Addressable Quantum Gates at PLanQC

Addressable Quantum Gates

Addressable Quantum Gates is the name of a novel formalism introduced in this 2021 paper. I gave a talk presenting it at the 2021 PLanQC workshop : the talk

Summary

We extend the circuit model of quantum computation so that the wiring between gates is soft-coded within registers inside the gates. The addresses in these registers can be manipulated and put into superpositions. This aims at capturing indefinite causal orders and making their geometrical layout explicit: we express the quantum switch and the polarizing beam-splitter within the model. This also aims at providing a concrete model of distributed quantum computing featuring quantum evolving networks. In this context, our main contribution is a full characterization of the anonymity constraints. Indeed, the names used as addresses should not matter beyond the wiring they describe, i.e. quantum evolutions should commute with renamings. We show that these quantum evolutions can still act non-trivially upon the names.

Besides the physical and computer science application of the framework described here, this paper features an interesting mathematical result. That is, a caracterisation of matrices commuting with all permutation matrices - so-called ''nameblind matrices''.