Plunging the dephts of Quantum Mechanics

Okay everybody...lets see how far we can plunge into Quantum Mechanics before we get over our heads! Woohoo!

To start out, I have a couple views/questions/comments/ideas:

Einstein's theory states that as we approach the speed of light, time slows down. So essentially, if we had an endless source of energy, we could stop time by reaching the speed of light. However it would be imposssible to have an endless source because that would require a perpetual motion machine...think it could ever happen? why couldnt it? electrons move at the speed of light...but they behave according to quantum laws...not newtonian laws...but still...its all matter in the end..isnt it?

everything is made up of something.
Atoms are made of protons, neutrons, and electrons. P's, N's, and E's are made of quarks. quarks are made up of other things, and those things are made up of other things, etc. Its all recursive. A big endless loop. Everything has to be made up of something...so there really is no smallest piece of matter...

And also, how does something gain mass as it approaches the speed of light? Mass is the measure of how much matter you have...you dont gain matter just by going faster...i might be able to understand a weight change, and weight is affected by gravity, but how could you have a mass change? you dont gain matter as you go faster....

And what is energy composed of? Like I said earlier, everything must be composed of something...so what is energy made up of? Or is energy just a relative term relating to how something reacts, and not really a physical noun composed of matter?

All interesting thoughts...Lets discuss. :D

Quote:

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Originally posted by DavidP
And also, how does something gain mass as it approaches the speed of light?

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Think circular logic. :D

BTW: Quantum Mechanics r0x0r.

>Einstein's theory states that as we approach the speed of light, time slows down. So essentially, if we had an endless source of energy, we could stop time by reaching the speed of light. However it would be imposssible to have an endless source because that would require a perpetual motion machine...think it could ever happen? why couldnt it? electrons move at the speed of light...but they behave according to quantum laws...not newtonian laws...but still...its all matter in the end..isnt it? <

What would happen if went faster then the speed of light.

Traveling at the speed of light would not requie a perpetual motion machine. it would require a light sail. A device that instead of light bounsing off, or being absorbed by it light would push it. Hance going the speed of light.

>And what is energy composed of? Like I said earlier, everything must be composed of something...so what is energy made up of? Or is energy just a relative term relating to how something reacts, and not really a physical noun composed of matter? <

Energy is not composed of anything. It is also not a relative term relating to how something reacts. Its well (get back to this latter)

Supposedly in theory it is impossible to go faster than the speed of light due to infinite mass.

Quote:

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Originally posted by DavidP
Okay everybody...lets see how far we can plunge into Quantum Mechanics before we get over our heads! Woohoo!

To start out, I have a couple views/questions/comments/ideas:

Einstein's theory states that as we approach the speed of light, time slows down. So essentially, if we had an endless source of energy, we could stop time by reaching the speed of light. However it would be imposssible to have an endless source because that would require a perpetual motion machine...think it could ever happen? why couldnt it? electrons move at the speed of light...but they behave according to quantum laws...not newtonian laws...but still...its all matter in the end..isnt it?

everything is made up of something.
Atoms are made of protons, neutrons, and electrons. P's, N's, and E's are made of quarks. quarks are made up of other things, and those things are made up of other things, etc. Its all recursive. A big endless loop. Everything has to be made up of something...so there really is no smallest piece of matter...

And also, how does something gain mass as it approaches the speed of light? Mass is the measure of how much matter you have...you dont gain matter just by going faster...i might be able to understand a weight change, and weight is affected by gravity, but how could you have a mass change? you dont gain matter as you go faster....

And what is energy composed of? Like I said earlier, everything must be composed of something...so what is energy made up of? Or is energy just a relative term relating to how something reacts, and not really a physical noun composed of matter?

All interesting thoughts...Lets discuss. :D

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Electrons don't move at the speed of light, electrons in most materials move at speeds approaching the speed of light, they can be accelerated and decelerated like any other free particle in such strange technologies such as circuits, aerials, tv's particle accelerators, or naturally in the magnetic fields caused by, the Earth, the Sun...

Newtonian mechanics is all effectively first term approximation of the special relativity equations after doing things such as binomial expansion.

Electrons don't appear to be made of anything, they just are.
The evidence for quarks having structure is shakey at best.
Due to the uncertainty principle there is a smallest size we could possible measure, effectively, there is nothing smaller than that volume, or if there is we couldn't possibly observe it, or does that mean it doesn't exist.

