Think Science .

From a non-quantum perspective, there are only two ways to produce magnetic fields: using electric currents and having time-varying electric fields. Electric fields inside matter generally don’t vary in time with high enough frequencies to make their contributions to the magnetic properties of matter all that important, so electric currents are the main cause for matter’s magnetic properties, other than quantum effects. The primary quantum cause of magnetism is spin.

b) Paramagnetism: in some materials, the distribution of electrons in the material’s atoms is such that these atoms end up having a net magnetic dipole moment, that is, the atoms are really very much like tiny magnets of their own. However, these are usually randomly oriented and, as a result, a chunk of paramagnetic matter has no net magnetic field. When an external magnetic field is applied, these dipole moments align with the external field, producing a non-zero net magnetic field which is then attracted
piece of matter is diamagnetic, and the response is stronger the stronger the external magnetic field is, being essentially zero when there are no external magnetic fields being applied. to the external field. Just as with diamagnetism, the stronger the externally applied field, the stronger the response of the material is.

 However, the paramagnetic response, when it exists, is far stronger than the diamagnetic response (which always exists). Moreover, because it has to do with the alignment of otherwise randomly oriented magnetic dipoles, the paramagnetic response is very susceptible to the temperature of the material.

d) anti-ferromagnetism: this is similar to ferromagnetism, but neighboring electron spins aren’t aligned in the same direction. Instead, they’re aligned like this: up-down-up-down, etc, rather than up-up-up-up etc or down-down-down-down etc, which is the case in ferromagnetism. 

The relative intensities are as follows, from strongest to weakest response:

ferro > antiferro > para >> dia

(> meaning “stronger than”, >> meaning “much stronger than”)

As pointed out already, all materials are diamagnetic, some are paramagnetic, and some are ferromagnetic or anti-ferromagnetic (but not both at the same time).

If what you want is the actual proof, I suggest you look at any good book on statistical mechanics. One of my favorite books for that subject is

Fundamentals of Statistical and Thermal Physics, by Frederick Reif
http://www.amazon.com/Fundamentals-Statistical-Thermal-Physics-McGraw-Hill/dp/0070518009
The law of equipartition of energy is valid for a system (classical or quantum) (a) whose hamiltonian is a quadratic function of the generalized coordinates and momenta describing the system in question, and (b) in thermal contact with a reservoir at constant temperature.

Because of (b), the probability of any microstate of the system is proportional to exp(-ßH), where ß = 1/(kT) and H is the hamiltonian of the system. Thus, the average value of any dynamical quantity F(q, p), depending on the generalized coordinates q and/or momenta p, is given by

<F> = ( ? F(q, p) exp[ -ß H(q, p) ] dq dp ) / ( ? exp[ -ß H(q, p) ] dq dp )

So far, this is perfectly general. Now, if (a) is true, then you can actually compute the average above quite easily. To make things easier here (because of orkut’s limitations), let’s say that the Hamiltonian is H = q^2, that is, it’s quadratic on the generalized coordinate q.

What’s the average value of the energy of the system, then? It’s simply

<H> = <q^2> = ( ? q^2 exp[ -ß q^2 ] dq ) / ( ? exp[ -ß q^2 ] dq )

Now consider the integral Z(ß) = ? exp[ -ß q^2 ] dq as a function of ß. It’s the integral appearing as the denominator of <H>. Taking the derivative with respect to ß, you find:

dZ(ß)/dß = - ? q^2 exp[ -ß q^2 ] dq

which, except for the minus sign, is exactly the numerator appearing in <H>. Thus,

<q^2> = - (1/Z) dZ/dß = - (d/dß) [ ln Z(ß) ]

So, all we need is to compute Z(ß). The limits of integration (which I haven’t shown in the above) are from negative to positive infinity, since the coordinate can take any of those values. So, with u = sqrt(ß) q,

Z(ß) = ? exp[ -ß q^2 ] dq = ? exp[ -u^2 ] du / sqrt(ß) = ß^(-1/2) x some constant

lnZ(ß) = -(1/2) lnß + some constant

and

<q^2> = - (d/dß) [ ln Z(ß) ] = (1/2) (1/ß) = kT/2

So, the average value of any quadratic generalized coordinate is kT/2. The same is true for the generalized momenta. Hence, for a system described by N generalized coordinates and N generalized momenta, all of which appearing quadratically in the hamiltonian, the average energy is going to be given by

<E> = N kT/2 + N kT/2 = N kT

That’s true also if the generalized coordinates and/or the generalized momenta appear in H as general quadratic functions, that is, with linear terms as well.

This post is to show Nobel prize winners and their research in time span (1999-2009). Why i’m making this post? One reason i think is with this i can direct my friends to recent Nobel winners and their research. There are plenty of good material on the internet scattered on their research. So if anyone is interested in more information about research then they can Google up for more information.

