Addressable quantum gates

Abstract

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. 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. We specify the structure of "nameblind" matrices.

40 pages, 16 figures, published version

References in corpus (5)

• Experimental Verification of an Indefinite Causal Order
• Quantum circuits with classical versus quantum control of causal order
• Routed quantum circuits
• Existence of processes violating causal inequalities on time-delocalised subsystems
• Coherent control and distinguishability of quantum channels via PBS-diagrams

Cited by in corpus (3)

• Quantum networks theory
• On quantum superpositions of graphs, no-signalling and covariance
• Causal influence versus signalling for interacting quantum channels