Quantum Features in Practice: Indistinguishability and Nonlocality as Operational Resources

Quantum nonlocality has long been celebrated for its deep
foundational implications. But beyond its role in challenging classical
intuitions, it also shows promise as a practical resource for distributed
information processing. In this talk, I will share two recent works that
explore how such nonclassical features can be harnessed in concrete,
operational tasks. First, we explore a curious class of orthogonal quantum
states that defy identification through local means — they simply cannot
be distinguished if parties are restricted to local operations and
classical communication (LOCC). At first glance, this sounds like a
drawback. But it is turned into a strength: using these locally
unidentifiable states, we design a secret password distribution protocol.
The result is a built-in privacy that makes eavesdropping extremely
difficult. In the second part, we take a detour through history to revisit
Mei-Gu Guan’s 1960 Chinese postman problem. Here, we show that Bell’s
nonlocal correlations — a profound foundational aspect of Nature — can
actually help solve these very practical problems more efficiently. By
giving quantum correlations as shared advice to agents, we enable
coordination strategies that outperform any classical approach, even when
communication is limited. Taken together, these two works illustrate a
broader message: while rooted in foundational principles, features like
Bell nonlocality and indistinguishability can also be viewed as
operational resources — offering potential advantages in tasks involving
distributed information processing and secure communication.