In the first part of my talk I discuss the prediction and physical consequences of a new geometric zero-th order critical transition occurring to the Casimir torque at Theta=0 rotation angle between diffraction gratings. In the second part I discuss the theory predictions and proposal for the realization of a genuinely quantum thermal machine to be realized in systems out of thermal equilibrium. Here the recorded video: "https://online.kitp.ucsb.edu/online/flectro22/antezza/".