Keyring models: an approach to steerability

Area of Science:

• Quantum Information Science
• Quantum Foundations
• Quantum Many-Body Systems

Background:

• Quantum entanglement allows for non-classical correlations between systems.
• Quantum steering describes a phenomenon where measurements on one part of a bipartite system influence the state of the other part.
• Determining steerability is crucial for understanding quantum correlations and has applications in quantum communication.

Purpose of the Study:

• To introduce and utilize keyring models for analyzing quantum steering.
• To extend the analysis of steerability beyond T-states in two-qubit systems.
• To solve the steering problem for specific classes of two-qubit states.

Main Methods:

• Introduction of keyring models, a novel class of local hidden state models.
• Application of keyring models to study steerability under real projective measurements.
• Analysis of two-qubit states formed by mixing pure states with uniform noise and depolarizing channels.

Main Results:

• Complete solution for the steering problem of two-qubit states mixed with uniform noise under real projective measurements.
• Development of a framework using keyring models to tackle steerability beyond T-states.
• Partial solution provided for states involving independent depolarizing channels.

Conclusions:

• Keyring models offer a powerful tool for investigating quantum steering.
• The study provides a complete solution for a significant class of two-qubit states, advancing our understanding of quantum correlations.
• The findings pave the way for further research into steerability in more complex quantum systems and noise models.