Device-Independent Detection of Genuine Multipartite Entanglement for All Pure States

Area of Science:

• Quantum Information Science
• Quantum Many-Body Physics

Background:

• Detecting genuine multipartite entanglement is crucial for quantum information processing.
• Existing methods often require full state tomography, which is experimentally demanding.
• Device-independent approaches offer a path to entanglement verification without trusting the device's internal workings.

Purpose of the Study:

• To develop a device-independent method for detecting genuine multipartite entanglement in all multipartite pure states.
• To establish an efficient scheme applicable to states relevant in quantum computation and condensed-matter physics.
• To demonstrate the robustness of the proposed method against experimental imperfections.

Main Methods:

• Employing bipartite Bell inequalities on states deterministically generated from the initial state via local operations.
• Analyzing the scheme's efficiency and scalability for specific quantum states like cluster states and the AKLT model ground state.
• Investigating the overhead in terms of the number of measurements and system size.

Main Results:

• A general method is presented to detect genuine multipartite entanglement in arbitrary finite-dimensional multipartite pure states in a device-independent manner.
• The scheme is efficient for important classes of states, including cluster states and the Affleck-Kennedy-Lieb-Tasaki (AKLT) model ground state.
• For cluster states, entanglement detection requires measurements on a constant number of systems, with linear scaling overhead. For the AKLT model, the overhead scales polynomially.
• The proposed approach demonstrates robustness against experimental imperfections.

Conclusions:

• Genuine multipartite entanglement can be efficiently detected in a device-independent way for a broad range of quantum states.
• The method provides a practical tool for verifying entanglement in quantum computation and condensed-matter systems.
• The robustness against imperfections suggests feasibility for near-term quantum devices.