10 Myths About The Quantum Universe
For centuries, the laws of physics seemed completely deterministic. If you knew where every particle was, how fast it was moving, and what the forces were between them at any one instant, you could know exactly where they’d be and what they’d be doing at any point in the future. From Newton to Maxwell, the rules that governed the Universe had no built-in, inherent uncertainty to them in any form. Your only limits arose from your limited knowledge, measurements, and calculational power.
几个世纪以来，物理定律似乎是完全确定的。 如果你知道每个粒子的位置，运动的速度，以及在任何一个时刻它们之间的作用力，你就能准确地知道它们在未来的任何一个时刻会在哪里，以及它们会做什么。 从牛顿到麦克斯韦，支配宇宙的规则没有内在的、固有的任何形式的不确定性。 你们唯一的限制来自于你们有限的知识、测量和计算能力。
All of that changed a little over 100 years ago. From radioactivity to the photoelectric effect to the behavior of light when you passed it through a double slit, we began realizing that under many circumstances, we could only predict the probability that various outcomes would arise as a consequence of the quantum nature of our Universe. But along with this new, counterintuitive picture of reality, many myths and misconceptions have arisen. Here’s the true science behind 10 of them.
这一切在100多年前发生了改变。 从放射性到光电效应，再到光通过双缝时的行为，我们开始意识到，在许多情况下，我们只能预测宇宙的量子特性会产生各种结果的可能性。 但是伴随着这个新的，违反直觉的现实图景，许多神话和误解已经产生。 以下是其中10种方法背后的真正科学原理。
1.) Quantum effects only happen on small scales. When we think of quantum effects, we typically think about individual particles (or waves) and the bizarre properties they display. But large-scale, macroscopic effects happen that are inherently quantum in nature.
1.) 量子效应只发生在小尺度上。 当我们想到量子效应时，我们通常会想到单个粒子(或波)以及它们所表现出来的奇异属性。 但是大规模的宏观效应，本质上是量子效应。
Conducting metals cooled below a certain temperature become superconductors: where their resistance drops to zero. Building superconducting tracks where magnets levitate above them and travel around them without ever slowing down is a routine student science project these days, built on an inherently quantum effects.
导电金属在低于一定温度时冷却成为超导体: 在这种情况下，它们的电阻降到零。 建造超导轨道，磁铁悬浮在轨道上方，绕轨道飞行而不放慢速度，如今已成为学生们的常规科学项目，建立在固有的量子效应之上。
Superfluids can be created on large, macroscopic scales, as can quantum drums that simultaneously do and don’t vibrate. Over the past 25 years, 6 Nobel Prizes have been awarded for various macroscopic quantum phenomena.
超流体可以在宏观的大尺度上产生，就像量子鼓可以同时振动和不振动一样。 在过去的25年里，有6个诺贝尔奖被授予各种宏观量子现象。
2.) Quantum always means “discrete.” The idea that you can chop up matter (or energy) into individual chunks — or quanta — is an important concept in physics, but it doesn’t fully encompass what it means for something to be “quantum” in nature. For example: consider an atom. Atoms are made of atomic nuclei with electrons bound to them.
2.) 量子总是意味着“离散” 你可以把物质(或能量)分割成单独的块(或量子) ，这是物理学中的一个重要概念，但它并没有完全涵盖“量子”在自然界中的含义。 例如: 考虑一个原子。 原子是由原子核构成的，原子核上有与原子核相连的电子。
Now, think about this question: where is the electron at any moment in time?
现在，想想这个问题: 电子在任何时刻在哪里？
Even though the electron is a quantum entity, its position is uncertain until you measure it. Take many atoms and bind them together (such as in a conductor), and you’ll frequently discover that although there are discrete energy levels that the electrons occupy, their positions can literally be anywhere within the conductor. Many quantum effects are continuous in nature, and it’s eminently possible that space and time, at a fundamental, quantum level, are continuous, too.
即使电子是一个量子实体，它的位置在你测量它之前是不确定的。 把许多原子绑在一起(比如在导体中) ，你会经常发现，尽管电子占据着离散的能级，但是它们的位置可以在导体中的任何地方。 许多量子效应在本质上是连续的，而且在基本的量子水平上，空间和时间也很有可能是连续的。
3.) Quantum entanglement allows information to travel faster-than-light. Here’s an experiment we can perform:
3.)量子纠缠可以让信息以超光速的方式传播。下面是我们可以做的一个实验:
- create two entangled particles, 创造两个相互纠缠的粒子,
- separate them by a great distance, 把他们隔得很远,
- measure certain quantum properties (like the spin) of one particle on your end, 测量你那一端一个粒子的某些量子属性(如自旋),
- and you can know some information about the quantum state of other particle instantaneously: faster than the speed of light. 你可以立刻知道其他粒子的量子态的一些信息: 比光速还快
But here’s the thing about this experiment: no information is being transmitted faster than the speed of light. All that’s happening is that by measuring the state of one particle, you are constraining the probable outcomes of the other particle. If someone goes and measures the other particle, they will have no way of knowing that the first particle has been measured and the entanglement has been broken. The only way to determine whether entanglement has been broken or not is to bring the results of both measurements back together again: a process that can only occur at light speed or slower. No information can be passed faster than light; this was proven in a 1993 theorem.
