時(shí)間晶體的最新突破,是一種不需要外部輸入的結(jié)構(gòu)

時(shí)間晶體的最新突破,是一種不需要外部輸入的結(jié)構(gòu)

A newly theorised type of time crystal could revolutionise the potential of these fascinating structures. Unlike the time crystals that have been created to date, it would not require the application of an external stimulus to keep the atoms ticking.

一種新理論的時(shí)間晶體可能徹底改變這些迷人結(jié)構(gòu)的潛力。與迄今為止所創(chuàng)造的時(shí)間晶體不同，它不需要外部刺激來(lái)維持原子的運(yùn)轉(zhuǎn)。

The method hinges on inducing entangled particles to affect each other's 'spin' (a property like angular momentum) over a distance. But to understand the details of this latest approach, first we need to step back a little.

這種方法的關(guān)鍵在于誘導(dǎo)相互糾纏的粒子在一定距離內(nèi)影響彼此的“自旋”(一種類似角動(dòng)量的性質(zhì))。但要了解這一最新方法的細(xì)節(jié)，我們首先需要后退一步。

Time crystals may sound like some wacky sci-fi concept, but they're a real phenomenon, first theorised in 2012. From the outside, they look just like normal crystals. But inside, the atoms - arranged in an otherwise normal repeating lattice structure - are behaving quite peculiarly.

時(shí)間晶體可能聽起來(lái)像某種古怪的科幻概念，但它們是一種真實(shí)的現(xiàn)象，2012年首次提出理論。從外面看，它們就像普通的晶體。但在內(nèi)部，原子——以正常的重復(fù)晶格結(jié)構(gòu)排列——表現(xiàn)得相當(dāng)奇特。

To date, time crystals produced experimentally have required an external stimulus (such as a pulse of electromagnetic radiation) at ground state, or lowest-energy state, to induce their ticking. This was achieved in 2016, but since then, there has been debate over whether this fits what we imagine a real time crystal to be like.

到目前為止，實(shí)驗(yàn)產(chǎn)生的時(shí)間晶體需要在基態(tài)或最低能量態(tài)的外部刺激(如電磁輻射脈沖)來(lái)誘發(fā)滴答聲。這是在2016年實(shí)現(xiàn)的，但從那以后，關(guān)于這是否符合我們對(duì)真實(shí)時(shí)間水晶的想象，一直存在爭(zhēng)議。

In fact, it has seemed very much that time crystals without an energy input to its ground state are simply physically impossible, according to a 2015 paper. In physics this is known as a no-go theorem.

事實(shí)上，根據(jù)2015年的一篇論文，沒有能量輸入到基態(tài)的時(shí)間晶體在物理上幾乎是不可能的。在物理學(xué)中，這被稱為“不走”定理。

According to the physicists, in time crystals such interaction-at-a-distance could theoretically produce a time crystal ground state that needs no energy injection.

根據(jù)物理學(xué)家的說(shuō)法，在時(shí)間晶體中，這種距離上的相互作用理論上可以產(chǎn)生一種不需要能量注入的時(shí)間晶體基態(tài)。

In their new paper, they propose a system of particles within the time crystal, each of which has a spin. They demonstrate that there is a way to describe the entangled particles' spins using a string theory model that meets the 2015 paper's definition of a time crystal.

在他們的新論文中，他們提出了一個(gè)時(shí)間晶體內(nèi)的粒子系統(tǒng)，每個(gè)粒子都有自旋。他們證明，有一種方法可以用弦理論模型描述糾纏粒子的自旋，該模型符合2015年論文對(duì)時(shí)間晶體的定義。

Even if the particles were spinning out of sync, the interactions between the particles would produce the ticking of a time crystal, according to the researchers.

研究人員表示，即使粒子旋轉(zhuǎn)不同步，粒子之間的相互作用也會(huì)產(chǎn)生時(shí)間晶體的滴答聲。

Now, this system would be incredibly complicated, with each particle able to spin in superposition - that is, in an undetermined state of both up and down at the same time.

現(xiàn)在，這個(gè)系統(tǒng)會(huì)變得非常復(fù)雜，每個(gè)粒子都可以在疊加狀態(tài)下自旋，也就是說(shuō)，同時(shí)處于一種向上和向下的未知狀態(tài)。

In fact, the whole thing might not be feasible to create in a lab setting. Entangling particles in this manner is an idea that works well on paper, but is unlikely to be easily doable practically.

事實(shí)上，在實(shí)驗(yàn)室環(huán)境中創(chuàng)造整個(gè)東西可能是不可行的。以這種方式纏繞粒子的想法在紙面上很有效，但在實(shí)際中不太可能輕易實(shí)現(xiàn)。