Nonperturbative entangling gates between distant qubits using uniform cold atom chains.

Area of Science:

• Quantum Information Science
• Atomic Physics
• Condensed Matter Physics

Background:

• Implementing high-fidelity quantum gates between distant qubits is crucial for scalable quantum computing and networks.
• Existing methods often face challenges with scalability, qubit separation, and operational complexity.

Purpose of the Study:

• To introduce a novel, fast, and scalable method for creating two-qubit entangling gates between arbitrary distant qubits.
• To demonstrate the efficiency of the proposed gate mechanism with respect to qubit separation and its applicability to multiple operations.

Main Methods:

• Exploiting dispersionless propagation in uniform chains of interacting qubits acting as a quantum bus.
• Dynamically switching on a strong interaction between target qubits and the bus.
• Investigating the gate quality scaling with qubit separation and the necessity of sudden coupling changes.

Main Results:

• Achieved a fast and scalable two-qubit entangling gate with high quality that scales efficiently with qubit separation.
• Demonstrated that sudden switching of couplings is not required, simplifying experimental implementation.
• Showcased the ability to perform multiple gate operations without resetting the quantum bus.

Conclusions:

• The proposed method offers a promising route for building large-scale quantum networks by enabling efficient entanglement of distant qubits.
• The technique is experimentally feasible, with a suggested realization using cold atoms in optical lattices and Fresnel trapping potentials.