical theory' can now put to rest.
In this article, laboratory experimentation demonstrates that the Casimir Effect can...
According to Sean Carroll's The Cosmological constant(https://arxiv.org/pdf/astro-ph/0004075.pdf) (Eqn.20) cosmological observations imply that the magnitude of the vacuum energy density in natural units is given by
$$|\rho^{(obs)}_\Lambda|\le (10^{-12}\ \rm{GeV})^4.$$
Does this imply that the...
Homework Statement
Calculate the Casimir force in 1D using a Gaussian regulator.
Homework Equations
The Attempt at a Solution
I reached a point where I need to evaluate a sum of the form $$\sum_n n e^{-\epsilon^2n^2}$$ Can someone help me? I didn't really find anything useful online. I...
The Dynamical Casimir Effect is the production of real photons from the vacuum in a system where one has moving mirrors (see https://www.technologyreview.com/s/424111/first-observation-of-the-dynamical-casimir-effect/). The frequency of the photons is related to the ratio of the velocity v of...
Homework Statement
https://i.imgur.com/sI3JiB4.jpg
https://i.imgur.com/PLpnPZw.jpg
I have no idea how to solve the first question about the vacuum energy. I solved the second and third problems, but I'm hopelessly stuck at the first.
2. Homework Equations
The Hamiltonian can be written as...
So I have read that particle that move near the speed of light can separate virtual particle for there anti-particle counter-part creating a new particle from the energy put in, but would this effect happen in particle accelerators like the large hadron collider, sorry if I am misinterpreting...
From the basic definition of vacuum energy as being tied in with the Uncertainty principle, I would expect this not to include the Cosmic Background Radiation. Right? On the other hand, in figuring out
(a) the Casimir effect, one attributes the force to the field between the plates carrying...
How would sliding the plates parallel to each other in order to separate them (they are prevented from contacting to avoid friction) require the same amount of energy as pulling them apart? You're not pushing against the force (the net force at the edges pulling it back is balanced by opposite...
I was reading some articles about Casimir effect. It turns out that some virtual particles are created and suddenly disappears amd that these particles can exert a pressure on the plates. It seems that this creation breaks energy conservation law, but it cannot be.I would like to know which...
Two identical front surface mirrors are hung in a vacuum chamber with a high vacuum with a bit of bias of their mass wanting to lean into each other so they don't separate on their own. The metal surface is connected to a variable high voltage source. Both mirrors are connected to the same...
If you had the Casimir effect pushing two plates together, would that be an open or closed system? And why? I haven't been able to find a satisfying answer/explanation to that.
Have any experiments on the Casimir effect tried what happens if the plates are temporarily magnetized when they are pulled together by the effect? E.g. measurements of what happens to passing laser beams and the like?
Hi all,
Silly question perhaps: I had understood that the energy density of the vacuum is constant throughout spacetime. But, with the Casimir effect, for example, the geometry of (real) matter (i.e., parallel plates), changes the vacuum energy density in between the plates - is this correct...
Hello.
I read a lot about Casimir Effect. It creates attractive (or repulsive)force between two metal, parallel, electrically neutral, conducting plates. It causes that between plates, it is less electromagnetic field fluctuation wavelength than outside (vacuum). Logic tells me that if vacuum...
Would it be possible to create energy or a power source using plates that are connected in a way that when two plates are close enough the casimir effect would pull them together while also pulling two other plates apart which in turn would create a casimir effect and pulling those plates...
It seems to me that you would have to place two plates so close together and perfectly parallel for the effect to be visible. Correct me if I am wrong.
Please explain how the gravitational effects are accounted for in the Casimir Effect? At a basic level, I want to understand why the quantum vacuum fluctuations in the electromagnetic field are the cause of the attractive force rather than gravity.
I was thinking recently about the Casimir Effect and at what distance does the effect become negligible?
Is there any relevance on the surface area (or difference in areas) between the plates (I personally held the opposite, that any point can be considered to have equivalent pressure as any...
