Résumé:

(1) We will discuss recent results: (i) on the Casimir torque between two metallic one-dimensional gratings rotated by an angle θ with respect to each other [1]; and (ii) on the Casimir force occurring between interpenetrating gratings [2]. These findings pave the way to the design of a contactless quantum vacuum torsional spring, and sensors with possible relevance to micro and nanomechanical devices. (2) We propose a scheme for a quantum thermal machine made by atoms interacting with a single nonequilibrium electromagnetic field. We show that these machines can deliver all thermodynamic tasks (cooling, heating, and population inversion) by establishing quantum coherence with the body on which they act. Remarkably, this system allows these machines to reach efficiencies at maximum power very close to the Carnot limit, which is much more than in existing models [3]. ------- [1] Mauro Antezza, H. B. Chan, Brahim Guizal, V.N. Marachevsky, Riccardo Messina, Mingkang Wang, Phys. Rev. Lett. 124 013903 (2020) [2] Mingkang Wang, L. Tang, C.Y. Ng, Riccardo Messina, Brahim Guizal, J. A. Crosse, Mauro Antezza, C.T. Chan, H.B. Chan, Nature Communication 12 600 (2021) [3] Bruno Leggio, Bruno Bellomo, and Mauro Antezza, Phys. Rev. A 91, 012117 (2015)