P V Srinidhi supervised by Dr. Indranil Chakrabarty received her Master of Science by Research in Computer Science and Engineering (CSE). Here’s a summary of her research work on Resource theoretic study of quantum channels affecting negative conditional entropy:

Unlike the classical scenario, conditional entropy in quantum systems can be negative. Such systems play a pivotal role in information-processing tasks such as super dense coding, one-way entanglement distillation, and state merging, to name a few. Quantum conditional entropy’s central role led to the formulation of a resource theoretic study, establishing the notion of free and resource states and a characterization of free operations. In this thesis, we delve into the study of quantum channels that affect the negative conditional entropy of a quantum system. The main focus of this thesis is the characterization of these channels from topological and information-theoretic perspectives. We consider two classes of quantum channels – Negative Conditional Entropy Breaking (NCEB) channels and Negative Conditional Entropy Annihilating (NCEA) channels. We define such channels and examine their properties when combined serially. We also consider the property of parallel combinations of NCEB channels. Our exploration extends to complementary NCEB channels, whereby we discover the information-leaking nature of NCEB channels. We exemplify NCEB and NCEA channels through standard depolarizing channels and further the characterization. Specifically for NCEA channels, we establish a sufficiency condition for global depolarizing channels and transpose depolarizing channels. Following this, we establish the relationship of NCEB and NCEA with newly introduced classes of quantum channels, such as Coherent Information Breaking (CIB) and Mutual Information Breaking (MIB), along with standard channels like zero capacity and entanglement breaking channels. Finally, we consider the perspective of maintaining negative conditional entropy in quantum states, which involves the identification of non-NCEB or non-NCEA channels. In this regard, we provide prescriptions to detect channels that do not affect the negativity of conditional entropy.

April 2025