Quantum Tunneling through a Potential Barrier (Part 2)

FDTD simulation of a Gaussian wave packet with kinetic energy of 500 eV. The potential barrier has a height of 600 eV, and a thickness of 25 pm.

The black line represents the real part of the wave function, while the red line represents the imaginary part. The actual probability amplitude is found by taking the magnitude-square of the total wave function (see part 1 of the video with the same title).

The wave packet partially tunnels through the barrier, giving a total probability of about 17% of finding the particle on the other side.

This simulation was written and rendered in Matlab.

Category:

Education

Tags:

• quantum
• mechanics
• tunneling
• potential
• barrier
• matlab
• simulation
• demo

[henrikhhhhh]

awesome!

How about a Ride of the Valkyries soundtrack for emotional impact?

Do you have the code avaliable somewhere?

[nageljr]

I like the soundtrack idea. But I'm just too lazy.

I do have the codes all written in Matlab if you are genuinely interested. Just message me privately and we can work it out.

[boxa888]

nikola tesla did this on the industrial scale, (wardenclyffe tower) the high energy waves tunnels through the earth to all points giving almost instant energy transfer about 1.5 times faster than light! i put up info on his quantum effect, im sure this knowlege would advance quantum mechanics ten fold!

[nageljr]

The Wardenclyffe tower that Tesla tried to build is nothing more than a glorified transformer, and works by the classical law of Faraday induction. There is nothing "quantum mechanical" about it. It certainly can be used to transmit power wirelessly, but it is horribly inefficient and uneconomical. This is why he could never get it to work.

As for 1.5 times faster than light, that just goes against all known laws of electromagnetics and relativity.

[bellumcarmen]

Is this about diffraction???

[nageljr]

Nope. This is strictly a quantum mechanical effect. The "wave" you see could just as easily be a proton as an electron. The particle is tunneling through a barrier, even though the potential is greater than the energy of the particle itself.

[jwrosenbury]

@nageljr The wave is a probability distribution. I think it's a fast moving electron hitting a thin potential barrier (area of negative charge). The product of the red and black waves is the probability of finding the electron at a given point.

Most of the time the electron bounces off, but occasionally it finds it's way through. Take note, the electron doesn't have a location until it affects the outside world (i.e. is measured). So until that happens it is on both sides of the barrier.

[jwrosenbury]

@nageljr Waves can and do travel faster than light. Information can't. Wikipedia "phase velocity" and "group velocity" for a better understanding.

Tesla seems to have understood waves very well. But when he lived the quantum probability distribution was poorly understood. It's a shame as his intuitive understanding would come in handy in quantum physics. As it is, none of his work directly applies.

[raulfernandez2]

hi. i ve done great job with this. i m interested in low power design and i deal with quantum mechanics also. please send me the matlab code, if you want. thanks

[mb4321]

I am interested to get your Matlab codes. Can you please send them to me?

[hulkmedia]

incorrect.