Electrically controlled eight-spin-qubit entangled-state generation in a molecular break junction

Area of Science:

• Quantum Computing
• Molecular Spintronics
• Quantum Entanglement

Background:

• Generating multi-qubit entangled states, particularly using electric fields, is a significant challenge in quantum computing.
• Existing methods for creating entangled states are limited, and electrical control remains elusive.

Purpose of the Study:

• To report the first successful generation of an eight-spin-qubit entangled state using only electrical means.
• To investigate the feasibility of using a dinuclear Fe(II) complex in a molecular break junction for quantum entanglement.

Main Methods:

• Employed non-equilibrium Green's function (NEGF) based quantum-transport calculations.
• Integrated non-collinear spin density functional theory (SCDFT) with NEGF for accurate spin dynamics.
• Simulated the system within a molecular break junction setup.

Main Results:

• Successfully generated an eight-spin-qubit entangled state from the high-spin state of a dinuclear Fe(II) complex.
• Addressed critical aspects such as gate operation schemes, gating times, and decoherence.
• Determined that the high-spin state is preserved below an electric field strength of 0.78 V nm⁻¹.

Conclusions:

• Presents a novel method for achieving multi-qubit entanglement purely through electrical control.
• Highlights the potential of molecular systems, specifically dinuclear Fe(II) complexes, in advancing electrical quantum information processing.
• Offers a viable pathway for experimental realization of electrically generated entangled states.