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We present the results of a study of the time-averaged spectral energydistributions (SEDs) of eight flat spectrum radio quasars (FSRQs) present inthe second catalog of high energy sources detected beyond 50 GeV by the {\itFermi}-Large Area Telescope (2FHL). Both leptonic and hadronic scenarios areadopted to explain the multi-wavelength SEDs and we find them to be marginallyconsistent with the 2FHL spectra above 50 GeV. We derive the expected degree ofX-ray and $\gamma$-ray polarizations both for the average and elevated activitystates and note that: (i) a hadronic radiative model consistently predicts ahigher degree of high energy polarization compared to leptonic ones, and (ii)the X-ray polarization degree is higher than the $\gamma$-ray polarization inthe leptonic scenario, but similar to the $\gamma$-ray polarization if theobserved radiation is powered by hadronic processes. From the leptonicmodeling, the location of the $\gamma$-ray emitting region is found to be atthe outer edge of the broad line region (BLR) and is consistent with the$\gamma\gamma$ opacity estimates for the $\gamma$-ray absorption by the BLR. Weconclude that a majority of the FSRQs could be detected by the upcomingCherenkov Telescope Array, though future high energy polarimeters will be ableto detect them only during elevated activity states, which could providesupportive evidence for the hadronic origin of the X-ray and $\gamma$-rayemission.

Leptonic and Hadronic Modeling of Fermi-LAT Hard Spectrum Quasars and Predictions for High-Energy Polarization