Quantum

Paper

Real Randomized Benchmarking

A. K. Hashagen, S. T. Flammia, D. Gross, and J. J. Wallman,

Quantum 2, 85 (2018).

Randomized benchmarking provides a tool for obtaining precise quantitative estimates of the average error rate of a physical quantum channel. Here we define real randomized benchmarking, whi…

Paper

Quantum walking in curved spacetime: discrete metric

Pablo Arrighi, Giuseppe Di Molfetta, and Stefano Facchini,

Quantum 2, 84 (2018).

A discrete-time quantum walk (QW) is essentially a unitary operator driving the evolution of a single particle on the lattice. Some QWs have familiar physics PDEs as their continuum limit. S…

Paper

Measuring acceleration using the Purcell effect

Kacper Kożdoń, Ian T. Durham, and Andrzej Dragan,

Quantum 2, 83 (2018).

We show that a two-level atom resonantly coupled to one of the modes of a cavity field can be used as a sensitive tool to measure the proper acceleration of a combined atom-cavity system. To…

Paper

Randomness versus nonlocality in the Mermin-Bell experiment with three parties

Erik Woodhead, Boris Bourdoncle, and Antonio Acín,

Quantum 2, 82 (2018).

The detection of nonlocal correlations in a Bell experiment implies almost by definition some intrinsic randomness in the measurement outcomes. For given correlations, or for a given Bell vi…

Paper

Monogamy of entanglement without inequalities

Gilad Gour and Yu Guo,

Quantum 2, 81 (2018).

We provide a fine-grained definition for monogamous measure of entanglement that does not invoke any particular monogamy relation. Our definition is given in terms an equality, as oppose to…

Paper

In situ upgrade of quantum simulators to universal computers

Benjamin Dive, Alexander Pitchford, Florian Mintert, and Daniel Burgarth,

Quantum 2, 80 (2018).

Quantum simulators, machines that can replicate the dynamics of quantum systems, are being built as useful devices and are seen as a stepping stone to universal quantum computers. A key diff…

Paper

Quantum Computing in the NISQ era and beyond

John Preskill,

Quantum 2, 79 (2018).

Noisy Intermediate-Scale Quantum (NISQ) technology will be available in the near future. Quantum computers with 50-100 qubits may be able to perform tasks which surpass the capabilities of t…

Paper

A Short Path Quantum Algorithm for Exact Optimization

M. B. Hastings,

Quantum 2, 78 (2018).

We give a quantum algorithm to exactly solve certain problems in combinatorial optimization, including weighted MAX-2-SAT as well as problems where the objective function is a weighted sum o…

Paper

Reliable numerical key rates for quantum key distribution

Adam Winick, Norbert Lütkenhaus, and Patrick J. Coles,

Quantum 2, 77 (2018).

In this work, we present a reliable, efficient, and tight numerical method for calculating key rates for finite-dimensional quantum key distribution (QKD) protocols. We illustrate our approa…

Paper

Tomographically reconstructed master equations for any open quantum dynamics

Felix A. Pollock and Kavan Modi,

Quantum 2, 76 (2018).

Memory effects in open quantum dynamics are often incorporated in the equation of motion through a superoperator known as the memory kernel, which encodes how past states affect future dynam…

Paper

Hamiltonians for one-way quantum repeaters

Filippo M. Miatto, Michael Epping, and Norbert Lütkenhaus,

Quantum 2, 75 (2018).

Quantum information degrades over distance due to the unavoidable imperfections of the transmission channels, with loss as the leading factor. This simple fact hinders quantum communication,…

Paper

Halving the cost of quantum addition

Craig Gidney,

Quantum 2, 74 (2018).

We improve the number of T gates needed to perform an n-bit adder from $8n + O(1)$ to $4n + O(1)$. We do so via a "temporary logical-AND" construction which uses four T gates to store the logica…

Paper

Heralded generation of maximal entanglement in any dimension via incoherent coupling to thermal baths

Armin Tavakoli, Géraldine Haack, Marcus Huber, Nicolas Brunner, and Jonatan Bohr Brask,

Quantum 2, 73 (2018).

We present a scheme for dissipatively generating maximal entanglement in a heralded manner. Our setup requires incoherent interactions with two thermal baths at different temperatures, but n…

Paper

Robust Bell inequalities from communication complexity

Sophie Laplante, Mathieu Laurière, Alexandre Nolin, Jérémie Roland, and Gabriel Senno,

Quantum 2, 72 (2018).

The question of how large Bell inequality violations can be, for quantum distributions, has been the object of much work in the past several years. We say that a Bell inequality is normalize…

Paper

Codes and Protocols for Distilling $T$, controlled-$S$, and Toffoli Gates

Jeongwan Haah and Matthew B. Hastings,

Quantum 2, 71 (2018).

We present several different codes and protocols to distill $T$, controlled-$S$, and Toffoli (or $CCZ$) gates. One construction is based on codes that generalize the triorthogonal codes, allowing…

Paper

Phonon-assisted relaxation and decoherence of singlet-triplet qubits in Si/SiGe quantum dots

Viktoriia Kornich, Christoph Kloeffel, and Daniel Loss,

Quantum 2, 70 (2018).

We study theoretically the phonon-induced relaxation and decoherence of spin states of two electrons in a lateral double quantum dot in a SiGe/Si/SiGe heterostructure. We consider two types…

Category: Paper