量子计算与多世界：Deutsch 理论梳理

The Quantum Architect: David Deutsch, The Multiverse, and the Foundations of Universal Computation

量子架构师：大卫·多伊奇、多重宇宙与通用计算的基础

1. The 2023 Breakthrough Prize in Fundamental Physics: A Paradigm Shift in Recognition

1. 2023年基础物理学突破奖：认知的范式转变

1.1 The Stature and Mechanics of the Award

1.1 奖项的地位与机制

The Breakthrough Prize in Fundamental Physics stands as a monumental institution in the landscape of modern science, representing not just financial reward but a specific philosophy of recognition. Established in July 2012 by the Breakthrough Prize Board and supported by the foundation co-founded by the Russia-born Israeli entrepreneur and physicist Yuri Milner, the prize was initially designated as the Fundamental Physics Prize. Its inception marked a shift in how scientific achievement is celebrated, introducing a level of financial remuneration—USD $3 million—that is currently the most lucrative in the world, exceeding the monetary value of the Nobel Prize by more than double. This scale of funding reflects a deliberate effort to elevate the status of fundamental physics in the public consciousness and to provide substantial support to those driving the field forward.

基础物理学突破奖在现代科学版图中犹如一座丰碑，它不仅代表着经济上的奖励，更象征着一种特定的认可哲学。该奖项由突破奖委员会于2012年7月设立，并得到了由出生于俄罗斯的以色列企业家兼物理学家尤里·米尔纳联合创立的基金会的支持，最初被定名为基础物理学奖。它的设立标志着科学成就庆祝方式的转变，引入了目前全球最高的300万美元奖金，其金额是诺贝尔奖的两倍以上。这种资金规模反映了一种刻意的努力，旨在提升基础物理学在公众意识中的地位，并为推动该领域发展的科学家提供实质性的支持 1。

The prize is distinct in its scope and eligibility criteria. It is awarded to physicists across the spectrum of the discipline—theoretical, mathematical, or experimental—who have made transformative contributions to fundamental physics. A key differentiator from other major accolades is the specific emphasis on "recent advances," although the award structure accommodates broader achievements as well. The governance of the prize is overseen by the Breakthrough Prize Board, ensuring that the selection process adheres to rigorous standards of scientific excellence. The structure of the awards includes both an annual Breakthrough Prize in Fundamental Physics and a Special Breakthrough Prize. The latter is unique in its flexibility; unlike the annual award which adheres to a yearly schedule, the Special Prize may be conferred at any time to honor outstanding achievements, yet it carries the same substantial prize money of USD $3 million. This flexibility allows the Board to respond rapidly to momentous discoveries or careers that demand immediate recognition outside the traditional cycle.

该奖项在范围和资格标准上独树一帜。它授予该学科各个领域——理论、数学或实验——对基础物理学做出变革性贡献的物理学家。与其他主要奖项的一个关键区别在于它特别强调“近期进展”，尽管奖励结构也同样包容更广泛的成就。奖项的管理由突破奖委员会监督，确保选拔过程遵守严格的科学卓越标准。奖项的结构包括年度基础物理学突破奖和特别基础物理学突破奖。后者的独特之处在于其灵活性；与遵循年度时间表的年度奖项不同，特别奖可以在任何时间颁发以表彰杰出的成就，但它同样伴随着300万美元的巨额奖金。这种灵活性使得委员会能够对那些需要传统周期之外立即认可的重大发现或职业生涯做出迅速反应 1。

Furthermore, the ecosystem of the Breakthrough Prize includes a mechanism for nurturing future winners through the Physics Frontiers Prize. Laureates of this preliminary award are automatically nominated for the Breakthrough Prize in Fundamental Physics in the subsequent year. This creates a pipeline of recognition. If these nominees are not awarded the main prize in the following year, they are granted a consolation of USD $300,000 and retain their nomination status for the next five years. This tiered system ensures that high-caliber work remains in the spotlight and that researchers are continuously considered for the top honor, preventing significant contributions from being overlooked due to the constraints of a single year's selection process.

此外，突破奖的生态系统还包括一个通过“物理学前沿奖”培育未来获奖者的机制。这一初步奖项的获奖者会自动获得次年基础物理学突破奖的提名。这创造了一个认可的输送管道。如果这些被提名者在次年没有获得大奖，他们将获得30万美元的安慰奖，并在接下来的五年内保留提名资格。这种分层系统确保了高水准的工作能够持续受到关注，并且研究人员能够被持续考虑授予最高荣誉，从而防止重大贡献因单一年份选拔过程的限制而被忽视 1。

1.2 The 2023 Laureates and the Triumph of Quantum Information

1.2 2023年获奖者与量子信息的胜利

In a definitive acknowledgment of the maturation of quantum science, the 2023 Breakthrough Prize in Fundamental Physics was awarded to four pioneers whose work collectively founded the field of quantum information technology: David Deutsch of the University of Oxford, Peter Shor of the Massachusetts Institute of Technology (MIT), Charles Bennett of IBM Research, and Gilles Brassard of the University of Montreal. The citation explicitly honored their "foundational work in the field of quantum information," signaling a consensus that what was once a niche area of theoretical speculation has become a cornerstone of modern fundamental physics.

