Ultra-broadband, ultra-narrowband, and ultra-passband composite polarization half-wave plates, ultra-broadband composite polarization -rotators, and quantum-classical analogy

Area of Science:

• Quantum Optics and Information Processing
• Polarization Optics
• Quantum Control

Background:

• Composite pulses are crucial for precise quantum state manipulation.
• Existing methods for generating specific rotations (X, Y, Z) have limitations in bandwidth and robustness.
• The quantum-classical analogy provides a framework for developing advanced quantum control techniques.

Purpose of the Study:

• To present novel composite pulse sequences for ultra-broadband (UBB), ultra-narrowband (UNB), and ultra-passband (UPB) rotations on the Bloch-Poincaré sphere.
• To achieve ultra-robust, ultrasensitive, and ultrasquare quantum control of X (NOT) gates and ultra-robust control of Z phase gates.
• To demonstrate the superiority of the proposed sequences over existing methods in terms of precision and execution time.

Main Methods:

• Derivation of composite pulse sequences (UBBN/BatN, UNBN/SnakeN, UPBN/OctopusN, UBBPhN/BatPhN) using novel methods.
• Application of these sequences to achieve specific rotations (X, Y, Z) and quantum gates (X, Z).
• Comparison of performance metrics (broadness, narrowness, FWHM, execution time) with existing sequences (BB2, NB2, PB2).

Main Results:

• Successfully generated ultra-broadband, ultra-narrowband, and ultra-passband X, Y, and Z rotations.
• Achieved high-fidelity quantum control for X and Z gates with enhanced robustness against pulse area errors.
• The proposed UBB N, UNB N, UPB N, and UBBPh N sequences outperform existing methods in key precision parameters.

Conclusions:

• The novel composite pulse sequences provide superior quantum control capabilities.
• These sequences are interdisciplinary and applicable to various fields including NMR, MRI, quantum sensing, and quantum communication.
• The findings pave the way for more advanced quantum information processing and related technologies.