量子达尔文主义：一种可解释我们对实在的共识的新方式|观察者|达尔文主义|进化论|量子物理学

我们找到了一种新的方式来解释为什么我们对实在的本质达成共识。

一个受进化论启发的框架解释了量子模糊性如何产生我们的经典世界，它表明即使是不完美的观察者最终也能就客观现实达成一致。

作者：卡梅拉·帕达维奇-卡拉汉

2026年1月27日

我们通常能对物体的外观达成共识，但为什么呢？
Martin Bond / Alamy

从量子层面来看，我们的世界似乎本质上是模糊的，但我们实际体验到的却并非如此。研究人员现在开发出一种方法，可以测量我们所体验到的客观现实从这种模糊状态中涌现的速度，这进一步证实了受进化原理启发的框架能够解释客观实在的涌现机制。

在量子领域，每个物体——例如单个原子——都存在于一系列可能的状态之中，只有在被测量或观测之后才会呈现出明确定义的“经典”状态。但我们观测到的却是完全经典的物体，它们不存在任何模糊不清的部分，而造成这种现象的机制长期以来一直困扰着物理学家。

2000年，新墨西哥州洛斯阿拉莫斯国家实验室的沃伊切赫·祖雷克提出了“量子达尔文主义”。他认为，类似于自然选择的过程能够确保我们所观察到的物体状态，是所有可能状态中最“适应”的状态，因此也是在到达观察者的过程中，通过与环境相互作用而最能自我复制的状态。当两个只能接触到物理实在片段的观察者对某些客观事实达成一致时，是因为他们观察到的都是这些相同的复制体之一。

都柏林大学学院的史蒂夫·坎贝尔和他的同事们现在已经证明，即使不同的观察者收集有关物体的信息的方式（即观察物体的方式）不是最复杂或最精确的，他们也可能对客观实在达成一致。

“如果一个观察者捕捉到某个片段，他/她可以选择进行任何他/她想做的测量。我也可以捕捉到另一个片段，我也可以选择进行任何我想做的测量。那么，经典客观性是如何产生的呢？这就是……”“我们出发的地方，”他说。

研究人员将客观性涌现的问题重新定义为量子传感中的一个问题。例如，如果待测的客观事实是物体发光的频率，那么观察者必须获得关于该频率的精确信息，类似于配备光传感器的计算机的工作方式。在理想情况下，这种装置可以进行超精确的测量，并迅速得出关于光频率的明确结论——这种情况可以用一个名为“量子费舍尔信息”（QFI）的数学公式来量化。在这项新研究中，研究人员纽约州罗切斯特大学的团队成员加布里埃尔·兰迪表示，他们以 QFI 为基准，比较了不同的、不太精确的观测方案如何得出相同、准确的结论。

引人注目的是，该团队的计算表明，对于足够大的物理实在碎片，即使是进行不完美测量的观察者最终也可以收集到足够的信息，从而得出与理想的 QFI 标准相同的关于客观性的结论。

兰迪说：“一种简单的测量方法实际上可以和更复杂的测量方法一样有效。这是理解古典性出现的一种方式：当碎片变得庞大时。”足够多的时候，观察者们甚至在简单的测量上也开始达成一致。” 通过这种方式，这项研究为我们理解为什么当我们观察宏观世界时，我们会对其物理属性（例如一杯咖啡的颜色）达成一致提供了又一步。

“这项研究表明，完美、理想的测量并非必要，”阿根廷布宜诺斯艾利斯大学的迭戈·维斯尼亚奇（Diego Wisniacki）说道。他表示，量子信息不稳定性（QFI）是量子信息理论的基石，但此前从未被引入量子达尔文主义，因此它可以将这个仍处于理论阶段的量子框架与成熟的实验（例如量子器件中的实验）联系起来。利用光基或超导量子比特。

“这是我们理解量子达尔文主义的又一块‘砖’，”意大利巴勒莫大学的G·马西莫·帕尔马说。“而且，这种研究方法更接近于实验学家对实验室实际观察结果的描述。”

他说，研究人员在研究中使用的模型非常简单，因此，虽然他们的方法可能为新的实验打开大门，但还需要对更复杂的系统进行计算，才能使量子达尔文主义建立在更坚实的基础之上。“如果我们能够超越现有模型，那将是一项真正的重大突破。”帕尔马说：“简单的玩具模型。”

兰迪表示，研究人员已经对将他们的理论研究转化为实验很感兴趣——例如，使用由囚禁离子制成的量子比特，他们可以观察客观性出现的时间尺度与已知这些量子比特保持其量子性的特定时间相比如何。

期刊参考文献：
《物理评论A》DOI：10.1103/hn78-7xx3
主题：
量子物理学

计量学方法论视角下的古典客观性

安东尼·基利、戴安娜·A·奇泽姆、阿克拉姆·图伊尔、塞巴斯蒂安·德夫纳、加布里埃尔·兰迪和史蒂夫·坎贝尔

《物理评论A》—— 2026年1月14日接收

DOI：https://doi.org/10.1103/hn78-7xx3

导出引用

摘要

我们提出了一种精确刻画经典性出现过程的方法，该方法结合了量子达尔文主义的形式体系和量子计量学的工具。我们证明，量子费舍尔信息为评估经典客观性涌现的速率提供了一个有用的度量。此外，我们的形式体系允许我们探究测量方法的选择如何影响观察者确定系统状态的精度。对于自旋星模型的典型例子，我们证明了最优测量会导致经典性以指数级速率涌现。虽然其他测量必然会导致较慢的涌现速度，但我们的重要发现是，次优测量仍然可以达到克拉默-拉奥界限。通过将涌现的经典性重新表述为信息获取协议，我们的框架为量子达尔文主义提供了一个精确的操作描述。

