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Network quantum steering enables randomness certification without seed randomness Quantum (IF 5.1) Pub Date : 2024-07-19 Shubhayan Sarkar
Quantum networks with multiple sources allow the observation of quantum nonlocality without inputs. Consequently, the incompatibility of measurements is not a necessity for observing quantum nonlocality when one has access to multiple quantum sources. Here we investigate the minimal scenario without inputs where one can observe any form of quantum nonlocality. We show that even two parties with two
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Characterising transformations between quantum objects, ‘completeness’ of quantum properties, and transformations without a fixed causal order Quantum (IF 5.1) Pub Date : 2024-07-17 Simon Milz, Marco Túlio Quintino
Many fundamental and key objects in quantum mechanics are linear mappings between particular affine/linear spaces. This structure includes basic quantum elements such as states, measurements, channels, instruments, non-signalling channels and channels with memory, and also higher-order operations such as superchannels, quantum combs, n-time processes, testers, and process matrices which may not respect
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A graph-based formalism for surface codes and twists Quantum (IF 5.1) Pub Date : 2024-07-18 Rahul Sarkar, Theodore J. Yoder
Twist defects in surface codes can be used to encode more logical qubits, improve the code rate, and implement logical gates. In this work we provide a rigorous formalism for constructing surface codes with twists generalizing the well-defined homological formalism introduced by Kitaev for describing CSS surface codes. In particular, we associate a surface code to $any$ graph $G$ embedded on $any$
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Deep learning of many-body observables and quantum information scrambling Quantum (IF 5.1) Pub Date : 2024-07-18 Naeimeh Mohseni, Junheng Shi, Tim Byrnes, Michael J. Hartmann
Machine learning has shown significant breakthroughs in quantum science, where in particular deep neural networks exhibited remarkable power in modeling quantum many-body systems. Here, we explore how the capacity of data-driven deep neural networks in learning the dynamics of physical observables is correlated with the scrambling of quantum information. We train a neural network to find a mapping
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Security of discrete-modulated continuous-variable quantum key distribution Quantum (IF 5.1) Pub Date : 2024-07-18 Stefan Bäuml, Carlos Pascual-García, Victoria Wright, Omar Fawzi, Antonio Acín
Continuous variable quantum key distribution with discrete modulation has the potential to provide information-theoretic security using widely available optical elements and existing telecom infrastructure. While their implementation is significantly simpler than that for protocols based on Gaussian modulation, proving their finite-size security against coherent attacks poses a challenge. In this work
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Mixed-State Quantum Spin Liquids and Dynamical Anyon Condensations in Kitaev Lindbladians Quantum (IF 5.1) Pub Date : 2024-07-17 Kyusung Hwang
Quantum spin liquids and anyons, used to be subjects of condensed matter physics, now are realized in various platforms of qubits, offering unprecedented opportunities to investigate fundamental physics of many-body quantum entangled states. Qubits are inevitably exposed to environment effects such as decoherence and dissipation, which are believed to be detrimental to many-body entanglement. Here
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Critical behaviors of non-stabilizerness in quantum spin chains Quantum (IF 5.1) Pub Date : 2024-07-17 Poetri Sonya Tarabunga
Non-stabilizerness – commonly known as magic – measures the extent to which a quantum state deviates from stabilizer states and is a fundamental resource for achieving universal quantum computation. In this work, we investigate the behavior of non-stabilizerness around criticality in quantum spin chains. To quantify non-stabilizerness, we employ a monotone called mana, based on the negativity of the
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Entropic distinguishability of quantum fields in phase space Quantum (IF 5.1) Pub Date : 2024-07-17 Sara Ditsch, Tobias Haas
