Quantum

Paper

Optimal quantum metrology of distant black bodies

Mark E. Pearce, Earl T. Campbell, and Pieter Kok,

Quantum 1, 21 (2017).

Measurements of an object's temperature are important in many disciplines, from astronomy to engineering, as are estimates of an object's spatial configuration. We present the quantum optima…

Paper

Uncertainty relations: An operational approach to the error-disturbance tradeoff

Joseph M. Renes, Volkher B. Scholz, and Stefan Huber,

Quantum 1, 20 (2017).

The notions of error and disturbance appearing in quantum uncertainty relations are often quantified by the discrepancy of a physical quantity from its ideal value. However, these real and i…

Paper

Hitting statistics from quantum jumps

A. Chia, T. Paterek, and L. C. Kwek,

Quantum 1, 19 (2017).

We define the hitting time for a model of continuous-time open quantum walks in terms of quantum jumps. Our starting point is a master equation in Lindblad form, which can be taken as the qu…

Paper

Decoupling with random diagonal unitaries

Yoshifumi Nakata, Christoph Hirche, Ciara Morgan, and Andreas Winter,

Quantum 1, 18 (2017).

We investigate decoupling, one of the most important primitives in quantum Shannon theory, by replacing the uniformly distributed random unitaries commonly used to achieve the protocol, with…

Paper

Entanglement and squeezing in continuous-variable systems

Manuel Gessner, Luca Pezzè, and Augusto Smerzi,

Quantum 1, 17 (2017).

We introduce a multi-mode squeezing coefficient to characterize entanglement in $N$-partite continuous-variable systems. The coefficient relates to the squeezing of collective observables in t…

Paper

QCMA hardness of ground space connectivity for commuting Hamiltonians

David Gosset, Jenish C. Mehta, and Thomas Vidick,

Quantum 1, 16 (2017).

In this work we consider the ground space connectivity problem for commuting local Hamiltonians. The ground space connectivity problem asks whether it is possible to go from one (efficiently…

Paper

Classification of all alternatives to the Born rule in terms of informational properties

Thomas D. Galley and Lluis Masanes,

Quantum 1, 15 (2017).

The standard postulates of quantum theory can be divided into two groups: the first one characterizes the structure and dynamics of pure states, while the second one specifies the structure…

Paper

A largely self-contained and complete security proof for quantum key distribution

Marco Tomamichel and Anthony Leverrier,

Quantum 1, 14 (2017).

In this work we present a security analysis for quantum key distribution, establishing a rigorous tradeoff between various protocol and security parameters for a class of entanglement-based…

Paper

A Stronger Theorem Against Macro-realism

John-Mark A. Allen, Owen J. E. Maroney, and Stefano Gogioso,

Quantum 1, 13 (2017).

Macro-realism is the position that certain macroscopic observables must always possess definite values: e.g. the table is in some definite position, even if we do not know what that is preci…

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).

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…

Paper

A purification postulate for quantum mechanics with indefinite causal order

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

Quantum 1, 10 (2017).

To study which are the most general causal structures which are compatible with local quantum mechanics, Oreshkov $et$ $al.$ [1] introduced the notion of a process: a resource shared between som…

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).

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 diagram as…

Paper

Achieving quantum supremacy with sparse and noisy commuting quantum computations

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

Quantum 1, 8 (2017).

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).

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).

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).

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…

Category: Paper