Christoph Hirche, Cambyse Rouzé, and Daniel Stilck França,

Quantum 6, 862 (2022).

The data processing inequality is the most basic requirement for any meaningful measure of information. It essentially states that distinguishability measures between states decrease if we a…

Nishant Jain, Brian Coyle, Elham Kashefi, and Niraj Kumar,

Quantum 6, 861 (2022).

Approximate combinatorial optimisation has emerged as one of the most promising application areas for quantum computers, particularly those in the near term. In this work, we focus on the qu…

Henrik Wilming,

Quantum 6, 858 (2022).

I show that if a finite-dimensional density matrix has strictly smaller von Neumann entropy than a second one of the same dimension (and the rank is not bigger), then sufficiently (but finit…

Caroline de Groot, Alex Turzillo, and Norbert Schuch,

Quantum 6, 856 (2022).

We systematically investigate the robustness of symmetry protected topological (SPT) order in open quantum systems by studying the evolution of string order parameters and other probes under…

Casper Gyurik, Chris Cade, and Vedran Dunjko,

Quantum 6, 855 (2022).

Even after decades of quantum computing development, examples of generally useful quantum algorithms with exponential speedups over classical counterparts are scarce. Recent progress in quan…

Teiko Heinosaari, Maria Anastasia Jivulescu, and Ion Nechita,

Quantum 6, 853 (2022).

We study the partially ordered set of equivalence classes of quantum measurements endowed with the post-processing partial order. The post-processing order is fundamental as it enables to co…

Pablo Martinez-Azcona and Aurélia Chenu,

Quantum 6, 852 (2022).

Quantum chaos cannot develop faster than $\lambda \leq 2 \pi/(\hbar \beta)$ for systems in thermal equilibrium [Maldacena, Shenker & Stanford, JHEP (2016)]. This `MSS bound' on the Lyapunov ex…

Dominic Gribben, Aidan Strathearn, Gerald E. Fux, Peter Kirton, and Brendon W. Lovett,

Quantum 6, 847 (2022).

Tracing out the environmental degrees of freedom is a necessary procedure when simulating open quantum systems. While being an essential step in deriving a tractable master equation it repre…

Matthias Englbrecht, Tristan Kraft, and Barbara Kraus,

Quantum 6, 846 (2022).

Stabilizer states and graph states find application in quantum error correction, measurement-based quantum computation and various other concepts in quantum information theory. In this work,…

Guoding Liu, Xingjian Zhang, and Xiongfeng Ma,

Quantum 6, 845 (2022).

Quantum information science provides powerful technologies beyond the scope of classical physics. In practice, accurate control of quantum operations is a challenging task with current quant…

Trystan Surawy-Stepney, Jonas Kahn, Richard Kueng, and Madalin Guta,

Quantum 6, 844 (2022).

We propose and investigate a new method of quantum process tomography (QPT) which we call projected least squares (PLS). In short, PLS consists of first computing the least-squares estimator…

Michele Masini, Stefano Pironio, and Erik Woodhead,

Quantum 6, 843 (2022).

According to the entropy accumulation theorem, proving the unconditional security of a device-independent quantum key distribution protocol reduces to deriving tradeoff functions, i.e., boun…

Shiv Akshar Yadavalli and Ravi Kunjwal,

Quantum 6, 839 (2022).

We consider the problem of entanglement-assisted one-shot classical communication. In the zero-error regime, entanglement can increase the one-shot zero-error capacity of a family of classic…

Nikolaos Koukoulekidis, Hyukjoon Kwon, Hyejung H. Jee, David Jennings, and M. S. Kim,

Quantum 6, 838 (2022).

Outcome probability estimation via classical methods is an important task for validating quantum computing devices. Outcome probabilities of any quantum circuit can be estimated using Monte…

Andy J. Goldschmidt, Jonathan L. DuBois, Steven L. Brunton, and J. Nathan Kutz,

Quantum 6, 837 (2022).

A critical engineering challenge in quantum technology is the accurate control of quantum dynamics. Model-based methods for optimal control have been shown to be highly effective when theory…

Alba Cervera-Lierta, Mario Krenn, and Alán Aspuru-Guzik,

Quantum 6, 836 (2022).

Logic Artificial Intelligence (AI) is a subfield of AI where variables can take two defined arguments, True or False, and are arranged in clauses that follow the rules of formal logic. Sever…

Marcel Dall’Agnol, Tom Gur, Subhayan Roy Moulik, and Justin Thaler,

Quantum 6, 834 (2022).

We initiate the systematic study of QMA algorithms in the setting of property testing, to which we refer as QMA $\textit{proofs of proximity}$ (QMAPs). These are quantum query algorithms that…

Jannes Nys and Giuseppe Carleo,

Quantum 6, 833 (2022).

Through the introduction of auxiliary fermions, or an enlarged spin space, one can map local fermion Hamiltonians onto local spin Hamiltonians, at the expense of introducing a set of additio…

Ulysse Chabaud and Saeed Mehraban,

Quantum 6, 831 (2022).

We study bosonic quantum computations using the Segal-Bargmann representation of quantum states. We argue that this holomorphic representation is a natural one which not only gives a canonic…

Alicja Dutkiewicz, Barbara M. Terhal, and Thomas E. O’Brien,

Quantum 6, 830 (2022).

Quantum phase estimation is a cornerstone in quantum algorithm design, allowing for the inference of eigenvalues of exponentially-large sparse matrices.The maximum rate at which these eigenv…

Chenfeng Cao, Chao Zhang, Zipeng Wu, Markus Grassl, and Bei Zeng,

Quantum 6, 828 (2022).

Quantum error correction is believed to be a necessity for large-scale fault-tolerant quantum computation. In the past two decades, various constructions of quantum error-correcting codes (Q…

Junghee Ryu and Hoon Ryu,

Quantum 6, 827 (2022).

We characterize the quantum entanglement of the realistic two-qubit signals that are sensitive to charge noises. Our working example is the time response generated from a silicon double quan…

Marios Christodoulou, Andrea Di Biagio, and Pierre Martin-Dussaud,

Quantum 6, 826 (2022).

