We benchmark the quantum processing units of largest annealers to date, 5000+ qubit annealer Advantage and its 2000+ predecessor D-Wave 2000Q, using tail assignment exact cover problems from aircraft scheduling scenarios. The set contains small, intermediate, large with both sparsely connected almost fully instances. find that outperforms 2000Q for all problems, a notable increase in success rate problem size. In particular, is also able solve 120 logical qubits cannot anymore. Furthermore,...

Abstract The performance of the quantum approximate optimization algorithm is evaluated by using three different measures: probability finding ground state, energy expectation value, and a ratio closely related to approximation ratio. set problem instances studied consists weighted MaxCut problems 2-satisfiability problems. Ising model representations latter possess unique states highly degenerate first excited states. executed on computer simulators IBM Q Experience. Additionally, data...

A revised version of the massively parallel simulator a universal quantum computer, described in this journal eleven years ago, is used to benchmark various gate-based algorithms on some most powerful supercomputers that exist today. Adaptive encoding wave function reduces memory requirement by factor eight, making it possible simulate computers with up 48 qubits Sunway TaihuLight and K computer. The exhibits close-to-ideal weak-scaling behavior TaihuLight, an IBM Blue Gene/Q, Intel Xeon...

With the advent of public access to small gate-based quantum processors, it becomes necessary develop a benchmarking methodology such that independent researchers can validate operation these processors. We explore usefulness number simple circuits as benchmarks for computing devices and show performing identity operations are very simple, scalable sensitive gate errors therefore well suited this task. illustrate procedure by presenting benchmark results IBM Quantum Experience, cloud-based...

The real-time broadening of density profiles starting from nonequilibrium states is at the center transport in condensed-matter systems and dynamics ultracold atomic gases. Initial close to equilibrium are expected evolve according linear response, e.g., as given by current correlator evaluated exactly equilibrium. Significantly off equilibrium, response break down even a description terms canonical ensembles questionable. We unveil that single pure with maximum amplitude yield perfect...

In the model of gate-based quantum computation, qubits are controlled by a sequence gates. superconducting qubit systems, these gates can be implemented voltage pulses. The success implementing particular gate expressed various metrics such as average fidelity, diamond distance, and unitarity. We analyze pulses for system two transmon coupled resonator, inspired architecture IBM Quantum Experience. obtained numerical solution time-dependent Schr\"odinger equation system. find that reflect...

We study large-scale applications using a GPU-accelerated version of the massively parallel J\"ulich universal quantum computer simulator (JUQCS--G). First, we benchmark JUWELS Booster, GPU cluster with 3744 NVIDIA A100 Tensor Core GPUs. Then, use JUQCS--G to relation between annealing (QA) and approximate optimization algorithm (QAOA). find that very coarsely discretized QA, termed (AQA), performs surprisingly well in comparison QAOA. It can either be used initialize QAOA, or avoid costly...

We study collective plasmon excitations and screening of pure disordered single- bilayer black phosphorus (BP) beyond the low energy continuum approximation. The dynamical polarizability phosphorene is computed using a tight-binding model that properly accounts for band structure in wide range. Electron-electron interaction considered within random phase Damping modes due to different kinds disorder, such as resonant scatterers long-range disorder potentials, analyzed. further show an...

Shor’s factoring algorithm is one of the most anticipated applications quantum computing. However, limited capabilities today’s computers only permit a study for very small numbers. Here, we show how large GPU-based supercomputers can be used to assess performance numbers that are out reach current and near-term hardware. First, original algorithm. While theoretical bounds suggest success probabilities 3–4%, find average above 50%, due high frequency “lucky” cases, defined as successful...

Using a specially constructed set of hard 2-SAT problems with four satisfying assignments, we study the scaling and sampling performance numerical simulation quantum annealing as well that physical annealers offered by D-Wave. To this end, use both standard reverse protocols in our simulations on D-Wave annealer. In case ideal behavior can be explained perturbation theory time to solution depends minimum energy gap between ground state first excited Hamiltonian. The corresponding results...

D-Wave quantum annealers offer reverse annealing as a feature allowing them to refine solutions optimization problems. This paper investigates the influence of key parameters, such times and reversal distance, on behavior by studying models containing up 1000 qubits. Through analysis theoretical experimental data, we explore interplay between classical processes. Our findings provide deeper understanding that can better equip users fully harness potential

We have developed a fully microscopic theory of magnetic properties the prototype molecular magnet ${\mathrm{Mn}}_{12}$. First, intramolecular been studied by means first-principles density functional based methods, with local correlation effects being taken into account within approximation plus $U$ $(\text{LDA}+U)$ approach. Using force theorem, we calculated interatomic isotropic and anisotropic exchange interactions full tensors single-ion anisotropy for each Mn ion....

