Singlet–triplet qubits
Two electron spins encode a qubit in their singlet–triplet subspace.
$$H_{ST}=\frac{J}{2}\sigma_z+\frac{\Delta E_Z}{2}\sigma_x$$
Physical intuition
Two electron spins encode a qubit in their singlet–triplet subspace.
Deep dive: physical mechanism
Exchange and magnetic gradients drive rotations of an encoded qubit.
What is measured experimentally?
Return probability versus pulse time shows oscillations.
Assumptions, noise and limitations
Leakage into polarized triplets must be controlled.
Research and simulation exercise
Simulate rotations under tunable exchange.
Connect the ideas
Explore the chapter overview, learning path, and references.