Time at the Planck scale ($\sim 10^{-44} \mathrm{s}$) is an unexplored physical regime. It is widely believed that probing Planck time will remain for long an impossible task. Yet, we propose…

Martin Larocca, Piotr Czarnik, Kunal Sharma, Gopikrishnan Muraleedharan, Patrick J. Coles, and M. Cerezo,

Quantum 6, 824 (2022).

Variational Quantum Algorithms (VQAs) have received considerable attention due to their potential for achieving near-term quantum advantage. However, more work is needed to understand their…

Steven Herbert,

Quantum 6, 823 (2022).

This paper proposes a method of quantum Monte Carlo integration that retains the full quadratic quantum advantage, without requiring any arithmetic or quantum phase estimation to be performe…

Peter Leviant, Qian Xu, Liang Jiang, and Serge Rosenblum,

Quantum 6, 821 (2022).

Bosonic qubits encoded in continuous-variable systems provide a promising alternative to two-level qubits for quantum computation and communication. So far, photon loss has been the dominant…

Yoav Afik and Juan Ramón Muñoz de Nova,

Quantum 6, 820 (2022).

Top quarks represent unique high-energy systems since their spin correlations can be measured, thus allowing to study fundamental aspects of quantum mechanics with qubits at high-energy coll…

Francesco Massa, Preeti Yadav, Amir Moqanaki, Walter O. Krawec, Paulo Mateus, Nikola Paunković, André Souto, and Philip Walther,

Quantum 6, 819 (2022).

Quantum key distribution, which allows two distant parties to share an unconditionally secure cryptographic key, promises to play an important role in the future of communication. For this r…

Sarah True and Alioscia Hamma,

Quantum 6, 818 (2022).

Entanglement is the defining characteristic of quantum mechanics. Bipartite entanglement is characterized by the von Neumann entropy. Entanglement is not just described by a number, however;…

Bartosz Regula,

Quantum 6, 817 (2022).

We develop two general approaches to characterising the manipulation of quantum states by means of probabilistic protocols constrained by the limitations of some quantum resource theory. Fir…

Yu Tong, Victor V. Albert, Jarrod R. McClean, John Preskill, and Yuan Su,

Quantum 6, 816 (2022).

Quantum many-body systems involving bosonic modes or gauge fields have infinite-dimensional local Hilbert spaces which must be truncated to perform simulations of real-time dynamics on class…

Mark A. Webster, Benjamin J. Brown, and Stephen D. Bartlett,

Quantum 6, 815 (2022).

We propose an extension to the Pauli stabiliser formalism that includes fractional $2\pi/N$ rotations around the $Z$ axis for some integer $N$. The resulting generalised stabiliser formalism – den…

Stavros Efthymiou, Marco Lazzarin, Andrea Pasquale, and Stefano Carrazza,

Quantum 6, 814 (2022).

Quantum technologies are moving towards the development of novel hardware devices based on quantum bits (qubits). In parallel to the development of quantum devices, efficient simulation tool…

Craig Gidney, Michael Newman, and Matt McEwen,

Quantum 6, 813 (2022).

We improve the planar honeycomb code by describing boundaries that need no additional physical connectivity, and by optimizing the shape of the qubit patch. We then benchmark the code using…

Lewis A. Clark, Bartosz Markowicz, and Jan Kołodyński,

Quantum 6, 812 (2022).

Optomechanical systems are rapidly becoming one of the most promising platforms for observing quantum behaviour, especially at the macroscopic level. Moreover, thanks to their state-of-the-a…

Zane M. Rossi and Isaac L. Chuang,

Quantum 6, 811 (2022).

Recent work shows that quantum signal processing (QSP) and its multi-qubit lifted version, quantum singular value transformation (QSVT), unify and improve the presentation of most quantum al…

Guilherme L. Zanin, Michael Antesberger, Maxime J. Jacquet, Paulo H. Souto Ribeiro, Lee A. Rozema, and Philip Walther,

Quantum 6, 810 (2022).

Maxwell's Demon is at the heart of the interrelation between quantum information processing and thermodynamics. In this thought experiment, a demon generates a temperature gradient between t…

Enes Aybar, Artur Niezgoda, Safoura S. Mirkhalaf, Morgan W. Mitchell, Daniel Benedicto Orenes, and Emilia Witkowska,

Quantum 6, 808 (2022).

In this work, we study temperature sensing with finite-sized strongly correlated systems exhibiting quantum phase transitions. We use the quantum Fisher information (QFI) approach to quantif…

Zhenning Liu and Alexandru Gheorghiu,

Quantum 6, 807 (2022).

A proof of quantumness is a type of challenge-response protocol in which a classical verifier can efficiently certify the $\textit{quantum advantage}$ of an untrusted prover. That is, a quantu…

Paul K. Faehrmann, Mark Steudtner, Richard Kueng, Maria Kieferova, and Jens Eisert,

Quantum 6, 806 (2022).

Quantum simulation, the simulation of quantum processes on quantum computers, suggests a path forward for the efficient simulation of problems in condensed-matter physics, quantum chemistry,…

Ciaran McDonnell and Beatriz Olmos,

Quantum 6, 805 (2022).

We analyze the topological and dynamical properties of a system formed by two chains of identical emitters coupled to a waveguide, whose guided modes induce all-to-all excitation hopping. We…

Enrico Fontana, M. Cerezo, Andrew Arrasmith, Ivan Rungger, and Patrick J. Coles,

Quantum 6, 804 (2022).

Very little is known about the cost landscape for parametrized Quantum Circuits (PQCs). Nevertheless, PQCs are employed in Quantum Neural Networks and Variational Quantum Algorithms, which m…

Niel de Beaudrap and Steven Herbert,

Quantum 6, 803 (2022).

