Quantum

Paper

Efficient Bayesian phase estimation using mixed priors

Ewout van den Berg,

Quantum 5, 469 (2021).

We describe an efficient implementation of Bayesian quantum phase estimation in the presence of noise and multiple eigenstates. The main contribution of this work is the dynamic switching be…

Paper

$a\times b=c$ in $2+1$D TQFT

Matthew Buican, Linfeng Li, and Rajath Radhakrishnan,

Quantum 5, 468 (2021).

We study the implications of the anyon fusion equation $a\times b=c$ on global properties of $2+1$D topological quantum field theories (TQFTs). Here $a$ and $b$ are anyons that fuse together to give…

Paper

Efficient qubit phase estimation using adaptive measurements

Marco A. Rodríguez-García, Isaac Pérez Castillo, and P. Barberis-Blostein,

Quantum 5, 467 (2021).

Estimating correctly the quantum phase of a physical system is a central problem in quantum parameter estimation theory due to its wide range of applications from quantum metrology to crypto…

Paper

Analyzing the barren plateau phenomenon in training quantum neural networks with the ZX-calculus

Chen Zhao and Xiao-Shan Gao,

Quantum 5, 466 (2021).

In this paper, we propose a general scheme to analyze the gradient vanishing phenomenon, also known as the barren plateau phenomenon, in training quantum neural networks with the ZX-calculus…

Paper

Quantum advantage from energy measurements of many-body quantum systems

Leonardo Novo, Juani Bermejo-Vega, and Raúl García-Patrón,

Quantum 5, 465 (2021).

The problem of sampling outputs of quantum circuits has been proposed as a candidate for demonstrating a quantum computational advantage (sometimes referred to as quantum "supremacy"). In th…

Paper

Modeling and mitigation of cross-talk effects in readout noise with applications to the Quantum Approximate Optimization Algorithm

Filip B. Maciejewski, Flavio Baccari, Zoltán Zimborás, and Michał Oszmaniec,

Quantum 5, 464 (2021).

Measurement noise is one of the main sources of errors in currently available quantum devices based on superconducting qubits. At the same time, the complexity of its characterization and mi…

Paper

A Threshold for Quantum Advantage in Derivative Pricing

Shouvanik Chakrabarti, Rajiv Krishnakumar, Guglielmo Mazzola, Nikitas Stamatopoulos, Stefan Woerner, and William J. Zeng,

Quantum 5, 463 (2021).

We give an upper bound on the resources required for valuable quantum advantage in pricing derivatives. To do so, we give the first complete resource estimates for useful quantum derivative…

Paper

Time-optimal quantum transformations with bounded bandwidth

Dan Allan, Niklas Hörnedal, and Ole Andersson,

Quantum 5, 462 (2021).

In this paper, we derive sharp lower bounds, also known as quantum speed limits, for the time it takes to transform a quantum system into a state such that an observable assumes its lowest a…

Paper

Spectrally multimode integrated SU(1,1) interferometer

Alessandro Ferreri, Matteo Santandrea, Michael Stefszky, Kai H. Luo, Harald Herrmann, Christine Silberhorn, and Polina R. Sharapova,

Quantum 5, 461 (2021).

Nonlinear SU(1,1) interferometers are fruitful and promising tools for spectral engineering and precise measurements with phase sensitivity below the classical bound. Such interferometers ha…

Paper

Parallel entangling gate operations and two-way quantum communication in spin chains

Rozhin Yousefjani and Abolfazl Bayat,

Quantum 5, 460 (2021).

The power of a quantum circuit is determined through the number of two-qubit entangling gates that can be performed within the coherence time of the system. In the absence of parallel quantu…

Paper

Time-dependent unbounded Hamiltonian simulation with vector norm scaling

Dong An, Di Fang, and Lin Lin,

Quantum 5, 459 (2021).

The accuracy of quantum dynamics simulation is usually measured by the error of the unitary evolution operator in the operator norm, which in turn depends on certain norm of the Hamiltonian.…

Paper

Versatile Super-Sensitive Metrology Using Induced Coherence

Nathaniel R. Miller, Sven Ramelow, and William N. Plick,

Quantum 5, 458 (2021).

We theoretically analyze the phase sensitivity of the Induced-Coherence (Mandel-Type) Interferometer, including the case where the sensitivity is "boosted" into the bright input regime with…

Paper

How dynamics constrains probabilities in general probabilistic theories

Thomas D. Galley and Lluis Masanes,

Quantum 5, 457 (2021).

We introduce a general framework for analysing general probabilistic theories, which emphasises the distinction between the dynamical and probabilistic structures of a system. The dynamical…

Paper

Contextual Subspace Variational Quantum Eigensolver

William M. Kirby, Andrew Tranter, and Peter J. Love,

Quantum 5, 456 (2021).

We describe the $\textit{contextual subspace variational quantum eigensolver}$ (CS-VQE), a hybrid quantum-classical algorithm for approximating the ground state energy of a Hamiltonian. The ap…

Paper

Multi-time correlations in the positive-P, Q, and doubled phase-space representations

Piotr Deuar,

Quantum 5, 455 (2021).

A number of physically intuitive results for the calculation of multi-time correlations in phase-space representations of quantum mechanics are obtained. They relate time-dependent stochasti…

Paper

Qubit-efficient encoding schemes for binary optimisation problems

Benjamin Tan, Marc-Antoine Lemonde, Supanut Thanasilp, Jirawat Tangpanitanon, and Dimitris G. Angelakis,

Quantum 5, 454 (2021).

We propose and analyze a set of variational quantum algorithms for solving quadratic unconstrained binary optimization problems where a problem consisting of $n_c$ classical variables can be i…

Category: Paper