This course introduces open quantum systems—quantum systems that interact with their environment, leading to decoherence and entanglement loss. The course covers the main equations governing non-unitary dynamics, with emphasis on the Lindblad master equation, and explores how different noise environments are modeled in experimental settings. Students will learn key formalisms such as density matrices, quantum operations, and measurement theory, In addition, students will dive into the relevant cQED framework, which forms the basis of control and measurement in state-of-the-art architectures such as superconducting qubits.