Efficient multimode Wigner tomography

Area of Science:

• Quantum Information Science
• Quantum Computing
• Quantum Optics

Background:

• Quantum systems can create complex states across multiple bosonic cavity modes.
• Traditional quantum state tomography requires exponential resources, limiting scalability with system size.
• Characterizing multi-mode quantum states is computationally and experimentally challenging.

Purpose of the Study:

• To implement a novel state reconstruction method with polynomial scaling.
• To overcome the limitations of exponential scaling in traditional quantum state tomography.
• To enable efficient characterization of complex multi-mode quantum states.

Main Methods:

• Developed and implemented a state reconstruction technique with polynomial sampling requirements.
• Utilized Wigner tomography for state reconstruction.
• Experimentally demonstrated the method on a 3D circuit quantum electrodynamics (cQED) system.

Main Results:

• The new method's sampling requirement scales polynomially with the number of modes.
• Successfully reconstructed multi-mode entangled W states up to 4 modes.
• Achieved comparable efficiency to existing methods for 2 modes, with significant improvements for 3 and 4 modes.

Conclusions:

• The polynomial scaling method offers a more efficient approach for characterizing complex quantum states.
• This technique shows significant advantages for systems with a higher number of modes.
• The findings pave the way for more scalable quantum state characterization in advanced quantum systems.