Questions tagged [casimir-effect]
A small attractive force that acts between two close parallel uncharged conducting plates, resulting from the quantum fluctuations of the field.
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Does the vacuum energy of the Casimir effect gravitate?
Since there is negative energy density between the plates, would this lead to anti gravity or perhaps gravity, since the vacuum energy between the plates is technically not less than 0, but less than ...
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Casimir effect and lambshift, uncontroversial evidence of the zero point field? (SED)
"By far the most accepted evidence of the reality of the zpf is the Casimir effect, that is, the force between two parallel neutral metallic plates resulting from the modification of the field by ...
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Negative Energy [duplicate]
I am uneducated on physics so please excuse my ignorance. I've been looking into negative energy which hasn't made much sense to me thus far. Through what I've read I think negative energy is simply ...
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Does that the regularized sums of series and integrals divergent to infinity appear in measurements prove that they represent actual infinite values?
There is a philosophic debate about whether there could be infinite quantities in nature.
Definitely we cannot measure infinite quantities with measurement instruments.
But we know the regularized ...
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Casimir Effect & Redshifting
The classic plate experiment highlights how omitted wavelengths of light create an energy differential and pressure. This pressure is dependent on the distance between the plates, including how this ...
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Doubt about the derivation of Casimir Effect
I was reading about Casimir effect from David Tong's QFT notes and I was struggling to understand one thing.
At page 27, equation (2.33) describes the energy in between the plates, then why does the ...
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Realistic model for the stress-energy tensor for the Casimir effect
According to Visser M. in the book "Lorentzian Wormholes: from Einstein to Hawking", a realistic model for the stress-energy tensor of the Casimir effect is presented in equation (12.31):
$$ ...
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Force in the Casimir effect
In the Casimir effect, after performing the regularization, it is found that the zero point energy between two conducting plates in a distance $L$ from eachother is (in the 1D case),
$$E=-\frac{\hbar ...
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Does derivation of Casimir effect include infrared regularization?
The derivation of the Casimir effect in $1 + 1$ approximates, say, the left mirror and the asymptotic "in" region of spacetime as two fixed mirrors separated by a spacial distance of $L \to \...
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Do Van de Waals forces occur between macroscopic non-conducting objects?
Van de Waals (VdW) forces are intermolecular forces that are for example, due to spontaneous polarisation effects between atoms. As far as I understand, they occur between any type of atom/molecule/...
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Confusion about Van der Waals force
So I just came across this video from Veritasium , "Using Synthetic Gecko Skin To Climb A Wall" and couldn't get my head around the fact that even though Van der Waals force is classified as ...
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Casimir force extraction
The Casimir effect happens due to the difference in field on both sides of the slabs. And they are brought together by this potential difference. Doesn't that mean we extracted a work out of the ...
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How would the Casimir effect work if the metal plate was long enough?
Gravitational time dilation is a form of time dilation, an actual difference of elapsed time between two events as measured by observers situated at varying distances from a gravitating mass.
This ...
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Why does the 1/2 go away in vacuum energy?
This source http://www.hep.caltech.edu/%7Ephys199/lectures/lect5_6_cas.pdf on page 3 says $E_{0} = \frac{1}{2}\sum_{k}\omega_{k} = \sum_{k}\omega_{k}$ (Natural units are being used and $E_{0}$ is the ...
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Is it legitimate to use analytic continuation to equate a diverging series with a finite number in a physical theory of nature?
Analytic continuation can be used in mathematics to assign a finite value to an infinite series that diverges to infinity. Is it correct and legitimate to equate this value to a diverging infinite ...
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What determines if the casimir effect pushes or pulls
I've read an article where chinese researchers have made a mechanism that uses the casimir effect to push two things apart but i'm confused by this cause i've only ever heard of the casimir effect ...
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3d Casimir effect
Why do the virtual photons have to be in alignment with the normal of the plates in the Casimir effect?
Are diagonal photons restricted to a different set of harmonics depending on their angle? And if ...
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Why only harmonics allowed in the Casimir effect?
My question is really a request for an intuitive explanation as to why only harmonic frequencies of photons allowed between two conduction plates.
Why do the plates have to be conductive?
And can real ...
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Boundary conditions of the Casimir's effect on Sakurai
On 3rd edition of Sakurai's modern relativistic quantum mechanics, section 7.8.3 when discussing the Casimir effect, we want to write down an expression for the vacuum energy for two metal plates ...
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Euler-Maclaurin formula for Casimir Effect
I’ve been reading this http://www.hep.caltech.edu/~phys199/lectures/lect5_6_cas.pdf for a derivation of the Casimir Effect. On page 4 we see that
$$\Delta{E} = \frac{\pi}{L}\left(\sum_{\nu = 1}^{\...
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Casimir Effect derivation for energy
I was looking at the Casimir Effect, and I computed that $ka = n\pi$ where $k$ is the 4-momentum of the field and $a$ is the spacetime point where the scalar field becomes 0. Since $k$ is a 4-vector, ...
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Rotating plate and Casimir force
Between two plates there exists because of the Casimir-effect a force.
Imagine if both (or one) of the plates start rotating. Would the force and direction change? Would there be an interaction ...
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Does the Casimir force also define a 'casimir capacitance?'
If you have two plates with distance $\Delta d$ then a Casimir-force will exist between the plates. In contrast if you have two other capacitors with charge $+Q$ and $-Q$ there will be also a force (...
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Using the same variable to compute the zero-point energy difference of Casimir Effect
I am reading the original work of Casimir: On the attraction between two perfectly conducting plates (1948)
In general, the zero-point energy is
$$U_0 =\frac12 \hbar c \sum_{k_x=0}^{\infty} \sum_{...
