Quantum computer
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Quantum Computing in the NISQ era and beyond Open
Noisy Intermediate-Scale Quantum (NISQ) technology will be available in the near future. Quantum computers with 50-100 qubits may be able to perform tasks which surpass the capabilities of today's classical digital computers, but noise in …
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Quantum sensing Open
"Quantum sensing" describes the use of a quantum system, quantum properties, or quantum phenomena to perform a measurement of a physical quantity. Historical examples of quantum sensors include magnetometers based on superconducting quantu…
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Solving the quantum many-body problem with artificial neural networks Open
Machine learning and quantum physics Elucidating the behavior of quantum interacting systems of many particles remains one of the biggest challenges in physics. Traditional numerical methods often work well, but some of the most interestin…
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The theory of variational hybrid quantum-classical algorithms Open
Many quantum algorithms have daunting resource requirements when compared to what is available today. To address this discrepancy, a quantum-classical hybrid optimization scheme known as 'the quantum variational eigensolver' was developed …
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A quantum engineer's guide to superconducting qubits Open
The aim of this review is to provide quantum engineers with an introductory guide to the central concepts and challenges in the rapidly accelerating field of superconducting quantum circuits. Over the past twenty years, the field has matur…
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Circuit quantum electrodynamics Open
Quantum mechanical effects at the macroscopic level were first explored in\nJosephson junction-based superconducting circuits in the 1980's. In the last\ntwenty years, the emergence of quantum information science has intensified\nresearch …
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Quantum computational chemistry Open
One of the most promising suggested applications of quantum computing is solving classically intractable chemistry problems. This may help to answer unresolved questions about phenomena such as high temperature superconductivity, solid-sta…
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Noisy intermediate-scale quantum algorithms Open
A universal fault-tolerant quantum computer that can efficiently solve problems such as integer factorization and unstructured database search requires millions of qubits with low error rates and long coherence times. While the experimenta…
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Quantum circuit learning Open
We propose a classical-quantum hybrid algorithm for machine learning on\nnear-term quantum processors, which we call quantum circuit learning. A quantum\ncircuit driven by our framework learns a given task by tuning parameters\nimplemented…
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Adiabatic quantum computation Open
Adiabatic quantum computing (AQC) started as an approach to solving optimization problems, and has evolved into an important universal alternative to the standard circuit model of quantum computing, with deep connections to both classical …
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Quantum Machine Learning in Feature Hilbert Spaces Open
A basic idea of quantum computing is surprisingly similar to that of kernel methods in machine learning, namely, to efficiently perform computations in an intractably large Hilbert space. In this Letter we explore some theoretical foundati…
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Error Mitigation for Short-Depth Quantum Circuits Open
Two schemes are presented that mitigate the effect of errors and decoherence in short-depth quantum circuits. The size of the circuits for which these techniques can be applied is limited by the rate at which the errors in the computation …
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Sensitivity optimization for NV-diamond magnetometry Open
Solid-state spin systems including nitrogen-vacancy (NV) centers in diamond constitute an increasingly favored quantum sensing platform. However, present NV ensemble devices exhibit sensitivities orders of magnitude away from theoretical l…
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Strong Quantum Computational Advantage Using a Superconducting Quantum Processor Open
Scaling up to a large number of qubits with high-precision control is essential in the demonstrations of quantum computational advantage to exponentially outpace the classical hardware and algorithmic improvements. Here, we develop a two-d…
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Machine learning & artificial intelligence in the quantum domain: a review of recent progress Open
Quantum information technologies, on the one hand, and intelligent learning systems, on the other, are both emergent technologies that are likely to have a transformative impact on our society in the future. The respective underlying field…
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Evaluating analytic gradients on quantum hardware Open
An important application for near-term quantum computing lies in optimization\ntasks, with applications ranging from quantum chemistry and drug discovery to\nmachine learning. In many settings --- most prominently in so-called\nparametrize…
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Quantum computational advantage with a programmable photonic processor Open
A quantum computer attains computational advantage when outperforming the best classical computers running the best-known algorithms on well-defined tasks. No photonic machine offering programmability over all its quantum gates has demonst…
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Circuit-centric quantum classifiers Open
The current generation of quantum computing technologies call for quantum algorithms that require a limited number of qubits and quantum gates, and which are robust against errors. A suitable design approach are variational circuits where …
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Evidence for the utility of quantum computing before fault tolerance Open
Quantum computing promises to offer substantial speed-ups over its classical counterpart for certain problems. However, the greatest impediment to realizing its full potential is noise that is inherent to these systems. The widely accepted…
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The Variational Quantum Eigensolver: A review of methods and best practices Open
The variational quantum eigensolver (or VQE) uses the variational principle\nto compute the ground state energy of a Hamiltonian, a problem that is central\nto quantum chemistry and condensed matter physics. Conventional computing\nmethods…
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Molecular spins for quantum computation Open
Spins in solids or in molecules possess discrete energy levels, and the associated quantum states can be tuned and coherently manipulated by means of external electromagnetic fields. Spins therefore provide one of the simplest platforms to…
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Logical quantum processor based on reconfigurable atom arrays Open
Suppressing errors is the central challenge for useful quantum computing 1 , requiring quantum error correction (QEC) 2–6 for large-scale processing. However, the overhead in the realization of error-corrected ‘logical’ qubits, in which in…
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An integrated diamond nanophotonics platform for quantum-optical networks Open
Integrated quantum nanophotonics Technologies that exploit the rules of quantum mechanics offer a potential advantage over classical devices in terms of sensitivity. Sipahigil et al. combined the quantum optical features of silicon-vacancy…
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Probing topological spin liquids on a programmable quantum simulator Open
Synthesizing topological order Topologically ordered matter exhibits long-range quantum entanglement. However, measuring this entanglement in real materials is extremely tricky. Now, two groups take a different approach and turn to synthet…
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High-Fidelity Quantum Logic Gates Using Trapped-Ion Hyperfine Qubits Open
We demonstrate laser-driven two-qubit and single-qubit logic gates with respective fidelities 99.9(1)% and 99.9934(3)%, significantly above the ≈99% minimum threshold level required for fault-tolerant quantum computation, using qubits stor…
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Elucidating reaction mechanisms on quantum computers Open
Significance Our work addresses the question of compelling killer applications for quantum computers. Although quantum chemistry is a strong candidate, the lack of details of how quantum computers can be used for specific applications make…
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Optimal Hamiltonian Simulation by Quantum Signal Processing Open
The physics of quantum mechanics is the inspiration for, and underlies, quantum computation. As such, one expects physical intuition to be highly influential in the understanding and design of many quantum algorithms, particularly simulati…
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Quantum random number generators Open
Random numbers are a fundamental resource in science and engineering with\nimportant applications in simulation and cryptography. The inherent randomness\nat the core of quantum mechanics makes quantum systems a perfect source of\nentropy.…
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Engineering Non-Linear Decay Dynamics: Pulse-Level Control and Software-Defined Qubit Rescue on Superconducting Processors Open
The scalability of Noisy Intermediate-Scale Quantum (NISQ) devices is fundamentally constrained by material defects, most notably Two-Level Systems (TLS) that induce resonant decoherence in superconducting qubits. These defects severely li…
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From the Quantum Approximate Optimization Algorithm to a Quantum Alternating Operator Ansatz Open
The next few years will be exciting as prototype universal quantum processors emerge, enabling the implementation of a wider variety of algorithms. Of particular interest are quantum heuristics, which require experimentation on quantum har…