Quantum

Paper

On Basing One-way Permutations on NP-hard Problems under Quantum Reductions

Nai-Hui Chia, Sean Hallgren, and Fang Song,

Quantum 4, 312 (2020).

A fundamental pursuit in complexity theory concerns reducing worst-case problems to average-case problems. There exist complexity classes such as PSPACE that admit worst-case to average-case…

Paper

Braiding quantum gates from partition algebras

Pramod Padmanabhan, Fumihiko Sugino, and Diego Trancanelli,

Quantum 4, 311 (2020).

Unitary braiding operators can be used as robust entangling quantum gates. We introduce a solution-generating technique to solve the $(d,m,l)$-generalized Yang-Baxter equation, for…

Paper

Neural Network Decoders for Large-Distance 2D Toric Codes

Xiaotong Ni,

Quantum 4, 310 (2020).

We still do not have perfect decoders for topological codes that can satisfy all needs of different experimental setups. Recently, a few neural network based decoders have been studied, with…

Paper

Universal quantum modifications to general relativistic time dilation in delocalised clocks

Shishir Khandelwal, Maximilian P.E. Lock, and Mischa P. Woods,

Quantum 4, 309 (2020).

The theory of relativity associates a proper time with each moving object via its world line. In quantum theory however, such well-defined trajectories are forbidden. After introducing a gen…

Paper

Gadget structures in proofs of the Kochen-Specker theorem

Ravishankar Ramanathan, Monika Rosicka, Karol Horodecki, Stefano Pironio, Michał Horodecki, and Paweł Horodecki,

Quantum 4, 308 (2020).

The Kochen-Specker theorem is a fundamental result in quantum foundations that has spawned massive interest since its inception. We show that within every Kochen-Specker graph, there exist i…

Paper

Quantum-inspired algorithms in practice

Juan Miguel Arrazola, Alain Delgado, Bhaskar Roy Bardhan, and Seth Lloyd,

Quantum 4, 307 (2020).

We study the practical performance of quantum-inspired algorithms for recommendation systems and linear systems of equations. These algorithms were shown to have an exponential asymptotic sp…

Paper

Quantum Algorithms for Simulating the Lattice Schwinger Model

Alexander F. Shaw, Pavel Lougovski, Jesse R. Stryker, and Nathan Wiebe,

Quantum 4, 306 (2020).

The Schwinger model (quantum electrodynamics in 1+1 dimensions) is a testbed for the study of quantum gauge field theories. We give scalable, explicit digital quantum algorithms to simulate…

Paper

Mapping graph state orbits under local complementation

Jeremy C. Adcock, Sam Morley-Short, Axel Dahlberg, and Joshua W. Silverstone,

Quantum 4, 305 (2020).

Graph states, and the entanglement they posses, are central to modern quantum computing and communications architectures. Local complementation – the graph operation that links all local-Cli…

Paper

On maximum-likelihood decoding with circuit-level errors

Leonid P. Pryadko,

Quantum 4, 304 (2020).

Error probability distribution associated with a given Clifford measurement circuit is described exactly in terms of the circuit error-equivalence group, or the circuit subsystem code previo…

Paper

A robust W-state encoding for linear quantum optics

Madhav Krishnan Vijayan, Austin P. Lund, and Peter P. Rohde,

Quantum 4, 303 (2020).

Error-detection and correction are necessary prerequisites for any scalable quantum computing architecture. Given the inevitability of unwanted physical noise in quantum systems and the prop…

Paper

Sum-of-squares decompositions for a family of noncontextuality inequalities and self-testing of quantum devices

Debashis Saha, Rafael Santos, and Remigiusz Augusiak,

Quantum 4, 302 (2020).

Violation of a noncontextuality inequality or the phenomenon referred to `quantum contextuality' is a fundamental feature of quantum theory. In this article, we derive a novel family of nonc…

Paper

Law without law: from observer states to physics via algorithmic information theory

Markus P. Müller,

Quantum 4, 301 (2020).

According to our current conception of physics, any valid physical theory is supposed to describe the objective evolution of a unique external world. However, this condition is challenged by…

Paper

A link between symmetries of critical states and the structure of SLOCC classes in multipartite systems

Oskar Słowik, Martin Hebenstreit, Barbara Kraus, and Adam Sawicki,

Quantum 4, 300 (2020).

Central in entanglement theory is the characterization of local transformations among pure multipartite states. As a first step towards such a characterization, one needs to identify those s…

Paper

Entanglement-breaking superchannels

Senrui Chen and Eric Chitambar,

Quantum 4, 299 (2020).

In this paper we initiate the study of entanglement-breaking (EB) superchannels. These are processes that always yield separable maps when acting on one side of a bipartite completely positi…

Paper

Quasirandom quantum channels

Tom Bannink, Jop Briët, Farrokh Labib, and Hans Maassen,

Quantum 4, 298 (2020).

Mixing (or quasirandom) properties of the natural transition matrix associated to a graph can be quantified by its distance to the complete graph. Different mixing properties correspond to d…

Paper

A Quantum Money Solution to the Blockchain Scalability Problem

Andrea Coladangelo and Or Sattath,

Quantum 4, 297 (2020).

We put forward the idea that classical blockchains and smart contracts are potentially useful primitives not only for classical cryptography, but for quantum cryptography as well. Abstractly…

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