  Quantum superposition is normally sustained in a microscopic regime governed
by Heisenberg uncertainty principle applicable to a single particle. Quantum
correlation between paired particles implies the violation of local realism
governed by classical physics. Over the last decades, quantum features have
been implemented in various quantum technologies including quantum computing,
communications, and sensing. Such quantum features are generally known to be
impossible by any classical means. Here, a macroscopic quantum correlation is
presented for coherence manipulations of polarization-path correlations of a
continuous wave laser, satisfying the joint-parameter relation in an
inseparable product-basis form. For the coherence control of the
polarization-path correlation, a pair of electro-optic modulators is used in a
noninterfering Mach-Zehnder interferometer for deterministic switching between
paired polarization bases, resulting in the polarization product-basis
superposition in a selective product-basis choice manner by a followed pair of
acousto-optic modulators. This unprecedented macroscopic quantum feature opens
the door to a new understanding of quantum mechanics beyond the microscopic
regime for future classical optics-compatible quantum information.
