  We provide numerical evidence for a temporal quantum-mechanical interference
phenomenon: time molecules (TM). A variety of such stroboscopic states are
observed in the dynamics of two interacting qubits subject to a periodic
sequence of $\pi$-pulses with the period $T$. The TMs appear periodically in
time and have a large duration, $\delta t_\mathrm{TM} \gg T$. All TMs
demonstrate an almost zero value of the total polarization and a strong
enhancement of the entanglement entropy $S$ up to the maximum value $S=\ln 2$
of a corresponding Bell state. The TMs are generated by the commensurability of
the Floquet eigenvalues and the presence of maximally entangled Floquet
eigenstates. The TMs remain stable with detuned system parameters and with an
increased number of qubits. The TMs can be observed in microwave experiments
with an array of superconducting qubits.