We present a general way of quantifying the entropic uncertainty of quantum field configurations in phase space in terms of entropic distinguishability with respect to the vacuum. Our approach is based on the functional Husimi $Q$-distribution and a suitably chosen relative entropy, which we show to be non-trivially bounded from above by the uncertainty principle. The resulting relative entropic uncertainty
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Complexity of Digital Quantum Simulation in the Low-Energy Subspace: Applications and a Lower Bound Quantum (IF 5.1) Pub Date : 2024-07-15 Weiyuan Gong, Shuo Zhou, Tongyang Li
Digital quantum simulation has broad applications in approximating unitary evolution of Hamiltonians. In practice, many simulation tasks for quantum systems focus on quantum states in the low-energy subspace instead of the entire Hilbert space. In this paper, we systematically investigate the complexity of digital quantum simulation based on product formulas in the low-energy subspace. We show that
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Efficiently improving the performance of noisy quantum computers Quantum (IF 5.1) Pub Date : 2024-07-15 Samuele Ferracin, Akel Hashim, Jean-Loup Ville, Ravi Naik, Arnaud Carignan-Dugas, Hammam Qassim, Alexis Morvan, David I. Santiago, Irfan Siddiqi, Joel J. Wallman
Using near-term quantum computers to achieve a quantum advantage requires efficient strategies to improve the performance of the noisy quantum devices presently available. We develop and experimentally validate two efficient error mitigation protocols named ``Noiseless Output Extrapolation" and ``Pauli Error Cancellation" that can drastically enhance the performance of quantum circuits composed of
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Thermal masses and trapped-ion quantum spin models: a self-consistent approach to Yukawa-type interactions in the $λ\!ϕ^4$ model Quantum (IF 5.1) Pub Date : 2024-07-15 Pablo Viñas Martínez, Esperanza López, Alejandro Bermudez
The quantum simulation of magnetism in trapped-ion systems makes use of the crystal vibrations to mediate pairwise interactions between spins, which are encoded in the internal electronic states of the ions, and measured in experiments that probe the real-time dynamics. These interactions can be accounted for by a long-wavelength relativistic theory, where the phonons are described by a coarse-grained
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Quantum-embeddable stochastic matrices Quantum (IF 5.1) Pub Date : 2024-07-10 Fereshte Shahbeigi, Christopher T. Chubb, Ryszard Kukulski, Łukasz Pawela, Kamil Korzekwa
The classical embeddability problem asks whether a given stochastic matrix $T$, describing transition probabilities of a $d$-level system, can arise from the underlying homogeneous continuous-time Markov process. Here, we investigate the quantum version of this problem, asking of the existence of a Markovian quantum channel generating state transitions described by a given $T$. More precisely, we aim
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Estimation of high-dimensional unitary transformations saturating the Quantum Cramér-Rao bound Quantum (IF 5.1) Pub Date : 2024-07-10 J. Escandón-Monardes, D. Uzcátegui, M. Rivera-Tapia, S. P. Walborn, A. Delgado
We propose an estimation procedure for $d$-dimensional unitary transformations. For $d\gt2$, the unitary transformations close to the identity are estimated saturating the quantum Cramér-Rao bound. For $d=2$, the estimation of all unitary transformations is also optimal with some prior information. We show through numerical simulations that, even in the absence of prior information, two-dimensional
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Operational Quantum Mereology and Minimal Scrambling Quantum (IF 5.1) Pub Date : 2024-07-11 Paolo Zanardi, Emanuel Dallas, Faidon Andreadakis, Seth Lloyd
In this paper we will attempt to answer the following question: what are the natural quantum subsystems which emerge out of a system's dynamical laws? To answer this question we first define generalized tensor product structures (gTPS) in terms of observables, as dual pairs of an operator subalgebra $\cal A$ and its commutant. Second, we propose an operational criterion of minimal information scrambling
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Simulation-assisted learning of open quantum systems Quantum (IF 5.1) Pub Date : 2024-07-11 Ke Wang, Xiantao Li
Models for open quantum systems, which play important roles in electron transport problems and quantum computing, must take into account the interaction of the quantum system with the surrounding environment. Although such models can be derived in some special cases, in most practical situations, the exact models are unknown and have to be calibrated. This paper presents a learning method to infer
