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 qubit, a quantum particle of two possible states, is analogous to the classical bit.
Representation
A qutrit has three orthogonal basis states, or vectors, often denoted
where the coefficients are probability amplitudes, such that the sum of their squares is unity:
The qutrit's basis states are orthogonal. Qubits achieve this by utilizing Hilbert space
A string of n qutrits represents 3n different states simultaneously.
Qutrits have several peculiar features when used for storing quantum information. For example, they are more robust to decoherence under certain environmental interactions. In reality, manipulating qutrits directly might be tricky, and one way to do that is by using an entanglement with a qubit.