科學(xué)家破解了58年前的量子之謎

科學(xué)家破解了58年前的量子之謎

Curiosity-driven research can yield exciting discoveries. The latest is an accidental breakthrough by Australian engineers that has unintentionally solved a 58-year old mystery in quantum science.

好奇心驅(qū)動的研究可以產(chǎn)生令人興奮的發(fā)現(xiàn)。最近，澳大利亞工程師的一項(xiàng)意外突破，無意中解開了量子科學(xué)領(lǐng)域一個長達(dá)58年的謎團(tuán)。

As described in the journal Nature, they have worked out how to do what Nobel Laureate Nicolaas Bloembergen first suggested in 1961 but no-one has yet cracked: control the nucleus of a single atom using electric rather than magnetic fields.

正如《自然》(Nature)雜志所描述的，他們已經(jīng)找到了諾貝爾獎得主尼古拉•布隆伯根(Nicolaas Bloembergen) 1961年首次提出、但至今無人破解的方法:利用電場而非磁場來控制單個原子的原子核。

The discovery is a big deal.

這一發(fā)現(xiàn)意義重大。

It will simplify the control of individual atoms placed in nano electric devices, with implications for overhauling nuclear magnetic resonance – a technique used in a diverse range of fields such as modern physics, medicine, chemistry and mining.

它將簡化對置于納米電子設(shè)備中的單個原子的控制，并對核磁共振技術(shù)的革新產(chǎn)生影響。核磁共振技術(shù)廣泛應(yīng)用于現(xiàn)代物理、醫(yī)學(xué)、化學(xué)和采礦等領(lǐng)域。

Magnetic Resonance Imaging (MRI) machines, for instance, are used by hospitals to make three-dimensional images of the inside of a patient’s body without making any cuts, says lead scientist Andrea Morello from the University of New South Wales.

例如，新南威爾士大學(xué)的首席科學(xué)家安德里亞·莫雷羅(Andrea Morello)說，醫(yī)院使用磁共振成像儀對病人的身體內(nèi)部進(jìn)行三維成像，而不需要進(jìn)行任何切割。

“It works by detecting the presence of hydrogen nuclear spins within the body,” he explains, “and it does so by applying pulses of oscillating magnetic fields.

他解釋說:“它的工作原理是通過在人體內(nèi)探測到氫原子核自旋的存在，并通過施加振蕩磁場的脈沖來實(shí)現(xiàn)。”。

“What we (re)-discovered is that a similar result can be obtained by using electric, instead of magnetic fields.”

“我們(重新)發(fā)現(xiàn)，使用電場而不是磁場也可以得到類似的結(jié)果。”

UNSW/TONY MELOV

Although this had been theoretically proposed decades ago, it turned out to be extremely difficult to apply in practice, “so it was effectively forgotten for half a century”, Morello says, until his team’s random stroke of luck.

盡管這一理論早在幾十年前就提出了，但在實(shí)踐中卻極其困難，“所以它實(shí)際上被遺忘了半個世紀(jì)”，莫雷洛說，直到他的團(tuán)隊偶然的運(yùn)氣。

Their research seeks to understand how the “classical” world we experience emerges from the microscopic quantum world.

他們的研究旨在了解我們所經(jīng)歷的“經(jīng)典”世界是如何從微觀量子世界中浮現(xiàn)出來的。

“This experiment requires ‘kicking’ the nucleus with very strong oscillating magnetic fields, to make its evolution chaotic. But as we did so, we inadvertently damaged (like a fuse) the antenna that delivers these magnetic fields to the nucleus.”

“這個實(shí)驗(yàn)需要用非常強(qiáng)的振蕩磁場‘踢’原子核，讓它的演化變得混亂。但就在我們這么做的時候，我們無意中損壞了(像保險絲一樣)向原子核傳遞磁場的天線。”

The damaged antenna could then only produce an electric field. What surprised them was that the experiment still worked.

受損的天線只能產(chǎn)生電場。但讓他們吃驚的是這個實(shí)驗(yàn)仍然有效。

The big difference between electric and magnetic fields is how they spread out. Electric fields are produced by an electrode and decay very quickly, making them much easier to shield – think Faraday cage, says Morello – than magnetic fields, which spread out more.

電場和磁場的最大區(qū)別在于它們是如何分布的。電場是由電極產(chǎn)生的，并且衰減得非?？?，這使得它們更容易被屏蔽，就像法拉第籠一樣，而磁場則分散得更廣。

“Our research involves controlling individual atoms at the nanometre scale, to build quantum computers and quantum sensors; being able to address the atoms by electric fields will give us a great advantage, because we will be able to localise the fields around each atom.”

“我們的研究包括在納米尺度上控制單個原子，建造量子計算機(jī)和量子傳感器;能通過電場定位原子將會給我們帶來巨大的優(yōu)勢，因?yàn)槲覀儗⒛軌蚨ㄎ幻總€原子周圍的電場。”

He describes it like trying to move a ball on a billiard table – using magnetic fields would be like shaking the whole table, which will move all the balls and spoil the game.

他把它描述為試圖在臺球桌上移動一個球——使用磁場就像搖動整個桌子，這會移動所有的球并破壞游戲。

“Doing it by electric fields, instead, is like being handed an actual stick, with which you can just hit the ball you want to move.”

“相反，通過電場來做，就像遞給你一根真正的棍子，你可以用它來打你想要移動的球。”

Morello is excited about the potential applications, from understanding how the world we experience arises from the quantum realm to building sensors of electromagnetic fields with greater sensitivity.

從理解我們所經(jīng)歷的世界如何從量子領(lǐng)域產(chǎn)生，到建造靈敏度更高的電磁場傳感器，莫雷洛對潛在的應(yīng)用感到興奮。

“And all this, in a simple electronic device made in silicon, controlled with small voltages applied to a metal electrode!”

“而這一切，都是在一個簡單的硅制電子裝置里，用施加在金屬電極上的小電壓來控制的!”