Protecting dissipative quantum state preparation via dynamical decoupling

TL;DR

This paper demonstrates that dynamical decoupling sequences can effectively protect dissipative quantum state preparation processes from qubit dephasing, enhancing their robustness in inhomogeneously broadened systems.

Contribution

The study introduces a method of combining dynamical decoupling with dissipative state preparation, showing near-independence from pulse sequence details and effectiveness against various noise types.

Findings

Protection efficiency depends on average pulse interval

Effective against inhomogeneous dephasing in many-body states

Randomized pulse timing also provides protection

Abstract

We show that dissipative quantum state preparation processes can be protected against qubit dephasing by interlacing the state preparation control with dynamical decoupling (DD) control consisting of a sequence of short $\pi$-pulses. The inhomogeneous broadening can be suppressed to second order of the pulse interval, and the protection efficiency is nearly independent of the pulse sequence but determined by the average interval between pulses. The DD protection is numerically tested and found to be efficient against inhomogeneous dephasing on two exemplary dissipative state preparation schemes that use collective pumping to realize many-body singlets and linear cluster states respectively. Numerical simulation also shows that the state preparation can be efficiently protected by $\pi$-pulses with completely random arrival time. Our results make possible the application of these state preparation schemes in inhomogeneously broadened systems. DD protection of state preparation against dynamical noises is also discussed using the example of Gaussian noise with a semiclasscial description.