Fluctuations Definition and 146 Threads

Hi PF Can quantum fluctuations create space? And if so, could quantum fluctuations have created the universe and therefore spacetime we live in? \Schreiber

Hi Guys, I am working on some fluorescence correlation spectroscopy and I have some data generated by the machine I use. The data has the correlation plot of G(tau) vs the delay time (tau) which is an exponential decay. The data also has the count rate given for the duration for the...

Hello! I'm getting muddled with the notation in my notes, in which I have \overline{(E-\overline{E})(P-\overline{P})} From which you can get \overline{EP} - \overline{E} \ \overline{P}I can see where these come from, but not where the \overline{E \overline{P}} - \overline{\overline{E} P}...

Wikipedia defines quantum fluctuations as: "In quantum physics, a quantum fluctuation is the temporary change in the amount of energy in a point in space,[1] arising from Werner Heisenberg's uncertainty principle. According to one formulation of the principle, energy and time can be related by...

Since spacetime bubbles with quantum fluctuation energy, and energy is equivalent to mass, and mass generates gravity, wouldn't spacetime be awashed with gravity?

I'm writing a paper (not homework) and would like to refer to how the entire Earth's O2 levels rise when it's spring/summer in the northern hemisphere. I understand that this happens because most of the Earth's plant life is there. Can anyone please tell me the proper name of this phenomena, or...

Some physicists are giving up on physical particles and talking about quantum fluctuations in a vacuum. So, what exactly is a quantum fluctuation in a vacuum?

Layman here Is the notion that our universe derived from a fluctuation which took place in a quantum vacuum scientific theory or just a hypothesis? I tend to believe the later, yet there are many scientists(particular motivated atheists) who talk about it as if it is scientific theory. Can...

I came across this http://scienceblogs.com/startswithabang/2010/11/the_simplest_argument_for_dark.php cutesy pop-sci-ish explanation of how we know there's dark matter. If you scroll about 1/3 of the way down, it shows plots of the CMB's power spectrum as a function of multipole moment, l...

There is a new theory being put forth that gravity may amplify vacuum energy to the point that the amplified vacuum energy may predominate over classical vacuum energy, which would cause it to influence astrophysical processes: http://www.physorg.com/news193330592.html It's just a...

http://www.physorg.com/news193330592.html In the above article, a mechanism is suggested whereby a massive body gains mass from quantum fluctuations. This seems to contradict Hawking Radiation, where interaction with virtual particles result in a (very) massive body radiating away energy! Why...

Hi! I'm not sure if my post is in the correct sub-forum, but I think 'Quantum Physics' will result in more detailed answers.. I'm not a physicist, I'm a mathematician and don't know too much about Quantum Theory, just the basics. I've read some stuffs about the issue, introdutory books, this...

Homework Statement In deriving <E2>-<E>2 starting from <E>=U=sum(Eiexp(-beta Ei))/sum(exp(-beta Ei). the taking derivative of U with respect to beta, the book always notes E (thus Volume) is held constant. what i am trying to do is taking the derivative of U with respect to beta or T...

Hello!:wink: May I ask for a little assistance in filling in the gaps of my understanding? :S I understand that the current large scale structure of the Universe is thought to be the result of early fluctuations in density which have been stretched out in the expansion of the Universe. I...

Does the process of pair production mean that the quantum vacuum fluctuations can produce atoms(given enough time) as the following quote on wikipedia seems to suggest? Has it been experimentally confirmed that atoms can be formed in the seething with virtual particles zero-point energy state of...

Hi, If I have a Lagrangian that looks like L=-\frac{1}{2} \partial^a{\phi}\partial_a{\phi}-\frac{1}{2} \mu \phi^2 -\frac{1}{24}\lambda \phi^4 . Where \lambda>0 Then how do I figure out the mass for small fluctuations about \phi=0 ? I don't think I really understand what it means...

i saw a chart that showed that the temp has gone up single digit degrees every 100k years in a rapid manner and then followed by a downward ratcheting of temp into the levels where Earth experiences an ice age. What is the dynamic that causes the temp drop after a rapid rise? Do we need a...

CMB fluctuations and large scale fluctuations nowadays do not match ? The CMB dark matter density fluctuations for big scales is d_rho/rho~ 10^-5 and lower. The scale factor increased ~ 1000 times from last scattering to now. Linear perturbation theory predicts that the density fluctuations...

What would be the effect on a choked mass flow rate if there were fluctuations in the downstream pressure? Thanks

The slope of the primordial power spectrum (the power spectrum of density fluctuations produced by inflation in the very early Universe before it had been modified by gravitational/hydro dynamics) is often written, P(k) = A * k and then in the same line referred to as scale invariant or the...

It is emphasized by Mr. bradenberger the concept of super Hubble subhorizon fluctuations. I appreciate the idea that Hubble radius and horizon are different ideas since they are physically distinct and particle horizon depends on the dynamics of cosmos evolution while Hubble radius only depends...

It is my understanding that quantum fluctuations arise from implications of the Uncertainty Principle. Specifically: http://upload.wikimedia.org/math/b/d/1/bd1bb25a5159f9c74803afca6ad65935.png And that this means that conservation of energy can appear to be violated for a set time "T."...

"It's confirmed, matter is merely vacuum fluctuations." This was the title of a NewSci article tht just appeared http://www.newscientist.com/article/dn16095-its-confirmed-matter-is-merely-vacuum-fluctuations.html Lattice QCD calculation that took a year of supercomputer time at the Jülich...

