Increase of Uncertainty over Time

In summary, it appears that the increase in the variance of the wave function over time is proportional to (1+t^2)1/2.
  • #1
Hornbein
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Looking at the literature it appears that the increase in the variance of the wave function over time is proportional to (1+t^2)1/2. Is that right?
 
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  • #2
Are you talking about certain form of Gaussian wavepacket?
 
  • #3
blue_leaf77 said:
Are you talking about certain form of Gaussian wavepacket?

I'm assuming it is a plain vanilla Gaussian, yes.
 
  • #4
Hornbein said:
it appears that the increase in the variance of the wave function over time is proportional to (1+t^2)1/2. Is that right?

More or less. You need another constant in there.

http://quantummechanics.ucsd.edu/ph130a/130_notes/node83.html

(the first result in a Google search for "gaussian wave packet spreading")
 
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  • #5
Hornbein said:
I'm assuming it is a plain vanilla Gaussian, yes.
The exact form involves some more constants as is pointed out by jtbell above.
Not all wavepacket evolves in time that way, the temporal behavior depends on the form of the wavepacket itself and on whether the packet is in free space or not. If the packet propagates in a free-potential space, only the position basis wavepacket evolves - the momentum basis wavefunction remains unchanged. If, on the other hand, there is a varying potential, the wavepacket experiences a "force" and consequently the momentum basis wavefunction will also undergo a change in time in addition to the position wavepacket.
 
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  • #6
blue_leaf77 said:
The exact form involves some more constants as is pointed out by jtbell above.
Not all wavepacket evolves in time that way, the temporal behavior depends on the form of the wavepacket itself and on whether the packet is in free space or not. If the packet propagates in a free-potential space, only the position basis wavepacket evolves - the momentum basis wavefunction remains unchanged. If, on the other hand, there is a varying potential, the wavepacket experiences a "force" and consequently the momentum basis wavefunction will also undergo a change in time in addition to the position wavepacket.

Thanks, that's very helpful for a qualitative understanding.
 

FAQ: Increase of Uncertainty over Time

What is "increase of uncertainty over time"?

"Increase of uncertainty over time" refers to the phenomenon in which the level of uncertainty or unpredictability in a system or situation grows as time passes. This can occur in various fields such as economics, climate change, and scientific research.

What factors contribute to the increase of uncertainty over time?

There are several factors that can contribute to the increase of uncertainty over time. Some examples include the accumulation of new data or evidence, the introduction of new variables or factors, and the complexity of the system or situation being studied.

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The increase of uncertainty over time can make decision-making more difficult and risky. As uncertainty grows, it becomes harder to accurately predict outcomes and make informed decisions. This can lead to hesitation or delays in decision-making, or even poor decisions based on incomplete or inaccurate information.

What can be done to mitigate the increase of uncertainty over time?

There are several strategies that can help mitigate the increase of uncertainty over time. These include regularly reviewing and updating data, conducting thorough research and analysis, seeking multiple perspectives and expert opinions, and implementing adaptive management strategies that can adjust to changing circumstances.

How can scientists address the increase of uncertainty over time in their research?

Scientists can address the increase of uncertainty over time by acknowledging and accounting for uncertainty in their research design and methodology. This can include using statistical methods to quantify uncertainty, conducting sensitivity analyses, and clearly communicating the level of uncertainty in their findings. Collaboration with other researchers and incorporating multiple lines of evidence can also help reduce uncertainty in scientific research.

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