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(dòng)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(wú)意中解開了量子科學(xué)領(lǐng)域一個(gè)長(zhǎng)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(jiǎng)得主尼古拉•布隆伯根(Nicolaas Bloembergen) 1961年首次提出、但至今無(wú)人破解的方法:利用電場(chǎng)而非磁場(chǎng)來(lái)控制單個(gè)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(jiǎn)化對(duì)置于納米電子設(shè)備中的單個(gè)原子的控制，并對(duì)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(shuō)，醫(yī)院使用磁共振成像儀對(duì)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(shuō):“它的工作原理是通過(guò)在人體內(nèi)探測(cè)到氫原子核自旋的存在，并通過(guò)施加振蕩磁場(chǎng)的脈沖來(lái)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(chǎng)而不是磁場(chǎng)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(gè)世紀(jì)”，莫雷洛說(shuō)，直到他的團(tuán)隊(duì)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(lái)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(gè)實(shí)驗(yàn)需要用非常強(qiáng)的振蕩磁場(chǎng)‘踢’原子核，讓它的演化變得混亂。但就在我們這么做的時(shí)候，我們無(wú)意中損壞了(像保險(xiǎn)絲一樣)向原子核傳遞磁場(chǎng)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(chǎng)。但讓他們吃驚的是這個(gè)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(chǎng)和磁場(chǎng)的最大區(qū)別在于它們是如何分布的。電場(chǎng)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(chǎng)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(gè)原子，建造量子計(jì)算機(jī)和量子傳感器;能通過(guò)電場(chǎng)定位原子將會(huì)給我們帶來(lái)巨大的優(yōu)勢(shì)，因?yàn)槲覀儗⒛軌蚨ㄎ幻總€(gè)原子周圍的電場(chǎng)。”

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(tái)球桌上移動(dòng)一個(gè)球——使用磁場(chǎng)就像搖動(dòng)整個(gè)桌子，這會(huì)移動(dòng)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(guò)電場(chǎng)來(lái)做，就像遞給你一根真正的棍子，你可以用它來(lái)打你想要移動(dòng)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(chǎng)傳感器，莫雷洛對(duì)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(gè)簡(jiǎn)單的硅制電子裝置里，用施加在金屬電極上的小電壓來(lái)控制的!”