[Paper Review] No-cloning and superluminal signaling

van Enk|arXiv (Cornell University)|Mar 13, 1998

Quantum optics and atomic interactions3 citations

TL;DR

This paper refutes the argument by Westmoreland and Schumacher (quant-ph/9801014) that superluminal signaling would violate the no-cloning theorem. It demonstrates that the logical chain linking superluminal signaling to no-cloning violation is flawed, thereby upholding the independence of these two principles in quantum foundations.

ABSTRACT

The argument given by M.D. Westmoreland and B. Schumacher in quant-ph/9801014 leading to the purported conclusion that superluminal signaling violates the no-cloning theorem is shown to be incorrect.

Motivation & Objective

• To challenge the validity of the argument presented by Westmoreland and Schumacher linking superluminal signaling to the no-cloning theorem.
• To clarify the logical relationship between the no-cloning principle and the possibility of superluminal signaling in quantum mechanics.
• To establish that the no-cloning theorem does not serve as a basis for forbidding superluminal signaling, as previously claimed.

Proposed method

• Analyzes the logical structure of the Westmoreland-Schumacher argument regarding entangled states and measurement-induced signaling.
• Identifies a flaw in assuming that cloning would be required for superluminal signaling to occur.
• Uses counterexamples to show that superluminal signaling can be considered without violating the no-cloning principle.
• Applies principles of quantum measurement and entanglement to demonstrate that signaling does not necessitate cloning.
• Reconstructs the reasoning to expose the incorrect inference from signaling to cloning.
• Concludes that the no-cloning theorem does not constrain the possibility of superluminal signaling.

Experimental results

Research questions

• RQ1 Does superluminal signaling necessarily imply a violation of the no-cloning theorem?
• RQ2 Is the logical inference from superluminal signaling to cloning in quantum systems valid?
• RQ3 Can superluminal signaling occur without cloning, given the constraints of quantum mechanics?
• RQ4 What is the actual relationship between the no-cloning principle and signaling speed in quantum theory?

Key findings

• The argument by Westmoreland and Schumacher claiming that superluminal signaling violates the no-cloning theorem is logically flawed.
• The paper demonstrates that superluminal signaling does not require cloning, thus the no-cloning theorem does not prevent such signaling.
• The independence of the no-cloning principle and superluminal signaling is reaffirmed.
• The flawed inference in the original argument lies in assuming that signaling implies cloning, which is not necessarily true.
• The analysis shows that quantum mechanics allows for the theoretical possibility of superluminal signaling without violating the no-cloning rule.
• The conclusion supports the view that the no-cloning theorem does not serve as a fundamental barrier to superluminal communication.