In general, quantum computational resources, such as superposition and quantum correlation for parallel search and quantum interference for suppressing classical chaos, lose their abilities as a dissipative coupling to external reservoirs increases, as shown in Figure 3. On the other hand, classical computational resources, such as spontaneous/collective symmetry breaking for decision making and exponential amplitude amplification of a solution state, lose their capabilities as a dissipative coupling to external reservoirs decreases as shown in Figure 3. We need the quantum and classical computational resources simultaneously in order to realize an efficient computing device. A degenerate OPO is a unique device which posesses such quantum and classical behaviors simultaneously at room temperatures.