作为对量子科学成熟的决定性认可，2023年基础物理学突破奖授予了四位先驱，他们的工作共同奠定了量子信息技术领域的基础：牛津大学的大卫·多伊奇、麻省理工学院（MIT）的彼得·肖尔、IBM研究中心的查尔斯·贝内特以及蒙特利尔大学的吉尔·布拉萨德。颁奖词明确表彰了他们在“量子信息领域的基础性工作”，这标志着一种共识的形成：即曾经只是理论推测的小众领域，现已成为现代基础物理学的基石 2。

The selection of these four individuals highlights the interdisciplinary nature of the field, bridging theoretical physics, mathematics, and computer science. Peter Shor, the Morss Professor of Applied Mathematics at MIT, was specifically cited for his eponymous algorithm—Shor's algorithm—which demonstrated the potential for quantum computers to factor extremely large numbers exponentially faster than classical machines, as well as for his work on algorithms to correct errors in quantum computers. Shor’s reaction to the prize was one of humility and validation; he expressed gratitude that the prize went to quantum information and quantum computation theory, stating, "My three co-winners were the most influential people in founding this field. I consider them friends, and they all clearly deserve it." This statement reinforces the collaborative and cumulative nature of scientific discovery in this domain.

这四位个人的入选凸显了该领域的跨学科性质，连接了理论物理学、数学和计算机科学。麻省理工学院应用数学莫尔斯教授彼得·肖尔因其同名算法——肖尔算法——而被特别提及，该算法展示了量子计算机在分解极大数方面比经典机器快指数级的潜力，以及他在量子计算机纠错算法方面的工作。肖尔对获奖的反应是谦逊和认可；他对奖项授予量子信息和量子计算理论表示感谢，并表示：“我的三位共同获奖者是该领域最具影响力的奠基人。我视他们为朋友，他们显然都受之无愧。”这一声明加强了该领域科学发现的协作性和累积性特征 2。

The Breakthrough Prize Foundation’s announcement provided a broader context for the award, noting that the ideas developed by Deutsch, Shor, Bennett, and Brassard "not only paved the way for today's fast-developing quantum computers; they are now also at the frontiers of fundamental physics, especially in the study of metrology — the science of measurement — and of quantum gravity." This insight is crucial; it positions quantum information not merely as an engineering challenge or a computational tool, but as a fundamental lens through which the deepest laws of the universe, including gravity and measurement itself, are being re-examined. The award thus validates the decades of theoretical labor that transformed quantum mechanics from a description of particles into a theory of information processing.

突破奖基金会的公告为该奖项提供了更广阔的背景，指出多伊奇、肖尔、贝内特和布拉萨德提出的思想“不仅为今天快速发展的量子计算机铺平了道路；它们现在也处于基础物理学的前沿，特别是在计量学（测量科学）和量子引力研究方面。”这一见解至关重要；它将量子信息定位为不仅仅是工程挑战或计算工具，而是重新审视宇宙最深层定律（包括引力和测量本身）的一个基本透镜。因此，该奖项验证了数十年的理论工作，这些工作将量子力学从对粒子的描述转变为一种信息处理理论 2。

Simultaneously, the 2023 cycle also recognized advancements in mathematics, awarding the Breakthrough Prize in Mathematics to Daniel A. Spielman, an MIT alumnus, for contributions to theoretical computer science and mathematics. Michel Goemans, head of MIT's Department of Mathematics, remarked on the synergy between these fields, noting that both Shor and Spielman would have been natural nominees for a "Breakthrough Prize in Theoretical Computer Science" if such a category existed. This observation underscores the blurring lines between physics, mathematics, and computer science, a convergence that David Deutsch himself has championed throughout his career by treating computation as a physical process.

与此同时，2023年的评选周期也认可了数学领域的进步，将数学突破奖授予麻省理工学院校友丹尼尔·A·斯皮尔曼，以表彰他对理论计算机科学和数学的贡献。麻省理工学院数学系主任米歇尔·戈曼斯评论了这些领域之间的协同作用，指出如果存在“理论计算机科学突破奖”这一类别，肖尔和斯皮尔曼都将是该奖项的天然提名人选。这一观察强调了物理学、数学和计算机科学之间界限的模糊，这种融合正是大卫·多伊奇在其整个职业生涯中通过将计算视为物理过程而极力倡导的 2。

2. David Deutsch: Biographical Trajectory and Academic Lineage

2. 大卫·多伊奇：生平轨迹与学术谱系

2.1 Early Life and Educational Foundation

2.1 早年生活与教育基础

David Elieser Deutsch’s journey began on May 18, 1953, in Haifa, Israel, where he was born to Oskar and Tikva Deutsch. The family's narrative soon shifted to London, United Kingdom, establishing a life that blended immigrant resilience with entrepreneurial spirit; his parents owned and operated the Alma restaurant on Cricklewood Broadway. This environment provided the backdrop for Deutsch’s formative years. His primary and secondary education took place in London, first at Geneva House School in Cricklewood and subsequently at William Ellis School in Highgate. These institutions laid the scholastic groundwork for a mind that would later challenge the fundamental assumptions of physics.

大卫·埃利泽·多伊奇的旅程始于1953年5月18日的以色列海法，他是奥斯卡·多伊奇和提克瓦·多伊奇的儿子。这个家庭的故事很快转移到了英国伦敦，建立了一种融合了移民韧性和创业精神的生活；他的父母在克里克伍德百老汇拥有并经营着阿尔玛餐厅。这种环境成为了多伊奇成长岁月的背景。他的小学和中学教育是在伦敦完成的，首先是在克里克伍德的日内瓦豪斯学校，随后是在海格特的威廉埃利斯学校。这些机构为一个后来挑战物理学基本假设的头脑奠定了学术基础 5。

Moving to higher education, Deutsch matriculated at the University of Cambridge, specifically attending Clare College. Here, he read Natural Sciences, a rigorous tripos that exposes students to a broad spectrum of scientific disciplines before specialization. He distinguished himself by taking Part III of the Mathematical Tripos, a course globally renowned for its difficulty and its role as a preparatory ground for leading theoretical physicists. This period at Cambridge was instrumental in equipping Deutsch with the mathematical arsenal necessary to tackle complex problems in field theory and computation.