There are 2 different but related descriptions of mass.
Inertial mass, which is (at its simplest) the ratio of the force applied to a body to the acceleration that force produces, ie from F=ma, and graviational mass, which is the mass that produces the observed gravitational effect in F=G*M1*M2/R^2.
In all cases these masses appear to be identical. There both really measure the affects of forces from slightly different angles.

As you approach the speed of light, the force you need to accelerate to a higher speed increases, but not as described by F=ma, since this is only a first term approximation, in effect, your effective mass has increased.

Energy is a relative scale really discussing how things react, its not a thing as such, unless it condenses into matter:) ,

It's not impossible to travel faster than light, it's just impossible to accelerate from below the speed of light to above the speed of light if you have mass.
You can travel at the speed of light if you have no mass, if you were always travelling faster than the speed of light, you can carry on doing so, don't ask about this though, I have no real idea about the physics described by this situation, and I should imagine not many other people do either, If I did I'd have a noble prize

RobS:

>>>
if you were always travelling faster than the speed of light, you can carry on doing so,
<<<

One of the hypothetical consequences of particles which travel faster than light, (tachyons), is that it would take progressively more and more negative energy to slow them down to the speed of light. Interesting concept I think.

DavidP:

Electrons are not made of quarks. Electrons are the lightest members of the group of fundemental particles called Leptons, (the others being the muon and the tau). Each lepton comes as a matter/anti-matter pair and is associated with a neutrino, also matter/anti-matter pairs.

Another type of matter is quarks. These, at least according to current theory, are elemental, and cannot exist alone. Quarks form two basic classes of higher particles, Hadrons and Mesons. Hadrons consist of 3 quarks, mesons 2.

A final group of particles are known as bosons. These are force carrying particles. The term particle is really being stretched to the limit with these things. It is thought that all of the fundemental forces are transmitted by the exchange of bosons. One of the greatest acheivements of particle physics was the unification of the electro-magnetic force and the weak nuclear force. The theory predicted the existance of three new bosons, the w+, w- and z0. These particles were eventually detected at CERN. Now, the strong nuclear force is thought to mediated by gluons which come in an array of colours as well as the more traditional parameters. The field of quantum chromodynamics is attempting to show that the electro-weak force and the strong force are manifestations of the same thing. The hunt right now is for a chappy called the Higgs boson. Two events were recorded at CERN a year ago which might have been attributable to a Higgs decay, but alas the funding for the machine ran out and the search has switched to the Tevatron at FermiLab for the time being.

You ask what is energy composed of, well, E=mc^2. Matter and energy are equivalent. Think of matter as frozen energy.

I know some of the suggestions of ftl physics, its just all too unprovable at the moment, if I had negative energy concentrations, I'd rather try to make wormholes.

Neutrinos are leptons, electrons are the lightest charged leptons, neutrinos if they have no mass, are lighter and the electron neutrino and muon neutrino if the have mass are lighter than electrons but the Tau netrino may be heavier, the experimental limits place the mass limit at higher than electronic mass.

Quarks cannot exist alone in the current conditions in the universe, just after the big bang there woud have been a quark-gluon plasma, with effectively free quarks, but the nature of the strong nuclear force does not allow this to happen in our cold, low energy density conditions, apart from in CERN and fermilab possible, perhaps maybe once or twice.

QCD is interesting, "colour" works well to describe the phemonena of strong force and hadrons, and stops violation of Pauli's exclusion principle of fermions.

Finding the higgs boson would be useful since most current QM theories are really bad for saying why things have mass at all, and what causes everything to have different masses and this would help, it might of course not be the right explanation.

Funding didn't run out for the machine per say CERN, they're replacing it which means they have to shut down the current one.
The LHC when its installed should give some interesting results.

I wonder if I should scan some of my degree notes and post them...

>>>
Funding didn't run out for the machine per say CERN, they're replacing it which means they have to shut down the current one.
<<<

Yes, I know. The thing is, it was due to be decommissioned earlier, but an extension of funding was granted when the first hints of a result were forthcoming. It was this extension funding which ran out.

You seem quite up on this, any particular reasons...

Casual interest... ;-)

>>> You seem quite up on this

As do you....

>>> , any particular reasons...

