Quantum Ping Pong Balls

  • Thread starter Allday
  • Start date
164
1
I ran accross an interesting problem in quantum uncertainty today. I'm working out the details right now, but I thought I would share. This might belong in brain teasers or something like that, but I know some people love problems like these (others consider them a complete waste of time)

Imagine dropping a ping pong ball of radius R onto an identical ping pong ball from a height of 10R. The balls undergo perfectly elastic collisions. What combination of delta x and delta p yield the most number of bounces while still satisfying the uncertainty relation delta x * delta p > hbar. Make any reasonable assumptions.

Now Classical physics allows perfect initial allignment and an infinite number of bounces if there are no pertubations. However there is a tradeoff in uncertainty of position (the farther away from center it hits the faster it will bounce off) and uncertainty in momentum (a bigger uncertainty there will lead to a "drift" of the ping pong ball away from the center, when we use quantum. How do we keep that durn ping pong ball on for as many bounces as physically possible.

I made some quick calculations and got about eight bounces
 

DrClaude

Mentor
6,969
3,140
The uncertainty principle is about measurements. I don't see how the two balls colliding would count as a measurement.

I made some quick calculations and got about eight bounces
The fact that the result is independent of the size of the ball or its mass is very suspicious.
 

Want to reply to this thread?

"Quantum Ping Pong Balls" You must log in or register to reply here.

Related Threads for: Quantum Ping Pong Balls

Replies
13
Views
2K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Hot Threads

Top