Quantum Chemistry in the Age of Quantum Computing

Chemical Reviews, Journal Year: 2019, Volume and Issue: 119(19), P. 10856 - 10915

Published: Aug. 30, 2019

Practical challenges in simulating quantum systems on classical computers have been widely recognized the physics and chemistry communities over past century. Although many approximation methods introduced, complexity of mechanics remains hard to appease. The advent computation brings new pathways navigate this challenging complex landscape. By manipulating states matter taking advantage their unique features such as superposition entanglement, promise efficiently deliver accurate results for important problems chemistry, electronic structure molecules. In two decades, significant advances made developing algorithms physical hardware computing, heralding a revolution simulation systems. This Review provides an overview that are relevant chemistry. intended audience is both chemists who seek learn more about computing researchers would like explore applications

Language: Английский

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Noisy intermediate-scale quantum algorithms

Reviews of Modern Physics, Journal Year: 2022, Volume and Issue: 94(1)

Published: Feb. 15, 2022

Noisy quantum computers can in principle perform reliable computations, but truly scalable systems require noise levels lower than are presently achieved. Still, moderate-complexity computations be performed. This review discusses what is possible this ``noisy intermediate scale'' (NISQ) era. Topic areas include the simulation of many-body physics and chemistry, combinatorial optimization, machine learning. It evident that NISQ era has produced new paradigms for programming will built upon as further perfected.

Language: Английский

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Strong Quantum Computational Advantage Using a Superconducting Quantum Processor

Physical Review Letters, Journal Year: 2021, Volume and Issue: 127(18)

Published: Oct. 25, 2021

Scaling up to a large number of qubits with high-precision control is essential in the demonstrations quantum computational advantage exponentially outpace classical hardware and algorithmic improvements. Here, we develop two-dimensional programmable superconducting processor, Zuchongzhi, which composed 66 functional tunable coupling architecture. To characterize performance whole system, perform random circuits sampling for benchmarking, system size 56 20 cycles. The cost simulation this task estimated be 2-3 orders magnitude higher than previous work on 53-qubit Sycamore processor [Nature 574, 505 (2019)NATUAS0028-083610.1038/s41586-019-1666-5. We estimate that finished by Zuchongzhi about 1.2 h will take most powerful supercomputer at least 8 yr. Our establishes an unambiguous infeasible computation reasonable amount time. computing platform opens new door explore novel many-body phenomena implement complex algorithms.

Language: Английский

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An adaptive variational algorithm for exact molecular simulations on a quantum computer

Nature Communications, Journal Year: 2019, Volume and Issue: 10(1)

Published: July 8, 2019

Quantum simulation of chemical systems is one the most promising near-term applications quantum computers. The variational eigensolver, a leading algorithm for molecular simulations on hardware, has serious limitation in that it typically relies pre-selected wavefunction ansatz results approximate wavefunctions and energies. Here we present an arbitrarily accurate instead fixing upfront, this grows systematically operator at time way dictated by molecule being simulated. This generates with small number parameters, to shallow-depth circuits. We numerical simulations, including prototypical strongly correlated molecule, which show our performs much better than unitary coupled cluster approach, terms both circuit depth accuracy. Our highlight potential adaptive exact present-day hardware.

Language: Английский

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The Variational Quantum Eigensolver: A review of methods and best practices

Physics Reports, Journal Year: 2022, Volume and Issue: 986, P. 1 - 128

Published: Sept. 23, 2022

The variational quantum eigensolver (or VQE), first developed by Peruzzo et al. (2014), has received significant attention from the research community in recent years. It uses principle to compute ground state energy of a Hamiltonian, problem that is central chemistry and condensed matter physics. Conventional computing methods are constrained their accuracy due computational limits facing exact modeling exponentially growing electronic wavefunction for these many-electron systems. VQE may be used model complex wavefunctions polynomial time, making it one most promising near-term applications computing. One important advantage algorithms have been shown present some degree resilience noise hardware. Finding path navigate relevant literature rapidly become an overwhelming task, with many improve different parts algorithm, but without clear descriptions how diverse fit together. potential practical advantages algorithm also widely discussed literature, varying conclusions. Despite strong theoretical underpinnings suggesting excellent scaling individual components, studies pointed out various pre-factors could too large reach over conventional methods. This review aims at disentangling provide comprehensive overview progress made on discuss future areas fundamental deliver its promises. All components reviewed detail. These include representation Hamiltonians computer, optimization process find energies, post processing mitigation errors, suggested best practices. We identify four main research: (1) optimal measurement schemes reduction circuit repetitions required; (2) scale parallelization across computers; (3) ways overcome appearance vanishing gradients systems, number iterations required scales system size; (4) extent which suffers noise, whether this can mitigated tractable manner. answers open questions will determine routes achieve as hardware up levels reduced.

