Quantum Software Centre

Day 2 (Wednesday 12 April) @ 11:15–12:45

Lisa Kohl (CWI)

Secure computation with silent preprocessing from learning parity with noise

Protocols for secure multi-party computation (SMPC) dating back to the 1980’s allow two or more parties to securely evaluate any (efficiently computable) function on their private inputs without revealing anything beyond the function output. Unfortunately, these generic approaches introduce large overheads, rendering them infeasible for use in practice. Up to date, constructing protocols for secure computation that are efficient enough to run in practice remains a challenging task.

In this talk, I will give an overview of latest developments in the line of work on pseudorandom correlation generators, which allow secure computation with silent preprocessing, where a communication-efficient and input-independent preprocessing phase is followed by a light-weight online phase. The security of our protocols relies on (variants of) the learning parity with noise assumption, which resists all known classical and quantum attacks.

Based on joint works with Elette Boyle, Geoffroy Couteau, Niv Gilboa, Yuval Ishai, Nicolas Resch, Peter Rindal and Peter Scholl.

Casper Gyurik (Leiden University)

Quantum algorithms and the homology problem

Recently, a lot of work has been done studying the computational aspects of the problem of determining Betti numbers of simplicial complexes (i.e., the homology problem), with a particular focus on quantum algorithms. In this talk I will provide an overview of the recent results regarding the computational aspects of the homology problem, both from a (quantum) algorithmic perspective as well as a computational complexity perspective.

Gayane Vardoyan (TU Delft)

Developing a Framework for Quantum Network Utility Maximization

Network Utility Maximization (NUM) is a powerful mathematical framework that can be used to design and analyse classical communication protocols. NUM has enabled the development of distributed algorithms for solving the resource allocation problem, while at the same time providing certain guarantees, e.g., that of fair treatment, to the users of a network. In this talk, I will discuss our recent work on extending the notion of NUM to quantum networks, and introduce three quantum utility functions – each incorporating a different entanglement measure. The aim of the study is both to gain an understanding of some of the ways in which quantum users may perceive utility, as well as to explore structured and theoretically-motivated methods of simultaneously servicing multiple users in distributed quantum systems. Using our quantum NUM constructions, we develop an optimization framework for networks that use the single-photon scheme for entanglement generation, which enables us to solve the resource allocation problem while exploring rate-fidelity tradeoffs within the network topologies that we consider.  We find that our utility functions result in contrasting behaviors which provide some ideas regarding the suitability of quantum network utility definitions to different quantum applications.