Key Info

Basic Information

Portrait: Univ.-Prof. Dr. Mario Berta © Copyright: Mario Berta
Univ.-Prof. Dr. Mario Berta
Faculty / Institution:
Mathematics, Computer Science and Natural Sciences
Organizational Unit:
Teaching and research area for quantum algorithms
Excellent Science
Project duration:
01.11.2022 to 31.10.2027
EU contribution:
1.499.835 euros
  EU flag and ERC logo This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 948139)  


Entropy for Quantum Information Science


Entropy for quantum systems is the fundamental, interdisciplinary concept to quantify the advantage of quantum technologies for processing of information. It is well-established that the quantum advantage originates from the strong correlations found in the entanglement spectrum of multipartite quantum states, as exactly chraacterised by the information-theoretic tool quantum entropy. Contrary to the case of classical systems, however, our knowledge about the mathematics of quantum entropy is much more limited. Nonetheless, special entropy inequalities that are known to hold in the quantum case, such as the strong sub-additivity of quantum entropy, give crucial insights into the entanglement structure of multipartite quantum states. In this project, I will focus on understanding multipartite entropic constraints, which will lead to tight characterisations of the ultimate, physical limits of quantum information processing.

My recent mathematical works in quantum information led to operational extensions of the concept of strong sub-additivity from the seventies. Starting from that, I propose a research program that will lead to an understanding of quantum entropy that is on the same level as for the classical, commutative case. In the first part of my project, I will establish techniques in matrix analysis and optimisation theory to understand the interplay of arbitrarily many non-commuting operators. This mathematical framework will allow to prove novel quantum entropy inequalities that lead to refined approximations on the entanglement structure of multipartite quantum states. Second, I will employ the newly obtained entropic constraints to derive approximation algorithms for a plethora of fundamental problems in quantum information science. This includes schemes for achieving the physical limits of cryptography, resolving entropic additivity questions in information theory, and providing algorithms for the description of strongly interacting many body systems.

Additional Information

Prof. Berta transferred the grant to RWTH Aachen University from his former Host Institution, Imperial College London.