Hi there! Alright, so let me start off by saying I'm a biochemist by trade, but have an extreme (and possibly unhealthy) interest in the more bizarre aspects of modern physics. Admittedly, I don't understand the mathematical formalisms associated with the theories I know of, so bear with me if...
I don't recall where I saw this...but the author said that the Casimir effect experimentally proved that vacuum fluctuations exist. Does the Casimir effect really prove that or is it consistent with vacuum fluctuations?
Thanks for any comments you care to make.
All we know that space creates particle pairs,virtual particles,they make a pressure and we call it casimir effect.I want to ask in universe Is there such a way to calculate How many particles created per volume per second.Or calculate energy density ?
Thanks
While the main problems of a functioning starship are commonly known such as energy requirements and radiation I have realized another problem when near the speed of light.
The dynamic Casimir effect occurs when a reflecting object reaches relativistic velocities.
Therefore a starship with a...
So I was reading an excerpt from Lifshitz about the Casimir effect, and besides the obvious dependency on plate separation and geometry, he indicated that the strength of the force also depends on the dielectric value of the plates. What I'm wondering is what the force distribution for the...
Just wondering if anyone here is familiar with the dynamical Casimir effect? It's part of my dissertation and have a couple of questions.
I've read that the photons produced are "always pair-produced from the vacuum in two-mode squeezed states, not in coherent states."
Since only one photon is...
I know that the Casimir Effect Force is calculated by the equation F=(π h c A) / 480 L4. However, how can you calculated the Casimir Force if there is for example, a bubble. If there is a sphere how can you calculate the force because I don't know what the area would be or how to find it.
I am at the very last part of a relatively long derivation of the Casimir effect, and I just don't understand the final step D:
So far, I have derived the ground state energy to be \langle 0| \hat{H} |0\rangle = \delta (0) \int _{-\infty}^{\infty} dp \frac{1}{2} E
And for a massless field...
I currently watched a video on youtube about Casimir effect
and here's the link
The professor in the video talks about Casimir effect and Hawking's black hole radiation
While talking about black hole radiation, he says that mass of black hole decreases if some particle or antiparticle loses...
The force in the Casimir effect can be "explained" by two causes, see,
http://en.wikipedia.org/wiki/Casimir_effect#Possible_causes
In some optics experiments we must account for the fluctuations of the quantum vacuum to get the right experimental results. See,
Vacuum noise...
Can we say that a point light source (turned off) together with a two slit interferometer and say a photographic plate detector exclude certain photon modes? Light does not go to certain parts of the photographic plate so can we say that the source (turned off), the interferometer, and the...
Hello. Is there absolute testifiable proof that these theories are true or correct?
Can someone for example tell me what a 'quantum fluctuation' is? Is this what can happen
in the 'pure' vacuum of outer-space? Does it also not make sense at all to think of the concept of space as a 'pure...
Hello look at (3.24). Above it, it states "We make the same switch to polar coordinates (x, φ) in the (x, y) plane, and substitute y ≡
(ax/nπ):"
Should (x, φ) be (r, φ)? Is this a typo?
Thank you.
http://aphyr.com/data/journals/113/comps.pdf
Hello, I am looking at the wave equation for the casimir effect and I was hoping if some could tell me what type of what equation is it and what techinque is used to derive it. The wave equation can be found here: http://en.wikipedia.org/wiki/Casimir_effect
Thank you
Good day.
I want to ask for such a thing:
If I put in a vacuum photon pulsed laser with a wavelength of 10 nm and against Casimir cavity of two metal plates with a gap of 10 nm.
From the laser pulse will shoot photons in the cavity.
Occurs dynamic Casimir effect?
Thank you.
Goodbye.
Hello, I am reading this paper on the casimir effect and I am failing to understand where the 1/(2âˆ)^2 comes in and how the polar coordinates are converted to Cartesian. The equations are (3.23) and (3.24).
http://aphyr.com/data/journals/113/comps.pdf
Thank you!