Year 1999
GERARDUS ‘T HOOFT, and  MARTINUS J.G. VELTMAN, for quantum structure of electroweak interactions in physics.

Year 2000
ZHORES I. ALFEROV, and HERBERT KROEMER for developing semiconductor heterostructures used in high-speed- and opto-electronics.

JACK ST. CLAIR KILBY, for inventing the integrated circuit.
In 2000, prize were half awarded to these two different developements.

Year 2001
ERIC A. CORNELL, WOLFGANG KETTERLE and CARL E. WIEMAN, Prize was jointly awarded for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms.

Year 2002
RAYMOND DAVIS JR., and MASATOSHI KOSHIBA, received half jointly award for detection of cosmic neutrinos.

RICCARDO GIACCONI, received other half of the prize for the discovery of the cosmic x-ray sources.

Year 2003
ALEXEI A. ABRIKOSOV, VITALY L. GINZBURG and ANTHONY J. LEGGETT, receieved joint prize for the contributions in superconductors and superfluids.

Year 2004
DAVID J. GROSS, H. DAVID POLITZER and FRANK WILCZEK, joint award for the discovery of asymptotic freedom in the theory of the strong interaction.

Year 2005
ROY J. GLAUBER, joint award for the quantum theory of optical coherence.

Other half awarded to the JOHN L. HALL and THEODOR W. HÄNSCH, for the contribution of laser-based precision spectroscopy, including the optical frequency comb technique.

Year 2006
JOHN C. MATHER and GEORGE C. SMOOT, joint awarded for the discovery of the black body form and anisotropy of the cosmic microwave background radiation.

Year 2007
ALBERT FERT and PETER GRÜNBERG, joint awarded the discovery of Giant Magnetoresistance.

Year 2008
YOICHIRO NAMBU, joint award for the contribution of the mechanism of spontaneous broken symmetry in subatomic physics.

MAKOTO KOBAYASHI and TOSHIHIDE MASKAWA, received other half of the prize for the discovery of the origin of the broken symmetry

These are the Nobel prize winners for the year 1999-2008. Some interesting sites you can find on internet where work of these Nobel winners is summarized.

Check Sir Gerrard t’hooft official site for his work and lecture noes. http://www.phys.uu.nl/~thooft/

One of our friend presented his views on why electrons exist but god can’t. This discussion was on AVT forums and we got offended by one religious preacher. So in response to his query, one of our friend replied to that person.

 His reply was :

Even if you cannot directly see electrons, you can show that they exist by studying clues that they leave, such as static electricity, electric currents, the fact that they deviate their paths under the influence of a magnetic field, and so on. These clues are reproducible in general as well as under controlled conditions (that is, in a laboratory). As a result, the behavior of electrons is predictable.

Now, what clues does god leave us of his existence, assuming he does exist? Atheists would claim “none”. Theists would claim that the universe itself and life and certain so-called miracles are the clues god leaves of his existence. However, the universe itself and life are amenable to scientific study without having to make the assumption that god exists. Miracles - assuming that they happen in the first place - aren’t reproducible at all, especially under controlled situations, and thus cannot be predicted. In other words, there really is no evidence that god exists. And that’s where your analogy fails, because there IS plenty of evidence that electrons exist.

 Let me put it differently. Imagine “electron believers” and “electron atheists”:

See the difference? That’s why your analogy does not apply.

 Hehe, i hope you enjoyed his reply. I like this reply to such an extent that i decided to make a post of it for all of you. If you happen to see any such religious preacher then ask him to read this reply. 

Albert Einstein made a number of statements that are somewhat open to a bit of interpretation.

I believe in the God of Spinoza who reveals Himself in the orderly harmony of what exists, not in a God who concerns himself with the fates and notions of human being.

Religion is bind without science, science is lame without religion.

I find this article[http://www.ffrf.org/fttoday/2004/nov/raner.php] very helpful.

It quotes some corresponence with Einstein where he stated:

From the viewpoint of a Jesuit priest I am, of course, and have always been an atheist. …. It is always misleading to use anthropomorphical concepts in dealing with things outside the human sphere–childish analogies. We have to admire in humility the beautiful harmony of the structure of the world–as far as we can grasp it. And that is all.

And asked for further clarification he said:

I have repeatedly said that in my opinion the idea of a personal God is a childlike one. You may call me an agnostic, but I do not share the crusading spirit of the professional atheist whose fervor is mostly due to a painful act of liberation from the fetters of religious indoctrination received in youth. I prefer an attitude of humility corresponding to the weakness of our intellectual understanding of nature and of our own being.

More Albert Einstein quotes can be found at

atheistsunited.org.[http://www.atheistsunited.org/wordsofwisdom/Edwards/einstein.html]