• Corpus ID: 251371327

Non-unitary versus unitary optimization in the} control of open quantum systems

@inproceedings{Fonseca2022NonunitaryVU,
  title={Non-unitary versus unitary optimization in the\} control of open quantum systems},
  author={Marllos E. Fonseca and Felipe Fernandes Fanchini and E Lima and Leonardo K. Castelano},
  year={2022}
}

• Marllos E. Fonseca, F. F. Fanchini, +1 author L. K. Castelano
• Published 5 August 2022
• Physics, Computer Science

In this work, we compare the performance of the Krotov method for open quantum systems (non-unitary optimization) with the Krotov method for closed quantum systems (unitary optimization) in finding optimal controls aimed at manipulating qubits and qutrits in the presence of the environment. In the case of unitary optimization, the Krotov method is applied to quantum system neglecting its interaction with the environment, afterwards the resulting controls are used to manipulate the system along with the eviromental noise. We consider two distinct control problems: target-state preparation from a given initial state and quantum gate implementation. For the state preparation, we have found that the performance of the controls obtained from the non-unitary optimization outperform that of the controls obtained from the unitary optimization. However, in the case of the implementation of quantum gates, we have found that the optimal controls obtained from the unitary evolution exhibit a mean fidelity similar to that obtained from the non-unitary evolution. Since unitary optimization does not depend on decay rates nor on specific kinds of noise, besides being less computationally demanding, our results suggest that the best current practice to implement quantum gates in open quantum systems is to employ unitary optimization.