1.
Exploring Many-Body Localization with Multiqubit Superconducting Circuits
王浩华
浙江大学
Here I will review our recent activities on designing and fabricating the multiqubit superconducting circuits featuring different types of connection architectures. In particular, I will introduce a type of superconducting quantum processors featuring multiple individually-accessible Xmon qubits that are controllably coupled to a bus resonator, based on which we observe an energy-resolved many-body localization transition. By initializing the multiqubit state which encodes the total energy of the system and measuring the subsequent time-evolved observables, we find that the onset of localization occurs at different disorder strengths, with distinguishable energy scales. With the flexibility in circuit layout and experimental control, our multiqubit superconducting circuits may provide a promising platform for simulating the intriguing physics of quantum many-body systems.
2.
Near-Term Quantum Simulation and its Applications
袁骁
北京大学前沿计算中心
Realizing a universal quantum computer is challenging with current technology. Before having a fully-fledged quantum computer, a more realistic question is what we can do with current and near-term quantum hardware. In this talk, we first review the algorithms that are designed for noisy-intermediate-scaled-quantum devices with the so-called hybrid or variational approach. Then, we consider three major challenges in implementing these algorithms related to problem encoding, optimization, and error mitigation. We show recent progresses for overcoming these challenges and discuss potential future directions. With the rapid development of quantum hardware, error-mitigated variational quantum simulation may finally enable genuine quantum advantage demonstration in the noisy-intermediate-scaled quantum era.
3.
超导量子计算
朱晓波
中国科学技术大学上海研究院
由于量子计算在某些问题的处理能力上相比于经典计算机有着压倒性的优势，被普遍认为是下一代的计算技术，因而引起了广泛的关注。超导方案因具有良好的可扩展性，目前备受关注。然而，实用化的量子计算需要在大规模扩展所集成的比特数目的同时，保持对每一个量子比特以及比特间的高保真操作，难度极高。本次报告将简要介绍超导量子计算的现状及近期和中远期目标，并讲解我们围绕上述核心目标所取得的一系列进展。
4.
Near-term Quantum Algorithms for Quantum Information
王鑫
百度量子计算研究所
Hybrid quantum-classical systems have the potency to utilize existing quantum computers to their fullest extent. Using this framework, we introduce near-term quantum algorithms for several fundamental tasks in quantum information, including Gibbs state preparation, quantum data decomposition, and quantum fidelity/trace distance estimation. These results explore new avenues for quantum information processing beyond the conventional protocols and reveal the capability of matrix decomposition and norm computation on near-term quantum devices. We also expect these results may shed light on quantum machine learning and quantum optimization in the future.
5.
Clifford Sampling for Quantum Circuit Characterisation and Error Mitigation
李颖
中国工程物理研究院
To perform useful tasks on noisy intermediate-scale quantum computer, we need to employ powerful error mitigation techniques. The quasi-probability method (probabilistic error cancellation) permits perfect error compensation at the cost of additional circuit executions. In this talk, I will present a scalable way to characterise quantum circuits using Clifford sampling. Based on Clifford sampling, we can find the optimal random circuit distribution in error mitigation. This new error mitigation protocol is practical for intermediate-scale quantum computing.
6.
Toward Ultra-high-fidelity Quantum Computing Systems
邓纯青
阿里巴巴达摩院量子实验室
A practical and large-scale quantum computer must contain hundreds of logical qubits with error correction built-in. Such a system requires a larger number of physical qubits where quantum operations can be performed at very high fidelity. Besides achieving qubit gates with error-rates below the quantum error correction threshold, it is necessary to reach low errors for all the elementary operations, including qubit initialization, single- and two-qubit gates, and qubit readout, to demonstrate a logical qubit. Moreover, it is important to keep lowing all these errors further to reduce the resource overhead of quantum error correction. In this talk, I will give an update of our technology developments, including device design, fabrication, cryogenic testing and system benchmarking toward ultra-high-fidelity quantum operations in a superconducting quantum computing system.
7.