ACCEPTED PAPER

Metrological approach to the emergence of classical objectivity

Anthony Kiely, Diana A. Chisholm, Akram Touil, Sebastian Deffner, Gabriel Landi, and Steve Campbell

Phys. Rev. A -Accepted14 January, 2026

DOI: https://doi.org/10.1103/hn78-7xx3

Export Citation

Abstract

We present a precise characterization of the onset of classicality that combines the formalism of quantum Darwinism with the tools from quantum metrology. We show that the quantum Fisher information provides a useful metric for assessing the rate at which classical objectivity emerges. Furthermore, our formalism allows us to explore how the choice of measurement impacts the precision with which an observer can determine the state of the system. For a paradigmatic example of the spin-star model, we demonstrate that optimal measurements lead to the emergence of classicality at an exponential rate. Although other measurements necessarily lead to slower emergence, we importantly show that suboptimal measurements can still saturate the Cramér-Rao bound. By recasting emergent classicality as an information acquisition protocol, our framework provides a precise operational description of quantum Darwinism.

We have a new way to explain why we agree on the nature of reality

An evolution-inspired framework for how quantum fuzziness gives rise to our classical world shows that even imperfect observers can eventually agree on an objective reality

By Karmela Padavic-Callaghan

27 January 2026

We can usually agree what objects look like, but why?

Martin Bond / Alamy

Our world seems to be fundamentally fuzzy at the quantum level, yet we do not experience it that way. Researchers have now developed a recipe for measuring how quickly the objective reality that we do experience emerges from this fuzziness, strengthening the case that a framework inspired by evolutionary principles can explain why it emerges at all.

In the quantum realm, each object – such as a single atom – exists in a cloud of possible states and assumes a well-defined, or “classical”, state only after being measured or observed. But we observe strictly classical objects free of existentially fuzzy parts, and the mechanism that makes this so has long puzzled physicists.

In 2000, Wojciech Zurek at Los Alamos National Laboratory in New Mexico proposed “quantum Darwinism”, where a process similar to natural selection would ensure that the states of objects that we see are those that are most “fit” among all of the many states that could exist, and therefore best at replicating themselves through their interactions with the environment on their way to an observer. When two observers that only have access to fragments of physical reality agree on something objective about it, it is because they are both observing one of these identical copies.

How a quantum innovation may quash the idea of the multiverse

Steve Campbell at University College Dublin and his colleagues have now proved that different observers are likely to agree on an objective reality even if the way they gather information about an object – the way they observe it – is not the most sophisticated or optimally precise.

“If one observer captures some fragment, they can choose to do whatever measurement they want. I can capture another fragment, and I can choose to do whatever measurement that I want. So how is it that classical objectivity arises? That’s where we started,” he says.

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The researchers recast the problem of objectivity’s emergence as a problem in quantum sensing. If the objective fact at hand is, for example, the frequency at which an object shines light, then the observers must obtain accurate information about that frequency, in a similar way to how a computer equipped with a light sensor would. In the best-case scenario, this set-up could capture super-precise measurements and quickly reach a definitive conclusion about light’s frequency – a scenario quantified by a mathematical formula called “quantum Fisher information”, or QFI. In the new work, the researchers used QFI as a benchmark against which they could compare how different, less precise observation schemes reach the same, accurate conclusions, says team member Gabriel Landi at the University of Rochester in New York state.

Strikingly, the team’s calculations showed that for big enough fragments of physical reality, even observers doing imperfect measurements could eventually gather enough information to reach the same conclusions about objectivity as the ideal QFI standard.

We've discovered a door to a hidden part of reality – what's inside?

“A silly measurement can actually do as well as a much more sophisticated measurement,” says Landi. “That’s one way of seeing the emergence of classicality: when the fragments become big enough, observers start agreeing even with simple measurements.” In this way, the work offers another step towards understanding why when we observe our macroscopic world, we agree on its physical properties, such as the colour of a cup of coffee.

“The work highlights that perfect, ideal measurements are not required,” says Diego Wisniacki at the University of Buenos Aires in Argentina. He says that QFI is a mainstay of quantum information theory but it hadn’t been introduced into quantum Darwinism before, so it could bridge this still rather theoretical quantum framework with well-established experiments – for example, in quantum devices with light-based or superconducting qubits.

“This is one more ‘brick’ in our understanding of quantum Darwinism,” says G. Massimo Palma at the University of Palermo in Italy. “And is a way [of studying it] which is closer to an experimentalist’s description of what you actually observe in a lab.”

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The model the researchers used in their study is very simple, so while their method may open doors to new experiments, calculations for more complex systems will be needed to put quantum Darwinism on even firmer foundations, he says. “It would be a really great breakthrough if we could go beyond simple toy models,” says Palma.

Landi says the researchers are already interested in turning their theoretical investigations into an experiment – for example, with qubits made from trapped ions, where they could see how the timescale for the emergence of objectivity compares to the specific times during which those qubits are known to keep their quantumness.

Journal reference:

Physical Review A DOI: 10.1103/hn78-7xx3

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