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 (-5[1])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 (15[1])(*) isothermal processes along with two processes of this type make up the Carnot cycle. Heat capacity at constant pressure is divided by heat capacity at constant volume to give an “index” (10[1])named for this adjective. 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■