Homework Statement Recalling that k=R/Na (Na is Avogadro's number), show that the density of fluctuations of an ideal gas are given by : <(dp)^2> / p^2 = 1 / (N*Na) where p is the density (mass/V) That is, the relative mean square density deviation is the reciprocal of the number of...

Im trying to understand inflation, specially the part of structure formation, so I am following Mukhanov's Book. There he does an analysis on quantum fluctuations, more specifically he quantize the Newtonian potential and finds the power spectrum and turns out to be scale invariant. I kind of...

Reconstructing Primordial Fluctuations from Temperature Anisotropy Hi For a summer project, I am required to read the paper "Measuring Primordial Non-Gaussianity in the Cosmic Microwave Background", Komatsu et al (http://arxiv.org/abs/astro-ph/0305189v2). On page 3, the following...

I have heard many claims about many things over the years, but this on interested me very much, and I'd like to know if there is truth behind it. According to this documentary I watched, the Earth's magnetic fields have reversed many times in the past. Apparently, some believe we are about due...

hi, could someone please explain to me the attached excerpt, more specifically, why one has to multiply with the ratio. any ideas will be welcome! thanks

I saw in some sites that vacuum fluctuations are due to uncertainty principle but i couldn't understand how these two are related...uncertainty principle speaks about the uncertainty about particle's position and momentum..vacuum fluctuations speaks about creation of particle pairs and...

Do vacuum fluctuations produce only particle - antiparticle of photons Or it would also produce pairs of electrons-positron and so on...if it also produce various pairs of particle-anti particle other than photons then what it is probability of the production of each such different pair?

vaccum fluctuations are happening everywhere and so the negative energy photon can decrease its near by object not only black hole and the other photon exists as radiation..but this doesn't happen i think... then why it should happen near event horizon...i think i explained what i thought...

Hello, I was wondering something about the quantum field theory. Do vacuum fluctuations (the ones that create virtual-antiparticle pairs) come from nothing? I have heard three different responses to these. The first is that they do come from nothing, the second is that come from zero-point...

Vaccum fluctuations? How to understand vacuum fluctuations mathematically without getting into the virtual particles that is so stereotypical of POP sci articles? Am i right in saying that the vacuum expectation value of the square of electric field is inversely proportional to the fourth...

Homework Statement Estimate the probability that a stamp with mass 1 gram lying on a table is lifted 1 \mu m or higher by thermal fluctuations. Homework Equations - The Attempt at a Solution I'm not sure how to start. What should I think about, what is relevant here? I feel...

Hi! I'm new here, but I hope that someone would evenly help me! My first question is about the problem (3.3 on page 100 from Loudon - The Quantum Theory of Light 3ed) in the attachment; the second question is about discussing (I)the physical origin of fluctuations of the electromagnetic...

My question is, if only from a real particle emitted and absorbed virtual photons that make vacuum-polarzation (decay in virtual e-e+) do contribute to the shielding of this real particle. Or can also vacuum fluctuations that pop in and out of existence contribute to the shielding of the...

i don't know for sure if this goes here, so, instead of deleting it, if it doesn't belong here, could someone move it for me or tell me where it does go? Light Fluctuations After reading an article in the Collier’s Encyclopedia of 1968 (“Phyfe to Reni”-book 19-pages 709-719)-yes, I...

I am confused with the Scharnhorst and Casimir effects. The confusion started here. As it seams that there is no response to my questions in post #9, I will try here. I stated there my understanding about perturbation theory which leads to Feynman diagrams: The amplitudes for the fluctuations...

I'm just confused on this point. The Uncertainty Principle states that there is always a minimum of uncertainty on small scales, leading to quantum fluctuations. However, can we say that quantum fluctuations of spacetime are quantum fluctuations of energy or are they different?

In the heat death of the universe? where would it get its energy needed to fluctuate?

Brian Greene in "The Fabric of the Cosmos" gives the above three as indirect, universal fields in which we exist but have not yet directly detected. Could they be mathematically interlinked among themselves or with immediately observable phenomena?

[FONT=Arial]In quantum vacuum fluctuations it's been said that particles will come in and out of existence, correct? But you can state that particles pop in and out of existence all you like, but they aren't really coming from 'nothing' at all. The 'Vacuum' isn't a real 'nothingness' and quantum...

Can spin fluctuations explain superconductivity? Hawrylak and colleagues use a magnetic field to tune their quantum dot so that the spins of electrons hopping onto or off it must be aligned up or down. This is just the kind of gate mechanism that a spintronic transistor demands - it turns...

Can Photons interact with or be absorbed by Quantum Vacuum Fluctuations? Would it be possible for a photon traveling in space interact with a particle from a quantum vacuum fluctuation? Say you have a particle antiparticle pair arise at just the right moment and the right frequency that one...

Hey guys! As of lately, I've indulged deeply into the entire affair of Quantum Mechanics, field theories and the like, all in an attempt to comprehend how the universe came out to be, what caused it, and what is it's ultimate fate. Despite my sincere efforts, and after reading plenty of...

Perhaps this is an easy one for you experts our there. When we consider an electron that occupies some local and small region of space, and then we assume that this electron [if it means anything to talk about a particular one] is un-measured - back in an unknown state- but that by the laws of...