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1. Quantum Chaos is Quantum

   https://doi.org/10.22331/q-2021-05-04-453  

   Leone, Lorenzo; Oliviero, Salvatore F.; Zhou, You; Hamma, Alioscia (May 2021, Quantum)

   null (Ed.)

   It is well known that a quantum circuit on N qubits composed of Clifford gates with the addition of k non Clifford gates can be simulated on a classical computer by an algorithm scaling as poly ( N ) exp ⁡ ( k ) \cite{bravyi2016improved}. We show that, for a quantum circuit to simulate quantum chaotic behavior, it is both necessary and sufficient that k = Θ ( N ) . This result implies the impossibility of simulating quantum chaos on a classical computer. 

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2. Quantum repeaters: From quantum networks to the quantum internet

   https://doi.org/10.1103/RevModPhys.95.045006  

   Azuma, Koji; Economou, Sophia E.; Elkouss, David; Hilaire, Paul; Jiang, Liang; Lo, Hoi-Kwong; Tzitrin, Ilan (December 2023, Reviews of Modern Physics)

   A quantum internet is the holy grail of quantum information processing, enabling the deployment of a broad range of quantum technologies and protocols on a global scale. However, numerous challenges must be addressed before the quantum internet can become a reality. Perhaps the most crucial of these is the realization of a quantum repeater, an essential component in the long-distance transmission of quantum information. As the analog of a classical repeater, extender, or booster, the quantum repeater works to overcome loss and noise in the quantum channels constituting a quantum network. Here the conceptual frameworks and architectures for quantum repeaters, as well as the experimental progress toward their realization, are reviewed. Various near-term proposals to overcome the limits to the communication rates set by point-to-point quantum communication are also discussed. Finally, the manner in which quantum repeaters fit within the broader challenge of designing and implementing a quantum internet is overviewed. 

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3. Quantum Science and Quantum Technology

   https://doi.org/10.1214/19-STS745  

   Wang, Yazhen; Song, Xinyu (February 2020, Statistical Science)
4. Quantum spacetime on a quantum simulator

   https://doi.org/10.1038/s42005-019-0218-5  

   Li, Keren; Li, Youning; Han, Muxin; Lu, Sirui; Zhou, Jie; Ruan, Dong; Long, Guilu; Wan, Yidun; Lu, Dawei; Zeng, Bei; et al (December 2019, Communications Physics)
5. A quantum walk control plane for distributed quantum computing in quantum networks

   https://doi.org/10.1109/QCE52317.2021.00048  

   de Andrade, Matheus Guedes; Dai, Wenhan; Guha, Saikat; Towsley, Don (November 2021, 2021 IEEE International Conference on Quantum Computing and Engineering (QCE))

   Quantum networks are complex systems formed by the interaction among quantum processors through quantum channels. Analogous to classical computer networks, quantum networks allow for the distribution of quantum computation among quantum computers. In this work, we describe a quantum walk protocol to perform distributed quantum computing in a quantum network. The protocol uses a quantum walk as a quantum control signal to perform distributed quantum operations. We consider a generalization of the discrete-time coined quantum walk model that accounts for the interaction between a quantum walker system in the network graph with quantum registers inside the network nodes. The protocol logically captures distributed quantum computing, abstracting hardware implementation and the transmission of quantum information through channels. Control signal transmission is mapped to the propagation of the walker system across the network, while interactions between the control layer and the quantum registers are embedded into the application of coin operators. We demonstrate how to use the quantum walker system to perform a distributed CNOT operation, which shows the universality of the protocol for distributed quantum computing. Furthermore, we apply the protocol to the task of entanglement distribution in a quantum network. 

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