Quantum information processing with large nuclear spins in GaAs semiconductors.

Area of Science:

• Quantum Information Processing
• Semiconductor Spintronics
• Nuclear Magnetic Resonance (NMR)

Background:

• Nuclear spins in semiconductors offer a platform for quantum information processing.
• Quadrupolar splittings in nuclear spin levels (I=3/2) due to non-equidistance are not fully exploited.
• Coherent manipulation of nuclear spins is crucial for scalable quantum technologies.

Purpose of the Study:

• To propose and theoretically describe a novel NMR method for quantum information processing.
• To investigate multiphoton transitions and their application in manipulating nuclear spins.
• To explore the nonperturbative time evolution of spin states and identify observable quantum phenomena.

Main Methods:

• Theoretical modeling of nuclear spin dynamics in GaAs semiconductors.
• Derivation of effective Hamiltonians in a generalized rotating frame for arbitrary spin I.
• Analysis of multiphoton transitions exploiting quadrupolar splittings.
• Nonperturbative time evolution calculations under magnetic radiofrequency fields.

Main Results:

• Identification of an experimentally observable regime for multiphoton Rabi oscillations.
• Theoretical description of spin state evolution using derived effective Hamiltonians.
• Observation of Berry phase interference in the nonlinear regime.
• Demonstration of coherent manipulation of I=3/2 nuclear spins in GaAs.

Conclusions:

• The proposed NMR method provides a viable route for quantum information processing using nuclear spins in GaAs.
• Multiphoton transitions and quadrupolar splittings are key to achieving observable quantum effects like Rabi oscillations and Berry phase interference.
• The theoretical framework is general and applicable to arbitrary nuclear spin systems.