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A proposal to demonstrate non-abelian anyons on a NISQ device Quantum (IF 5.1) Pub Date : 2024-07-11 Jovan Jovanović, Carolin Wille, Daan Timmers, Steven H. Simon
In this work we present a proposal for realising non-Abelian anyons on a NISQ device. In particular we explore the feasibility of implementing the quantum double model $D(D_4)$. We propose techniques to drastically simplify the circuits for the manipulation and measurements of anyons. Numerical simulations with realistic noise models suggest that current NISQ technology is capable of probing signatures
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A new twist on the Majorana surface code: Bosonic and fermionic defects for fault-tolerant quantum computation Quantum (IF 5.1) Pub Date : 2024-07-10 Campbell McLauchlan, Benjamin Béri
Majorana zero modes (MZMs) are promising candidates for topologically-protected quantum computing hardware, however their large-scale use will likely require quantum error correction. Majorana surface codes (MSCs) have been proposed to achieve this. However, many MSC properties remain unexplored. We present a unified framework for MSC "twist defects" $\unicode{x2013}$ anyon-like objects encoding quantum
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Matrix product state approximations to quantum states of low energy variance Quantum (IF 5.1) Pub Date : 2024-07-10 Kshiti Sneh Rai, J. Ignacio Cirac, Álvaro M. Alhambra
We show how to efficiently simulate pure quantum states in one dimensional systems that have both finite energy density and vanishingly small energy fluctuations. We do so by studying the performance of a tensor network algorithm that produces matrix product states whose energy variance decreases as the bond dimension increases. Our results imply that variances as small as $\propto 1/\log N$ can be
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Algebra of Nonlocal Boxes and the Collapse of Communication Complexity Quantum (IF 5.1) Pub Date : 2024-07-10 Pierre Botteron, Anne Broadbent, Reda Chhaibi, Ion Nechita, Clément Pellegrini
Communication complexity quantifies how difficult it is for two distant computers to evaluate a function $f(X,Y)$, where the strings $X$ and $Y$ are distributed to the first and second computer respectively, under the constraint of exchanging as few bits as possible. Surprisingly, some nonlocal boxes, which are resources shared by the two computers, are so powerful that they allow to $collapse$ communication
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Subsystem CSS codes, a tighter stabilizer-to-CSS mapping, and Goursat’s Lemma Quantum (IF 5.1) Pub Date : 2024-07-10 Michael Liaofan Liu, Nathanan Tantivasadakarn, Victor V. Albert
The CSS code construction is a powerful framework used to express features of a quantum code in terms of a pair of underlying classical codes. Its subsystem extension allows for similar expressions, but the general case has not been fully explored. Extending previous work of Aly, Klappenecker, and Sarvepalli [5], we determine subsystem CSS code parameters, express codewords, and develop a Steane-type
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The Gauge Theory of Measurement-Based Quantum Computation Quantum (IF 5.1) Pub Date : 2024-07-04 Gabriel Wong, Robert Raussendorf, Bartlomiej Czech
Measurement-Based Quantum Computation (MBQC) is a model of quantum computation, which uses local measurements instead of unitary gates. Here we explain that the MBQC procedure has a fundamental basis in an underlying gauge theory. This perspective provides a theoretical foundation for global aspects of MBQC. The gauge transformations reflect the freedom of formulating the same MBQC computation in different
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Good Gottesman-Kitaev-Preskill codes from the NTRU cryptosystem Quantum (IF 5.1) Pub Date : 2024-07-04 Jonathan Conrad, Jens Eisert, Jean-Pierre Seifert
We introduce a new class of random Gottesman-Kitaev-Preskill (GKP) codes derived from the cryptanalysis of the so-called NTRU cryptosystem. The derived codes are $good$ in that they exhibit constant rate and average distance scaling $\Delta \propto \sqrt{n}$ with high probability, where $n$ is the number of bosonic modes, which is a distance scaling equivalent to that of a GKP code obtained by concatenating
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Lattice-Based Quantum Advantage from Rotated Measurements Quantum (IF 5.1) Pub Date : 2024-07-04 Yusuf Alnawakhtha, Atul Mantri, Carl A. Miller, Daochen Wang
