Triggering single-molecule qubit spin dynamics via non-Abelian geometric phase effects

Area of Science:

• Quantum physics and materials science
• Molecular nanomagnets
• Quantum information processing

Background:

• Controlling spin dynamics in molecular nanomagnets is crucial for quantum technologies.
• Existing methods often face limitations due to slow operational speeds or decoherence.
• Understanding the non-Abelian geometric propagator is key to novel control techniques.

Purpose of the Study:

• To demonstrate macroscopic rotations for controlling spin dynamics in molecular nanomagnets.
• To explore the application of this control for realizing single-qubit quantum gates.
• To investigate the potential of molecular nanomagnets as quantum sensors and for preparing specific quantum states.

Main Methods:

• Utilizing the non-Abelian character of the time-evolution operator via macroscopic rotations.
• Applying non-adiabatic macroscopic rotations to control spin dynamics in integer spin nanomagnets.
• Explicitly modeling CoCl2(tu)4 and TbPc2 single-molecule/ion magnets.

Main Results:

• Macroscopic rotations can trigger and control spin dynamics in both Kramers and non-Kramers molecular nanomagnets.
• Single-qubit quantum gates demonstrated on CoCl2(tu)4 with gate operations as fast as 10 ps.
• CoCl2(tu)4 proposed as a quantum gyroscope; TbPc2 can be prepared in maximal angular momentum states.

Conclusions:

• Macroscopic rotations offer a powerful, fast, and versatile method for controlling quantum states in molecular nanomagnets.
• This approach enables practical applications in quantum computing (gates) and quantum sensing (gyroscopes).
• The findings pave the way for novel experimental protocols in molecular spintronics and quantum information science.