Università della Svizzera italiana

Lattice-based protocols for privacy

Boschini, Cecilia ; Wolf, Stefan (Dir.) ; Camenisch, Jan (Codir.)

Thèse de doctorat : Università della Svizzera italiana, 2020 ; 2020INFO002.

Privacy and control over data have become a public concern. Simultaneously, the increasing likelihood of the construction of a general purpose quantum computer has led companies and governments to demand for quantum safe alternatives to the protocols used today. New schemes have been elaborated, whose conjectured security against a quantum computer relies on the hardness to solve different...

Università della Svizzera italiana

Causal loops : logically consistent correlations, time travel, and computation

Ämin, Baumeler ; Wolf, Stefan (Dir.)

Thèse de doctorat : Università della Svizzera italiana, 2017 ; 2017INFO002.

Causal loops are loops in cause-effect chains: An effect can be the cause of that effect's cause. We show that causal loops can be unproblematic, and explore them from different points of view. This thesis is motivated by quantum theory, general relativity, and quantum gravity. By accepting all of quantum theory one can ask whether the possibility to take superpositions extends to causal...

Università della Svizzera italiana

No-signalling attacks and implications for (quantum) nonlocality distillation

Salwey, Leonhard Benno ; Wolf, Stefan (Dir.) ; Brassard, Gilles (Codir.)

Thèse de doctorat : Università della Svizzera italiana, 2015 ; 2015INFO008.

The phenomenon of nonlocality, which can arise when entangled quantum systems are suitably measured, is perhaps one of the most puzzling features of quantum theory to the philosophical mind. It implies that these measurement statistics cannot be explained by hidden variables, as requested by Einstein, and it thus suggests that our universe may not be, in principle, a well-determined entity...