# Non-unitary Process and Quantum Communication

## TL;DR

This paper challenges the no-communication theorem by demonstrating that non-unitary quantum processes can enable information transfer through quantum observation, suggesting new possibilities beyond traditional unitary assumptions.

## Contribution

It introduces a thought experiment showing that non-unitary processes can facilitate communication, expanding the understanding of quantum information transfer beyond standard unitary frameworks.

## Key findings

- Non-unitary processes can enable information transfer.
- The no-communication theorem relies on unitary assumptions.
- Quantum observation can transmit information with non-unitary processes.

## Abstract

The no-communication theorem states that the observation of a subsystem of an entangled state does not affect another subsystem. Nevertheless, this theorem is based on the assumption that all quantum processes are unitary. We examine a feasible thought experiment and show that a non-unitary process included in this thought experiment enables the transmission of information by means of the quantum observation process.