进入高等教育阶段，多伊奇被剑桥大学录取，就读于克莱尔学院。在这里，他攻读了自然科学，这是一个严格的学位考试课程，让学生在专业化之前接触广泛的科学学科。他在数学优等学位考试的第三部分中表现出色，该课程以难度极高和作为顶尖理论物理学家预备地而闻名全球。剑桥的这段时期对于装备多伊奇解决场论和计算复杂问题所需的数学武器库至关重要 5。

2.2 The Oxford Connection and Academic Ancestry

2.2 牛津渊源与学术传承

Following his undergraduate success, Deutsch transitioned to the University of Oxford for his doctoral studies, joining Wolfson College. His DPhil research was situated at the cutting edge of theoretical physics, focusing on quantum field theory in curved space-time. This specific area of study attempts to reconcile quantum mechanics with the geometry of general relativity, a theme that resonates with his later work on the nature of reality and the multiverse.

本科取得成功后，多伊奇转至牛津大学攻读博士学位，加入沃尔夫森学院。他的博士研究处于理论物理学的前沿，专注于弯曲时空中的量子场论。这一特定研究领域试图将量子力学与广义相对论的几何学相协调，这一主题与他后来关于现实本质和多重宇宙的工作产生了共鸣 5。

Crucially, Deutsch’s supervision placed him in a direct intellectual lineage with one of the giants of 20th-century physics. He was supervised by Dennis Sciama and Philip Candelas. Dennis Sciama is a pivotal figure in the history of astrophysics and cosmology, known not only for his own work but for mentoring a generation of brilliant physicists, including Stephen Hawking. Sciama himself was a doctoral student of Paul Dirac, one of the founding fathers of quantum mechanics. This connects Deutsch directly to the source of the very theory he would later revolutionize. The connection to Dirac is more than genealogical; it is thematic. Just as Dirac predicted the existence of antimatter through pure mathematical reasoning, Deutsch would later predict the existence of quantum computation through rigorous physical logic.

至关重要的是，多伊奇的导师安排将他置于20th世纪物理学巨匠的直接智力谱系中。他由丹尼斯·夏玛和菲利普·坎德拉斯指导。丹尼斯·夏玛是天体物理学和宇宙学史上的关键人物，不仅因其自身的工作而闻名，还因指导了一代杰出的物理学家（包括史蒂芬·霍金）而著称。夏玛本人是量子力学奠基人之一保罗·狄拉克的博士生。这将多伊奇直接与他后来彻底改变的那个理论的源头联系了起来。与狄拉克的联系不仅仅是谱系上的，更是主题上的。正如狄拉克通过纯数学推理预言了反物质的存在一样，多伊奇后来也将通过严格的物理逻辑预言量子计算的存在 6。

After completing his doctorate, Deutsch spent several years as a researcher at the University of Texas at Austin, a period that allowed for the maturation of his ideas before he returned to Oxford. He has since established a permanent academic home there. Currently, he serves as a non-stipendiary Visiting Professor of Physics at the University of Oxford and is a founding member of the Centre for Quantum Computation at the Clarendon Laboratory. His continued association with Oxford is cemented by his role as an Honorary Fellow of Wolfson College.5

博士毕业后，多伊奇在德克萨斯大学奥斯汀分校担任研究员数年，这一时期让他的思想得以成熟，随后他回到了牛津。此后，他在那里建立了永久的学术家园。目前，他担任牛津大学物理系无薪客座教授，并且是克拉伦登实验室量子计算中心的创始成员。他作为沃尔夫森学院荣誉院士的角色进一步巩固了他与牛津的持续联系 5。

2.3 Recognition and Awards

2.3 荣誉与奖项

David Deutsch’s contributions have been recognized with a series of distinguished awards, reflecting the increasing acceptance and importance of his theoretical innovations.

大卫·多伊奇的贡献获得了一系列杰出奖项的认可，反映了他的理论创新日益被接受且重要性与日俱增。

Institute of Physics' Paul Dirac Prize and Medal (1998): This was a particularly meaningful accolade given his academic lineage. He was awarded the premier award for theoretical physics from the Institute of Physics for "pioneering work in quantum computation leading to the concept of a quantum computer." The citation specifically highlighted his contribution to understanding how such devices might be constructed from quantum logic gates in quantum networks.

Edge of Computation Science Prize (2005): This prize recognized "individual achievement in scientific work that embodies extensions of the computational idea — the design space created by Turing." It acknowledged his work as "cutting edge" and transformative.

Fellowship of the Royal Society (2008): Election to the Royal Society is one of the highest honors in science, recognizing Deutsch's status as a leading scientific mind in the UK and the Commonwealth.

Dirac Medal of the International Centre for Theoretical Physics (ICTP) (2017): Another major international honor linking him to the legacy of Dirac.

Micius Quantum Prize (2018): A prestigious prize specifically focused on quantum communications and computation.

Isaac Newton Medal and Prize (2021): Awarded by the Institute of Physics, further cementing his standing in the physics community.

