Dynamical decoupling for spin qubits
Pulse sequences can cancel slow fluctuations.
$$U_{\rm echo}=e^{-iH\tau}X e^{-iH\tau}$$
Physical intuition
Pulse sequences can cancel slow fluctuations.
Deep dive: physical mechanism
A spin echo reverses phase accumulation from approximately static longitudinal noise.
What is measured experimentally?
Echo and CPMG decay reveal noise spectra.
Assumptions, noise and limitations
Pulses cannot remove all fast noise and may introduce control errors.
Research and simulation exercise
Compare Ramsey and echo under quasistatic noise.
Connect the ideas
Explore the chapter overview, learning path, and references.