Always been a bit of a scinece geek, visited CERN of a school trip, during my A-Levels, when I was 17ish, did Physics a University, included a lot of this kind of stuff, now more of a continued professional interest, I'm still a physicist at heart, career change perhaps due, but I'm not up to date or intelligent enough. Maybe with some practice and a masters...

Problem with this stuff is the equipment. I can go out and buy some glassware and reagents and tinker with chemistry in my garden shed, but if I started excavating 20km circular tunnels under the lawn, I think the local planning authority might send someone round!

Where I work at the moment makes super power kystroms for particle physics research, but they're not profitable enough, we're not taking orders beyong the end of the FY, and then we're closing off production, if you get in quick you could buy one.

They're quite power hungry though, ~1MW output.

Practice would involve me acquiring a shed load of cash and going back to uni, which I could live with, but if I had that much money I'd probably do something else...

Quote:

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Problem with this stuff is the equipment. I can go out and buy some glassware and reagents and tinker with chemistry in my garden shed, but if I started excavating 20km circular tunnels under the lawn, I think the local planning authority might send someone round!

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This makes sense. I took high school chemistry. I though it was great, really enjoyed it, but I opted for computer science because it is something that I can afford to pursue on my own. As it is, developing a professional software product is no easy task, you need to hire a team, you need general business skills, and project management skills. Yet it is possible to accomplish all this in one lifetime. Building a facility to do scientific research on the other hand seems rather unreachable.

>>> power hungry though, ~1MW output.

Hmmm, that might not go un-noticed either.

Strangly enough, one of our big costs on those is testing them, for hours and hours and hours.

It would be a good news story, mysterious power surge blacks out Copenhagen or wherever.

CERN public funding is (was about 6 years ago) about £0.50 per person in the EU per year. Worse problem is placing these things, you need 30km circumference tunnels in geologically stable areas. It helps if they're isolated as well, the detectors in CERN can detect the TGV going past about 30 miles away.

When you consider the discoveries made at CERN, the quibbling over financing it really does look obscene doesn't it.

Trouble is the public perception of the work. It is very easy to say it is all academic, abstract concepts and a lot of maths, where's the products? The space program produced loads of spin off products, where's my CERN non-stick pan? I don't know how to solve this because to understand the value, one needs to understand some of the concepts, and many people cannot or will not. Roll an anti gravity device out of the door and that'll be different.

>>> circumference tunnels in geologically stable areas

Geneva is far from a good choice of location. The entire alpine region is still subject to tectonic activity. I would have thought a site in an ancient shield would be better. Still, the thing seemed to work.

CERN's location is more political. All the important parts are in Switzerland, a neutral country, so that in case of war, it should all be left alone, and all the scientists should be safe.

>>> CERN's location is more political

Again, I was aware of that, and as usual, politics and sense rarely go hand in hand.

>>> a neutral country

I wonder if that term really has outlived it's day. I don't think in the current situation, Switzerlands neutrality would count for much, especially when one considers their involvement in the world financial markets. This is, however, a total digression.

To come back to the subject, you said earlier...

>>> The evidence for quarks having structure is shakey at best.

... I'd be interested in looking at any research which showed a structure within a quark, however tentative. Where did you see this? (I did see something about a resonant state in the b quark about 6 months back - but that was found to be a fault in the data).

As another aside, the b and t, do you call them top and bottom or truth and beauty?

Internal Quark structure was claimed by a group out of Fermilab about 2 years ago but the data wasn't good. I've not heard anything since... but I've not been reading as much as I could about this.

They're top and bottom to me,

>>> They're top and bottom to me,

Me too. I've seen the truth and beauty a few times recently though - yuck.

>>> Fermilab about 2 years ago but the data wasn't good.

This may actually have been the same thing then. If I remember correctly, some dubious data from some commisioning/calibration runs after an overhaul on the Tevatron got included in a research project which showed a possible resonance within the b quark. It was later totally debunked. It was the debunking I was reading about 6 months back.

If anybody's interested, I have about fifty chapters of Volume
One of Feynman's lectures on physics in pdf format. I'd be
happy to post them on my website for anyone who wants them.
I might be able to get more.

Drop a line here.

rick barclay

I would be, I've read some of them, not all of them and I understood a fair bit too.