Trapdoor claw-free functions (TCFs) are immensely valuable in cryptographic interactions between a classical client and a quantum server. Typically, a protocol has the quantum server prepare a superposition of two-bit strings of a claw and then measure it using Pauli-$X$ or $Z$ measurements. In this paper, we demonstrate a new technique that uses the entire range of qubit measurements from the $XY$-plane
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Polynomial Equivalence of Complexity Geometries Quantum (IF 5.1) Pub Date : 2024-07-02 Adam R. Brown
This paper proves the polynomial equivalence of a broad class of definitions of quantum computational complexity. We study right-invariant metrics on the unitary group—often called `complexity geometries' following the definition of quantum complexity proposed by Nielsen—and delineate the equivalence class of metrics that have the same computational power as quantum circuits. Within this universality
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Protecting coherence from the environment via Stark many-body localization in a Quantum-Dot Simulator Quantum (IF 5.1) Pub Date : 2024-07-02 Subhajit Sarkar, Berislav Buča
Semiconductor platforms are emerging as a promising architecture for storing and processing quantum information, e.g., in quantum dot spin qubits. However, charge noise coming from interactions between the electrons is a major limiting factor, along with the scalability of many qubits, for a quantum computer. We show that a magnetic field gradient can be implemented in a semiconductor quantum dot array
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Wigner Analysis of Particle Dynamics and Decoherence in Wide Nonharmonic Potentials Quantum (IF 5.1) Pub Date : 2024-07-02 Andreu Riera-Campeny, Marc Roda-Llordes, Piotr T. Grochowski, Oriol Romero-Isart
We derive an analytical expression of a Wigner function that approximately describes the time evolution of the one-dimensional motion of a particle in a nonharmonic potential. Our method involves two exact frame transformations, accounting for both the classical dynamics of the centroid of the initial state and the rotation and squeezing about that trajectory. Subsequently, we employ two crucial approximations
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Error-corrected Hadamard gate simulated at the circuit level Quantum (IF 5.1) Pub Date : 2024-07-02 György P. Gehér, Campbell McLauchlan, Earl T. Campbell, Alexandra E. Moylett, Ophelia Crawford
We simulate the logical Hadamard gate in the surface code under a circuit-level noise model, compiling it to a physical circuit on square-grid connectivity hardware. Our paper is the first to do this for a logical unitary gate on a quantum error-correction code. We consider two proposals, both via patch-deformation: one that applies a transversal Hadamard gate (i.e. a domain wall through time) to interchange
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On the practical usefulness of the Hardware Efficient Ansatz Quantum (IF 5.1) Pub Date : 2024-07-03 Lorenzo Leone, Salvatore F.E. Oliviero, Lukasz Cincio, M. Cerezo
Variational Quantum Algorithms (VQAs) and Quantum Machine Learning (QML) models train a parametrized quantum circuit to solve a given learning task. The success of these algorithms greatly hinges on appropriately choosing an ansatz for the quantum circuit. Perhaps one of the most famous ansatzes is the one-dimensional layered Hardware Efficient Ansatz (HEA), which seeks to minimize the effect of hardware
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Graph-theoretic insights on the constructability of complex entangled states Quantum (IF 5.1) Pub Date : 2024-07-03 L. Sunil Chandran, Rishikesh Gajjala
The most efficient automated way to construct a large class of quantum photonic experiments is via abstract representation of graphs with certain properties. While new directions were explored using Artificial intelligence and SAT solvers to find such graphs, it becomes computationally infeasible to do so as the size of the graph increases. So, we take an analytical approach and introduce the technique
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Relating non-local quantum computation to information theoretic cryptography Quantum (IF 5.1) Pub Date : 2024-06-27 Rene Allerstorfer, Harry Buhrman, Alex May, Florian Speelman, Philip Verduyn Lunel
Non-local quantum computation (NLQC) is a cheating strategy for position-verification schemes, and has appeared in the context of the AdS/CFT correspondence. Here, we connect NLQC to the wider context of information theoretic cryptography by relating it to a number of other cryptographic primitives. We show one special case of NLQC, known as $f$-routing, is equivalent to the quantum analogue of the