但是这个实验的问题是: 没有任何信息的传输速度超过光速。 所发生的一切就是，通过测量一个粒子的状态，你约束了另一个粒子的可能结果。 如果有人去测量另一个粒子，他们将无法知道第一个粒子已经被测量，纠缠已经被打破。 确定纠缠是否已经被破坏的唯一方法是将两个测量的结果重新放在一起: 这个过程只能以光速或者更慢的速度进行。 没有任何信息可以比光传递得更快，这一点在1993年的一个定理中得到了证明。
4.) Superposition is fundamental to quantum physics. Imagine you have multiple possible quantum states that a system can be in. Maybe it can be in state “A” with 55% probability, state “B” with 30% probability, and state “C” with 15% probability. Whenever you go to make a measurement, however, you never see a mix of these possible states; you’ll only get a single-state outcome: either it’s “A,” “B,” or “C.”
4.) 叠加态是量子物理的基础。 假设一个系统可以处于多种可能的量子状态。 也许它处于状态“ a”的概率是55% ，状态“ b”的概率是30% ，状态“ c”的概率是15% 。 然而，无论何时进行测量，都不会看到这些可能状态的混合; 只会得到单一状态的结果: 要么是“ a” ，“ b” ，要么是“ c”
Superpositions are incredibly useful as intermediate calculational steps to determine what your possible outcomes (and their probabilities) will be, but we can never measure them directly. In addition, superpositions don’t apply to all measurables equally, as you can have a superposition of momenta but not positions or vice versa. Unlike entanglement, which is a fundamental quantum phenomenon, superposition is not quantifiably or universally measurable.
叠加是非常有用的中间计算步骤，以确定你可能的结果(和它们的概率)是什么，但我们永远不能直接衡量他们。 此外，叠加并不能平均地应用于所有的测量值，因为你可以有动量的叠加，但不能有位置，反之亦然。 与作为基本量子现象的纠缠不同，叠加不是可以量化的，也不是可以普遍测量的。
5.) There’s nothing wrong with us all choosing our favorite quantum interpretation. Physics is all about what you can predict, observe, and measure in this Universe. Yet with quantum physics, there are multiple ways to conceive of what’s occurring at a quantum level that all agree equally with experiments. Reality can be:
5.) 我们选择自己最喜欢的量子解释并没有什么错。 物理学是关于在这个宇宙中你可以预测、观察和测量的一切。 然而，对于量子物理学，有多种方法来设想在量子层面上发生的事情，这些方法都与实验一致。 现实可能是:
- a series of quantum wavefunctions that instantaneously “collapse” when a measurement is made, 一系列量子波函数在测量时瞬间“坍缩” ,
- an infinite ensemble of quantum waves, where a measurement selects one member of the ensemble, 一个无限的量子波的集合，其中一个测量选择集合中的一个成员,
- a superposition of forwards-moving and backwards-moving potentials that meet in a “quantum handshake,” 前进和后退势能的叠加，在”量子握手”中相遇
- an infinite number of possible worlds corresponding to the possible outcomes, where we simply occupy one path, 对应于可能结果的无数个可能世界，我们只占据一条路,
as well as many others. Yet choosing one interpretation over another teaches us nothing except, perhaps, our own human biases. It’s better to learn what we can observe and measure under various conditions, which is physically real, than to prefer an interpretation that has no experimental benefit over any other.
和其他人一样。 然而，选择一种解释而不是另一种解释并不能教会我们什么，也许除了我们自己的人类偏见之外。 学习在各种条件下我们可以观察和测量的东西，这是物理上真实的，而不是喜欢一种没有任何实验益处的解释。
6.) Teleportation is possible, thanks to quantum mechanics. There actually is a real phenomenon known as quantum teleportation, but it most definitively does not mean that it’s physically possible to teleport a physical object from one location to another. If you take two entangled particles and keep one close by while sending the other one to a desired distination, you can teleport the information from the unknown quantum state on one end to the other end.
6.) 心灵运输是可能的，多亏了量子力学。 确实存在一种叫做量子遥传的现象，但这并不意味着物理上可以将一个物体从一个地方传送到另一个地方。 如果你拿两个纠缠的粒子，让其中一个靠近，同时把另一个发送到你想要的距离，你就可以把信息从一端的未知量子态传送到另一端。
This has enormous restrictions on it, however, including that it only works for single particles and that only information about an indeterminate quantum state, not any physical matter, can be teleported. Even if you could scale this up to transmit the quantum information that encodes an entire human being, transferring information is not the same as transferring matter: you cannot teleport a human, ever, with quantum teleportation.
