For questions related to quantum trits i.e. three-level (dimensional) quantum mechanical systems. They are higher dimensional analogues of qubits (aka quantum bits), which are two-level (dimensional) quantum mechanical systems.

A qutrit is a unit of quantum information that exists as a superposition of three orthogonal quantum states.

The qutrit is analogous to the classical trit, just as the , a quantum particle of two possible states, is analogous to the classical bit.

(source: Wikipedia)