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Bayesian Optimization for Robust State Preparation in Quantum Many-Body Systems Quantum (IF 5.1) Pub Date : 2024-06-27 Tizian Blatz, Joyce Kwan, Julian Léonard, Annabelle Bohrdt
New generations of ultracold-atom experiments are continually raising the demand for efficient solutions to optimal control problems. Here, we apply Bayesian optimization to improve a state-preparation protocol recently implemented in an ultracold-atom system to realize a two-particle fractional quantum Hall state. Compared to manual ramp design, we demonstrate the superior performance of our optimization
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Efficient Quantum Algorithm for Filtering Product States Quantum (IF 5.1) Pub Date : 2024-06-27 Reinis Irmejs, Mari Carmen Bañuls, J. Ignacio Cirac
We introduce a quantum algorithm to efficiently prepare states with a small energy variance at the target energy. We achieve it by filtering a product state at the given energy with a Lorentzian filter of width $\delta$. Given a local Hamiltonian on $N$ qubits, we construct a parent Hamiltonian whose ground state corresponds to the filtered product state with variable energy variance proportional to
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Objectivity of classical quantum stochastic processes Quantum (IF 5.1) Pub Date : 2024-06-27 Piotr Szańkowski, Łukasz Cywiński
We investigate what can be concluded about a quantum system when sequential quantum measurements of its observable – a prominent example of the so-called quantum stochastic process – fulfill the Kolmogorov consistency condition and thus appear to an observer as a sampling of a classical trajectory. We identify a set of physical conditions imposed on the system dynamics, that when satisfied, lead to
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Which entropy for general physical theories? Quantum (IF 5.1) Pub Date : 2024-06-25 Paolo Perinotti, Alessandro Tosini, Leonardo Vaglini
We address the problem of quantifying the information content of a source for an arbitrary information theory, where the information content is defined in terms of the asymptotic achievable compression rate. The functions that solve this problem in classical and quantum theory are Shannon's and von Neumann's entropy, respectively. However, in a general information theory there are three different functions
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Reduction of finite sampling noise in quantum neural networks Quantum (IF 5.1) Pub Date : 2024-06-25 David A. Kreplin, Marco Roth
Quantum neural networks (QNNs) use parameterized quantum circuits with data-dependent inputs and generate outputs through the evaluation of expectation values. Calculating these expectation values necessitates repeated circuit evaluations, thus introducing fundamental finite-sampling noise even on error-free quantum computers. We reduce this noise by introducing the variance regularization, a technique
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Synthesizing and multiplexing autonomous quantum coherences Quantum (IF 5.1) Pub Date : 2024-06-25 Artur Slobodeniuk, Tomáš Novotný, Radim Filip
Quantum coherence is a crucial prerequisite for quantum technologies. Therefore, the robust generation, as autonomous as possible, of quantum coherence remains the essential problem for developing this field. We consider a method of synthesizing and multiplexing quantum coherence from spin systems without any direct drives only coupled to bosonic baths. The previous studies in this field have demonstrated
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Quantum chi-squared tomography and mutual information testing Quantum (IF 5.1) Pub Date : 2024-06-20 Steven T. Flammia, Ryan O'Donnell
For quantum state tomography on rank-$r$ dimension-$d$ states, we show that $\widetilde{O}(r^{.5}d^{1.5}/\epsilon) \leq \widetilde{O}(d^2/\epsilon)$ copies suffice for accuracy $\epsilon$ with respect to (Bures) $\chi^2$-divergence, and $\widetilde{O}(rd/\epsilon)$ copies suffice for accuracy $\epsilon$ with respect to quantum relative entropy. The best previous bound was $\widetilde{O}(rd/\epsilon)
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Comparison of Discrete Variable and Continuous Variable Quantum Key Distribution Protocols with Phase Noise in the Thermal-Loss Channel Quantum (IF 5.1) Pub Date : 2024-06-20 Sebastian P. Kish, Patrick J. Gleeson, Angus Walsh, Ping Koy Lam, Syed M. Assad
