背景介绍：
随着科技的飞速发展，计时技术的精准度成为了衡量科技进步的重要标志之一。原子钟，作为目前最为精准的计时设备，已广泛应用于GPS导航、互联网通信和股市交易等关键领域。然而，科学家们并未止步于此，他们一直在探索更为精准的计时方式。最近，一篇发表在《自然》杂志上的论文引起了广泛关注，论文中的研究人员宣布正在着手打造原子钟的继任者——核时钟。这一新型时钟有望将计时精准度提升至前所未有的高度，为科学研究和实际应用带来革命性的突破。
The world’s first nuclear clock
is on the horizon
世界第一台核时钟即将问世
It would be 1000 times more accurate than today’s atomic timekeepers
它将比今天的原子钟精确上千倍
For the discerning timekeeper, only an atomic clock will do. Whereas the best quartz timepieces will lose a millisecond every six weeks, an atomic clock might not lose a thousandth of one in a decade. Such devices underpin everything from GPS and the internet to stock-market trading.
对于追求极致精准的计时员而言，唯有原子钟方能满足其严苛要求。最优质的石英钟每六周便会损失一毫秒的时间，相比之下，原子钟在十年内可能连千分之一毫秒都不会损失。这类精密设备支撑着从GPS导航、互联网通信到股市交易等一系列关键领域。
That may seem good enough for most. But in a paper recently published in Nature, researchers report being ready to build its successor: the nuclear clock. Ekkehard Peik, one of the field’s pioneers, says such a clock could be a factor of 1,000 times better than today’s standard atomic clocks.
对于广大民众而言，原子钟的精准度似乎已经无可挑剔。然而，在最近一期《自然》杂志上发表的一篇论文中，研究人员宣布他们已经着手准备打造原子钟的继任者——核时钟。该领域的先驱艾克哈德·佩克指出，这样的时钟在精准度上可能比现今的标准原子钟高出上千倍。
In atomic clocks, the electrons around an atom’s nucleus are jolted into a higher energy state by incoming radiation of a specific frequency. Each wave cycle of the radiation therefore corresponds to a “tick” measuring a small fraction of a second. Nuclear clocks would follow the same principles, but use the transitions of neutrons and protons inside the nucleus.
在原子钟的运行机制中，原子核周围的电子在特定频率的入射辐射作用下，被激发至更高的能量状态。因此，辐射的每个波周期都对应于测量一秒的一小部分“滴答声”。而核时钟将遵循相同的物理原则，但其利用的是原子核内部中子与质子的转变。
The most promising candidate nucleus is thorium-229, which, uniquely, has a nuclear transition that lasers should be able to trigger. The exact frequency at which this occurs, however, has long been unknown.
在众多候选原子核中，钍-229因其能通过激光触发核转变的特性而备受瞩目。然而，长期以来，这一转变发生的精确频率一直是个未知数。
The authors of the latest paper, led by Chuankun Zhang and Jun Ye from the University of Colorado in Boulder, circumvented the problem by using a custom-built laser capable of exposing thorium-229 to a range of similar frequencies.
这篇最新论文的作者团队由科罗拉多大学博尔德分校的张传坤教授和叶军教授领衔，他们通过使用一种能将钍-229暴露在相似频率范围内的定制激光器，巧妙地解决了这一难题。
When they fired it at the target, one particular beam matched the nuclear transition frequency. The system needs further optimising, but “It’s the first demonstration that all the components of a nuclear clock are here,” says Mr Zhang.
当向目标发射时，一个特定的激光束成功与核转变频率相匹配。尽管该系统仍需进一步优化，但张教授表示：“这是核时钟所有组件首次被整合在一起的演示。”
Because atomic clocks are more than accurate enough for most practical uses, scientists are not seeking to replace them. They are more excited about having two independent ways of measuring time: atomic clocks, which depend solely on the electromagnetic force governing the electrons’ movement; and nuclear clocks, which also obey the strong nuclear force.
鉴于原子钟对于大多数实际应用场景而言已足够精确，科学家们并非旨在取代它们。他们更为兴奋的是能够拥有两种独立的时间测量方式：一种是完全依赖于控制电子运动的电磁力的原子钟；另一种是服从强核力的核时钟。
One use to which this could be put is testing Einstein’s theories of relativity. These posit, among other things, that clocks will tick more slowly in stronger gravitational fields. Those relativistic effects should be the same regardless of the clock. If the nuclear clock responds differently, then the theories may need revising.
核时钟的另一项潜在用途是测试爱因斯坦的相对论。这些理论表明，在更强的引力场中，时钟的滴答声将变得更为缓慢。无论采用何种时钟，这些相对论效应都应当保持一致。如果核时钟的反应与预期不同，那么现有的理论或许需要得到修正。
Another question concerns the physical constants on which the different forces rely, such as the fine-structure constant, which determines the strength of the electromagnetic force. These seem to have fixed values, an oddity in a constantly evolving universe.
另一个值得探讨的问题涉及不同力所依赖的物理常数，例如精细结构常数，它决定了电磁力的强度。这些常数似乎都拥有固定的值，这在不断演变的宇宙中显得尤为奇特。
Measuring time in ways that depend on different forces would offer a sensitive way to test any drift. If an atomic clock fell out of sync with a nuclear clock, for example, some change in the underlying physics might be responsible. Only time will tell.
通过采用不同力的方式测量时间，我们将能够获得一种灵敏的手段来检测时间的偏差。例如，如果原子钟与核时钟出现不同步的情况，那么基础物理学中的某些变化或许就是导致这一现象的罪魁祸首。最终，只有时间才能告诉我们答案。
重难点词汇：
jolt [dʒəʊlt] n.震动；颠簸；摇晃 v. 使震动；使颠簸
circumvent [səˈkʌmvənt] v. 规避；设法避免；以巧妙手段绕过
posit [ˈpəʊzɪt] v. 假定；认为…为真；安置
oddity [ˈɒdɪti] n. 奇特的人或事；古怪；异常
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