Hardy's Paradox and lorentz invariant realist interpretation

In summary, the conversation discusses the limitations of realist interpretations in being made Lorentz invariant, with a focus on the many-world interpretation and GRW theories. It is argued that these theories cannot be made local, but can be made Lorentz invariant. The conversation also mentions the error in Lucien Hardy's conclusion that realist Lorentz invariant models make wrong predictions. The distinction between Lorentz invariance and locality is also clarified, with examples of theories that possess one property but not the other. The conversation ends with a brief discussion on the nonlocality of classical relativistic kinetic theory.
  • #1
JG11
18
2
Does Hardy's paradox show that all realist interpretations cannot be made lorentz invariant? Or is it just realist hidden variable theories?
 
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  • #2
It depends on what exactly do you mean by a realist theory which is not a hidden variable theory. If by realist theory you mean a theory of objects existing out there irrespective of our observations, then the theorem refers to all realist theories.
 
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  • #3
Demystifier said:
It depends on what exactly do you mean by a realist theory which is not a hidden variable theory. If by realist theory you mean a theory of objects existing out there irrespective of our observations, then the theorem refers to all realist theories.
So this would even apply to the many world interpretation and the GRW theories?
 
  • #4
JG11 said:
So this would even apply to the many world interpretation and the GRW theories?
Yes, provided that "Lorentz invariant" is replaced with the word "local". GRW theories are explicitly non-local. MWI is also not local, but in a somewhat subtle sense explained in https://lanl.arxiv.org/abs/1703.08341 .
 
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  • #5
Demystifier said:
Yes, provided that "Lorentz invariant" is replaced with the word "non-local". GRW theories are explicitly non-local. MWI is also not local, but in a somewhat subtle sense explained in https://lanl.arxiv.org/abs/1703.08341 .
Can the MWI be made lorentz invariant then? GRW? I guess not because of what Hardys paradox shows...?
 
  • #6
JG11 said:
Can the MWI be made lorentz invariant then? GRW? I guess not because of what Hardys paradox shows...?
As I said (but perhaps not sufficiently clearly), this theorem should actually be interpreted as the statement that MWI and GRW cannnot be made local. For a non-local but Lorentz invariant GRW-like theory see https://arxiv.org/abs/quant-ph/0406094
 
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  • #7
Demystifier said:
As I said (but perhaps not sufficiently clearly), this theorem should actually be interpreted as the statement that MWI and GRW cannnot be made local. For a non-local but Lorentz invariant GRW-like theory see https://arxiv.org/abs/quant-ph/0406094
Interesting. Say that one formulates the MWI to be as non local as bohmian mechanics (I guess by inserting the non locality by hand), would it still be empirically lorentz invariant like bohmian mechanics?
 
  • #8
JG11 said:
would it still be empirically lorentz invariant like bohmian mechanics?
Not only empirically Lorentz invariant, but even fundamentally Lorentz invariant.
 
  • #9
Demystifier said:
Not only empirically Lorentz invariant, but even fundamentally Lorentz invariant.
Does Lucien Hardy come to the wrong conclusion that realist lorentz invariant models make the wrong predictions?
 
  • #10
JG11 said:
Does Lucien Hardy come to the wrong conclusion that realist lorentz invariant models make the wrong predictions?
Yes. If you want to see what exactly the Hardy's error is, see Sec. A.1.1 of my https://lanl.arxiv.org/abs/1309.0400 .
 
  • #11
Demystifier said:
provided that "Lorentz invariant" is replaced with the word "local".
"Lorentz invariant" and "local" are two very different properties of a theory. Nonrelativistic QFT is often local. On the other hand, classical relativistic kinetic theory is Lorentz invariant but nonlocal.
 
  • #12
A. Neumaier said:
classical relativistic kinetic theory is Lorentz invariant but nonlocal.
Why is it nonlocal? Where does the nonlocality come from?
 

FAQ: Hardy's Paradox and lorentz invariant realist interpretation

What is Hardy's Paradox?

Hardy's Paradox is a thought experiment proposed by physicist Lucien Hardy in 1992. It involves two entangled particles and the concept of non-locality, which challenges our understanding of causality and the nature of reality.

How does Hardy's Paradox relate to Lorentz Invariant Realist Interpretation?

Lorentz Invariant Realist Interpretation (LIRI) is a proposed solution to Hardy's Paradox. It suggests that the paradox can be resolved by considering the existence of a preferred reference frame in which the two entangled particles are in causal contact. This interpretation is based on the Lorentz invariance principle in special relativity.

What is the main argument of LIRI?

The main argument of LIRI is that the paradox arises due to a misunderstanding of the concept of non-locality. LIRI suggests that non-locality should not be seen as a violation of causality, but rather as a consequence of the existence of a preferred reference frame.

How does LIRI address the issue of causality?

LIRI argues that causality is still preserved in the preferred reference frame, as events in this frame occur in a definite order. The apparent non-locality is a result of the fact that different reference frames can have different perceptions of the same events.

Is LIRI a widely accepted interpretation of Hardy's Paradox?

No, LIRI is a relatively new and controversial interpretation. While it offers a potential solution to Hardy's Paradox, it has not been widely accepted by the scientific community. Further research and experimentation are needed to fully understand the implications of LIRI and its compatibility with other theories such as quantum mechanics.

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