Beyond Weak Coupling: Evaluating Entropy in Strongly Interacting Qubits

Understanding entropy production in quantum systems is key to analyzing dissipation in quantum devices. Entropy flow should not be approximated by its flow into a weakly coupled probe reservoir in the regime of strong coupling between a quantum system and its environment. We present a novel formalism to evaluate the entropy flow in a qubit strongly disturbed by its environment nonperturbatively and discuss the significant innovations introduced by this approach.