Breakthrough Prize in Fundamental Physics (2023): The culmination of recent recognition, shared with his peers for founding the field of quantum information.1

英国物理学会保罗·狄拉克奖章（1998年）： 考虑到他的学术谱系，这是一个特别有意义的荣誉。他获得了英国物理学会颁发的理论物理学最高奖项，以表彰他“在量子计算方面的开创性工作，导致了量子计算机概念的诞生”。颁奖词特别强调了他对理解如何通过量子网络中的量子逻辑门构建此类设备的贡献。

计算科学边缘奖（2005年）： 该奖项旨在表彰“体现了计算思想扩展的科学工作中的个人成就——即由图灵创造的设计空间”。它承认他的工作是“前沿”且具有变革性的。

皇家学会院士（2008年）： 当选皇家学会院士是科学界的最高荣誉之一，认可了多伊奇作为英国和英联邦领先科学头脑的地位。

国际理论物理中心（ICTP）狄拉克奖章（2017年）： 另一个将他与狄拉克的遗产联系起来的重大国际荣誉。

墨子量子奖（2018年）： 一个专门关注量子通信和计算的著名奖项。

艾萨克·牛顿奖章和奖金（2021年）： 由英国物理学会颁发，进一步巩固了他在物理学界的地位。

基础物理学突破奖（2023年）： 近期认可的顶峰，与他的同行分享，以表彰他们建立了量子信息领域 1。

Beyond academia, Deutsch is a celebrated author. His books, The Fabric of Reality and The Beginning of Infinity, have influenced public discourse on science. In The Fabric of Reality, he constructs a "Theory of Everything" not just of physics, but of knowledge, weaving together quantum physics, epistemology (specifically Popperian), the theory of computation (Turing), and the theory of evolution (Dawkins/Darwin). He argues that "the fabric of reality" is the worldview implied by our best explanations, fundamentally grounded in the idea that we are fallible but capable of infinite knowledge growth.8

除了学术界，多伊奇也是一位著名的作家。他的著作《真实性的构造》和《无穷的开始》影响了公众对科学的讨论。在《真实性的构造》中，他构建了一个不仅仅是物理学的，而是关于知识的“万物理论”，将量子物理学、认识论（特别是波普尔式的）、计算理论（图灵）和进化论（道金斯/达尔文）编织在一起。他认为，“真实性的构造”是我们最好的解释所暗示的世界观，其根本基础在于这样一种观念：我们是易错的，但有能力实现知识的无限增长 8。

3. The Theoretical Bedrock: The Church-Turing Principle and the Universal Quantum Computer

3. 理论基石：邱奇-图灵原理与通用量子计算机

3.1 Reinterpreting the Church-Turing Hypothesis

3.1 重新诠释邱奇-图灵假设

In 1985, David Deutsch published a paper in the Proceedings of the Royal Society of London titled "Quantum theory, the Church-Turing principle and the universal quantum computer." This document is widely regarded as the birth certificate of quantum computing. Before this paper, computation was largely viewed through the lens of abstract mathematics and logic, governed by the Church-Turing thesis which asserts that any function naturally regarded as computable can be computed by a Turing machine. Deutsch, however, identified a profound oversight in this perspective: computation is a physical process. It is performed by physical objects (computers) obeying physical laws. Therefore, the nature of computation must depend on the nature of physics.

1985年，大卫·多伊奇在《伦敦皇家学会会刊》上发表了一篇题为《量子理论、邱奇-图灵原理与通用量子计算机》的论文。这份文件被广泛认为是量子计算的出生证明。在这篇论文之前，计算主要被视为抽象数学和逻辑的产物，受邱奇-图灵命题的支配，该命题断言任何自然被视为可计算的函数都可以由图灵机计算。然而，多伊奇指出了这一观点中的一个深刻疏忽：计算是一个物理过程。它是由遵守物理定律的物理对象（计算机）执行的。因此，计算的本质必须取决于物理学的本质 10。

Deutsch argued that underlying the Church-Turing hypothesis is an implicit physical assertion. He formalized this into a strong physical principle: "Every finitely realizable physical system can be perfectly simulated by a universal model computing machine operating by finite means." This formulation shifted the debate from logic to physics. He then proceeded to demonstrate a contradiction. Classical physics is continuous; its variables (like position and momentum) can take on a continuum of values. A Turing machine, however, is discrete; it operates in distinct steps with distinct states. Consequently, a classical physical system with continuous variables cannot be perfectly simulated by a discrete Turing machine. Thus, according to Deutsch, classical physics and the universal Turing machine do not obey the physical Church-Turing principle.10

多伊奇认为，邱奇-图灵假设的背后隐含着一个物理断言。他将其形式化为一个强物理原理：“每一个有限可实现的物理系统都可以被一个通过有限手段运行的通用模型计算机完美模拟。” 这一表述将争论从逻辑转移到了物理学。随后，他着手论证了一个矛盾。经典物理学是连续的；其变量（如位置和动量）可以取连续的值。然而，图灵机是离散的；它以不同的步骤和不同的状态运行。因此，具有连续变量的经典物理系统无法被离散的图灵机完美模拟。因此，根据多伊奇的观点，经典物理学和通用图灵机并不遵守物理邱奇-图灵原理 10。

3.2 The Universal Quantum Computer

3.2 通用量子计算机

To resolve this inconsistency, Deutsch proposed a new class of model computing machines: the quantum generalization of the Turing machine, or the Universal Quantum Computer. He demonstrated that unlike classical physics, quantum theory is compatible with the physical Church-Turing principle. A universal quantum computer could, in principle, perfectly simulate any finite physical system, including other quantum systems. This proved that quantum computers are necessary to make proper sense of Turing’s theory in a physical universe.10