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Is Casimir's Sail possible?
In the Casimir effect, the pressure of virtual particles between parallel plates, that are very close to each other is less then the pressure in free vacuum.
Is it possible then to make "a sail&...
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Water wave analog of Casimir effect — Does it involve the zeta function? If not, why do QED calculations involve the zeta function?
It is known that the Casimir effect has a water wave analog from classical wave theory. See also this video for a demonstration.
In what ways are the calculations for the effect in QED and the effect ...
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Would the Casimir effect make this perpetually rotating engine possible?
If I understand the Casimir effect right, two microscopic plates approach each other in a vacuum because the space between them is limited allowing only shorter wavelengths to arise from quantum ...
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Does Matter Expel the Quantum Vacuum?
The Casimir effect is demonstrated by measuring forces between two bodies, the first being between very narrowly spaced parallel plates. A net force occurs that is attributable to the properties of ...
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Does negative energy in Casimir effect cause repulsive gravity?
In the Casimir effect a negative vacuum energy exists between two plates. Does this cause repulsive gravity?
Can this have consequences for the situation near the big bang, in relation to inflation?
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Silly doubt on Cherenkov radiation and QFT
Firstly, consider the casimir effect. A interesting feature of this effect is that an attractive force appears which is generated by negative energy. This attractive force arises because the ...
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Casimir effect without a quantum field outside of the plates?
In the usual example of the Casimir effect we have two metal plates seperated by some small distance and a quantum field that lives both outside and inside of these plates. The boundary condition for ...
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What is really going on with a squeezed vacuum?
In the paper by Eric Davis referenced here:
https://www.mysterywire.com/documents/traversable-wormholes-stargates-and-negative-energy/
We find the following references to a squeezed vacuum on page 12, ...
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Minimal working example of Casimir effect-like negative energy
In the Casimir effect, the region between two parallel conducting plates is said to have negative energy density. One of the reason this is interesting is because it seems to violate some energy ...
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Are there Casimir effect at the tip of a toy top to the ground? [closed]
I am not a physic major rather a enthusiast and wanted to ask about the casimir effect between the tip of a top to the ground, after watching a guy spinning a top in the TV?
Certainly there may not be ...
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Vacuum catastrophe: why isn't a large length (1mm) cutoff plausible?
I've been trying to get a better grasp of the vacuum catastrophe problem, that is vacuum energy as calculated in QFT vs the observed value in cosmology differs by 120 orders of magnitude. The issue ...
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Are space and matter interchangeable?
In this post I am referencing the following 'Sixty Symbols' video: Casimir Effect & Black Holes
The video mentions that the Casimir effect can be used to prove that virtual particles are created ...
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Casimir Effect and Regularization
In Quauntum Field Theory in a Nutshell by A. Zee, Section 1.9, about the Casimir Effect he introduces a regulator $e^{-an/d}$ where $a$ has units of length in natural units and $d$ is the space ...
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Moore's function
In the dynamical Casimir effect, the Casimir force is given in terms of Moore's function R which satisfies $$R(t+L(t))-R(t-L(t))=2$$ where $L(t)$ is the trajectory of a moving mirror (while another ...
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Is the cavity QED treatment just a nice shortcut?
I was reading about the Casimir effect in an optical cavity and I came across the following paper by Casimir and Polder:
https://doi.org/10.1103/PhysRev.73.360
Which, if I am not wrong, states that ...
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If Casimir vacuum has negative energy, why it is attractive, and not repulsive?
I heard that negative energy should be repulsive. Why Casimir vacuum is attractive then?
Can we explain it by saying Casimir vacuum is electromagnetically attractive but gravitationally repulsive?
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Casimir Vacuum gravity propulsion?
This question is quite similar to Poor man's Alcubierre drive? but definitely not a duplicate since the direction of movement, in my proposal, is the opposite. This is also similar but different. (...
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Will changing the energy density of the vacuum alter its permitivity or permeability? [closed]
If one uses lasers or a variation of the Casimir effect to change the energy density of a region of free space, will this also change the permeability and the permittivity of this same region? Why or ...
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Casimir Effects in Small Hyperspherical Universes, Small Wormholes and Small Black Holes
If there was a path in the geometry of space-time that 'looped around', it seems like any particles (real or virtual) in the loop would have to match the periodic boundary conditions of that loop.
It ...
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Casimir Effect and parallel $D$-Branes
In the well-known setup for the calculation of the Casimir effect, we take 2 perfectly reflecting plates, impose the appropriate boundary conditions on the relevant fields (scalar, vector, etc.) and ...
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Flow of virtual particles in the Casimir effect
In the Casimir effect experiment two plates are held near each other and in the edges of those plates a region of space with high virtual particle density meets with a region between the plates which ...
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Considering the negative energy density in the Casimir effect and general relativity worm holes, are these experiments feasible?
The question came after I answered the question here, and reading the link provided where negative mass is needed to create wormholes,
Microlensing by natural wormholes: theory and simulations
We ...
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Is this solution for interstellar travel viable?
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 ...
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Do negative energies exist in the Standard Model?
As far as I understand, the Hamiltonian of QED and QCD are positive definite. The QED Hamiltonian in Coulomb Gauge is given by the following (credits David Tong QFT Notes):
$$
H=\int d^{3} x\left[\...
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Why do we not observe a greater Casimir force than we do?
I am very new to quantum field theory, so forgive me if this question is a bit silly. The Casimir force is usually explained by the zero point energy of the field. You assume that the frequencies of ...
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Casimir effect - distance dependence
If one decreases the distance between the two plates in a Casimir configuration, the Casimir pressure is getting stronger. Can somebody give me an inuitive explanation why this is the case?
Greetings
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