5 papers
On the undecidability of quantum channel capacities
Archishna Bhattacharyya, Arthur Mehta, Yuming Zhao
An important distinction in our understanding of capacities of classical versus quantum channels is marked by the following question: is there an algorithm which can compute (or ev…
Positivity is undecidable in tensor products of free algebras
Arthur Mehta, William Slofstra, Yuming Zhao
It is well known that an element of the algebra of noncommutative *-polynomials is positive in all *-representations if and only if it is a sum of squares. This provides an effecti…
Lifting the maximally-entangledness assumption in robust self-testing for synchronous games
Matthijs Vernooij, Yuming Zhao
Robust self-testing in non-local games allows a classical referee to certify that two untrustworthy players are able to perform a specific quantum strategy up to high precision. Pr…
Robust self-testing for nonlocal games with robust game algebras
Yuming Zhao
We give an operator-algebraic formulation of robust self-testing in terms of states on C*-algebras. We show that a quantum correlation p is a robust self-test only if among all (ab…
Postselection technique for optical Quantum Key Distribution with improved de Finetti reductions
Shlok Nahar, Devashish Tupkary, Yuming Zhao +2
The postselection technique is an important proof technique for proving the security of quantum key distribution protocols against coherent attacks. In this work, we go through mul…