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Mirrors And Virtual Particles


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Cool article -

 

http://io9.com/5806580/mirrors-can-actually-create-light-through-the-magic-of-quantum-weirdness?utm_source=io9+Newsletter&utm_campaign=86be5c3580-UA-142218-29&utm_medium=email

 

If you take two flat mirrors and place them very close together, the virtual particles that pop into existence between the mirrors will actually force them together. But that's nothing compared to when mirrors approach the speed of light.

 

We've talked about virtual particles before, but for our purposes all we really need to know is that, according to our understanding of quantum mechanics, pairs of particles and their corresponding antiparticles will pop into existence, then almost immediately annihilate each other. These are known as quantum fluctuations.

 

So how do the mirrors come into it? Basically, if the two mirrors are close enough together, the distance between them actually becomes smaller than the wavelengths of the virtual particles. This in turn creates an imbalance between the vacuum pressure inside the mirrors and that on the outside, creating an attractive force that brings the two mirrors together. This is known as the static Casimir effect, and it was experimentally demonstrated in 1998.

 

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Cool article -

 

http://io9.com/5806580/mirrors-can-actually-create-light-through-the-magic-of-quantum-weirdness?utm_source=io9+Newsletter&utm_campaign=86be5c3580-UA-142218-29&utm_medium=email

 

If you take two flat mirrors and place them very close together, the virtual particles that pop into existence between the mirrors will actually force them together. But that's nothing compared to when mirrors approach the speed of light.

 

We've talked about virtual particles before, but for our purposes all we really need to know is that, according to our understanding of quantum mechanics, pairs of particles and their corresponding antiparticles will pop into existence, then almost immediately annihilate each other. These are known as quantum fluctuations.

 

So how do the mirrors come into it? Basically, if the two mirrors are close enough together, the distance between them actually becomes smaller than the wavelengths of the virtual particles. This in turn creates an imbalance between the vacuum pressure inside the mirrors and that on the outside, creating an attractive force that brings the two mirrors together. This is known as the static Casimir effect, and it was experimentally demonstrated in 1998.

 

 

Good link Brother J! :goodjob:

 

I've been interested in virtual particles for a while and knew about the static Casimir Effect, but this dynamic application is news to me.

 

Oh, wait a minute please...

(Looks over shoulder. :Look: Nope nothing yet.)

Sorry 'bout that!

 

So let me see if I've got this right.

Pairs of virtual particles pop into existence as quantum fluctuations and are then separated in this experiment. Then, instead of annihilating each other, one of them can change from a virtual particle to a real one - hence the production of real and detectable photons? Y'know, that sounds very similar to Hawking radiation, where the boundary conditions of a black hole separate paired virtual particles and give rise to an output of real photons.

 

Waitaminute!

(Glances back again. :Look: )

Still all clear!

 

Ahem...

Where was I? Oh yes...

Ok, so if photons are being produced, surely this can't be in violation of the principle of the Conservation of Energy? It seems to me that the energy output yielded by these photons has to be accounted for in some way. Otherwise this is a Thermodynamic paradox!

 

Oh, excuse me again!

(Looks and listens for a moment. :Look: )

Sorry about this Bro, but the use of that word make me nervous.

 

Yes, if we suppose that this laboratory experiment could be scaled up to industrial levels of output, wouldn't this mean 'free' energy for all? Batteries would become obsolete - why store energy when you can make it from nothing? Our homes and cities could be lit at night, for no cost at all. Established power industries would be rendered useless but, on the flip side, the environmental damage they cause would be alleviated.

So, something doesn't seem to add up here. :blink:

 

Your thoughts?

 

BAA.

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Virtual particles have been around a long time, if you'll excuse the pun.

 

When a creationist whines that you can't get something from nothing (as in the universe), you point them to virtual particles.

 

Hawking radiation and how it works, not. You have a slope a thousand miles long. On it you put two balls at about the 750 mile mark from the bottom. One rolls down (into the black hole) and the other rolls uphill (and escapes the black hole).

