Can Randomness be Predictable in Quantum Physics?

  • Thread starter Subatomic
  • Start date
In summary, the conversation discusses the predictability of quantum physics and the concept of randomness. Some argue that it is impossible to know all variables in a given situation and that random factors play a role in predicting outcomes. The question arises about the true randomness of these factors and whether they can be predicted in a closed environment. It is mentioned that in classical mechanics, everything is deterministic but not necessarily predictable. In quantum mechanics, the uncertainty principle states that the more one knows about a particle's position, the less they know about its speed, making it impossible to predict the future with complete certainty. However, probability distributions can be predicted according to the Schrodinger Equation.
  • #1
Subatomic
1
0
Alright, so I am new to the whole "Quantum Physics" thing, so please don't jump down my throat. I have seen this question asked elsewhere, however a lingering question persists in my mind.

Let's assume that we know all variables involved in a particular situation. Some will assert that:

a) This is just not possible. We can never know all variables in a given situation (it would take too much time!).
b) This is just not possible. There are situations in which random factors affect the situation, making it impossible to predict (at a subatomic level) what will really happen.
c) Even if we know all variables, it is still not possible to predict the random factors associated with it.

Now, I may not have produced the most eloquent set of circumstances, but the question I have for you folk is, what if those "random factors" that I hear so much about, are still not so random? I mean, when you pose the question of: will two identical unstable nuclei will not decay at the same identical time?; how do we know that at an even deeper level, these are really identical? Or that came into existence at exactly the same frame in time?

I assert that for this particular question of randomness, if you will, that in exactly the same closed environment, if both unstable nuclei were created at the exact same time in the exact same coordinates within their closed environment, and have the exact same makeup, that they WILL, indeed, decay at the exact same time.

Please tell me if I'm foolish.
 
Physics news on Phys.org
  • #2
You may want to look up Bell's inequalities and Hidden Variables
 
  • #3
If you have a state vector, e.g. |neutron>, this is all you can say and know about a neutron. Anyway, you can't say when it will decay.
 
  • #4
What exactly do you mean by "predictable"?

I don't know the finer details of QM, but I do know that in Classical Mechanics everything is deterministic (i.e. given the current state + laws of motion, it fixes the universe at all other times), but most classical systems are not predictable. This might seem confusing, but in some systems the solution can't be solved analytically and can only be calculated numerically (i.e. to a certain allowed error -- and in chaotic systems small initial errors eventually result in a considerable difference), so even though the future is fixed in Classical Mechanics, it's not really possible to know it.
 
  • #5
No not everything in qm is predictable. You can predict, that in a certain time 50% of a given amount of nuclei will decay. But you can't say which individual nucleus will deacy when.
 
  • #6
Hey
yeh i was new not long ago :)
but no you cannot predict every future according to quantum physics
you have an idea of what will happen, according to the liikelyhoods, but that only goes up to 50% of what you may know
this happens becouse of the uncertainty principle, to predict what will happen in the future than you need to know the speed of a particle, and its exact position. To know these youo need to shine a photon onto the particle, but to find out the position of a particle, shining a photon on it changes its speed.
the same goes for position
The more you know of one thing the less you know of the other.
So we cannot know the future
 
  • #7
according to QM nothing is predictable except probability distributions, which evolve determistically according to the Schrodinger Eqn.

tom.stoer said:
No not everything in qm is predictable. You can predict, that in a certain time 50% of a given amount of nuclei will decay. But you can't say which individual nucleus will deacy when.

Isn't it possible (but very unlikely) that no nuclei will decay?
 
  • #8
Of course 50% are valid only for a large number of nuclei - strictly speaking in the limit of infinitly many nuclei - according to the "law of large numbers". I am sorry for the sloppiness.
 

1. Is everything truly predictable?

The concept of predictability is complex and can be interpreted in different ways. In some cases, certain events or phenomena may seem predictable, while others may not be. Ultimately, it is difficult to determine whether everything is truly predictable or not.

2. Can we predict the future?

While some aspects of the future may be predicted with a certain degree of accuracy, it is not possible to predict everything that will happen in the future. The future is influenced by a multitude of factors, making it unpredictable to a certain extent.

3. What factors affect predictability?

There are many factors that can affect predictability, such as the complexity of a system, the amount of data available, and the accuracy of the predictions being made. External factors, such as unexpected events or human behavior, can also play a role in the predictability of a situation.

4. Can we use technology to make accurate predictions?

Technology, such as artificial intelligence and data analysis, can help us make more accurate predictions in certain situations. However, it is important to remember that technology is not infallible and can also be subject to errors and biases.

5. How can we improve predictability?

One way to improve predictability is to gather and analyze more data. This can help us better understand patterns and trends, leading to more accurate predictions. Additionally, continuously monitoring and updating our predictions can also help improve their accuracy over time.

Similar threads

Replies
12
Views
687
Replies
17
Views
2K
Replies
13
Views
1K
Replies
19
Views
1K
  • Quantum Physics
2
Replies
38
Views
2K
  • Quantum Physics
Replies
3
Views
613
Replies
8
Views
922
Replies
21
Views
938
  • Quantum Physics
Replies
15
Views
1K
Replies
7
Views
996
Back
Top