Probability and probability amplitude

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Discussion Overview

The discussion revolves around the concepts of probability and probability amplitude in quantum mechanics, particularly focusing on the mathematical expressions involving state vectors and their inner products. Participants explore the implications of these expressions for understanding probabilities and interference terms.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant asserts that for a state |A>=a|0>+b|1>, the inner product equals a^2+b^2=1, suggesting that no interference term is present.
  • Another participant clarifies that represents probability, while would indicate a transition amplitude, which could involve interference.
  • A question is raised about whether the transition from A to B requires ||^2 to find interference terms, and whether solely indicates probability without interference implications.
  • One participant provides a detailed expansion of to include terms that suggest interference, questioning where the interference term is located.
  • Another participant challenges the expectation of interference between orthogonal states, implying that such interference may not be present.
  • A later reply discusses the normalization condition a^2+b^2=1 but argues that is not simply a^2+b^2, introducing additional terms that complicate the relationship.

Areas of Agreement / Disagreement

Participants express differing views on the presence and interpretation of interference terms in the context of probability amplitudes and inner products. No consensus is reached regarding the correct interpretation of these mathematical expressions.

Contextual Notes

Participants highlight potential confusion regarding the definitions and implications of inner products, transition amplitudes, and the conditions under which interference terms arise. The discussion remains open to interpretation based on the mathematical framework employed.

phyky
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|A>=a|0>+b|1>
<A|A>=probability amp |<A|A>|^2=probability
If the state is same, so <A|A>= a^2+b^2=1. then i find the probability and no interference term in it!
so can i say <A|A>=|<A|A>|^2 and no square is needed? since if i square it become a^4+b^4=??
what wrong with it! and where should i place interference term?!
 
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|A> is the probability amplitude.
<A|A> is the probability.
Maybe you are confusing the situation with transition amplitudes where <A|B> is the amplitude of transition from A to B?
 
so if transition from A to B it need |<B|A>|^2 to find interference term? and <A|A> show only probability but nothing about interference? but its outer product |A><A| does show interference?
 
|A>=a|0>+b|1> so <A|A>=a^2<0|0>+b^2<1|1>+a*b<0|1>+b*a<1|0> where <i|j>=0 <i|i>=1. where the interference term?
 
You looking for interference between orthogonal states then. Why would you expect there to be some?
 
As for a normalized wave function |A>, a^2+b^2=1. However, <A|A>is not equal to a^2+b^2but a^2+b^2+a*b+ab* , generally speaking, the latter is not equal to 1. <A|A>=|A>|^2, would it help?
 

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