Language: Английский

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Noise-induced barren plateaus in variational quantum algorithms

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Nov. 29, 2021

Variational Quantum Algorithms (VQAs) may be a path to quantum advantage on Noisy Intermediate-Scale (NISQ) computers. A natural question is whether noise NISQ devices places fundamental limitations VQA performance. We rigorously prove serious limitation for noisy VQAs, in that the causes training landscape have barren plateau (i.e., vanishing gradient). Specifically, local Pauli considered, we gradient vanishes exponentially number of qubits $n$ if depth ansatz grows linearly with $n$. These noise-induced plateaus (NIBPs) are conceptually different from noise-free plateaus, which linked random parameter initialization. Our result formulated generic includes as special cases Alternating Operator Ansatz and Unitary Coupled Cluster Ansatz, among others. For former, our numerical heuristics demonstrate NIBP phenomenon realistic hardware model.

Language: Английский

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Recent Progress and Future Prospects on All-Organic Polymer Dielectrics for Energy Storage Capacitors

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(3), P. 3820 - 3878

Published: Dec. 23, 2021

With the development of advanced electronic devices and electric power systems, polymer-based dielectric film capacitors with high energy storage capability have become particularly important. Compared polymer nanocomposites widespread attention, all-organic polymers are fundamental been proven to be more effective choices in process scalable, continuous, large-scale industrial production, leading many applications. In past decade, efforts intensified this field great progress newly discovered polymers, production technologies, extension toward emerging computational strategies. This review summarizes recent based on conventional as well heat-resistant materials focus strategies enhance properties performances. The key parameters such constant, loss, breakdown strength, density, charge-discharge efficiency, thoroughly studied. addition, applications computer-aided calculation including density functional theory, machine learning, genome rational design performance prediction dielectrics reviewed detail. Based a comprehensive understanding developments, guidelines prospects for future proposed.

Language: Английский

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Hybrid Quantum-Classical Algorithms and Quantum Error Mitigation

Journal of the Physical Society of Japan, Journal Year: 2021, Volume and Issue: 90(3), P. 032001 - 032001

Published: Feb. 1, 2021

Quantum computers can exploit a Hilbert space whose dimension increases exponentially with the number of qubits. In experiment, quantum supremacy has recently been achieved by Google team using noisy intermediate-scale (NISQ) device over 50 However, question what be implemented on NISQ devices is still not fully explored, and discovering useful tasks for such topic considerable interest. Hybrid quantum-classical algorithms are regarded as well-suited execution combining classical computers, expected to first applications computing. Meanwhile, mitigation errors processors also crucial obtain reliable results. this article, we review basic results hybrid error techniques. Since computing an actively developing field, expect basis future studies.

Language: Английский

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Theory of variational quantum simulation

Quantum, Journal Year: 2019, Volume and Issue: 3, P. 191 - 191

Published: Oct. 7, 2019

The variational method is a versatile tool for classical simulation of variety quantum systems. Great efforts have recently been devoted to its extension computing efficiently solving static many-body problems and simulating real imaginary time dynamics. In this work, we first review the conventional principles, including Rayleigh-Ritz problems, Dirac Frenkel principle, McLachlan's time-dependent We focus on dynamics discuss connections three principles. Previous works mainly unitary evolution pure states. introduce mixed states under general stochastic evolution. show how results can be reduced state case with correction term that takes accounts global phase alignment. For evolution, also extend it scenario Gibbs preparation. further elaborate design ansatz compatible post-selection measurement implementation generalised algorithms circuits. Our work completes theory applicable near-term hardware.

Language: Английский

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Variational quantum algorithms

Nature Reviews Physics, Journal Year: 2021, Volume and Issue: 3(9), P. 625 - 644

Published: Aug. 12, 2021

Language: Английский

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