  Novel physical concepts that originate from quantum mechanics, such as
non-Hermitian systems (dealing mostly with PT and anti-PT symmetry) and bound
states in the continuum (BICs), have attracted great interest in the optics and
photonics community. To date, BICs and anti-PT symmetry seem to be two
independent topics. Here, we for the first time propose a parallel
cascaded-resonator system to achieve BICs and anti-PT symmetry simultaneously.
We found that the requirements for the Fabry-P\'erot BIC and anti-PT symmetry
can both be satisfied when the phase shift between any two adjacent resonators
is an integer multiple of {\pi}. We further analyzed the cascaded-resonator
systems which consist of different numbers of resonators and demonstrated their
robustness to fabrication imperfections. The proposed structure can readily be
realized on an integrated photonic platform, which can have many applications
that benefit from the advantages of both BICs and anti-PT symmetry, such as
ultralow-linewidth lasing, enhanced optical sensing, and optical signal
processing.
