Practical distributed quantum information processing with LOCCNet

Abstract

Distributed quantum information processing is essential for building quantum networks and enabling more extensive quantum computations. In this regime, several spatially separated parties share a multipartite quantum system, and the most natural set of operations is Local Operations and Classical Communication (LOCC). As a pivotal part in quantum information theory and practice, LOCC has led to many vital protocols such as quantum teleportation. However, designing practical LOCC protocols is challenging due to LOCC’s intractable structure and limitations set by near-term quantum devices. Here we introduce LOCCNet, a machine learning framework facilitating protocol design and optimization for distributed quantum information processing tasks. As applications, we explore various quantum information tasks such as entanglement distillation, quantum state discrimination, and quantum channel simulation. We discover protocols with evident improvements, in particular, for entanglement distillation with quantum states of interest in quantum information. Our approach opens up new opportunities for exploring entanglement and its applications with machine learning, which will potentially sharpen our understanding of the power and limitations of LOCC. An implementation of LOCCNet is available in Paddle Quantum, a quantum machine learning Python package based on PaddlePaddle deep learning platform.

Enumerating all bilocal Clifford distillation protocols through symmetry reduction

“…We find that the optimal protocol for n = 4 achieves the same fidelity as the concatenated DEJMPS protocol for n = 5, and can be executed with a circuit of the same depth as the concatenated DEJMPS protocol. This protocol achieves the same distillation statistics as the protocol found with different means in the recent work from [49]. For n = 5 there is a large gap between the optimised protocols and the concatenated DEJMPS protocol.…”

Entangling remote microwave quantum computers with hybrid entanglement swap and variational distillation

“…As explained in the main text, to obtain states with further lower infidelity, we consider distillation protocols on two-copy of the output qubits produced from hybrid LVQCs or direct swap approach. Various entanglement distillation protocols on DV systems have been proposed, including BBPSSW [30], DEJMPS [31] and LOC-CNet [33]. We mainly focus on the DEJMPS protocol which is proved to be optimal for bell-diagonal states with rank up to three, and a DEJMPS-inspired DV LVQC, shown in Fig.…”

“…Distillation protocols.-Next, we design distillation protocols to obtain high-fidelity DV entanglement ρq,q between two transmon qubits from the noisy two-mode squeezing between microwave modes ρm,m . Distillation has been explored separately for either DV [26,[30][31][32][33][34][35][36][37] or CV [38][39][40][41][42][43][44][45][46][47][48] entanglement. Here, we require a hybrid distillation protocol that produces high fidelity DV entanglement from noisy CV entanglement.…”

A Distributed Architecture for Secure Delegated Quantum Computation

“…Both distributed quantum computation and delegated quantum computation have been investigated broadly; see references [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ] and [ 6 , 11 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ], respectively. Typically, the distributed architecture for quantum computation makes use of photons as flying qubits between computational nodes, where each node is equipped with a quantum computer.…”