  The Q&U Bolometric Interferometer for Cosmology (QUBIC) is a novel kind of
polarimeter optimized for the measurement of the $B$-mode polarization of the
Cosmic Microwave Background (CMB), which is one of the major challenges of
observational cosmology. The signal is expected to be of the order of a few
tens of nK, prone to instrumental systematic effects and polluted by various
astrophysical foregrounds which can only be controlled through multichroic
observations. QUBIC is designed to address these observational issues with a
novel approach that combines the advantages of interferometry in terms of
control of instrumental systematics with those of bolometric detectors in terms
of wide-band, background-limited sensitivity.
