Schroedinger Cats and Consistent Histories

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In summary, Griffiths discusses his consistent histories interpretation of quantum mechanics, in which an experiment can be described in multiple valid ways, called consistent families of possible histories. To answer a specific question, a relevant family of histories must be chosen, which may or may not involve macroscopic quantum superpositions (MQS), also known as Schrodinger cat states. It is rare to find a relevant family that does not involve MQS, as most things are in contact with the environment, which decoheres them. However, an actual example of a Schrodinger cat state is the double slit experiment with one photon at a time. This raises the question of whether a live cat can ever be in a Schrodinger cat state, as it
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Swamp Thing
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In https://arxiv.org/abs/quant-ph/9810016, Griffiths says the following about his consistent histories interpretation of QM:

1. An experiment can be described in many ways that are equally valid. Each such narration / description is called a consistent family of possible histories.

2. To answer any particular question about the experiment, one has to choose a family of histories that actually helps to answer that question. There may be more than one useful family for a given question.

3. Some consistent families involve MQS (Macroscopic Quantum Superpositions), aka Schroedinger cat states.

Now my question is, for any given question, can we be sure of finding a relevant family that DOES NOT involve an MQS?
 
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Swamp Thing said:
Now my question is, for any given question, can we be sure of finding a relevant family that DOES NOT involve an MQS?

No.

But such are very very rare. Another name for consistent histories is decoherent histories. Just about everything out there is in contact with the environment, which effectively decoheres them so they are not in so called Schrodinger Cat states.

As an aside I know theoretically what a Schrodinger Cat state is, but have never even heard an actual example of one - I am sure they exist - but what actually is one? Maybe the classical double slit with one photon at a time - the photons are not decohered, but that is hardly macroscopic. Note in the Schrodinger Cat thought experiment since a live cat, in order to be alive, is in contact with an environment - ie breaths air, sweats etc. So it is not and can never be in an actual Schrodinger Cat state - yet that's what they call it - interesting isn't it.

Added later:
Found the following:
http://photonics.anu.edu.au/qoptics/Research/schrodingercatst.html

So that is a definite example - but it's rather contrived. I think all such states likely are - but I am not 100% sure. Strange again isn't it.

Thanks
Bill
 
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Thank you!
 

1. What is the concept of "Schroedinger Cats and Consistent Histories"?

The concept refers to the thought experiment proposed by physicist Erwin Schroedinger in which a cat is placed in a sealed box with a device that has a 50/50 chance of releasing poison. According to quantum mechanics, until the box is opened, the cat exists in a state of being both alive and dead simultaneously. Consistent histories is a theoretical framework used to explain and interpret this phenomenon.

2. Is the concept of "Schroedinger Cats and Consistent Histories" a proven scientific theory?

No, the concept remains a thought experiment and has not been proven through empirical evidence. It is a theoretical framework used to explain the behavior of particles in quantum mechanics.

3. How does the concept of "Schroedinger Cats and Consistent Histories" relate to quantum mechanics?

The concept is based on the principles of quantum mechanics, which state that particles can exist in multiple states simultaneously until they are observed or measured. The thought experiment with the cat illustrates this concept in a macroscopic scale.

4. Can the concept of "Schroedinger Cats and Consistent Histories" be applied to real-life situations?

No, the concept is purely theoretical and has not been observed in real-life situations. It is used to explain the behavior of particles at the quantum level, which is not observable in everyday life.

5. Are there any criticisms or controversies surrounding the concept of "Schroedinger Cats and Consistent Histories"?

Yes, there are various criticisms and controversies surrounding the concept, including its lack of empirical evidence and the philosophical implications of a cat existing in two states simultaneously. Some scientists also argue that it goes against the established principles of classical physics. However, the concept remains a valuable tool for understanding quantum mechanics and continues to be studied and debated by scientists.

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