# The Rise of Quantum Information and Communication Technologies
## 2 Challenges and Opportunities Enabling the Rise of QICTs  
Society and today's industry are experiencing a profound techno-economic transformation. Technologies such as software-defined networks (SDN) and Network Function Virtualization (NFV) allow the design and deployment of 5G infrastructure and Cloud-edge computing, with high levels of programmability and flexibility when providing any sort of digital service. The need to look at the long-term evolution and sustainability of these ICT and telecommunication scenarios is stimulating a rethinking of the ways of performing computation, communications and networking based on quantum technologies. There is evidence that second quantum revolution is progressing fast, based on the capabilities to detect and manipulate single quantum particles (e.g., electrons, photons, ions, etc. ), not achieved during the second quantum revolution. Specifically, there are three main quantum phenomena that a second revolution aims at engineering and controlling: superposition, entanglement [4] and measurement. It is expected that, in less than 10 years, we will see a significative impact on many markets, including security, finance, medicine, energy, transportation, etc. International innovation activities and standardization bodies agree on identifying four main application areas: communications, computing, simulations and sensing and metrology. Quantum communications include two main subdomains: (1) quantum-safe communications and (2) the teleportation of quantum information (e.g., quantum internet) [5]. Quantum-safe communications are leveraging systems such as quantum key distribution (QKD) and quantum random number generators (QRNGs), which have rather high technology readiness levels (TRLs). We should be reminded that TRLs represent a systematic metric/measurement convention for assessments of the maturity of a particular technology and the consistent comparison of maturity between different types of technology [6]. QKD is a symmetric secret key negotiation protocol and technology offering unconditional secrecy based on the laws of quantum mechanics. QKD is an area in which interest and investments are growing very rapidly as shown through recent developments, both theoretically and experimentally. Concerning the state of the art in QKD, reference [7] provides a rigorous threat analysis based on the most recent recommendations and practical network deployment security issues. For the second application area, quantum computers operate faster than classical computers do when solving complex optimization and combinatorial problems (the processing time is reduced from exponential to polynomial time). Trapped ions and superconducting qubits seem to be quantum technologies which that satisfy the five required criteria for quantum computing, formerly defined by [PERSON] [8]; also, other approaches are gaining momentum, such as impurity spins in solids, neutral Rydberg atoms and topological photonics. The application area of quantum simulations regards those applications where well-controlled quantum systems can be used to simulate other systems that are less accessible and more complex for direct simulation. Quantum sensing and metrology concern applications where the high sensitivities of quantum systems are needed to measure physical properties with high precision (e.g., magnetic and heat sensors, gravimeters, clocks, GPS-free navigators, etc.). Overall, some quantum services and applications are becoming commercially available (e.g., QKD, QRNG, quantum computers, quantum simulations, atomic clocks and some quantum sensors), thus offering early opportunities for developing and providing QICT services; nevertheless, there are still bottlenecks in quantum technologies. In quantum communications, for instance, the development of quantum repeaters represents a key technological breakthrough that would allow the exploitation of long-distance QKD and distributed quantum networks.