This paper builds on the idea of simulating stabiliser circuits through transformations of {quadratic form expansions}. This is a representation of a quantum state which specifies a formula…

Jingzhen Hu, Qingzhong Liang, and Robert Calderbank,

Quantum 6, 802 (2022).

The challenge of quantum computing is to combine error resilience with universal computation. Diagonal gates such as the transversal $T$ gate play an important role in implementing a universal…

Archak Purkayastha, Giacomo Guarnieri, Steve Campbell, Javier Prior, and John Goold,

Quantum 6, 801 (2022).

We introduce unique class of cyclic quantum thermal machines (QTMs) which can maximize their performance at the finite value of cycle duration $\tau$ where they are most irreversible. These QT…

T. J. Volkoff and Yiğit Subaşı,

Quantum 6, 800 (2022).

We propose a continuous-variable (CV) SWAP test that requires no ancilla register, thereby generalizing the ancilla-free SWAP test for qubits. In this ancilla-free CV SWAP test, the computat…

Max D. Porter and Ilon Joseph,

Quantum 6, 799 (2022).

In certain regimes, the fidelity of quantum states will decay at a rate set by the classical Lyapunov exponent. This serves both as one of the most important examples of the quantum-classica…

Wonho Jang, Koji Terashi, Masahiko Saito, Christian W. Bauer, Benjamin Nachman, Yutaro Iiyama, Ryunosuke Okubo, and Ryu Sawada,

Quantum 6, 798 (2022).

There is no unique way to encode a quantum algorithm into a quantum circuit. With limited qubit counts, connectivity, and coherence times, a quantum circuit optimization is essential to make…

Alejandro Sopena, Max Hunter Gordon, Diego García-Martín, Germán Sierra, and Esperanza López,

Quantum 6, 796 (2022).

The Algebraic Bethe Ansatz (ABA) is a highly successful analytical method used to exactly solve several physical models in both statistical mechanics and condensed-matter physics. Here we br…

Carlo Marconi, Pau Colomer Saus, María García Díaz, and Anna Sanpera,

Quantum 6, 794 (2022).

We investigate attractor quantum neural networks (aQNNs) within the framework of coherence theory. We show that: i) aQNNs are associated to non-coherence-generating quantum channels; ii) the…

Hao Hu, Jiyoung Im, Jie Lin, Norbert Lütkenhaus, and Henry Wolkowicz,

Quantum 6, 792 (2022).

Security proof methods for quantum key distribution, QKD, that are based on the numerical key rate calculation problem, are powerful in principle. However, the practicality of the methods ar…

Eric Culf and Thomas Vidick,

Quantum 6, 791 (2022).

We establish a strong monogamy-of-entanglement property for subspace coset states, which are uniform superpositions of vectors in a linear subspace of $\mathbb{F}_2^n$ to which has been applie…

Ian Jauslin and Marius Lemm,

Quantum 6, 790 (2022).

We consider random translation-invariant frustration-free quantum spin Hamiltonians on $\mathbb Z^D$ in which the nearest-neighbor interaction in every direction is randomly sampled and then d…

Simon Milz, Jessica Bavaresco, and Giulio Chiribella,

Quantum 6, 788 (2022).

The capacity of distant parties to send signals to one another is a fundamental requirement in many information-processing tasks. Such ability is determined by the causal structure connectin…

Azat F. Aminov, Alexey A. Sokolik, and Yurii E. Lozovik,

Quantum 6, 787 (2022).

The Andreev-Bashkin effect, or superfluid drag, is predicted in a system of Bose-condensed excitonic polaritons in optical microcavity coupled by electron-exciton interaction with a supercon…

Craig Gidney,

Quantum 6, 786 (2022).

Topological quantum computations are built on a foundation of two basic tasks: preserving logical observables through time and moving logical observables through space. Memory experiments, w…

George Moreno, Ranieri Nery, Cristhiano Duarte, and Rafael Chaves,

Quantum 6, 785 (2022).

The notorious quantum measurement problem brings out the difficulty to reconcile two quantum postulates: the unitary evolution of closed quantum systems and the wave-function collapse after…

Tasio Gonzalez-Raya and Mikel Sanz,

Quantum 6, 783 (2022).

Open-air microwave quantum communication and metrology protocols must be able to transfer quantum resources from a cryostat, where they are created, to an environment dominated by thermal no…

Amara Katabarwa, Sukin Sim, Dax Enshan Koh, and Pierre-Luc Dallaire-Demers,

Quantum 6, 782 (2022).

Parameterized quantum circuits (PQCs) are a central component of many variational quantum algorithms, yet there is a lack of understanding of how their parameterization impacts algorithm per…

Teague Tomesh, Zain H. Saleem, and Martin Suchara,

Quantum 6, 781 (2022).

We present a new hybrid, local search algorithm for quantum approximate optimization of constrained combinatorial optimization problems. We focus on the Maximum Independent Set problem and d…

Thomas D. Galley, Flaminia Giacomini, and John H. Selby,

Quantum 6, 779 (2022).

Recently, table-top experiments involving massive quantum systems have been proposed to test the interface of quantum theory and gravity. In particular, the crucial point of the debate is wh…

Maria Prat Colomer, Luke Mortimer, Irénée Frérot, Máté Farkas, and Antonio Acín,

Quantum 6, 778 (2022).

Mutually unbiased bases correspond to highly useful pairs of measurements in quantum information theory. In the smallest composite dimension, six, it is known that between three and seven mu…

Carlos Bravo-Prieto, Julien Baglio, Marco Cè, Anthony Francis, Dorota M. Grabowska, and Stefano Carrazza,

Quantum 6, 777 (2022).

We propose and assess an alternative quantum generator architecture in the context of generative adversarial learning for Monte Carlo event generation, used to simulate particle physics proc…

Ryan LaRose, Andrea Mari, Sarah Kaiser, Peter J. Karalekas, Andre A. Alves, Piotr Czarnik, Mohamed El Mandouh, Max H. Gordon, Yousef Hindy, Aaron Robertson, Purva Thakre, Misty Wahl, Danny Samuel, Rahul Mistri, Maxime Tremblay, Nick Gardner, Nathaniel T. Stemen, Nathan Shammah, and William J. Zeng,

Quantum 6, 774 (2022).

