4 research outputs found
Multisystem measurements in generalized probabilistic theories and their role in information processing
Advantages of multi-copy nonlocality distillation and its application to minimizing communication complexity
Nonlocal correlations are a central feature of quantum theory, and
understanding why quantum theory has a limited amount of nonlocality is a
fundamental problem. Since nonlocality also has technological applications,
e.g., for device-independent cryptography, it is useful to understand it as a
resource and, in particular, whether and how different types of nonlocality can
be interconverted. Here we focus on nonlocality distillation which involves
using several copies of a nonlocal resource to generate one with more
nonlocality. We introduce several distillation schemes which distil an extended
part of the set of nonlocal correlations including quantum correlations. Our
schemes are based on a natural set of operational procedures known as wirings
that can be applied regardless of the underlying theory. Some are sequential
algorithms that repeatedly use a two-copy protocol, while others are genuine
three-copy distillation protocols. In some regions we prove that genuine
three-copy protocols are strictly better than two-copy protocols. By applying
our new protocols we also increase the region in which nonlocal correlations
are known to give rise to trivial communication complexity. This brings us
closer to an understanding of the sets of nonlocal correlations that can be
recovered from information-theoretic principles, which, in turn, enhances our
understanding of what is special about quantum theory.Comment: 5+6 pages, several figure