>CERN public funding is (was about 6 years ago) about £0.50 per person in the EU per year. <

>When you consider the discoveries made at CERN, the quibbling over financing it really does look obscene doesn't it.<

Half a pound per person sounds like quite a bit to me. How does
that figure measure up against EU spending per capita for
social services? Defense? Et cetera, et cetera? All those 1/2
pounders can add up to quite a bundle. Then subtract your
per capita spending from that which the common bloke spends
on himself just to survive, and then I think you might have a
better idea of what's obscene and what's not. Most people
would rather eat and watch soccer than research tachyons
and such. Perhaps we could ask Osama for a contribution?

rick barclay

Quote:

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Originally posted by RobS
I would be, I've read some of them, not all of them and I understood a fair bit too.

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I'll get on it in a day or two. Please be patient.

rick barclay

rick barclay:

Whatever you say.

In direct taxation I pay about £5000, of which £0.50 gets sent to CERN. It does add up though, latest EU population figures are 380 million, so they get given a fair amount of cash.

So about 190UKP a year. Covers buildings, plant, maintenence, power etc, not to mention a small army of staff who are employed and paying tax rather than unemployed claiming benefit. And it produces some good science. Bargain I'd say.

That's only the public EU funding, other countries and research institutes also put in funding since it allows them access to the facilities and the data.

Yes, I'm well aware of the external funding. My point really is that .5 UKP is little more than the price of a postage stamp here, and as you also point out, the science is made available.

Consider the amounts of public money that the US puts into places like Brookhaven and Sandia, and much of that work is never made public.

I maintain that CERN is not an excessive demand on the member governments in the way that rick, with his talk of food and football, would like to believe.

:confused:

Dang...went from 0 replies to 30 replies..

Okay...

What is light composed of? I know that when an excited electron moves back down to a lower energy level, it releases a photon of light...

but what is that photon of light composed of? Everything must be composed of something...or maybe it is the absence of something...etc....

my favorite quote from enstein himself

"He who thinks he understands quatum mechanics does not."

Quote:

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Originally posted by adrianxw
Yes, I'm well aware of the external funding. My point really is that .5 UKP is little more than the price of a postage stamp here, and as you also point out, the science is made available.

Consider the amounts of public money that the US puts into places like Brookhaven and Sandia, and much of that work is never made public.

I maintain that CERN is not an excessive demand on the member governments in the way that rick, with his talk of food and football, would like to believe.

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Ok, Ok. Cool your roll, Adrian. You can argue with the other
blokes who actually have to dish up half a pound so you can
play with your toys. I'm sure it's all worth it.

I've posted the Feynman Lecture's on Physics in five zipped
files at flashdaddee.com. There are a total of, I think 34
chapters and an index. If more become available, I'll let
everyone know. Hope you all enjoy them.

rick barclay

DavidP:

>>> What is light composed of?

As you rightly say, photons. A photon is a boson. If you think about it, when an excited atom reverts to a lower energy state, it emits a photon, this photon can be absorbed by another atom thus promoting it to the excited state. This is exactly the idea of bosons. The force is transferred from one place to another by a force carrying "particle", in this case a photon. The weak nuclear force is mediated by w+, w- and z0 bosons, the strong nuclear force by a flock of gluons, for which there is some direct evidence.

Gravity is, at the moment at least, the odd one out. The model has been extended to contain the "Graviton" but there is no evidence for it, and it remains hypothetical. Many theories at present predict, for example, gravity waves, (pulses of gravity), from big cosmic events. A few experiments are in the pipeline now based on very acurately aligned lasers running at right angles to each other, and trying to detect distortions which a passing gravity wave would cause. It's early days yet. A more ambitious scheme is to set up a space based system along similar lines but with enormously longer "legs" thus renderind it far more sensitive, but this is a good few years away.

rick barclay:

Whatever you say.

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Originally posted by adrianxw Many theories at present predict, for example, gravity waves, (pulses of gravity), from big cosmic events. A few experiments are in the pipeline now based on very acurately aligned lasers running at right angles to each other, and trying to detect distortions which a passing gravity wave would cause. It's early days yet. A more ambitious scheme is to set up a space based system along similar lines but with enormously longer "legs" thus renderind it far more sensitive, but this is a good few years away.

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If anyone's interested, information on these two projects can be found at

http://www.ligo.caltech.edu/ (ground-based)

and

http://lisa.jpl.nasa.gov/ (space-based)