We introduce Mitiq, a Python package for error mitigation on noisy quantum computers. Error mitigation techniques can reduce the impact of noise on near-term quantum computers with minimal o…

Anton Trushechkin,

Quantum 6, 771 (2022).

Detection-efficiency mismatch is a common problem in practical quantum key distribution (QKD) systems. Current security proofs of QKD with detection-efficiency mismatch rely either on the as…

Nikitas Stamatopoulos, Guglielmo Mazzola, Stefan Woerner, and William J. Zeng,

Quantum 6, 770 (2022).

We introduce a quantum algorithm to compute the market risk of financial derivatives. Previous work has shown that quantum amplitude estimation can accelerate derivative pricing quadraticall…

Miller Eaton, Carlos González-Arciniegas, Rafael N. Alexander, Nicolas C. Menicucci, and Olivier Pfister,

Quantum 6, 769 (2022).

We present an algorithm to reliably generate various quantum states critical to quantum error correction and universal continuous-variable (CV) quantum computing, such as Schrödinger cat sta…

Pablo A. M. Casares, Roberto Campos, and M. A. Martin-Delgado,

Quantum 6, 768 (2022).

Quantum Phase Estimation is one of the most useful quantum computing algorithms for quantum chemistry and as such, significant effort has been devoted to designing efficient implementations.…

Nithin Raveendran, Narayanan Rengaswamy, Filip Rozpędek, Ankur Raina, Liang Jiang, and Bane Vasić,

Quantum 6, 767 (2022).

Quantum error correction has recently been shown to benefit greatly from specific physical encodings of the code qubits. In particular, several researchers have considered the individual cod…

Pei-Sheng Lin, Tamás Vértesi, and Yeong-Cherng Liang,

Quantum 6, 765 (2022).

It is well-known that in a Bell experiment, the observed correlation between measurement outcomes – as predicted by quantum theory – can be stronger than that allowed by local causality, yet…

Dario Cilluffo,

Quantum 6, 764 (2022).

Measuring time means counting the occurrence of periodic phenomena. Over the past centuries a major effort was put to make stable and precise oscillators to be used as clock regulators. Here…

Edward Farhi, Jeffrey Goldstone, Sam Gutmann, and Leo Zhou,

Quantum 6, 759 (2022).

The Quantum Approximate Optimization Algorithm (QAOA) is a general-purpose algorithm for combinatorial optimization problems whose performance can only improve with the number of layers $p$. W…

Yuki Takeuchi, Yasuhiro Takahashi, Tomoyuki Morimae, and Seiichiro Tani,

Quantum 6, 758 (2022).

Several noisy intermediate-scale quantum computations can be regarded as logarithmic-depth quantum circuits on a sparse quantum computing chip, where two-qubit gates can be directly applied…

Kunal Marwaha and Stuart Hadfield,

Quantum 6, 757 (2022).

We consider the power of local algorithms for approximately solving Max $k$XOR, a generalization of two constraint satisfaction problems previously studied with classical and quantum algorithm…

Richard Cleve, Benoit Collins, Li Liu, and Vern Paulsen,

Quantum 6, 755 (2022).

We consider a bipartite transformation that we call self-embezzlement and use it to prove a constant gap between the capabilities of two models of quantum information: the conventional model…

András Gilyén, Zhao Song, and Ewin Tang,

Quantum 6, 754 (2022).

We give a classical algorithm for linear regression analogous to the quantum matrix inversion algorithm [Harrow, Hassidim, and Lloyd, Physical Review Letters'09] for low-rank matrices [Wossn…

Stephen Z. D. Plachta, Markus Hiekkamäki, Abuzer Yakaryılmaz, and Robert Fickler,

Quantum 6, 752 (2022).

Quantum finite automata (QFA) are basic computational devices that make binary decisions using quantum operations. They are known to be exponentially memory efficient compared to their class…

Samuel L. Jacob, Massimiliano Esposito, Juan M. R. Parrondo, and Felipe Barra,

Quantum 6, 750 (2022).

We consider a collision between a moving particle and a fixed system, each having internal degrees of freedom. We identify the regime where the motion of the particle acts as a work source f…

Riccardo Porotti, Antoine Essig, Benjamin Huard, and Florian Marquardt,

Quantum 6, 747 (2022).

Quantum control has been of increasing interest in recent years, e.g. for tasks like state initialization and stabilization. Feedback-based strategies are particularly powerful, but also har…

Namit Anand and Paolo Zanardi,

Quantum 6, 746 (2022).

Out-of-time-ordered correlators (OTOCs) have been extensively studied in recent years as a diagnostic of quantum information scrambling. In this paper, we study quantum information-theoretic…

Ali Hamed Moosavian, Seyed Sajad Kahani, and Salman Beigi,

Quantum 6, 744 (2022).

Evolutions of local Hamiltonians in short times are expected to remain local and thus limited. In this paper, we validate this intuition by proving some limitations on short-time evolutions…

Juan Miguel Arrazola, Olivia Di Matteo, Nicolás Quesada, Soran Jahangiri, Alain Delgado, and Nathan Killoran,

Quantum 6, 742 (2022).

Universal gate sets for quantum computing have been known for decades, yet no universal gate set has been proposed for particle-conserving unitaries, which are the operations of interest in…

Pieter W. Claeys and Austen Lamacraft,

Quantum 6, 738 (2022).

Recent works have investigated the emergence of a new kind of random matrix behaviour in unitary dynamics following a quantum quench. Starting from a time-evolved state, an ensemble of pure…

Daniel Burgarth, Paolo Facchi, Giovanni Gramegna, and Kazuya Yuasa,

Quantum 6, 737 (2022).

We derive a universal nonperturbative bound on the distance between unitary evolutions generated by time-dependent Hamiltonians in terms of the difference of their integral actions. We apply…

Daniel Grier and Luke Schaeffer,

Quantum 6, 734 (2022).

