You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Model Checking Quantum Systems --- A Survey 
Chapter Title:  V. MODEL CHECKING SUPER-OPERATOR-VALUED MARKOV CHAINS 
1. Abstract of Cited Paper (BIB001):  Abstract Although security of quantum cryptography is provable based on principles of quantum mechanics, it can be compromised by flaws in the design of quantum protocols. So, it is indispensable to develop techniques for verifying and debugging quantum cryptographic systems. Model-checking has proved to be effective in the verification of classical cryptographic protocols, but an essential difficulty arises when it is applied to quantum systems: the state space of a quantum system is always a continuum even when its dimension is finite. To overcome this difficulty, we introduce a novel notion of quantum Markov chain , especially suited for modelling quantum cryptographic protocols, in which quantum effects are encoded as super-operators labelling transitions, leaving the location information (nodes) being classical. Then we define a quantum extension of probabilistic computation tree logic (PCTL) and develop a model-checking algorithm for quantum Markov chains.

Literature Review:
The notion of super-operator-valued Markov chain is introduced in BIB002 as a higher-level model of quantum programs and quantum cryptographic protocols. A similar notion was proposed in BIB001 for a different purpose.