Entangling logical qubits with lattice surgery
Entangling logical qubits with lattice surgery
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DOI：
10.1038/s41586-020-03079-6
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发表时间：
2021-01-14
期刊：
影响因子：
64.8
通讯作者：
Monz, Thomas
中科院分区：
文献类型：
--
作者：
Erhard, Alexander;Poulsen Nautrup, Hendrik;Monz, Thomas
量子计算体系结构从早期的设计和当前的嘈杂设备发展到完全成熟的量子计算机，关键在于使用量子纠错实现容错(1-4)。然而，这些纠错能力伴随着对逻辑量子比特(编码在物理量子比特集合中并由纠错码保护的量子比特)执行必要的容错逻辑运算的开销(5-8)。实现逻辑运算最节省资源的方法之一是格子运算(9-11)，其中排列在格子上的多组物理量子比特可以合并和拆分，以实现纠缠门和传送逻辑信息。本文报道了在十量子比特离子陷阱量子信息处理器中，通过拓扑纠错码保护的两个量子比特之间的格子运算的实验实现。在这个系统中，我们可以通过一系列的局域和纠缠门以及对辅助量子比特的测量来进行必要的量子非破坏测量。特别地，我们演示了两个逻辑量子比特之间的纠缠，并实现了它们之间的逻辑态隐形传态。通过格子运算演示这些操作--量子计算的基本构件--是朝着高效实现容错量子计算迈出的一步。通过表面代码将两个逻辑量子比特编码成四个物理量子比特的集合，然后通过用于执行容错运算的格子运算进行纠缠。
The development of quantum computing architectures from early designs and current noisy devices to fully fledged quantum computers hinges on achieving fault tolerance using quantum error correction(1-4). However, these correction capabilities come with an overhead for performing the necessary fault-tolerant logical operations on logical qubits (qubits that are encoded in ensembles of physical qubits and protected by error-correction codes)(5-8). One of the most resource-efficient ways to implement logical operations is lattice surgery(9-11), where groups of physical qubits, arranged on lattices, can be merged and split to realize entangling gates and teleport logical information. Here we report the experimental realization of lattice surgery between two qubits protected via a topological error-correction code in a ten-qubit ion-trap quantum information processor. In this system, we can carry out the necessary quantum non-demolition measurements through a series of local and entangling gates, as well as measurements on auxiliary qubits. In particular, we demonstrate entanglement between two logical qubits and we implement logical state teleportation between them. The demonstration of these operations-fundamental building blocks for quantum computation-through lattice surgery represents a step towards the efficient realization of fault-tolerant quantum computation.Two logical qubits are encoded in ensembles of four physical qubits through the surface code, then entangled by lattice surgery, which is a protocol for carrying out fault-tolerant operations.