 

Sound likely?

 

A proton has two up quarks and one down quark, but these only account for 2% of the total energy of the proton so the other 98% is where?

 

If we find out, that may give us unlimited energy.

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Oops -sorry BAA I spaced it on this thread! Im on my phone due to internet issues but I do have some thoughts om what you posted...I return to work and their wonderful high speed Monday :grin:

 

Okay - back at work!

 

Essentially, I agree with your post BAA though obviously we are a long way off. However, in regards to the Uncertainty Principle if we did scale this experiment up would this be a reliable form of energy or would more factors come in to play with a larger scale? As far as I understand it in order for something to have a definite energy it must exist for more than just a short time...

 

As I understand it Pair Production is invoked to explain Hawking Radiation in that particle pairs are appearing and disappearing constantly as part of the Quantum Foam. Strong gravitational forces may force these particles apart before they can annihilate each other and if this happens in the presence of a black hole one particle may escape while the anti-particle gets captured by the black hole...how do you feel the state of the observer affects how we observe particles - Unruh radiation?

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I'm also a layman when it comes to this subject though I strive to understand it as well as I can...

 

Wikipedia explains this better than I can!

 

The vacuum energy also has important consequences for physical cosmology. Special relativity predicts that energy is equivalent to mass, and therefore, if the vacuum energy is "really there", it should exert a gravitational force. Essentially, a non-zero vacuum energy is expected to contribute to the cosmological constant, which affects the expansion of the universe. In the special case of vacuum energy, general relativity stipulates that the gravitational field is proportional to ρ-3p (where ρ is the mass-energy density, and p is the pressure). Quantum theory of the vacuum further stipulates that the pressure of the zero-state vacuum energy is always negative and equal to ρ. Thus, the total of ρ-3p becomes -2ρ: A negative value. This calculation implies a repulsive gravitational field, giving rise to expansion, if indeed the vacuum ground state has non-zero energy. However, the vacuum energy is mathematically infinite without renormalization, which is based on the assumption that we can only measure energy in a relative sense, which is not true if we can observe it indirectly via the cosmological constant.

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Oops -sorry BAA I spaced it on this thread! Im on my phone due to internet issues but I do have some thoughts om what you posted...I return to work and their wonderful high speed Monday :grin:

 

Okay - back at work!

 

Essentially, I agree with your post BAA though obviously we are a long way off. However, in regards to the Uncertainty Principle if we did scale this experiment up would this be a reliable form of energy or would more factors come in to play with a larger scale? As far as I understand it in order for something to have a definite energy it must exist for more than just a short time...

 

Agree. A long way off using the energy in the ways I speculated.

 

But wait!

Other factors? Larger scale?

Could it be that quantum effects aren't only limited to the very small, from the Planck scale up to nanoscale and no further? Please check out the article by Vlatko Vedral, "Living in a Quantum World"

http://www.scientificamerican.com/sciammag/?contents=2011-06

 

Also, in reading the Casimir Effect recently, I noticed that there's a good many (laymen like us, as well as scientists) who say that it's unnecessary to invoke the Quantum Foam and Virtual Particles to explain the effect. They maintain that it's just a matter of interpretation. I wonder how they'll explain it when we start to get more energy out of the experiment than can accounted for in any other way than Virtual Particles changing into real ones? You know, in total violation of Classical physics and of the Conservation of Energy! What then?

;)

 

As I understand it Pair Production is invoked to explain Hawking Radiation in that particle pairs are appearing and disappearing constantly as part of the Quantum Foam. Strong gravitational forces may force these particles apart before they can annihilate each other and if this happens in the presence of a black hole one particle may escape while the anti-particle gets captured by the black hole...how do you feel the state of the observer affects how we observe particles - Unruh radiation?

 

Hmmm... good one.

I lean away from the Copenhagen Interpretation, towards the Everett Interpretation.

