Recent content by cryptist

Where to pursuit academic career as a (non-EU and non-US citizen) physicist? Europe and US have major social, cultural, intellectual, demographic and academic differences. There are pro's and con's for each of course and I am very struggling to decide. I thought that some experienced people on...

Wow! That's it. Thank you for the code!

That's it! Wolfram should provide a similar package too I think. It shouldn't be so difficult. Thanks to you all for your answers.

I think I am getting what you say. But don't you think Wolfram team should find a solution for this? Maybe they should modify their codes, because this is the reason I get wrong answers on my study and it is clearly wrong. I am writing an exact expression, I think it should understand it before...

When I wrote Floor[Sqrt[1144/100 - 10.]/(2/10)] it gives 5 again. (With dot next to 10).

No. I tried what you said and I get wrong answer again.

It is NOT related to the thing that you mentioned, because with different numbers, I get right answers. For example 20.46-10 (substraction expression) gives the right result but 11.44-10 gives wrong result. So this prooves that there is a clear bug. Besides, 11.44 is an exact number. So it...

There is a crucial bug on both WolframAlpha and Mathematica. When we give the input "Floor(sqrt(11.44-10)/0.2)" it gives wrong answer. The actual answer is six (6) but wolframalpha gives five (5). The problem is Wolframalpha calculates 11.44-10 incorrectly. Although the answer is exactly 1.44...

Thank you for the detailed answer but I know the band gap theory. (Perhaps I've got misunderstood in this question, since I superficially got stamped as "starter") I can calculate electron concentration for undoped semiconductors, and theoretically it is possible to obtain ANY electron...

A structure with free electron density around 10^26 m^-3 is considered as a highly doped semiconductor or a metal? Or in other words, what is the lowest possible free electron concentration for a metal and what is the highest possible free electron concentration for a doped semiconductor?

From Abel–Ruffini theorem, we know that, there is no general algebraic solution to polynomial equations of degree five or higher. So there are general solutions for degrees n={1,2,3,4}. Does degree have to be an integer? What about the fractional degrees? Are there general solutions for example...

Thank you for the answer. So, in order to derive position opeator for momentum space, I have to start with the wavefunction in momentum space. Not in position space. That was my mistake as far as I understand.

Might be simple but I couldn't see. We can easily derive momentum operator for position space by differentiating the plane wave solution. Analogously I want to derive the position operator for momentum space, however I am getting additional minus sign. By replacing $$k=\frac{p}{\hbar}$$ and...

We have a constant ratio of them in vacuum. Is it same in a medium also? Or not? And in any case, what is the reason?

I don't think they are saying that light will faster than c. They are actually saying that by changing vacuum permittivity and vacuum permeability, it is possible to change the speed of light, c itself!