为了解决这一不一致性，多伊奇提出了一类新的模型计算机：图灵机的量子推广，即通用量子计算机。他证明，与经典物理学不同，量子理论与物理邱奇-图灵原理是兼容的。原则上，通用量子计算机可以完美模拟任何有限物理系统，包括其他量子系统。这证明了在物理宇宙中，为了正确理解图灵理论，量子计算机是必要的 10。

Deutsch theorized that such a machine would possess properties fundamentally unobtainable by any Turing machine. While he clarified that these machines would not compute "non-recursive functions" (functions that are logically impossible to compute), they would introduce a revolutionary capability: Quantum Parallelism. This is a method by which a quantum computer can perform certain tasks using a different complexity class than classical computers. Specifically, Deutsch showed that quantum parallelism allows a universal quantum computer to perform probabilistic tasks faster than any classical restriction of it could. This was the first formal evidence that the complexity-theoretic formulation of the Church-Turing thesis—which assumed all reasonable computers were polynomially equivalent in speed—was false.10

多伊奇从理论上推断，这样的机器将拥有任何图灵机根本无法获得的属性。虽然他澄清这些机器不会计算“非递归函数”（逻辑上无法计算的函数），但它们将引入一种革命性的能力：量子并行性。这是一种量子计算机可以使用与经典计算机不同的复杂性类别来执行某些任务的方法。具体来说，多伊奇表明，量子并行性允许通用量子计算机比任何受经典限制的计算机更快地执行概率任务。这是第一个正式证据，证明邱奇-图灵命题的复杂性理论表述——即假设所有合理的计算机在速度上都是多项式等价的——是错误的 10。

3.3 Philosophical Implications: The Necessity of Many Worlds

3.3 哲学蕴含：多重宇宙的必要性

The introduction of the universal quantum computer was not just a technical innovation; it was a philosophical battering ram. Deutsch argued that the intuitive explanation of quantum parallelism—where a computer seems to perform multiple calculations simultaneously—places an "intolerable strain" on all interpretations of quantum mechanics other than the Everett interpretation (Many-Worlds Interpretation). If a quantum computer can factor a large number by exploring vast solution spaces simultaneously, where do these calculations take place? Deutsch’s answer is that they take place in parallel universes. The sheer computational power of a quantum computer, he argues, is evidence of the multiverse's existence.

通用量子计算机的引入不仅是一项技术创新；它还是一个哲学上的攻城锤。多伊奇认为，对量子并行性的直观解释——即计算机似乎同时执行多个计算——给除了埃弗雷特诠释（多世界诠释）之外的所有量子力学诠释都带来了“无法承受的压力”。如果量子计算机可以通过同时探索巨大的解空间来分解大数，那么这些计算发生在哪里？多伊奇的回答是，它们发生在平行宇宙中。他认为，量子计算机的巨大计算能力正是多重宇宙存在的证据 10。

Furthermore, Deutsch posited that quantum complexity theory allows for a more physically reasonable definition of "complexity" and "knowledge" in a physical system compared to classical theory. This perspective redefines knowledge not as a static database but as a physical structure capable of causal resilience across the multiverse.10

此外，多伊奇指出，与经典理论相比，量子复杂性理论允许对物理系统中的“复杂性”和“知识”进行更符合物理理性的定义。这种观点将知识重新定义为不是静态数据库，而是一种在多重宇宙中具有因果韧性的物理结构 10。

4. The Structure of the Multiverse and Information Flow

4. 多重宇宙的结构与信息流

4.1 Defining the Multiverse through Information

4.1 通过信息定义多重宇宙

For David Deutsch, the multiverse is not a science fiction trope but an unavoidable consequence of taking quantum theory seriously as a description of reality. In his paper "The Structure of the Multiverse," he advances the argument that the structure of reality is fundamentally determined by the flow of information. He aligns himself with the lineage of Hugh Everett (1957), asserting that quantum-mechanical phenomena must be explained in terms of the simultaneous existence of parallel universes or histories.14

对于大卫·多伊奇来说，多重宇宙不是科幻小说中的桥段，而是严肃对待量子理论作为现实描述的必然结果。在他的论文《多重宇宙的结构》中，他提出了这样一个论点：现实的结构从根本上是由信息流决定的。他与休·埃弗雷特（1957年）一脉相承，断言必须用平行宇宙或历史的同时存在来解释量子力学现象 14。

The core of his analysis lies in the distinction between quantum and classical information processing. Deutsch defines a specific regime within the multiverse where "classical" physics appears to operate. He argues that in any region where classical information processing occurs—which he defines broadly to include not only classical computation but also all measurements and decoherent processes—the multiverse contains an ensemble of "causally autonomous" systems. Each of these autonomous systems resembles a classical physical system. This is a critical insight: classical reality is not fundamental; it is an emergent property of the quantum multiverse that appears when information flow is restricted in specific ways (specifically, when interference is suppressed).14

他分析的核心在于量子与经典信息处理的区别。多伊奇在多重宇宙中定义了一个“经典”物理学似乎在起作用的特定区域。他认为，在任何发生经典信息处理的区域——他将其宽泛地定义为不仅包括经典计算，还包括所有测量和退相干过程——多重宇宙包含了一个由“因果自主”系统组成的集合。这些自主系统中的每一个都类似于一个经典物理系统。这是一个关键的见解：经典现实不是基础性的；它是量子多重宇宙的一种涌现属性，当信息流受到特定方式的限制（具体来说，当干涉被抑制）时才会出现 14。

