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Impossibility of deleting an unknown quantum state
1Quantum Optics and Information Group, Informatics, University of Wales, UK. akpati@sees.bangor.ac.uk
Nature
|February 7, 2001
Summary
Quantum information cannot be perfectly deleted, even irreversibly. Unlike classical computers, quantum systems prevent deleting a copy of an arbitrary quantum state, impacting quantum computation applications.
Area of Science:
- Quantum Information Science
- Quantum Computation
- Quantum Physics
Background:
- The no-cloning theorem states that perfect cloning of an arbitrary quantum state is impossible.
- The possibility of deleting quantum information is crucial for potential applications in quantum computation, such as overwriting stored information.
Purpose of the Study:
- To investigate whether quantum information, specifically a photon's polarization state, can be deleted.
- To determine if a mechanism exists to transform two identical unknown quantum states into one state of the original unknown type and another in a standard state.
Main Methods:
- Theoretical analysis based on the linearity of quantum mechanics.
- Exploration of a hypothetical process to delete quantum information by creating a standard blank state.
Main Results:
- The linearity of quantum theory fundamentally prohibits the perfect deletion of an arbitrary quantum state.
- An irreversible process to delete quantum information, analogous to classical information deletion, is not possible in quantum mechanics.
Conclusions:
- The inability to perfectly delete quantum information poses a significant constraint on quantum computation.
- Unlike classical information, quantum information cannot be deleted, even irreversibly, due to the inherent principles of quantum theory.
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