John Clarke, Michel H. Devoret, and John M. Martinis have been awarded the 2025 Nobel Prize in Physics for their groundbreaking work on macroscopic quantum mechanical tunneling and energy quantization in electric circuits. Their experiments with superconducting Josephson circuits have made quantum effects clearly observable at the circuit scale, revealing discrete, anharmonic energy levels and coherent tunneling between macroscopically distinct states. This work is foundational for the development of modern superconducting qubits.