  Quantum computers can potentially provide an unprecedented speed-up with
respect to traditional computers. However, a significant increase in the number
of quantum bits (qubits) and their performance is required to demonstrate such
quantum supremacy. While scaling up the underlying quantum processor is
extremely challenging, building the electronics required to interface such
large-scale processor is just as relevant and arduous. This paper discusses the
challenges in designing a scalable electronic interface for quantum processors.
To that end, we discuss the requirements dictated by different qubit
technologies and present existing implementations of the electronic interface.
The limitations in scaling up such state-of-the-art implementations are
analyzed, and possible solutions to overcome those hurdles are reviewed. The
benefits offered by operating the electronic interface at cryogenic
temperatures in close proximity to the low-temperature qubits are discussed.
Although several significant challenges must still be faced by researchers in
the field of cryogenic control for quantum processors, a cryogenic electronic
interface appears the viable solution to enable large-scale quantum computers
able to address world-changing computational problems.
