We all know that subatomic particles exhibit quantum behavior. I was wondering if there's a cutoff in size where we stop exhibiting such behavior.
From what I have read, it seems to me that we still see quantum effects up to the nanometer level.
Answer
The classic experiment demonstrating quantum effects, the 2 slit experiment, has been preformed with subsequently larger and larger particles as our technology available to do it advanced. Originally, it was performed with electrons, which are just as much matter as any other matter, but are extremely small. The largest particle it has been demonstrated with are Buckminsterfullerene, which contain 60 Carbon atoms. For size comparison:
$$m_e = 5.485 x 10^{-4}u$$ $$m_{buckyball} = 720.642 u$$
There is a good reason that the experiment gets more difficult with increasing mass, and to be sure, the buckball experiment was quite an accomplishment. To the basics of quantum mechanics:
$$\Delta x\, \Delta p \ge \frac{\hbar}{2}$$
Alternatively, the de Broglie wavelength is:
$$\lambda = \frac{h}{p} = \frac{h}{m v}$$
I believe that in order to obtain the same wavelength with the same mass you have to decrease the velocity. The reason this could be problematic for such experiments is that it is hard to successfully create the conditions needed with a large and slower moving particle, such as needing a better vacuum.
No comments:
Post a Comment