We examine the following problem: given a collection of Clifford gates, describe the set of unitaries generated by circuits composed of those gates. Specifically, we allow the standard circu…

Weichen Tang and Ivan M. Khaymovich,

Quantum 6, 733 (2022).

Motivated by the many-body localization (MBL) phase in generic interacting disordered quantum systems, we develop a model simulating the same eigenstate structure like in MBL, but in the ran…

Hedayat Alghassi, Amol Deshmukh, Noelle Ibrahim, Nicolas Robles, Stefan Woerner, and Christa Zoufal,

Quantum 6, 730 (2022).

We propose an algorithm based on variational quantum imaginary time evolution for solving the Feynman-Kac partial differential equation resulting from a multidimensional system of stochastic…

Alessandro Roggero, Jakub Filipek, Shih-Chieh Hsu, and Nathan Wiebe,

Quantum 6, 727 (2022).

In this work we present the Scaled QUantum IDentifier (SQUID), an open-source framework for exploring hybrid Quantum-Classical algorithms for classification problems. The classical infrastru…

Zixuan Hu, Kade Head-Marsden, David A. Mazziotti, Prineha Narang, and Sabre Kais,

Quantum 6, 726 (2022).

Using quantum algorithms to simulate complex physical processes and correlations in quantum matter has been a major direction of quantum computing research, towards the promise of a quantum…

Srijita Kundu, Jamie Sikora, and Ernest Y.-Z. Tan,

Quantum 6, 725 (2022).

Oblivious transfer is a cryptographic primitive where Alice has two bits and Bob wishes to learn some function of them. Ideally, Alice should not learn Bob's desired function choice and Bob…

Pengfei Zhang, Chunxiao Liu, Shao-Kai Jian, and Xiao Chen,

Quantum 6, 723 (2022).

Non-unitary evolution can give rise to novel steady states classified by their entanglement properties. In this work, we aim to understand the effect of long-range hopping that decays with…

Simon Morelli, David Sauerwein, Michalis Skotiniotis, and Nicolai Friis,

Quantum 6, 722 (2022).

We consider the distribution of high-dimensional entangled states to multiple parties via noisy channels and the subsequent probabilistic conversion of these states to desired target states…

T. R. Scruby, D. E. Browne, P. Webster, and M. Vasmer,

Quantum 6, 721 (2022).

We build on recent work by B. Brown (Sci. Adv. 6, eaay4929 (2020)) to develop and simulate an explicit recipe for a just-in-time decoding scheme in three 3D surface codes, which can be used…

Andrea Skolik, Sofiene Jerbi, and Vedran Dunjko,

Quantum 6, 720 (2022).

Quantum machine learning (QML) has been identified as one of the key fields that could reap advantages from near-term quantum devices, next to optimization and quantum chemistry. Research in…

V. Yu. Shishkov, E. S. Andrianov, and Yu. E. Lozovik,

Quantum 6, 719 (2022).

The theoretical description of non-equilibrium Bose–Einstein condensate (BEC) is one of the main challenges in modern statistical physics and kinetics. The non-equilibrium nature of BEC make…

Mariami Gachechiladze, Bartłomiej Bąk, Marcin Pawłowski, and Nikolai Miklin,

Quantum 6, 717 (2022).

In a Bell test, the set of observed probability distributions complying with the principle of local realism is fully characterized by Bell inequalities. Quantum theory allows for a violation…

Debarshi Das, Ananda G. Maity, Debashis Saha, and A. S. Majumdar,

Quantum 6, 716 (2022).

Certification of quantum devices received from unknown providers is a primary requirement before utilizing the devices for any information processing task. Here, we establish a protocol for…

Sarah Jansen, Kenneth Goodenough, Sébastian de Bone, Dion Gijswijt, and David Elkouss,

Quantum 6, 715 (2022).

Entanglement distillation is an essential building block in quantum communication protocols. Here, we study the class of near-term implementable distillation protocols that use bilocal Cliff…

Naeimeh Mohseni, Thomas Fösel, Lingzhen Guo, Carlos Navarrete-Benlloch, and Florian Marquardt,

Quantum 6, 714 (2022).

Neural networks have emerged as a powerful way to approach many practical problems in quantum physics. In this work, we illustrate the power of deep learning to predict the dynamics of a qua…

John B. DeBrota and Peter J. Love,

Quantum 6, 713 (2022).

We describe a general approach to modeling rational decision-making agents who adopt either quantum or classical mechanics based on the Quantum Bayesian (QBist) approach to quantum theory. W…

Sven Jandura and Guido Pupillo,

Quantum 6, 712 (2022).

We identify time-optimal laser pulses to implement the controlled-Z gate and its three qubit generalization, the C$_2$Z gate, for Rydberg atoms in the blockade regime. Pulses are optimized usi…

Trevor Vincent, Lee J. O’Riordan, Mikhail Andrenkov, Jack Brown, Nathan Killoran, Haoyu Qi, and Ish Dhand,

Quantum 6, 709 (2022).

We introduce a new open-source software library $Jet$, which uses task-based parallelism to obtain speed-ups in classical tensor-network simulations of quantum circuits. These speed-ups result…

Paul Appel, Alexander J. Heilman, Ezekiel W. Wertz, David W. Lyons, Marcus Huber, Matej Pivoluska, and Giuseppe Vitagliano,

Quantum 6, 708 (2022).

We introduce finite-function-encoding (FFE) states which encode arbitrary $d$-valued logic functions, i.e., multivariate functions over the ring of integers modulo $d$, and investigate some of t…

Charles H. Baldwin, Karl Mayer, Natalie C. Brown, Ciarán Ryan-Anderson, and David Hayes,

Quantum 6, 707 (2022).

The quantum volume test is a full-system benchmark for quantum computers that is sensitive to qubit number, fidelity, connectivity, and other quantities believed to be important in building…

Gian Giacomo Guerreschi,

Quantum 6, 706 (2022).