4.2 Modeling the Multiverse

4.2 多重宇宙建模

To formalize this, Deutsch utilizes theoretical models of classical reversible computational networks and ensembles of classical computers. He analyzes how a quantum computer performs a "classical" computation and shows that while it produces a result consistent with a classical machine, the underlying process involves a branching of histories that the classical view cannot account for. The multiverse, therefore, has a rich internal structure even in regions that look classical. It is composed of vast numbers of histories that are identical in their macroscopic properties but distinct in their microscopic quantum state. The "classical" world we perceive is essentially a slice through this much larger structure.15

为了将其形式化，多伊奇利用了经典可逆计算网络和经典计算机集合的理论模型。他分析了量子计算机如何执行“经典”计算，并表明虽然它产生的结果与经典机器一致，但其底层过程涉及经典观点无法解释的历史分支。因此，即使在看起来像经典的区域，多重宇宙也具有丰富的内部结构。它由大量的历史组成，这些历史在宏观属性上是相同的，但在微观量子态上是截然不同的。我们感知到的“经典”世界本质上只是这个更庞大结构的一个切片 15。

4.3 Time and the Block Universe

4.3 时间与块状宇宙

This structural view of the multiverse extends to the nature of time itself. Deutsch, citing work by fictional author Greg Egan and physicists like Julian Barbour, explores the concept that "all possible states exist at every instant." In this view, the passage of time may be "in the eye of the beholder." This aligns with the "block universe" concept in relativity but is enhanced by the multiverse framework.

多重宇宙的这种结构观延伸到了时间本身的本质。多伊奇引用了科幻作家格雷格·伊根和物理学家朱利安·巴伯等人的作品，探讨了“所有可能的状态在每一瞬间都存在”的概念。在这个观点中，时间的流逝可能只是“观察者眼中的错觉”。这与相对论中的“块状宇宙”概念相一致，但被多重宇宙框架所增强.17

If all moments and all branches exist simultaneously in a vast mathematical object (the quantum state of the multiverse), then "time" is simply the correlation between different parts of this object. Our perception of moving through time is a result of the information flow between these static states. Deutsch suggests that the multiverse framework might be essential to truly understanding time, potentially resolving paradoxes about the Big Bang and black hole evaporation that classical perspectives fail to address. The multiverse is thus not just a space of parallel presents, but a complex structure of all possible histories existing as a timeless whole.17

如果所有时刻和所有分支同时存在于一个巨大的数学客体（多重宇宙的量子态）中，那么“时间”仅仅是这个客体不同部分之间的相关性。我们对时间流逝的感知是这些静态状态之间信息流的结果。多伊奇认为，多重宇宙框架对于真正理解时间可能至关重要，有可能解决经典视角无法解决的关于大爆炸和黑洞蒸发的悖论。因此，多重宇宙不仅是平行现在的空间，而且是作为永恒整体存在的所有可能历史的复杂结构 17。

5. The Deutsch-Wallace Theorem: Solving the Probability Problem

5. 多伊奇-华莱士定理：解决概率问题

5.1 The Challenge of Probability in a Deterministic Multiverse

5.1 确定性多重宇宙中的概率挑战

One of the most persistent criticisms of the Many-Worlds Interpretation is the "incoherence" of probability. In the standard Copenhagen interpretation, probability is fundamental: a measurement outcome is random. But in the Everettian multiverse, every possible outcome of a measurement actually occurs in some branch of reality. If an electron is in a superposition of Spin Up and Spin Down, and a measurement is performed, the universe splits into two: one where the observer sees Up, and one where the observer sees Down. Since both outcomes happen with 100% certainty (in their respective branches), what does it mean to say there is a "50% probability" of seeing Up? Critics argue that the concept of probability dissolves in a deterministic theory where everything happens.18

多世界诠释面临的最持久的批评之一是概率的“不连贯性”。在标准的哥本哈根诠释中，概率是基础性的：测量结果是随机的。但在埃弗雷特多重宇宙中，测量的每一个可能结果实际上都发生在现实的某个分支中。如果一个电子处于自旋向上和自旋向下的叠加态，并且进行了测量，宇宙就会分裂成两个：一个观察者看到向上的宇宙，和一个观察者看到向下的宇宙。既然两个结果都以100%的确定性发生（在它们各自的分支中），那么说看到向上的“概率是50%”意味着什么？批评者认为，在一个一切都会发生的确定性理论中，概率的概念就瓦解了 18。

5.2 The Decision-Theoretic Solution

5.2 决策理论解决方案

To rescue the concept of probability, David Deutsch and his Oxford colleague David Wallace developed a pioneering approach known as Decision Theory within the Everett framework. Their central thesis is that probability in quantum mechanics should not be understood as the objective chance of an event occurring, but as a rationality principle for an agent acting within the multiverse.18

为了挽救概率的概念，大卫·多伊奇和他在牛津的同事大卫·华莱士在埃弗雷特框架内开发了一种开创性的方法，称为决策理论。他们的核心论点是，量子力学中的概率不应被理解为事件发生的客观机会，而应被理解为在多重宇宙中行动的主体的理性原则 18。

Deutsch and Wallace argue that a rational agent (let's call her Alice) who knows she lives in a branching universe should care about all her future selves. The "probability" of an outcome is reinterpreted as the weight or value Alice should assign to a particular branch when making decisions. For example, if a bet pays out in a "thin" branch (low amplitude) but leads to bankruptcy in a "thick" branch (high amplitude), a rational Alice should decline the bet, not because the thin branch won't happen—it will—but because the measure of her future selves who suffer is greater than the measure of those who profit.

