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Second order gradient ascent pulse engineering.

P de Fouquieres1, S G Schirmer, S J Glaser

  • 1Centre for Quantum Computation, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom.

Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|September 3, 2011
PubMed
Summary

We improved the gradient ascent pulse engineering (GRAPE) algorithm for quantum system control. Our enhanced GRAPE algorithm offers faster convergence and reduced computation time for optimal control solutions.

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Area of Science:

  • Quantum Control
  • Quantum Information Science
  • Atomic, Molecular, and Optical Physics

Background:

  • Optimal control is crucial for manipulating quantum systems.
  • The gradient ascent pulse engineering (GRAPE) algorithm is a common method for optimal control.
  • Existing GRAPE algorithms can be computationally intensive and may suffer from slow convergence.

Purpose of the Study:

  • To enhance the gradient ascent pulse engineering (GRAPE) algorithm for improved performance in quantum system control.
  • To accelerate convergence and reduce computational time compared to standard GRAPE methods.

Main Methods:

  • Implemented more accurate gradient calculations within the GRAPE framework.
  • Integrated the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton algorithm for accelerated convergence.
  • Developed faster algorithms for calculating control derivatives.

Main Results:

  • Demonstrated considerable improvements in convergence rates across various test systems.
  • Showcased significant reductions in wall clock time compared to approximate gradient ascent methods.
  • Achieved faster and more efficient optimal control solutions for quantum systems.

Conclusions:

  • The enhanced GRAPE algorithm provides a substantial performance upgrade for quantum optimal control.
  • These improvements lead to more efficient and practical application of optimal control in quantum experiments.
  • The refined GRAPE method offers a valuable tool for advancing quantum technologies.