Recent content by shetland

Hallo, I want to know if the iPhone battery loses power over time? Does it lose power the more you use it?

Yes, though even from mathworld it is spelled as I used: http://mathworld.wolfram.com/Quadruple.html My question was lame, or showed off how ignorant I am - I am quite rusty - and realized how to do this in mathematica, and in addition sloughed through until I could use the wigner-eckhart...

I'm calculating the zz Component for the quadruple tensor. Q_{zz} = 3cos^2\theta-1 (r=1 in this case), and the Y_{lm}(\theta,\phi) would be l=2, m=0. I would like to calculate the result in either maple or mathematica - I have not used either very much - I want to check the result using...

right. I'm not thinking. Of course they can't all be diagonalized. Thanks. I thought about it as you suggested, clearly y and z are rotated by \cos{\pi}, z-> -z, y-> -y. For the first part of the hamiltonian, obviously S_z^2is unchanged, as is S^2, so its just a matter of the S± terms. I guess...

Monkey, I guess I'm tired. I looked a bit closer - the problem in the book is quite small. I have a misplaced parenthesis now - so you can do this by inspection, right? We know the value of S_i is 2\hbar, so that the rotation is then 2\pi, which brings the system back to original.

For S = 2, I have the following hamiltonian, H=a \left( 2\,{S}^{2}-4\,{S_{{z}}}^{2} \right) +4\,b \left( (\left { S_+}^{3}) +({S_-}^{3}) I'm to show that a rotation of 180º, e^{-i \pi S_x/ \hbar} leaves the hamiltonian unchanged. I started thinking I could use the baker-hausdorff formula...

As you probably know, typical "Caesar breath" calculations show that in each breath we take, there is a large probability that at least one atom is one that Caesar shared. I have looked at the math here, and find it fairly reasonable - though being able to distinguish between anyone particular...

I think the "new religion" comment to me was meant sarcastically, implying that idea had no merit. Frankly, I don't see any religious connotation; at most, it speaks to the issue that atoms are not "alive", alive in the sense we consider ourselves, :smile: , but that when we bring together a...

I'm about to start a grad level course using Chandler. The brief perusing I've done, I would agree - it appears that it gets directly to the point. As a bonus, tackles modern problems, such as monte carlo simulations. I had Reif as an undergrad, and still refer to this today - II think...

Also posted in skepticism forum: Hey everyone, Currently reading a new book by Bill Bryson, "A short history of nearly everything". Well, despite the title, clearly even a short history would be a very, very big book, still the read is quite addicting, and there are many scientific...

Hey everyone, Currently reading a new book by Bill Bryson, "A short history of nearly everything". Well, despite the title, clearly even a short history would be a very, very big book, still the read is quite addicting, and there are many scientific areas to which I was quite unfamiliar...

I wonder what percentage of the budget NASA had during the heyday of the Apollo program? I would hope that their are not program cut in other areas of NASA, to justify solely this particular goal.

Zooby, I was more curious about this from the standpoint of thermodynamics, and assure you, I'm not nearly nutty enough to try this at home! I'm taking a biophysics class at the moment, and we just revisited gibbs free energy and the role of 'free energy transducers', such that living...

Thanks, Zoobyshoe (grt handle, btw). Ok, maybe I shouldn't have said nil, but I think the efficiency of this type of heat engine is less than for instance in the case for internal combustion. So, the problem would come down to collecting (maybe not so big, since most A/C's have nice heat...

Can you use the heat energy extracted by an A/C to do some useful work? Or does this somehow violate the 1st law in such a way to negate energy conservation...doesn't appear so; of course, the heat energy coming out into the ambient temp would be small, nil, and thus the kind of work you could...