多伊奇和华莱士认为，一个知道自己生活在分支宇宙中的理性主体（我们要称她为爱丽丝）应该关心她所有的未来自我。结果的“概率”被重新解释为爱丽丝在做决定时应该分配给特定分支的权重或价值。例如，如果一个赌注在“细”分支（低振幅）中会得到回报，但在“粗”分支（高振幅）中会导致破产，理性的爱丽丝应该拒绝这个赌注，这并不是因为细分支不会发生——它会发生——而是因为受苦的未来自我的度量大于获利的未来自我的度量。

The Deutsch-Wallace Theorem formally proves that if an agent adheres to certain basic axioms of rationality (such as not preferring a gamble just because the labels of the outcomes are swapped), they must structure their preferences according to the Born Rule (the standard rule for calculating quantum probabilities). This derivation claims to obtain the probabilistic predictions of quantum theory directly from the non-probabilistic unitary dynamics, without needing a separate axiom for probability. Deutsch argues this solves the measurement problem by showing that "subjective uncertainty" is not needed; only a rational caring for one's successors in the multiverse is required.19

多伊奇-华莱士定理正式证明，如果一个主体遵守某些基本的理性公理（例如，不因为结果的标签被交换而偏好某个赌博），他们必须根据玻恩规则（计算量子概率的标准规则）构建他们的偏好。这一推导声称直接从非概率的幺正动力学中获得量子理论的概率预测，而不需要单独的概率公理。多伊奇认为这解决了测量问题，因为它表明不需要“主观不确定性”；只需要理性地关心多重宇宙中的后继者即可 19。

5.3 Criticism and Debate

5.3 批评与争论

This bold reformulation has sparked intense debate in the philosophy of physics community. Critics such as Itamar Pitowsky and Meir Hemmo have challenged the theorem. They question whether the Deutsch-Wallace theorem truly justifies the "Principal Principle" (the idea that one's internal belief should match objective physical chances). They argue that deriving probability from decision theory might be circular or that it fails to bridge the gap between the ontology of a deterministic multiverse and the observed statistics of experiments. Despite these objections, the Deutsch-Wallace approach remains the most robust defense of probability in the Many-Worlds Interpretation, transforming the discussion from one of metaphysics to one of rational choice theory.20

这种大胆的重构在物理哲学界引发了激烈的争论。伊塔马尔·皮托夫斯基和梅尔·海莫等批评者对该定理提出了质疑。他们质疑多伊奇-华莱士定理是否真正证明了“主要原则”（即一个人的内在信念应该与客观物理机会相匹配的观点）的合理性。他们认为，从决策理论推导概率可能是循环论证，或者它未能弥合确定性多重宇宙的本体论与实验观测统计数据之间的差距。尽管存在这些反对意见，多伊奇-华莱士方法仍然是多世界诠释中对概率最强有力的辩护，将讨论从形而上学转变为理性选择理论 20。

6. Mechanics of Quantum Computation: The Engine of Interference

6. 量子计算的机制：干涉引擎

6.1 Interference vs. Probability

6.1 干涉与概率

To understand why David Deutsch’s work garnered the Breakthrough Prize, one must understand the mechanism that makes quantum computers powerful: Interference. In classical computing, logic gates process bits that are definitely 0 or 1. In quantum computing, qubits exist in a superposition of states. However, simply having many states at once is not enough; that would just be a random mess. The key is that these states are described by amplitudes, which are complex numbers, not probabilities (which are strictly positive real numbers).23

要理解为什么大卫·多伊奇的工作获得了突破奖，就必须理解使量子计算机变得强大的机制：干涉。在经典计算中，逻辑门处理的是绝对为0或1的比特。在量子计算中，量子比特处于状态的叠加中。然而，仅仅同时拥有许多状态是不够的；那只会是一团随机的混乱。关键在于这些状态是由振幅描述的，振幅是复数，而不是概率（概率是严格的正实数） 23。

Amplitudes act like waves. Just as waves in a pond can add up to a larger wave or cancel each other out to flatness, quantum amplitudes can interfere.

振幅像波一样起作用。就像池塘里的波浪可以叠加成更大的波浪或相互抵消变得平坦一样，量子振幅也可以发生干涉。

Constructive Interference: When the phases of the quantum states align, their amplitudes add together, increasing the probability of measuring that outcome.

Destructive Interference: When the phases are opposite (peaks meeting troughs), the amplitudes cancel out, reducing the probability of that outcome to zero.

相长干涉： 当量子态的相位一致时，它们的振幅相加，增加了测量到该结果的概率。

相消干涉： 当相位相反（波峰遇上波谷）时，振幅相互抵消，将该结果的概率降低为零。

6.2 Constructing the Algorithm

6.2 构建算法

A quantum algorithm, as conceptualized by Deutsch and further developed by Shor, Grover, and others, is essentially a choreographed interference pattern. The goal is to design a sequence of quantum gates that forces the "wrong" answers to destructively interfere and the "right" answer to constructively interfere.