Classical simulators play a major role in the development and benchmark of quantum algorithms and practically any software framework for quantum computation provides the option of running th…

Jonas Glatthard and Luis A. Correa,

Quantum 6, 705 (2022).

There exist severe limitations on the accuracy of low-temperature thermometry, which poses a major challenge for future quantum-technological applications. Low-temperature sensitivity might…

Kun Zhang, Jietai Jing, Nicolas Treps, and Mattia Walschaers,

Quantum 6, 704 (2022).

Entanglement is an indispensable quantum resource for quantum information technology. In continuous-variable quantum optics, photon subtraction can increase the entanglement between Gaussian…

Torsten V. Zache, Christian Kokail, Bhuvanesh Sundar, and Peter Zoller,

Quantum 6, 702 (2022).

Topological phases are characterized by their entanglement properties, which is manifest in a direct relation between entanglement spectra and edge states discovered by Li and Haldane. We pr…

Meenu Kumari and Álvaro M. Alhambra,

Quantum 6, 701 (2022).

The average entanglement entropy (EE) of the energy eigenstates in non-vanishing partitions has been recently proposed as a diagnostic of integrability in quantum many-body systems. For it t…

Karol Gietka, Lewis Ruks, and Thomas Busch,

Quantum 6, 700 (2022).

We carefully examine critical metrology and present an improved critical quantum metrology protocol which relies on quenching a system exhibiting a superradiant quantum phase transition beyo…

Basudha Srivastava, Anton Frisk Kockum, and Mats Granath,

Quantum 6, 698 (2022).

We consider a topological stabilizer code on a honeycomb grid, the "XYZ$^2$" code. The code is inspired by the Kitaev honeycomb model and is a simple realization of a "matching code" discussed…

Stanislaw Kurdzialek,

Quantum 6, 697 (2022).

Photon losses are intrinsic for any translationally invariant optical imaging system with a non-trivial Point Spread Function, and the relation between the transmission factor and the cohere…

Eric C. Peterson, Lev S. Bishop, and Ali Javadi-Abhari,

Quantum 6, 696 (2022).

We describe an optimal procedure, as well as its efficient software implementation, for exact and approximate synthesis of two-qubit unitary operations into any prescribed discrete family of…

Hayata Yamasaki, Simon Morelli, Markus Miethlinger, Jessica Bavaresco, Nicolai Friis, and Marcus Huber,

Quantum 6, 695 (2022).

Entanglement shared among multiple parties presents complex challenges for the characterisation of different types of entanglement. One of the most fundamental insights is the fact that some…

Artur Slobodeniuk, Tomáš Novotný, and Radim Filip,

Quantum 6, 689 (2022).

Quantum coherence is an essential resource to gain advantage over classical physics and technology. Recently, it has been proposed that a low-temperature environment can induce quantum coher…

Ruho Kondo, Yuki Sato, Satoshi Koide, Seiji Kajita, and Hideki Takamatsu,

Quantum 6, 688 (2022).

Evaluating an expectation value of an arbitrary observable $A\in{\mathbb C}^{2^n\times 2^n}$ through naïve Pauli measurements requires a large number of terms to be evaluated. We approach this…

Jordi R. Weggemans, Alexander Urech, Alexander Rausch, Robert Spreeuw, Richard Boucherie, Florian Schreck, Kareljan Schoutens, Jiří Minář, and Florian Speelman,

Quantum 6, 687 (2022).

We study the correlation clustering problem using the quantum approximate optimization algorithm (QAOA) and qudits, which constitute a natural platform for such non-binary problems. Specific…

Alisa D. Manukhova, Andrey A. Rakhubovsky, and Radim Filip,

Quantum 6, 686 (2022).

Quantum coupling between mechanical oscillators and atomic gases generating entanglement has been recently experimentally demonstrated using their subsequent interaction with light. The next…

Michael J. Kewming and Sally Shrapnel,

Quantum 6, 685 (2022).

Fluctuation theorems allow one to make generalised statements about the behaviour of thermodynamic quantities in systems that are driven far from thermal equilibrium. In this article we use…

Timofey T. Sergeev, Ivan V. Vovcenko, Alexander A. Zyablovsky, and Evgeny S. Andrianov,

Quantum 6, 684 (2022).

Strong coupling regime takes place in open hybrid systems consisting of two or more physical subsystems when the coupling strength between subsystems exceeds the relaxation rate. The relaxat…

Ismael L. Paiva, Augusto C. Lobo, and Eliahu Cohen,

Quantum 6, 683 (2022).

Uncertainty relations play a crucial role in quantum mechanics. Well-defined methods exist for the derivation of such uncertainties for pairs of observables. Other approaches also allow the…

Adrian Parra-Rodriguez and Iñigo L. Egusquiza,

Quantum 6, 681 (2022).

We develop a systematic procedure to quantise canonically Hamiltonians of light-matter models of transmission lines coupled through lumped linear lossless ideal nonreciprocal elements, that…

Ian Convy and K. Birgitta Whaley,

Quantum 6, 680 (2022).

We consider the problem of continuous quantum error correction from a Bayesian perspective, proposing a pair of digital filters using logarithmic probabilities that are able to achieve near-…

Marco Túlio Quintino and Daniel Ebler,

Quantum 6, 679 (2022).

This work analyses the performance of quantum circuits and general processes to transform $k$ uses of an arbitrary unitary operation $U$ into another unitary operation $f(U)$. When the desired fun…

David Wierichs, Josh Izaac, Cody Wang, and Cedric Yen-Yu Lin,

Quantum 6, 677 (2022).

Variational quantum algorithms are ubiquitous in applications of noisy intermediate-scale quantum computers. Due to the structure of conventional parametrized quantum gates, the evaluated fu…

Raoul Heese, Patricia Bickert, and Astrid Elisa Niederle,

Quantum 6, 676 (2022).

We propose a quantum representation of binary classification trees with binary features based on a probabilistic approach. By using the quantum computer as a processor for probability distri…

Trevor Keen, Bo Peng, Karol Kowalski, Pavel Lougovski, and Steven Johnston,

Quantum 6, 675 (2022).