复合原子分子离子系统的量子调控
林毅恒
中国科学技术大学
量子信息实验技术目前正飞速发展，对单独体系的量子调控日趋完善，并逐步组合成复合体系，形成功能互补的有机整体。这里我们简介在离子阱体系中，使用多维度的复合量子调控的一些例子以及物理原理，并具体描述我们在相关领域开展的实验工作，包括使用多离子复合体系进行开放量子系统研究，以及使用原子和分子的复合体系进行分子转动谱线精密测量，进而产生单原子和单分子间的量子纠缠等。
8.
基于量子技术的单分子磁共振谱学和成像
石发展
中国科学技术大学物理学院&中科院微观磁共振重点实验室
单分子科学和技术是物理、化学和生物等各领域的研究前沿。传统磁共振谱学和成像在生物医学领域取得广泛应用，但通常仅能研究毫米尺度数以亿万计分子的集体行为。本报告将介绍基于金刚石氮-空位色心单自旋量子精密测量，其在磁检测上具有高分辨率高灵敏度的综合独特优势，可以实现单分子磁共振谱学和纳米分辨率磁成像。具体介绍的工作包括单分子磁共振谱学、超高谱线分辨率的零场纳米磁共振谱学、二维核磁共振谱学及纳米磁成像及应用等介绍。
9.
What Problems can be Solved by Exact One-Query Quantum Algorithms?
李绿周
中山大学
The query model (or black-box model) has attracted much attention from the communities of both classical and quantum computing. Usually, quantum advantages are revealed by presenting a quantum algorithm that has a better query complexity than its classical counterpart. For example, the well-known quantum algorithms including Deutsch-Jozsa algorithm, Simon algorithm and Grover algorithm all show a considerable advantage of quantum computing from the viewpoint of query complexity. Here we consider such a problem: what problem can be solved by an exact one-query quantum algorithm? An exact one-query quantum algorithm means that the quantum algorithm can make only one query and should return the correct result with certainty. An example of such kind of quantum algorithm is Deutsch-Jozsa algorithm.
10.
若干精确量子算法的优势
郑盛根
鹏城实验室
几乎所有n位布尔函数的精确经典查询复杂度被证明都为n. 在量子查询复杂度方面上，早在1998年，Beals等（FOCS’98）证明了n位的与函数(AND)的精确量子查询复杂度也为n. 所以学者们一般认为，在精确查询算法方面上，只是对某些特殊的布尔函数，量子相对于经典才会有优势。我们证明了除和AND函数同构的布尔函数之外，其它n位布尔函数的精确量子查询复杂度都小于n。也就是说几乎所有n位布尔函数的精确量子查询复杂度都小于n。这个结果使我们对精确量子算法的优势在广度上有了新的认识。同时，我们将一次精确查询算法进行刻画和对DJ算法进行了推广。
11.
量子程序设计理论、方法与工具
应明生
悉尼科技大学
在过去15年的时间里，我们组主要致力于较为系统地建立量子程序设计的理论，包括程序设计模型、逻辑基础及分析与验证方法。最近几年，我们逐步将所取得的理论成果与算法实现为量子程序编译器以及分析、测试与验证工具，计划经过一段时间的努力能够研发出一个有效的量子软件开发环境（平台）。本报告将概要汇报这些工作，特别希望通过这次会议寻找与其他研究组合作的机会。
12.
Quingo: A Programming Framework for Heterogeneous Quantum-Classical Computing with NISQ Features
付祥
国防科技大学
Noisy Intermediate-Scale Quantum (NISQ) technology proposes requirements that cannot be fully satisfied by existing Quantum Programming Languages (QPLs) or frameworks. First, noisy qubits require repeatedly-performed quantum experiments, which explicitly operate low-level details, such as pulses and timing of operations. This requirement is beyond the scope or capability of most existing QPLs. Though multiple existing QPLs or frameworks claim the support for near-term promising Heterogeneous Quantum-Classical Computing (HQCC) algorithms, extra code irrelevant to the computational steps has to be introduced, or the corresponding code can hardly be mapped to HQCC architectures while satisfying timing constraints in quantum-classical interaction.
