  We study the angular momentum transport inside the hot Jupiters under the the
influences of gravitational and thermal forcing. Due to the strong stellar
irradiation, radiative region develops on top of the convective region.
Internal gravity waves are launched at the radiative-convective boundaries
(RCBs). The thermal response is dynamical and plays an important role in the
angular momentum transport. By separating the gravitational and thermal forcing
terms, we identify the thermal effects for increasing the angular momentum
transport. For the low frequency (in the co-rotating frame with planets)
prograde (retrograde) tidal frequency, the angular momentum flux is positive
(negative). The tidal interactions tends to drive the planet to the synchronous
state. We find that the angular momentum transport associated with the internal
gravity wave is very sensitive to relative position between the RCB and the
penetration depth of the thermal forcing. If the RCB is in the vicinity of the
thermal forcing penetration depth, even with small amplitude thermal forcing,
the thermally driven angular momentum flux could be much larger than the flux
induced by gravitational forcing. The thermally enhanced torque could drive the
planet to the synchronous state in as short as a few $10^4$ years.
