Characterization of quantum algorithms by quantum process tomography using quadrupolar spins in solid-state nuclear...

Area of Science:

• Quantum Information Science
• Nuclear Magnetic Resonance (NMR) Spectroscopy
• Solid-State Quantum Computing

Background:

• Nuclear Magnetic Resonance (NMR) quantum computing, utilizing nuclear spins, has yielded successful quantum information processors.
• Quadrupolar spin systems offer potential for quantum computation but present unique manipulation and characterization challenges.

Purpose of the Study:

• To explore the use of quadrupolar spin-3/2 sodium nuclei in a NaNO3 single crystal as a virtual two-qubit system for NMR quantum computing.
• To adapt and apply process tomography for characterizing the quantum processor's behavior within this quadrupolar spin system.

Main Methods:

• Utilized sodium nuclei (spin-3/2) in a NaNO3 single crystal as a virtual two-qubit system.
• Employed strongly modulating pulses to manipulate the quadrupolar spin system, balancing fast manipulation with slow decoherence.
• Adapted process tomography techniques for characterizing quantum gates and algorithms in the quadrupolar spin environment.

Main Results:

• Successfully implemented and characterized a selection of quantum gates and algorithms on the virtual two-qubit system.
• Demonstrated that large quadrupolar coupling, compared to environmental interactions, facilitates effective manipulation.
• Achieved reasonably slow decoherence rates, enabling reliable quantum operations.

Conclusions:

• The study validates the use of quadrupolar spin-3/2 nuclei in NaNO3 crystals as a viable platform for NMR quantum computing.
• Adapted process tomography is effective for characterizing quantum operations in challenging quadrupolar spin systems.
• Fast manipulation and controlled decoherence are achievable in these systems, paving the way for advanced quantum information processing.