The probability for transitions that lack this property in a two-level system is equal to e to the square of the off-diagonal element of the Hamiltonian divided by h-bar times a constant. Action-angle variables can be used to determine quantities named with this adjective that stay constant as time goes to infinity. According to a theorem named for this adjective, a physical system stays in the same eigenstate if the Hamiltonian is perturbed slowly. Two (*) isothermal processes along with two processes of this type make up the Carnot cycle. (10[1])Heat capacity at constant pressure is divided by heat capacity at constant volume to give an “index” named for this adjective. (10[1])Processes that are both reversible and have this property are isentropic. For 10 points, identify this adjective that describes processes with no heat transfer. ■END■