The three key elements of a quantum simulation are state preparation, time evolution, and measurement. While the complexity scaling of time evolution and measurements are well known, many st…

Ämin Baumeler, Amin Shiraz Gilani, and Jibran Rashid,

Quantum 6, 673 (2022).

Non-causal correlations certify the lack of a definite causal order among localized space-time regions. In stark contrast to scenarios where a single region influences its own causal past, s…

Patrik Caspar, Enky Oudot, Pavel Sekatski, Nicolas Maring, Anthony Martin, Nicolas Sangouard, Hugo Zbinden, and Rob Thew,

Quantum 6, 671 (2022).

How can a multipartite single-photon path-entangled state be certified efficiently by means of local measurements? We address this question by constructing an entanglement witness based on l…

Kirill Plekhanov, Matthias Rosenkranz, Mattia Fiorentini, and Michael Lubasch,

Quantum 6, 670 (2022).

We propose to perform amplitude estimation with the help of constant-depth quantum circuits that variationally approximate states during amplitude amplification. In the context of Monte Carl…

Jia-Wei Ji, Yu-Feng Wu, Stephen C. Wein, Faezeh Kimiaee Asadi, Roohollah Ghobadi, and Christoph Simon,

Quantum 6, 669 (2022).

We propose a quantum repeater architecture that can operate under ambient conditions. Our proposal builds on recent progress towards non-cryogenic spin-photon interfaces based on nitrogen-va…

Benjamin Desef and Martin B. Plenio,

Quantum 6, 667 (2022).

Quantum error correcting codes (QECCs) are the means of choice whenever quantum systems suffer errors, e.g., due to imperfect devices, environments, or faulty channels. By now, a plethora of…

Jisho Miyazaki and Keiji Matsumoto,

Quantum 6, 665 (2022).

Multiparameter quantum estimation is made difficult by the following three obstacles. First, incompatibility among different physical quantities poses a limit on the attainable precision. Se…

Mohammadsadegh Khazali,

Quantum 6, 664 (2022).

This article proposes the first discrete-time implementation of Rydberg quantum walk in multi-dimensional spatial space that could ideally simulate different classes of topological insulator…

Fabio Costa,

Quantum 6, 663 (2022).

The causal order of events need not be fixed: whether a bus arrives before or after another at a certain stop can depend on other variables – like traffic. Coherent quantum control of causal…

Jitendra K. Verma, Lukáš Lachman, and Radim Filip,

Quantum 6, 660 (2022).

Many applications in quantum communication, sensing and computation need provably quantum non-Gaussian light. Recently such light, witnessed by a negative Wigner function, has been estimated…

William F. Braasch Jr. and William K. Wootters,

Quantum 6, 659 (2022).

Spekkens has introduced an $\textit{epistemically restricted classical theory}$ of discrete systems, based on discrete phase space. The theory manifests a number of quantum-like properties but…

Gael Sentís, Esteban Martínez-Vargas, and Ramon Muñoz-Tapia,

Quantum 6, 658 (2022).

We consider online strategies for discriminating between symmetric pure states with zero error when $n$ copies of the states are provided. Optimized online strategies involve local, possibly a…

Jinzhao Wang,

Quantum 6, 655 (2022).

Information-theoretic ideas have provided numerous insights in the progress of fundamental physics, especially in our pursuit of quantum gravity. In particular, the holographic entanglement…

Ray Ganardi, Marek Miller, Tomasz Paterek, and Marek Żukowski,

Quantum 6, 654 (2022).

Quantum systems generally exhibit different kinds of correlations. In order to compare them on equal footing, one uses the so-called distance-based approach where different types of correlat…

Yujie Zhang, Xinan Chen, and Eric Chitambar,

Quantum 6, 653 (2022).

A multiple access channel describes a situation in which multiple senders are trying to forward messages to a single receiver using some physical medium. In this paper we consider scenarios…

Matteo Fadel and Manuel Gessner,

Quantum 6, 651 (2022).

Steering criteria are conditions whose violation excludes the possibility of describing the observed measurement statistics with local hidden state (LHS) models. When the available data do n…

Andreas Bluhm, Ángela Capel, and Antonio Pérez-Hernández,

Quantum 6, 650 (2022).

The thermal equilibrium properties of physical systems can be described using Gibbs states. It is therefore of great interest to know when such states allow for an easy description. In parti…

Fabrizio Minganti and Dolf Huybrechts,

Quantum 6, 649 (2022).

The characterization of open quantum systems is a central and recurring problem for the development of quantum technologies. For time-independent systems, an (often unique) steady state desc…

Jorge Fuenzalida, Armin Hochrainer, Gabriela Barreto Lemos, Evelyn A. Ortega, Radek Lapkiewicz, Mayukh Lahiri, and Anton Zeilinger,

Quantum 6, 646 (2022).

Quantum imaging with undetected photons is a recently introduced technique that goes significantly beyond what was previously possible. In this technique, images are formed without detecting…

Saúl Pilatowsky-Cameo, David Villaseñor, Miguel A. Bastarrachea-Magnani, Sergio Lerma-Hernández, Lea F. Santos, and Jorge G. Hirsch,

Quantum 6, 644 (2022).

There is no unique way to quantify the degree of delocalization of quantum states in unbounded continuous spaces. In this work, we explore a recently introduced localization measure that qua…

Alexander Jahn, Zoltán Zimborás, and Jens Eisert,

Quantum 6, 643 (2022).

The study of critical quantum many-body systems through conformal field theory (CFT) is one of the pillars of modern quantum physics. Certain CFTs are also understood to be dual to higher-di…

Qiang Miao and Thomas Barthel,

Quantum 6, 642 (2022).

With increasing subsystem size and energy, bipartite entanglement entropies of energy eigenstates cross over from the groundstate scaling to a volume law. In previous work, we pointed out th…

Mahathi Vempati, Saumya Shah, Nirman Ganguly, and Indranil Chakrabarty,

Quantum 6, 641 (2022).