Discrete-variable (DV) quantum key distribution (QKD) based on single-photon detectors and sources have been successfully deployed for long-range secure key distribution. On the other hand, continuous-variable (CV) quantum key distribution (QKD) based on coherent detectors and sources is currently lagging behind in terms of loss and noise tolerance. An important discerning factor between DV-QKD and
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Quantum Computed Green’s Functions using a Cumulant Expansion of the Lanczos Method Quantum (IF 5.1) Pub Date : 2024-06-20 Gabriel Greene-Diniz, David Zsolt Manrique, Kentaro Yamamoto, Evgeny Plekhanov, Nathan Fitzpatrick, Michal Krompiec, Rei Sakuma, David Muñoz Ramo
In this paper, we present a quantum computational method to calculate the many-body Green's function matrix in a spin orbital basis. We apply our approach to finite-sized fermionic Hubbard models and related impurity models within Dynamical Mean Field Theory, and demonstrate the calculation of Green's functions on Quantinuum's H1-1 trapped-ion quantum computer. Our approach involves a cumulant expansion
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A distribution testing oracle separation between QMA and QCMA Quantum (IF 5.1) Pub Date : 2024-06-17 Anand Natarajan, Chinmay Nirkhe
It is a long-standing open question in quantum complexity theory whether the definition of $non-deterministic$ quantum computation requires quantum witnesses (QMA) or if classical witnesses suffice (QCMA). We make progress on this question by constructing a randomized classical oracle separating the respective computational complexity classes. Previous separations [3], [13] required a quantum unitary
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BosonSampling.jl: A Julia package for quantum multi-photon interferometry Quantum (IF 5.1) Pub Date : 2024-06-18 Benoit Seron, Antoine Restivo
We present a free open source package for high performance simulation and numerical investigation of boson samplers and, more generally, multi-photon interferometry. Our package is written in Julia, allowing C-like performance with easy notations and fast, high-level coding. Underlying building blocks can easily be modified without complicated low-level language modifications. We present a great variety
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Unifying flavors of fault tolerance with the ZX calculus Quantum (IF 5.1) Pub Date : 2024-06-18 Hector Bombin, Daniel Litinski, Naomi Nickerson, Fernando Pastawski, Sam Roberts
There are several models of quantum computation which exhibit shared fundamental fault-tolerance properties. This article makes commonalities explicit by presenting these different models in a unifying framework based on the ZX calculus. We focus on models of topological fault tolerance – specifically surface codes – including circuit-based, measurement-based and fusion-based quantum computation, as
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Quantum Merkle Trees Quantum (IF 5.1) Pub Date : 2024-06-18 Lijie Chen, Ramis Movassagh
Committing to information is a central task in cryptography, where a party (typically called a prover) stores a piece of information (e.g., a bit string) with the promise of not changing it. This information can be accessed by another party (typically called the verifier), who can later learn the information and verify that it was not meddled with. Merkle trees [1] are a well-known construction for
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Sample-optimal classical shadows for pure states Quantum (IF 5.1) Pub Date : 2024-06-17 Daniel Grier, Hakop Pashayan, Luke Schaeffer
We consider the classical shadows task for pure states in the setting of both joint and independent measurements. The task is to measure few copies of an unknown pure state $\rho$ in order to learn a classical description which suffices to later estimate expectation values of observables. Specifically, the goal is to approximate $\mathrm{Tr}(O \rho)$ for any Hermitian observable $O$ to within additive
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Variational Quantum Algorithms for Semidefinite Programming Quantum (IF 5.1) Pub Date : 2024-06-17 Dhrumil Patel, Patrick J. Coles, Mark M. Wilde
A semidefinite program (SDP) is a particular kind of convex optimization problem with applications in operations research, combinatorial optimization, quantum information science, and beyond. In this work, we propose variational quantum algorithms for approximately solving SDPs. For one class of SDPs, we provide a rigorous analysis of their convergence to approximate locally optimal solutions, under
