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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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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How we can study quantum fluctuations in empty space?

I have been recently studying quantum fluctuation in a vacuum and zero-point energy. I studied a lot of papers and found that physicists study these quantum vacuum fluctuations by the Casimir effect. ...
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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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Vacuum energy and Energy conservation [duplicate]

I understand from Noether's theorem, energy is not conserved in big scale space-time (because space-time is not static in big scales). Also, I have heard from physicists that in QFT, things like ...
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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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Can we go beyond Casimir Effect 2 plates Experiment?

Every one knows and talks about the 2 plates experiment but I woud like to go beyond that even if only in theory. Some say, the by pulling the plates apart, it would create a "distortion" ...
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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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Computation of Casimir from Milton's book

I'm studying the Casimir effect from Milton's book. In order to subtract the divergence in the force term between the two plates, he computed the following reduced green's function (page 25). My ...
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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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Is their any proof that space is filled with virtual particles or can they only be emitted by atomic nuclei and electrons? [duplicate]

Is their any evidence for non zero energy in space? The Casimir effect for two plates separated by a small distance suggests that there is little energy in space.
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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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Casimir effect on the edges of the plates

What kind of forces are felt by the edges of two plates experiencing the Casimir effect? I assume that if the edges were closed then they would feel a force towards the space between the plates, but ...
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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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Casimir energy in a circle for a scalar field with antiperiodic conditions

Following the section 2.3 of the book "Advances in the Casimir Effect" by M. Bordag, the Casimir energy is given, for a maseless field, by $$E(a) = E_0 (a) - E_{0M} (a)$$ where $E_0 (a)$ is ...
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Energy-momentum $T_{00}$ component for a scalar field in 2-dimensional spacetime

I'm reading the book "Advances in the Casimir Effect" by M. Bordag. In section 2.4 it says that the $00$-component of the energy-momentum tensor is given by (eq. 2.59): $$T_{00}(t,x)=\frac{\...
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Can the Casimir effect propel this system?

Between two extremely close metal plates, there is a force of attraction because the metal plates have to be nodes of any electromagnetic quantum fluctuations and so there are less virtual particles ...
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Does the region inside of buckyball have a slightly negative energy density due to the casimir effect?

I was considering a buckyball floating in a vacuum. It's surface is a strongly conducting surface and so I would expect some kind of Casimir effect to apply, i.e. the wavelength of virtual photons ...
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Should there be a Casimir effect for superconductors?

I was curious if a Casimir effect between superconductors makes sense theoretically and whether one has been detected experimentally. I found the following paper: arXiv:1902.09136 — which suggests ...
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Does the Casimir Effect Fluctuate?

I understand that two uncharged plates places nanometres apart experience a net force due to their interference with the quantized fields around them. I'm wondering whether or not this force ...
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Casimir energy vs Helmholtz free energy

In what way are the Casimir energy and Helmholtz free energy related / do they differ? In QFT one can compute the Helmholtz free energy as the vacuum expectation value of the zero point function. This ...
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Casimir effect and negative mass

The Casimir effect causes a limited number of wave functions, causing fewer particles between plates than outside and this could be considered as a negative mass. Then, if we have a technology good ...
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Using Casimir force as a thruster

In quantum mechanics, there is a phenomenon called the 'Casimir effect'. As two metal plates have a very small distance, the plates work as a potential well, causing limited wave function between the ...
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Electromagnetic field in the Casimir effect

So, I read, that the Casimir effect arises from the ground state of the electromagnetic field. But I don't understand where the electromagnetic field in the Casimir effect comes from, since we are ...
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Why do photons in the Casimir effect get destroyed when they collide with each other?

Shouldn't these photons create a stronger photon when they collide? If you shine a light at another light it gets stronger not destroyed. Why is it different in the Casimir effect case?
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Is there an analogue of the Casimir effect for gravity? [duplicate]

Having recently learned about the Casimir effect I began to wonder about spacetime and the effect of intervening bodies on gravitational forces: Does a mass have a "shadow" behind it or ...
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Casimir effect and law of conservation of energy

If we use a couple of plates and the casimir force attracts those plates, when the plates are close together, we reduce the surface area of the plates by pushing it downwards and then pull the plates ...
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Could a proton be produced using the dynamical Casimir effect?

According to the standard model, would it be theoretically possible to emit protons or other complex particles from the vacuum using the dynamical Casimir effect? Or is it only possible to emit ...
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Casimir effect evidence

How does the attraction between two metal plates support a new effect (or force)? Isn't it expected that two plates attract each other due to the London dispersion? If so, how does the experiment ...
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Blocking quantum effects

A Faraday cage blocks electromagnetic fields, provided they are not intense enough to change the state to something non-conductive (e.g. slicing it in two with a laser). Is there any analogous system ...
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Can real particles become virtual?

I know that virtual particles can become real for example with the dynamic Casimir Effect. But is the opposite also possible? I.e. can real particles become virtual?
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Is it possible to produce Fermions from the dynamical Casimir effect?

As I understand it, the dynamical Casimir effect has been demonstrated in the laboratory and has been found to allow the emission of photons from the vacuum. Given the right frequency of the ...
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Vacuum energy conversion (to heat)

Two metal plates placed close together in vacuum will collide due to more and more vacuum (electromagnetic) energy being converted from quantum EM modes to kinetic energy of the plates because of the ...
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Could the Casimir effect be bad science?

Could the Casimir effect be due to incident light used to observe the effect during the experiments? It seems to me that the effect occurs because of the photoelectric effect because the conditions to ...
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Casimir Force and bosonic String Theory dimensions

I was reading the lecture notes on Quantum field theory by David Tong. In the section on Casimir force he derived the force of attraction felt by the plates due to the field vacuum energy in $1+1$ ...
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Is the Casimir energy in CFT an observable?

We know that if we transform a 2d conformal field theory from a plane to a cylinder with perimeter $L$, the ground state energy will be shifted by $$E = -\frac{c}{24L}$$ due to the Schwarzian ...
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What's the current status of the Casimir force $\leftrightarrow$ vacuum energy controversy?

Most textbooks explain the Casimir force by using the infinitely large ground state energy associated with quantum fields. Since the total energy between two conducting plates is different from the ...
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An interesting Casimir configuration [duplicate]

A problem related to an interesting Casimir configuration.  I have the following configuration , related to a modified Casimir experiment.  We have two parallel metal plates and an orthogonal ...
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Solving a Casimir configuration, the U - bracket

A problem related to an interesting Casimir configuration.  I have the following configuration, related to a modified Casimir experiment.  We have two parallel metal plates and an orthogonal metal ...
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Poor man's Alcubierre drive?

In general relativity,  the fundamental notions are the curvature (Ricci tensor) and the stress energy tensor. Energy density and curvature are connected .  The Casimir vacuum between parallel plates ...
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Would a planet with mirror surface emit radiation due to dynamical Casimir effect? If so, where the energy would come from?

The dynamical casimir effect tells that an accelerating mirror should produce photons. Due to equivalence principle a mirror in uniform gravitational field also should produce photons. So, should a ...