Behavior of successive measurements

In summary, when a measurement is made on a quantum state, it changes the state to an eigenstate of the observable being measured. However, it is uncertain what happens at the moment of measurement. If the particle is measured again, it may or may not be in the same eigenstate, depending on whether the operator of the eigenstate commutes with the Hamiltonian. The shorter the time interval between measurements, the more likely the results will be the same.
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mike1000
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[Mentors' note: Split off from this thread as it was a digression there]
PeroK said:
You have a quantum state before a measurement: the state is evolving with time. A measurement changes the quantum state (to an eigenstate of the observable being measured); the new quantum state continues to evolve.

To what extent you can ask what is happening at the "instant of measurement" is a moot point.

After you make a measurement and find the particle to be in a particular eigenstate, if you measure that particle again will you find it to be in that same eigenstate?
 
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mike1000 said:
After you make a measurement and find the particle to be in a particular eigenstate, if you measure that particle again will you find it to be in that same eigenstate?
Only if it is in an eigenstate of the Hamiltonian.
 
  • #3
mike1000 said:
After you make a measurement and find the particle to be in a particular eigenstate, if you measure that particle again will you find it to be in that same eigenstate?
There's no way of knowing; measuring the particle again doesn't tell us anything about whether its state was an eigenstate of anything before we measured, it just gives us a measurement result. So the closest we can come to a sensible question might be something like "After you make a measurement and get the result corresponding to a particular eigenstate, if you measure that particle again will you get the same result?"

The answer to that question is "It depends".

The eigenstate in question is an eigenstate of some operator. What is that operator? Whatever it is, does it commute with the Hamiltonian? If so, the two measurements will be the same; if not, they may or may not be the same and the shorter the time interval between the two measurements, the more likely the two results will be the same.
 
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1. What is the behavior of successive measurements?

The behavior of successive measurements refers to the pattern or trend observed when taking multiple measurements of the same variable over time or under different conditions. It is the way in which the measurements change or remain consistent as more data is collected.

2. Why is it important to understand the behavior of successive measurements?

Understanding the behavior of successive measurements is important because it allows us to make accurate and reliable predictions and conclusions based on the data collected. It also helps us identify any potential errors or inconsistencies in the measurements.

3. How do you analyze the behavior of successive measurements?

The behavior of successive measurements can be analyzed through various statistical methods such as calculating the mean, median, and standard deviation. Graphs and charts can also be used to visually represent the data and identify any patterns or trends.

4. What factors can influence the behavior of successive measurements?

The behavior of successive measurements can be influenced by several factors, including the precision and accuracy of the measuring instrument, the skill and consistency of the person taking the measurements, and any external factors that may affect the variable being measured.

5. How can we improve the behavior of successive measurements?

To improve the behavior of successive measurements, it is important to use reliable and calibrated measuring instruments, ensure consistent and accurate measurement techniques, and minimize the impact of external factors. Regularly checking and adjusting for any sources of error can also help improve the behavior of successive measurements.

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