Quantum computational advantage using photons

Abstract

A light approach to quantum advantage Quantum computational advantage or supremacy is a long-anticipated milestone toward practical quantum computers. Recent work claimed to have reached this point, but subsequent work managed to speed up the classical simulation and pointed toward a sample size–dependent loophole. Quantum computational advantage, rather than being a one-shot experimental proof, will be the result of a long-term competition between quantum devices and classical simulation. Zhong et al. sent 50 indistinguishable single-mode squeezed states into a 100-mode ultralow-loss interferometer and sampled the output using 100 high-efficiency single-photon detectors. By obtaining up to 76-photon coincidence, yielding a state space dimension of about 10 30 , they measured a sampling rate that is about 10 14 -fold faster than using state-of-the-art classical simulation strategies and supercomputers. Science , this issue p. 1460

Applying the Hubbard-Stratonovich Transformation to Solve Scheduling Problems Under Inequality Constraints With Quantum Annealing

“…Note here that the power ω j is also normalized to be consistent with SOC ∈ [0, 1]. Lastly (7) guarantees that a bus can only be charged continuously, and not intermittently, at most once during each charging window. Hence, the original EV-bus charging problem Eqs 2-7 is an integer programming problem with inequality constraints.…”

“…In the previous Section 2.3, we have shown that some penalty functions can contain higher-order terms that can not be written into the QUBO objective function, cf. quadratic constraint (7) and the corresponding penalty (11).…”

“…Yet, controlling and manufacturing a quantum computer remains an unsolved challenge, although past decades have witnessed multiple breakthroughs. Despite the recently achieved significant milestones for quantum computing, with quantum supremacy tests being performed (Google's superconducting quantum computer Sycamore [6], photonic quantum computer JiuZhang [7]), it is still a fundamental research question to determine which problems and applications should be solved more efficiently by using quantum computing in place of classical computers; and to what extent. Given the current technological advancement, quantum annealing-a metaheuristic optimization algorithmachieves promising experimental performances in finding near-optimal solutions for some NP-hard optimization problems [8][9][10][11].…”

Quantum Error Mitigation using Symmetry Expansion

“…The ultimate goal of implementing a fully faulttolerant quantum error correction scheme for quantum algorithms with provable speed-up may still be years away. However, the recent rapid advance in quantum computing hardware has enabled certain Zhenyu Cai: cai.zhenyu.physics@gmail.com computational tasks to be performed that are well beyond classical capabilities [1,2], prompting the question of whether it is possible to perform any practically useful tasks with the noisy intermediate-scale quantum (NISQ) devices that we will soon have.…”

Aplicações da dinâmica de portadores de cargas em semicondutores como sistemas quânticos abertos

“…A IBM afirmou em um estudo que o problema proposto pelo Google não demoraria 10 mil anos para ser resolvido em uma máquina comum, mas apenas 2 dias e meio se uma técnica diferente fosse utilizada [11]. Ainda neste contexto, pesquisadores chineses relataram em [12] a criação de um computador quântico fotônico, denominado Jiuzhang, segundo os autores, tal computador leva aproximadamente 3 minutos e meio para realizar uma tarefa específica que levaria, segundo estimativa, em um dos melhores supercomputadores clássicos do mundo, o Sunway TaihuLight, cerca de 2,5 bilhões de anos. Alcançando assim a supremacia quântica.…”