然而，这对它有着巨大的限制，包括它只适用于单个粒子，并且只有关于不确定量子态的信息，而不是任何物理物质，可以被传送。 即使你可以扩展到传输编码整个人类的量子信息，传输信息和传输物质是不一样的: 你永远不能用量子遥传传送人类。
7.) Everything is uncertain in a quantum Universe. Some things are uncertain, but many things are extremely well-defined and well-known in a quantum Universe. If you take an electron, for example, you cannot know:
7.) 量子宇宙中的一切都是不确定的。 有些事情是不确定的，但是许多事情在量子宇宙中是非常明确和众所周知的。 举个例子，如果你拿一个电子来说，你不可能知道:
- its position and its momentum, 它的位置和动力,
- or its angular momentum in multiple, mutually perpendicular directions, 或者它的角动量在多个互相垂直的方向上,
exactly and simultaneously under any circumstances. But some things about the electron can be known exactly! We can know its rest mass, its electric charge, or its lifetime (which appears to be infinite) with exact certainty.
在任何情况下都是完全同步的。 但是关于电子的一些事情是可以精确地知道的！ 我们可以精确地知道它的静止质量，它的电荷，或者它的寿命(看起来是无限的)。
The only things that are uncertain in quantum physics are pairs of physical quantities that have a specific relationship between them: that are pairs of conjugate variables. This is why there are uncertainty relations between energy and time, voltage and free charge, or angular momentum and angular position. While many pairs of quantities have an inherent uncertainty between them, many quantities are still known exactly.
在量子物理学中唯一不确定的事情就是成对的物理量，它们之间有一种特定的关系: 成对的共轭变量。 这就是为什么在能量和时间，电压和自由电荷，或者角动量和角位置之间存在不确定关系的原因。 虽然许多数量对之间存在固有的不确定性，但许多数量仍然是确切知道的。
8.) Every particle of the same type has the same mass. If you could take two identical particles — like two protons or two electrons — and put them on a perfectly accurate scale, they’d always have the same exact mass as one another. But that’s only because protons and electrons are stable particles with infinite lifetimes.
8.) 同一类型的每个粒子都有相同的质量。 如果你可以把两个全同粒子ーー比如两个质子或两个电子ーー放在一个完全精确的尺度上，它们的质量总是完全相同的。 但这仅仅是因为质子和电子是稳定的粒子，具有无限的寿命。
If you instead took unstable particles that decayed after a short while — such as two top quarks or two Higgs bosons — and put them on a perfectly accurate scale, you wouldn’t get the same values. This is because there’s an inherent uncertainty between energy and time: if a particle only lives for a finite amount of time, then there’s an inherent uncertainty in the amount of energy (and hence, from E = mc², rest mass) that the particle has. In particle physics, we call this a particle’s “width,” and it can lead to a particle’s inherent mass being uncertain by up to a few percent.
相反，如果你将不稳定的粒子(比如两个顶夸克或两个希格斯玻色子)短时间内衰变，然后将它们放在一个完全准确的尺度上，你就不会得到相同的值。 这是因为在能量和时间之间存在着固有的不确定性: 如果一个粒子只存在有限的时间，那么这个粒子所具有的能量(因此，从 e mc2来看，静止质量)就存在着固有的不确定性。 在粒子物理学中，我们称之为粒子的“宽度” ，它可以导致粒子固有质量的不确定性达到百分之几。
9.) Einstein himself denied quantum mechanics. It’s true that Einstein had a famous quote about how, “God does not play dice with the Universe.” But arguing against a fundamental randomness inherent to quantum mechanics — which is what the context of that quote was about — is arguing about how to interpret quantum mechanics, not an argument against quantum mechanics itself.
9.) 爱因斯坦本人否认了量子力学。 诚然，爱因斯坦有句名言是关于“上帝不会和宇宙玩骰子”的 但是，反对量子力学的基本随机性—- 这就是引用的上下文—- 是在讨论如何解释量子力学，而不是反对量子力学本身。
In fact, the nature of Einstein’s argument was that there might be more to the Universe than we can presently observe, and if we could understand the rules we have not yet uncovered, perhaps what appears to be randomness to us here might reveal a deeper, non-random truth. Although this position has not yielded useful results, explorations of the fundamentals of quantum physics continues to be an active area of research, successfully ruling out a number of interpretations involving “hidden variables” present in the Universe.
事实上，爱因斯坦论证的本质是，宇宙中可能有比我们现在能观察到的更多的东西，如果我们能够理解我们尚未发现的规则，也许在我们看来是随机的东西，可能会揭示一个更深层次的、非随机的真理。 虽然这一立场没有产生有用的结果，但量子物理学基本原理的探索仍然是一个活跃的研究领域，成功地排除了一些涉及宇宙中存在的”隐变量”的解释。
10.) Exchanges of particles in quantum field theory completely describe our Universe. This is the “dirty little secret” of quantum field theory that physicists learn in graduate school: the technique we most commonly use for calculating the interactions between any two quantum particles. We visualize them as particles being exchanged between those two quanta, along with all possible further exchanges that could occur as intermediate steps.
10.) 量子场论中的粒子交换完整地描述了我们的宇宙。 这就是物理学家在研究生院学到的量子场论的“肮脏的小秘密” : 我们最常用来计算任意两个量子粒子之间相互作用的技术。 我们把它们想象成在这两个量子之间交换的粒子，以及所有可能的进一步交换，它们可以作为中间步骤发生。