Ground-state hyperfine qubit
= Ground-state hyperfine qubit
A <qubit> encoded in two resolved <hyperfine levels> of the same electronic <ground state>. Such states avoid optical excited-state decay and can support coherent radiofrequency or microwave control through a <magnetic dipole transition>. Technical magnetic noise and differential shifts can still dephase them; first-order field insensitivity requires additional choices of states and operating point.