Quantum – the open journal for quantum science

News

Quantum meets SciPost at YRM 2017

SciPost‘s Jean-Sébastien Caux and Quantum’s Christian Gogolin were both invited to speak about “the future of scientific publishing” at a dedicated session on that topic during YRM 2017 in Tarragona. …

Quantum obtains an ISSN

Quantum has been assigned an International Standard Serial Number (ISSN) by the ISSN International Centre. The ISSN is similar to the more widely known ISBN, which is used to uniquely …

Paper

Fast and high-fidelity entangling gate through parametrically modulated longitudinal coupling

Baptiste Royer, Arne L. Grimsmo, Nicolas Didier, and Alexandre Blais,

Quantum 1, 11 (2017). https://doi.org/10.22331/q-2017-05-11-11

We investigate an approach to universal quantum computation based on the modulation of longitudinal qubit-oscillator coupling. We show how to realize a controlled-phase gate by simultaneousl…

On experimentally relevant quantum speedups

This is an editorial on the article Achieving quantum supremacy with sparse and noisy commuting quantum computations by Michael J. Bremner, Ashley Montanaro and Dan J. Shepherd, published in Quantum …

Paper

A purification postulate for quantum mechanics with indefinite causal order

Mateus Araújo, Adrien Feix, Miguel Navascués, and Časlav Brukner,

Quantum 1, 10 (2017). https://doi.org/10.22331/q-2017-04-26-10

To study which are the most general causal structures which are compatible with local quantum mechanics, Oreshkov et al. introduced the notion of a process: a resource shared between some pa…

Paper

Finite-density phase diagram of a $(1+1)-d$ non-abelian lattice gauge theory with tensor networks

Pietro Silvi, Enrique Rico, Marcello Dalmonte, Ferdinand Tschirsich, and Simone Montangero,

Quantum 1, 9 (2017). https://doi.org/10.22331/q-2017-04-25-9

We investigate the finite-density phase diagram of a non-abelian $SU(2)$ lattice gauge theory in $(1+1)$-dimensions using tensor network methods. We numerically characterise the phase diagra…

Paper

Achieving quantum supremacy with sparse and noisy commuting quantum computations

Michael J. Bremner, Ashley Montanaro, and Dan J. Shepherd,

Quantum 1, 8 (2017). https://doi.org/10.22331/q-2017-04-25-8

The class of commuting quantum circuits known as IQP (instantaneous quantum polynomial-time) has been shown to be hard to simulate classically, assuming certain complexity-theoretic conjectu…

Paper

Proposal for witnessing non-classical light with the human eye

A. Dodel, A. Mayinda, E. Oudot, A. Martin, P. Sekatski, J.-D. Bancal, and N. Sangouard,

Quantum 1, 7 (2017). https://doi.org/10.22331/q-2017-04-25-7

We give a complete proposal showing how to detect the non-classical nature of photonic states with naked eyes as detectors. The enabling technology is a sub-Poissonian photonic state that is…

Paper

Extremal eigenvalues of local Hamiltonians

Aram W. Harrow and Ashley Montanaro,

Quantum 1, 6 (2017). https://doi.org/10.22331/q-2017-04-25-6

We apply classical algorithms for approximately solving constraint satisfaction problems to find bounds on extremal eigenvalues of local Hamiltonians. We consider spin Hamiltonians for which…

Paper

QInfer: Statistical inference software for quantum applications

Christopher Granade, Christopher Ferrie, Ian Hincks, Steven Casagrande, Thomas Alexander, Jonathan Gross, Michal Kononenko, and Yuval Sanders,

Quantum 1, 5 (2017). https://doi.org/10.22331/q-2017-04-25-5

Characterizing quantum systems through experimental data is critical to applications as diverse as metrology and quantum computing. Analyzing this experimental data in a robust and reproduci…