In this work, we propose Quingo, a modular programming framework for HQCC with NISQ features. Quingo highlights an external domain-specific language with timer-based timing control and opaque operation definition. By adopting a six-phase quantum program life-cycle model, Quingo enables aggressive optimization over quantum code through Just-In-Time compilation while preserving quantum-classical interaction with timing constraints satisfied. We propose a runtime system with a prototype design implemented in Python, which can orchestrate both quantum and classical software and hardware according to the six-phase life-cycle model. It allows components of the framework to focus on their genuine task, thus achieving a modular programming framework.
13.
Quantum Chemistry Simulation and Beyond
吕定顺
华为量子实验室
当前，摩尔定律逐渐失效，各种新型计算架构层出不穷，量子计算很可能是一种未来革命性的技术。量子计算是基于量子叠加、量子纠缠等量子力学特性的新计算，其潜在算法可把现在量子计算机需要耗时成千上万年的计算任务，压缩到几小时到几分钟完成。 当前量子计算处在含噪中等规模器件时代（Noise Intermediate-Scale Quantum）, 量子比特数可达（50-1000），业界普遍认为量子计算可能在量子化学模拟，组合优化，量子机器学习方面有潜在应用价值。本次报告，将聚焦基于经典-量子混合算法的量子多体模拟（量子化学模拟， Schwinger model, Hubbard model, Heisenberg model ）和基于量子近似优化算法的组合优化问题方面的研究和对未来的展望，并介绍华为针对这些应用场景开发的软件HiQ Fermion 和HiQ Optimizer。
14.
Analog Quantum Chemistry
石弢
中国科学院理论物理研究所
Using quantum systems to efficiently solve quantum chemistry problems is one of the long-sought applications of near-future quantum technologies. In this talk, I will show how to simulate in an analog way the quantum chemistry in ultracold atom systems. This is a very different path from current digital approaches, which typically project the Hamiltonian in atomic orbital basis sets and map it into qubit operators. In particular, we first discuss how to engineer the different parts of the Hamiltonian, numerically benchmarking the working conditions of the simulator. Then, we discuss the errors of the simulation appearing due to discretization and finite size effects, and, importantly, provide a way to mitigate them. Finally, we benchmark the simulator characterizing the behaviour of two-electron atoms (He) and molecules (HeH+).
15.
Verifying Random Quantum Circuits with Arbitrary Geometry Using Tensor Network States Algorithm
郭楚
信息工程大学
The ability to efficiently simulate random quantum circuits using a classical computer is increasingly important for developing Noisy Intermediate-Scale Quantum devices. Here we present a tensor network states based algorithm specifically designed to compute amplitudes for random quantum circuits with arbitrary geometry. Singular value decomposition based compression together with a two-sided circuit evolution algorithm are used to further compress the resulting tensor network. To further accelerate the simulation, we also propose a heuristic algorithm to compute the optimal tensor contraction path. We demonstrate that our algorithm is up to 2 orders of magnitudes faster than the Schrodinger-Feynman algorithm for verifying random quantum circuits on the 53-qubit Sycamore processor, with circuit depths below 12. We also simulate larger random quantum circuits up to 104 qubits, showing that this algorithm is an ideal tool to verify relatively shallow quantum circuits on near-term quantum computers.
16.
Majorana Qubit systems and their benchmarking scheme
刘东
清华大学
Majorana zero modes provide a potential platform for the storage and processing of quantum information with intrinsic error rates that decrease exponentially with inverse temperature and with the length scales of the system. I will review the recent progress in Majorana search and topological quantum computation from a theoretical point of view. These recent progress paves a way for the future tests of non-abelian braiding statistics and topological quantum information processing. However, if we want to validate Majorana behaviors seriously for quantum information applications, it is reasonable to treat the system as a black-box. We first designed a couple of novel classical hidden variable theories to capture certain key quantum mechanical properties of Majorana systems, which could help us to set up the boundaries and limitations of Majorana operations for quantum information processing. Secondly, we introduce a scheme using a sequence of measurements to reveal their behaviors for nonlocal information encoding.
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