  Quantum error correction is an indispensable ingredient for scalable quantum
computing. In this Perspective we discuss a particular class of quantum codes
called low-density parity-check (LDPC) quantum codes. The codes we discuss are
alternatives to the surface code, which is the currently leading candidate to
implement quantum fault-tolerance. We introduce the zoo of LDPC quantum codes
and discuss their potential for making quantum computers robust against noise.
In particular, we explain recent advances in the theory of LDPC quantum codes
related to certain product constructions and discuss open problems in the
field.
