No, joining two photons with wavelengths equivalent to yellow and blue will not result in a single photon with a wavelength corresponding to green. When two photons interact or combine, their energies and wavelengths do not add up to create a new photon with a different wavelength.
The color perception we experience is based on the interaction of light with our eyes and brain, which interpret different wavelengths as different colors. Yellow light corresponds to a specific range of wavelengths, and blue light corresponds to a different range. When these two colors are mixed or observed together, our eyes and brain perceive a combination of the two colors, often resulting in the perception of white light or a different color depending on the proportions of the yellow and blue light.
In the case of mixing yellow and blue light, the human visual system perceives a color close to white, not green. To obtain green light, you would generally need a specific wavelength within the green range of the visible spectrum, which falls between yellow and blue.