由多伊奇概念化并由肖尔、格罗弗等人进一步发展的量子算法，本质上是一个精心编排的干涉模式。其目标是设计一系列量子门，迫使“错误”答案发生相消干涉，而“正确”答案发生相长干涉 26。

For instance, in Grover’s Algorithm (used for searching unsorted databases), the system starts with all items in the database having equal amplitude. The algorithm applies an "Oracle" and a "Diffusion" operator. The Oracle flips the phase of the target item (marking it), and the Diffusion operator inverts all amplitudes around the average. This mathematical dance causes the amplitude of the target item to grow (amplify) while the amplitudes of all other items shrink. By repeating this process, the probability of measuring the correct answer approaches 100%. The algorithm does not check items one by one; it uses interference to filter the entire superposition simultaneously.27

例如，在格罗弗算法（用于搜索未排序数据库）中，系统开始时数据库中的所有项目具有相同的振幅。算法应用“预言机”和“扩散”算子。预言机翻转目标项目的相位（标记它），扩散算子围绕平均值反转所有振幅。这种数学之舞导致目标项目的振幅增长（放大），而所有其他项目的振幅收缩。通过重复这个过程，测量到正确答案的概率接近100%。该算法不是逐个检查项目；它使用干涉同时过滤整个叠加态 27。

Similarly, Shor’s Algorithm relies on the Quantum Fourier Transform (QFT) to create interference. It finds the period (rhythm) of a mathematical function. The QFT causes the amplitudes of the correct period to add up constructively, while the amplitudes of incorrect periods cancel out. This allows the computer to extract the global structure of the function (its period) without calculating every single point, enabling the factorization of large numbers—a feat impossible for classical computers in reasonable time.26

同样，肖尔算法依赖量子傅里叶变换（QFT）来产生干涉。它寻找数学函数的周期（节奏）。QFT导致正确周期的振幅相长叠加，而错误周期的振幅相互抵消。这使得计算机能够提取函数的全局结构（其周期），而无需计算每一个点，从而实现大数分解——这是经典计算机在合理时间内无法完成的壮举 26。

6.3 The Global Filter Mechanism

6.3 全局过滤机制

In summary, interference acts as a "global filter." It shapes the probabilities of outcomes. Without interference, a quantum computer would just be a very expensive random number generator. It is the deliberate engineering of wave cancellations that allows useful information to be extracted from the multiverse of possibilities. This understanding of computation—as the physical manipulation of interference patterns across parallel histories—is the direct legacy of David Deutsch’s pioneering vision.25

总之，干涉起到了“全局过滤器”的作用。它塑造了结果的概率。没有干涉，量子计算机只不过是一个非常昂贵的随机数生成器。正是这种对波抵消的刻意工程设计，使得有用信息能够从可能性的多重宇宙中被提取出来。这种对计算的理解——即作为对平行历史中干涉模式的物理操纵——正是大卫·多伊奇开创性愿景的直接遗产 25。

Works cited

Breakthrough Prize in Fundamental Physics - Wikipedia, accessed November 20, 2025,

Peter Shor wins Breakthrough Prize in Fundamental Physics | MIT News, accessed November 20, 2025,

Breakthrough Prize for the Physics of Quantum Information…and of Cells, accessed November 20, 2025,

Professor David Deutsch awarded Breakthrough Prize in Fundamental Physics, accessed November 20, 2025,

About Me - David Deutsch, accessed November 20, 2025,

David Deutsch - Wikipedia, accessed November 20, 2025,

David Deutsch - Wolfson College - University of Oxford, accessed November 20, 2025,

David Deutsch, accessed November 20, 2025,

Prof. David Deutsch - OxfordChabad.org, accessed November 20, 2025,

Quantum theory, the Church–Turing principle and the universal quantum computer | Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences - Journals, accessed November 20, 2025,

Quantum Theory, the Church-Turing Principle and the Universal Quantum Computer - D. Deutsch - cs.Princeton, accessed November 20, 2025,

Quantum theory, the Church–Turing principle and the universal quantum computer - Scite, accessed November 20, 2025,

[PDF] Quantum theory, the Church–Turing principle and the universal quantum computer, accessed November 20, 2025,

(PDF) The Structure of the Multiverse (2002) | David Deutsch | 160 Citations - SciSpace, accessed November 20, 2025,

The Structure of the Multiverse - arXiv, accessed November 20, 2025,

[PDF] The structure of the multiverse - Semantic Scholar, accessed November 20, 2025,

arXiv:0905.1283v1 [physics.pop-ph] 8 May 2009, accessed November 20, 2025,

Quantum theory of probability and decisions | Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences - Journals, accessed November 20, 2025,

Understanding Deutsch's Probability in a Deterministic Multiverse - How to use the personal web pages service, accessed November 20, 2025,

Everettian probabilities, the Deutsch-Wallace theorem and the Principal Principle - PhilSci-Archive, accessed November 20, 2025,

[quant-ph/0211104] Quantum Probability and Decision Theory, Revisited - arXiv, accessed November 20, 2025,

[2010.11591] Everettian probabilities, the Deutsch-Wallace theorem and the Principal Principle - arXiv, accessed November 20, 2025,

What Is Quantum Computing? | IBM, accessed November 20, 2025,

quantum Computing fundamentals | IBM Quantum Learning, accessed November 20, 2025,

Interference - Microsoft Quantum, accessed November 20, 2025,

Colliding Waves: How Quantum Interference Powers Quantum Computing, accessed November 20, 2025,

Quantum Interference in Quantum Computing: 2025 Full Guide - SpinQ, accessed November 20, 2025,

How does a quantum computer use interference to amplify the correct solution? - Milvus, accessed November 20, 2025,

Quantum algorithms, accessed November 20, 2025,