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Trading T gates for dirty qubits in state preparation and unitary synthesis Quantum (IF 5.1) Pub Date : 2024-06-17 Guang Hao Low, Vadym Kliuchnikov, Luke Schaeffer
Efficient synthesis of arbitrary quantum states and unitaries from a universal fault-tolerant gate-set e.g. Clifford+T is a key subroutine in quantum computation. As large quantum algorithms feature many qubits that encode coherent quantum information but remain idle for parts of the computation, these should be used if it minimizes overall gate counts, especially that of the expensive T-gates. We
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Improving social welfare in non-cooperative games with different types of quantum resources Quantum (IF 5.1) Pub Date : 2024-06-17 Alastair A. Abbott, Mehdi Mhalla, Pierre Pocreau
We investigate what quantum advantages can be obtained in multipartite non-cooperative games by studying how different types of quantum resources can lead to new Nash equilibria and improve social welfare — a measure of the quality of an equilibrium. Two different quantum settings are analysed: a first, in which players are given direct access to an entangled quantum state, and a second, which we introduce
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Quantum algorithm for time-dependent differential equations using Dyson series Quantum (IF 5.1) Pub Date : 2024-06-13 Dominic W. Berry, Pedro C. S. Costa
Time-dependent linear differential equations are a common type of problem that needs to be solved in classical physics. Here we provide a quantum algorithm for solving time-dependent linear differential equations with logarithmic dependence of the complexity on the error and derivative. As usual, there is an exponential improvement over classical approaches in the scaling of the complexity with the
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On Groups in the Qubit Clifford Hierarchy Quantum (IF 5.1) Pub Date : 2024-06-13 Jonas T. Anderson
Here we study the unitary groups that can be constructed using elements from the qubit Clifford Hierarchy. We first provide a necessary and sufficient canonical form that semi-Clifford and generalized semi-Clifford elements must satisfy to be in the Clifford Hierarchy. Then we classify the groups that can be formed from such elements. Up to Clifford conjugation, we classify all such groups that can
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Accelerating Quantum Computations of Chemistry Through Regularized Compressed Double Factorization Quantum (IF 5.1) Pub Date : 2024-06-13 Oumarou Oumarou, Maximilian Scheurer, Robert M. Parrish, Edward G. Hohenstein, Christian Gogolin
We propose the regularized compressed double factorization (RC-DF) method to classically compute compressed representations of molecular Hamiltonians that enable efficient simulation with noisy intermediate scale (NISQ) and error corrected quantum algorithms. We find that already for small systems with 12 to 20 qubits, the resulting NISQ measurement scheme reduces the number of measurement bases by
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Fold-Transversal Clifford Gates for Quantum Codes Quantum (IF 5.1) Pub Date : 2024-06-13 Nikolas P. Breuckmann, Simon Burton
We generalize the concept of folding from surface codes to CSS codes by considering certain dualities within them. In particular, this gives a general method to implement logical operations in suitable LDPC quantum codes using transversal gates and qubit permutations only. To demonstrate our approach, we specifically consider a [[30, 8, 3]] hyperbolic quantum code called Bring's code. Further, we show
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Estimating Coherent Contributions to the Error Profile Using Cycle Error Reconstruction Quantum (IF 5.1) Pub Date : 2024-06-13 Arnaud Carignan-Dugas, Shashank Kumar Ranu, Patrick Dreher
Mitigation and calibration schemes are central to maximize the computational reach of today's Noisy Intermediate Scale Quantum (NISQ) hardware, but these schemes are often specialized to exclusively address either coherent or decoherent error sources. Quantifying the two types of errors hence constitutes a desirable feature when it comes to benchmarking error suppression tools. In this paper, we present
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Complete Characterization of Entanglement Embezzlement Quantum (IF 5.1) Pub Date : 2024-06-13 Elia Zanoni, Thomas Theurer, Gilad Gour
