For , the
-qubit Pauli group is the finite
matrix group of
matrices consisting of scalar phases times Kronecker
products of the Pauli matrices. More explicitly,
on writing
,
it is
Here, is the
identity matrix
and
is the imaginary
unit. This convention includes all four scalar phases. Hashagen et al. (2018)
call the subgroup generated by Kronecker
products of
and
the real Pauli group, while Harper
et al. (2021) call
the Paulis modulo phase. These groups have different orders,
so the convention must be stated when quoting an order.
The group
has group order
. Its group center is
, and the quotient group by the center is
. The Pauli group is fundamental to the stabilizer
formalism for quantum error-correcting
codes (Gottesman 1997, Nielsen and Chuang 2000).
The one-qubit Pauli group , also denoted
(and
by Knill 2026), has group order
16. It is isomorphic to the central product of the dihedral
group
and the cyclic group
, and contains a subgroup isomorphic
to the quaternion group
. The Cayley graph of
generated by the three Pauli
matrices is the Möbius-Kantor graph
(Bavuma et al. 2024).