It's just that I'm inherently suspicious of the anthropic consequences of any paradigm where the consciousness of the observer has a 'magical' effect on the physical universe. Nope. My position is that focusing on the observer or any state they happen to be is a blind alley. A Many-World's approach (though currently untestable) solves things by removing the observer from their central roll, bringing all events and processes down to a level playing field.

 

So, Unruh radiation, being dependent on the acceleration of the observer, looks to be on shakier ground than, say, Cherenkov radiation. Both are cited as examples of Superradiance (along with Hawking Radiation), but only the Cherenkov BLUE GLOW has been independently verified as a bona fide physical phenomena.

 

Thanks,

 

BAA.

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When a creationist whines that you can't get something from nothing (as in the universe), you point them to virtual particles.

 

What makes this kind of spooky sounding, is it might mean that Ex nihilo is true.

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When a creationist whines that you can't get something from nothing (as in the universe), you point them to virtual particles.

 

What makes this kind of spooky sounding, is it might mean that Ex nihilo is true.

 

Not exactly Tabula Rasa.

 

This all hinges on what the words, 'nothing' and 'true' mean, who uses them and how.

 

As far as I understand, when Christians talk about creation-from-nothing, they generally mean this... http://en.wikipedia.org/wiki/Creatio_ex_nihilo

Christians cite C.E.N. as a divine mystery that is beyond human understanding which must be accepted on faith and by faith. They say that C.E.N. was a supernatural event that cannot be understood or analyzed by anyone except God. To them, it is true, but a truth that can only be accepted on faith and by faith. So science, which only ever deals with rational explanations of natural phenomenon in the natural universe, can say nothing about C.E.N., just as it can say nothing about the Virgin Birth or the Resurrection. In science, there are proofs and evidence and explanations. To compare a supernatural 'truth' like C.E.N. with a scientific explanation of anything is to compare apples with oranges - can't be done.

 

As far as I understand, when scientists talk about 'nothing', they don't use and mean this word in the same way as Christians.

Instead what's happening is that the scientists mentioned in BroJ's linked article seem to have found a way of harvesting energy from what is theorized to be an infinitely powerful energy field called the Quantum Foam. http://en.wikipedia.org/wiki/Quantum_foam This energy field isn't 'nothing' or 'nothingness', but it's fluctuations and the particles it produces (Virtual Particles) are so small and so short-lived that proving they exist in any real sense is considered to be impossible. Hence the moniker, virtual. So, in non-technical language, we can say that this appears to be energy-from-nothing, but in reality, we can't be sure that it is or it isn't. Because we can't accurately and definitively account for what's happening here, we can't say for sure wether Energy Conservation is actually violated or just appears to be violated. We just assume that it isn't. In fact, there are very severe limits on what we can say about Virtual Particles and the Quantum Foam. To give you an idea of just how small these suckers are, please go to the Wiki page about Orders of Magnitude. (Can't seem to link to it... sorry!)

I imagine it like this. If an atom were the size of Mount Everest, then a virtual particle might be the size of a grain of sand.

The Quantum Foam would be like a boiling, bubbling, endlessly shifting sea of these jostling, vibrating sand grains. That help?

 

Now, if this pans out and is independently confirmed, then John Wheeler's concept of the Quantum Foam will be strongly supported - but not proven. Heisenberg's Uncertainty Principle is effectively a brick wall in our path, preventing us from definitely knowing anything for certain about events and phenomena at this sub-atomic scale. We are left with probabilities, but not certainties. Strongly supported models and theories, but not proofs. Evidence and explanations, but not THE TRUTH!

 

If you want 100% certainty and truth look for these things in Religion.

 

Some more useful links I found...

 

http://io9.com/5731463/are-virtual-particles-for-real

http://www.infidels.org/library/modern/mark_vuletic/vacuum.html

http://particleadventure.org/virtual.html

http://forums.catholic.com/showthread.php?t=448614

 

Thanks,

 

BAA.

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