Parallel Information Transfer in a Multi-Node Quantum Information Processor

TL;DR

This paper presents a method for fast, actuator-controlled coupling of disjoint qubits across different nodes in a quantum processor, enabling efficient parallel quantum state transfer and universal internode gates.

Contribution

It introduces a novel interaction frame approach for coupling remote qubits using actuator-only modulation, enhancing speed and robustness in distributed quantum processing.

Findings

Effective cross-node coupling via exchange interaction

Fast implementation of universal internode quantum gates

Parallel quantum state swapping demonstrated

Abstract

We describe a method for coupling disjoint quantum bits (qubits) in different local processing nodes of a distributed node quantum information processor. An effective channel for information transfer between nodes is obtained by moving the system into an interaction frame where all pairs of cross-node qubits are effectively coupled via an exchange interaction between actuator elements of each node. All control is achieved via actuator-only modulation, leading to fast implementations of a universal set of internode quantum gates. The method is expected to be nearly independent of actuator decoherence and may be made insensitive to experimental variations of system parameters by appropriate design of control sequences. We show, in particular, how the induced cross-node coupling channel may be used to swap the complete quantum states of the local processors in parallel.