We present a comprehensive comparison of spin and energy dynamics in quantum classical models on different geometries, ranging from one-dimensional chains, over quasi-one-dimensional ladders, to two-dimensional square lattices. Focusing at formally infinite temperature, we particularly consider the autocorrelation functions local densities, where time evolution is governed either by linear Schr\"odinger equation case, or nonlinear Hamiltonian equations motion case mechanics. While, full...

The variational quantum eigensolver (VQE) is a hybrid classical algorithm designed for current and near-term devices. Despite its initial success, there lack of understanding involving several key aspects. There are problems with VQE that forbid favorable scaling towards advantage. In order to alleviate the problems, we propose extensively test annealing inspired heuristic supplements VQE. improved enables an efficient state-preparation mechanism, in recursive manner, quasidynamical unitary...

The analysis of empirical data through model-free inequalities leads to the conclusion that violations Bell-type by cannot have any significance unless one believes universe operates according rules a mathematical model.

A corpuscular simulation model of optical phenomena that does not require the knowledge solution a wave equation whole system and reproduces results Maxwell's theory by generating detection events one-by-one is presented.The event-based shown to give unified description multiple-beam fringes plane parallel plate, singlephoton Mach-Zehnder interferometer, Wheeler's delayed choice, photon tunneling, quantum erasers, two-beam interference, double-slit, Einstein-Podolsky-Rosen-Bohm Hanbury...

Data sets produced by three different Einstein-Podolsky-Rosen-Bohm (EPRB) experiments are tested against the hypothesis that statistics of this data is described quantum theory. Although these generate violate Bell inequalities for suitable choices time-coincidence window, analysis shows it highly unlikely compatible with theoretical description EPRB experiment, suggesting popular statements agree theory lack a solid scientific basis and more precise called for.

Given a quantum many-body system and the expectation-value dynamics of some operator, we study how this reference is altered due to perturbation system's Hamiltonian. Based on projection operator techniques, unveil that if exhibits random-matrix structure in eigenbasis unperturbed Hamiltonian, then effectively leads an exponential damping original dynamics. Employing combination dynamical typicality numerical linked cluster expansions, demonstrate our theoretical findings for random matrices...

We take the point of view that building a one-way bridge from experimental data to mathematical models instead other way around avoids running into controversies resulting attaching meaning symbols used in latter. In particular, we show adopting this offers new perspectives for constructing and interpreting results Einstein-Podolsky-Rosen-Bohm experiments. first prove Bell-type inequalities constraining values four correlations obtained by performing experiments under different conditions....

Data produced by laboratory Einstein-Podolsky-Rosen-Bohm (EPRB) experiments is tested against the hypothesis that statistics of this data given quantum theory thought experiment. Statistical evidence presented experimental data, while violating Bell inequalities, does not support hypothesis. It shown an event-based simulation model, providing a cause-and-effect description real EPRB at level detail which covered theory, reproduces results experiment, indicating there no fundamental obstacle...

Understanding (i) the emergence of diffusion from truly microscopic principles continues to be a major challenge in experimental and theoretical physics. At same time, isolated quantum many-body systems have experienced an upsurge interest recent years. Since such realization proper initial state is only possibility induce nonequilibrium process, understanding (ii) largely unexplored role specific vitally important. Our work reports substantial step forward tackles two issues context...

We study the charge conductivity of one-dimensional repulsive Hubbard model at finite temperature using method dynamical quantum typicality, focusing half filling. This numerical approach allows us to obtain current autocorrelation functions from systems with as many 18 sites, way beyond range standard exact diagonalization. Our data clearly suggest that Drude weight vanishes a power law function system size. The low-frequency dependence is consistent dc value and thus diffusion, despite...

We extensively test a recent protocol to demonstrate quantum fault tolerance on three systems: (1) real-time simulation of five spin qubits coupled an environment with two-level defects, (2) transmon computers, and (3) the 16-qubit processor IBM Q Experience. In simulations, dynamics full system is obtained by numerically solving time-dependent Schr\"odinger equation. find that fault-tolerant scheme provides systematic way improve results when errors are dominated inherent control...

We study the time evolution of reduced density matrix a system spin-1/2 particles interacting with an environment particles. The initial state composite is taken to be product pure and environment. latter prepared such that it represents at given finite temperature in canonical ensemble. evolves according time-dependent Schrödinger equation, interaction creating entanglement between It shown independent strength environment, all eigenvalues converge their stationary values, implying also...