Negative quantum conditional entropy states are key ingredients for information theoretic tasks such as superdense coding, state merging and one-way entanglement distillation. In this work,…

Fei Zhuang, Junkai Zeng, Sophia E. Economou, and Edwin Barnes,

Quantum 6, 639 (2022).

Landau-Zener physics is often exploited to generate quantum logic gates and to perform state initialization and readout. The quality of these operations can be degraded by noise fluctuations…

Piotr Sierant, Giuliano Chiriacò, Federica M. Surace, Shraddha Sharma, Xhek Turkeshi, Marcello Dalmonte, Rosario Fazio, and Guido Pagano,

Quantum 6, 638 (2022).

Quantum systems evolving unitarily and subject to quantum measurements exhibit various types of non-equilibrium phase transitions, arising from the competition between unitary evolution and…

Richard Meister, Simon C. Benjamin, and Earl T. Campbell,

Quantum 6, 637 (2022).

A highly anticipated use of quantum computers is the simulation of complex quantum systems including molecules and other many-body systems. One promising method involves directly applying a…

Roberto D. Baldijao, Marius Krumm, Andrew J. P. Garner, and Markus P. Mueller,

Quantum 6, 636 (2022).

Quantum Darwinism posits that the emergence of a classical reality relies on the spreading of classical information from a quantum system to many parts of its environment. But what are the e…

Jonathan Wurtz and Peter J. Love,

Quantum 6, 635 (2022).

The quantum approximate optimization algorithm (QAOA) is a near-term hybrid algorithm intended to solve combinatorial optimization problems, such as MaxCut. QAOA can be made to mimic an adia…

Sarah Brandsen, Kevin D. Stubbs, and Henry D. Pfister,

Quantum 6, 633 (2022).

Reinforcement learning with neural networks (RLNN) has recently demonstrated great promise for many problems, including some problems in quantum information theory. In this work, we apply RL…

Ryotaro Suzuki, Kosuke Mitarai, and Keisuke Fujii,

Quantum 6, 631 (2022).

Quantum circuits that are classically simulatable tell us when quantum computation becomes less powerful than or equivalent to classical computation. Such classically simulatable circuits ar…

Boxi Li, Shahnawaz Ahmed, Sidhant Saraogi, Neill Lambert, Franco Nori, Alexander Pitchford, and Nathan Shammah,

Quantum 6, 630 (2022).

The study of the impact of noise on quantum circuits is especially relevant to guide the progress of Noisy Intermediate-Scale Quantum (NISQ) computing. In this paper, we address the pulse-le…

Tyson Jones and Simon C. Benjamin,

Quantum 6, 628 (2022).

We explore a method for automatically recompiling a quantum circuit $\mathcal{A}$ into a target circuit $\mathcal{B}$, with the goal that both circuits have the same action on a specific input i…

Irene López Gutiérrez and Christian B. Mendl,

Quantum 6, 627 (2022).

A promising application of neural-network quantum states is to describe the time dynamics of many-body quantum systems. To realize this idea, we employ neural-network quantum states to appro…

Alicia B. Magann, Gerard McCaul, Herschel A. Rabitz, and Denys I. Bondar,

Quantum 6, 626 (2022).

The characterization of mixtures of non-interacting, spectroscopically similar quantum components has important applications in chemistry, biology, and materials science. We introduce an app…

Fernando G.S L. Brandão, Richard Kueng, and Daniel Stilck França,

Quantum 6, 625 (2022).

We give a quantum speedup for solving the canonical semidefinite programming relaxation for binary quadratic optimization. This class of relaxations for combinatorial optimization has so far…

Bernhard Irsigler and Tobias Grass,

Quantum 6, 624 (2022).

Quenching and annealing are extreme opposites in the time evolution of a quantum system: Annealing explores equilibrium phases of a Hamiltonian with slowly changing parameters and can be exp…

Lucas B. Vieira and Costantino Budroni,

Quantum 6, 623 (2022).

We investigate temporal correlations in the simplest measurement scenario, i.e., that of a physical system on which the same measurement is performed at different times, producing a sequence…

Giulia Rubino, Lee A. Rozema, Francesco Massa, Mateus Araújo, Magdalena Zych, Časlav Brukner, and Philip Walther,

Quantum 6, 621 (2022).

The study of causal relations has recently been applied to the quantum realm, leading to the discovery that not all physical processes have a definite causal structure. While indefinite caus…

Fei Shi, Mao-Sheng Li, Mengyao Hu, Lin Chen, Man-Hong Yung, Yan-Ling Wang, and Xiande Zhang,

Quantum 6, 619 (2022).

A set of multipartite orthogonal product states is locally irreducible, if it is not possible to eliminate one or more states from the set by orthogonality-preserving local measurements. An…

Davide Vodola, Manuel Rispler, Seyong Kim, and Markus Müller,

Quantum 6, 618 (2022).

Mapping the decoding of quantum error correcting (QEC) codes to classical disordered statistical mechanics models allows one to determine critical error thresholds of QEC codes under phenome…

David Plankensteiner, Christoph Hotter, and Helmut Ritsch,

Quantum 6, 617 (2022).

A full quantum mechanical treatment of open quantum systems via a Master equation is often limited by the size of the underlying Hilbert space. As an alternative, the dynamics can also be fo…

Marco Merkli,

Quantum 6, 615 (2022).

We develop a framework to analyze the dynamics of a finite-dimensional quantum system $\rm S$ in contact with a reservoir $\rm R$. The full, interacting $\rm SR$ dynamics is unitary. The reservoir…

Ignatius William Primaatmaja, Cassey Crystania Liang, Gong Zhang, Jing Yan Haw, Chao Wang, and Charles Ci-Wen Lim,

Quantum 6, 613 (2022).

Most quantum key distribution (QKD) protocols can be classified as either a discrete-variable (DV) protocol or continuous-variable (CV) protocol, based on how classical information is being…