Using local operations and classical communication (LOCC), entanglement can be manipulated but not created. However, entanglement can be $embezzled$. In this work, we completely characterize universal embezzling families and demonstrate how this singles out the original family introduced by van Dam and Hayden. To achieve this, we first give a full characterization of pure to mixed state LOCC-conversions
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TensorKrowch: Smooth integration of tensor networks in machine learning Quantum (IF 5.1) Pub Date : 2024-06-11 José Ramón Pareja Monturiol, David Pérez-García, Alejandro Pozas-Kerstjens
Tensor networks are factorizations of high-dimensional tensors into networks of smaller tensors. They have applications in physics and mathematics, and recently have been proposed as promising machine learning architectures. To ease the integration of tensor networks in machine learning pipelines, we introduce TensorKrowch, an open source Python library built on top of PyTorch. Providing a user-friendly
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Quantum Phase Transitions in periodically quenched systems Quantum (IF 5.1) Pub Date : 2024-06-11 Á. Sáiz, J. Khalouf-Rivera, J. M. Arias, P. Pérez-Fernández, J. Casado-Pascual
Quantum phase transitions encompass a variety of phenomena that occur in quantum systems exhibiting several possible symmetries. Traditionally, these transitions are explored by continuously varying a control parameter that connects two different symmetry configurations. Here we propose an alternative approach where the control parameter undergoes abrupt and time-periodic jumps between only two values
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Schrödinger as a Quantum Programmer: Estimating Entanglement via Steering Quantum (IF 5.1) Pub Date : 2024-06-11 Aby Philip, Soorya Rethinasamy, Vincent Russo, Mark M. Wilde
Quantifying entanglement is an important task by which the resourcefulness of a quantum state can be measured. Here, we develop a quantum algorithm that tests for and quantifies the separability of a general bipartite state by using the quantum steering effect, the latter initially discovered by Schrödinger. Our separability test consists of a distributed quantum computation involving two parties:
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Covariant operator bases for continuous variables Quantum (IF 5.1) Pub Date : 2024-05-29 A. Z. Goldberg, A. B. Klimov, G. Leuchs, L. L. Sanchez-Soto
Coherent-state representations are a standard tool to deal with continuous-variable systems, as they allow one to efficiently visualize quantum states in phase space. Here, we work out an alternative basis consisting of monomials on the basic observables, with the crucial property of behaving well under symplectic transformations. This basis is the analogue of the irreducible tensors widely used in
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Learning t-doped stabilizer states Quantum (IF 5.1) Pub Date : 2024-05-27 Lorenzo Leone, Salvatore F. E. Oliviero, Alioscia Hamma
In this paper, we present a learning algorithm aimed at learning states obtained from computational basis states by Clifford circuits doped with a finite number $t$ of $T$-gates. The algorithm learns an exact tomographic description of $t$-doped stabilizer states in terms of Pauli observables. This is possible because such states are countable and form a discrete set. To tackle the problem, we introduce
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NoRA: A Tensor Network Ansatz for Volume-Law Entangled Equilibrium States of Highly Connected Hamiltonians Quantum (IF 5.1) Pub Date : 2024-05-27 Valérie Bettaque, Brian Swingle
Motivated by the ground state structure of quantum models with all-to-all interactions such as mean-field quantum spin glass models and the Sachdev-Ye-Kitaev (SYK) model, we propose a tensor network architecture which can accomodate volume law entanglement and a large ground state degeneracy. We call this architecture the non-local renormalization ansatz (NoRA) because it can be viewed as a generalization
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Scalable, ab initio protocol for quantum simulating SU($N$)$\times$U(1) Lattice Gauge Theories Quantum (IF 5.1) Pub Date : 2024-05-23 Federica Maria Surace, Pierre Fromholz, Francesco Scazza, Marcello Dalmonte
We propose a protocol for the scalable quantum simulation of SU($N$)$\times$U(1) lattice gauge theories with alkaline-earth like atoms in optical lattices in both one- and two-dimensional systems. The protocol exploits the combination of naturally occurring SU($N$) pseudo-spin symmetry and strong inter-orbital interactions that is unique to such atomic species. A detailed ab initio study of the microscopic