2020年经济学人 量子领域没有蝴蝶效应(1)（在线收听）

In Ray Bradbury's science-fiction story "A Sound of Thunder", a character time-travels far into the past and inadvertently crushes a butterfly underfoot.

在雷·布莱伯利的科幻小说《一声惊雷》中，主角穿越到了遥远的过去，并在无意间踩死了一只蝴蝶。

The consequences of that minuscule change ripple through reality such that, upon the time-traveller's return, the present has been dramatically changed.

这一微小改变的结果波及现实，当这位时间旅行者返回现实，世界已经发生了巨大的变化。

The "butterfly effect" describes the high sensitivity of many systems to tiny changes in their starting conditions.

“蝴蝶效应”描绘的是诸多系统对初始条件中微小变化的高敏感度。

But while it is a feature of classical physics, it has been unclear whether it also applies to quantum mechanics,

但虽然这是经典物理学的一个特征，但它是否也适用于量子力学尚不清楚，

which governs the interactions of tiny objects like atoms and fundamental particles.

而量子力学控制着微小物体的相互作用，比如原子和基本粒子。

Bin Yan and Nikolai Sinitsyn, a pair of physicists at Los Alamos National Laboratory, decided to find out.

洛斯阿拉莫斯国家实验室的两名物理学家Bin Yan和Nikolai Sinitsyn决定找出答案。

As they report in Physical Review Letters, quantum-mechanical systems seem to be more resilient than classical ones.

正如他们在《Physical Review Letters》中报告的那样，量子力学系统似乎比经典物理系统更具复原性。

Strangely, they seem to have the capacity to repair damage done in the past as time unfolds.

奇怪的是，随着时间推移，它们似乎具备修复过去损伤的能力。

To perform their experiment, Drs Yan and Sinitsyn ran simulations on a small quantum computer made by IBM.

为了完成他们的实验，Yan和Sinitsyn博士在IBM制造的一台小型量子计算机中进行了模拟。

They constructed a simple quantum system consisting of "qubits"—

他们创建了一个由“量子位”组成的简单量子系统——

the quantum analogue of the familiar one-or-zero bits used by classical computers.

“量子位”是类似经典计算机中常用的一或零位的量子模拟。

Like an ordinary bit, a qubit can be either one or zero. But it can also exist in "superposition", a chimerical mix of both states at once.

和普通位一样，量子位要么是一，要么是零。但它也可以以“叠加”形式存在，即两种状态同时存在的一种空想混合。

Having established the system, the authors prepared a particular qubit by setting its state to zero.

建立了系统后，作者通过将其状态设为零来拟定一个特定的量子位。

That qubit was then allowed to interact with the others in a process called "quantum scrambling" which,

该量子位被允许和“量子置乱”中的其他量子位相互作用，

in this case, mimics the effect of evolving a quantum system backwards in time.

以此模拟时间倒退中量子系统进化的影响。

Once this virtual foray into the past was completed, the authors disturbed the chosen qubit,

一旦这种对过去的虚拟突袭完成，作者们就会扰乱所选择的量子位，

destroying its local information and its correlations with the other qubits.

摧毁了其局部信息，以及它和其他量子位的关联。

Finally, the authors performed a reversed scrambling process on the now-damaged system.

最后，作者们在现已损坏的系统中进行了反向置乱处理。

This was analogous to running the quantum system all the way forwards in time to where it all began.

这类似于让量子系统在时间中正向前行，来到它开始的地方。

They then checked to see how similar the final state of the chosen qubit was to the zero-state it had been assigned at the beginning of the experiment.

然后他们查看了被选量子位的最终状态和他们在实验之初设定的零状态有多么相似。