A physicist in the UK has created the fifth state of matter from her living room during the coronavirus lockdown using quantum technology.
Dr Amruta Gadge from the University of Sussex created a Bose-Einstein Condensate (BEC) – a state of matter where extremely cold atoms clump together and act as if they were a single entity.
Despite working from her living room two miles away from the lab, Dr Gadge was able to use her computer to control lasers and radio waves and create the BEC.
Researchers at the university’s quantum department think it’s the first time someone has established a BEC remotely in a lab that didn’t previously have one.
The achievement could provide a blueprint for using a computer to operate quantum technology remotely, in inaccessible environments such as space or underwater.
Quantum technology makes use of the spooky effects of quantum physics to vastly speed up information processing, which could lead to the most powerful computer on Earth.
Dr Amruta Gadge working from home, around two miles from the University of Sussex lab, with an image of the BEC on her screen
BOSE-EINSTEIN CONDENSATE: THE FIFTH FORM OF MATTER
A Bose-Einstein condensate (BEC) is known as the fifth state of matter, after solid, liquid, gas and plasma.
It is formed at a fraction above absolute zero and only in atoms that act like bosons, one of two types of fundamental particles.
When bosonic atoms are cooled to form a condensate, they can lose their individuality.
They behave like one big collective superatom, a bit like how photons become indistinguishable in a laser beam.
The first BEC was shown experimentally almost 25 years ago by researchers at the University of Colorado Boulder in the US.
‘We are all extremely excited that we can continue to conduct our experiments remotely during lockdown, and any possible future lockdowns,’ said Peter Krüger, professor of experimental physics at the University of Sussex.
‘Enhancing the capabilities of remote lab control is relevant for research applications aimed at operating quantum technology in inaccessible environments such as space, underground, in a submarine, or in extreme climates.’
The fifth state of matter follows solid, liquid, gas and plasma, which is produced when the atoms in a gas become ionised.
In the mid-1920s, Albert Einstein and Indian physicist Satyendra Nath Bose predicted that quantum mechanics can force a large number of particles to behave like a single particle, heralding research into the so-called fifth matter.
However, it wasn’t until June 1995 that scientists created the world’s first BEC, by cooling a gas of around 2,000 rubidium atoms.
A BEC consists of a cloud of hundreds of thousands of rubidium atoms, typically of gases, cooled down to temperatures more than a billion times colder than freezing.
Image confirming the successful creation of the BEC, from left to right, as the atoms become cooled to near absolute zero and act like a single mechanical entity
At these temperatures, atoms are close to absolute zero, or the point at which atoms stop moving.
Just above absolute zero, however, atoms take on a different property and coalesce into a single quantum object, which can sense very low magnetic fields.
The University of Sussex’s Quantum Systems & Devices research group, just outside of Brighton, conducts experiments with the aim of using a BEC as a magnetic sensor.
‘We use multiple carefully timed steps of laser and radio wave cooling to prepare rubidium gases at these ultra-low temperatures,’ said Professor Krüger.
‘This requires accurate computer control of laser light, magnets and electric currents in microchips based on vigilant monitoring of environmental conditions in the lab while nobody is able to be there to check in person.’
Just before lockdown measures ruled that those who can work from home should do so, the researchers set-up a 2D magnetic optical trap, an odd-looking set of metal apparatus that uses lasers and magnets, to produce trapped atoms.
Dr Gadge setting up the lasers that control the atoms at the university’s quantum lab prior to lockdown
Dr Gadge was able to make the complex calculations and run the sequence from her home by accessing the lab computers remotely.
‘The research team has been observing lockdown and working from home and so we have not been able to access our labs for weeks,’ she said.
‘The process has been a lot slower than if I had been in the lab as the experiment is unstable and I’ve had to give 10 to 15 minutes of cooling time between each run.
‘This is obviously not as efficient and way more laborious to do manually because I’ve not been able to do systematic scans or fix the instability like I could working in the lab.
An atom ‘trap’ used to create a Bose-Einstein condensate, in another experiment launched from Kiruna in Sweden. Bose-Einstein condensates (BECs) were predicted between 1924 to 1925 by Satyendra Nath Bose and Albert Einstein but the technology required to create them is only just emerging
‘But we were determined to keep our research going so we have been exploring new ways of running our experiments remotely.’
Trapped cold quantum gases are controlled to create extremely accurate and precise sensors to detect and study new materials, geometries and devices.
The research team are developing their sensors to be applied in areas such as electrical vehicle batteries, touch screens, solar cells and medical advancements such as brain imaging.
The team have also been working on having a second lab with a BEC running consistently over the past nine months as part of a wider project to develop a new type of magnetic microscopy and other quantum sensors.
Sussex is part of the UK’s national quantum computing network, formed in 2013 with the mission of commercialising the first universal quantum computer.
The university published its blueprint for how to build a quantum computer back in 2017, in Science Advances.
Last October, Google claimed to have made a quantum computing breakthrough with a processor that performs a calculation in minutes that would take classical computers 10,000 years.
However, Google’s big rivals in quantum technology research including IBM took issue with Google’s claim that it had achieved the so-called act of ‘quantum supremacy’ – solving problems that no classical machine can.
IBM, which is working on its own quantum computer design, argued that the random number generator task completed by Google’s ‘Sycamore’ quantum computer is technically achievable on a classical computer – after 10,000 years of processing.
‘Because the original meaning of the term quantum supremacy, as proposed by John Preskill in 2012, was to describe the point where quantum computers can do things that classical computers can’t, this threshold has not been met,’ IBM researchers wrote in a blog post.
Professor Winfried Hensinger, director of the Sussex Centre for Quantum Technologies, told Laboratory News at the time: ‘The problem they [Google] picked is a completely utterly useless problem – the next step will be to solve useful problems.’
WHAT IS A QUANTUM COMPUTER AND HOW DOES IT WORK?
The key to a quantum computer is its ability to operate on the basis of a circuit not only being ‘on’ or ‘off’, but occupying a state that is both ‘on’ and ‘off’ at the same time.
While this may seem strange, it’s down to the laws of quantum mechanics, which govern the behaviour of the particles which make up an atom.
At this micro scale, matter acts in ways that would be impossible at the macro scale of the universe we live in.
Quantum mechanics allows these extremely small particles to exist in multiple states, known as ‘superposition’, until they are either seen or interfered with.
A scanning tunneling microscope shows a quantum bit from a phosphorus atom precisely positioned in silicon. Scientists have discovered how to make the qubits ‘talk to one another
A good analogy is that of a coin spinning in the air. It cannot be said to be either a ‘heads’ or ‘tails’ until it lands.
The heart of modern computing is binary code, which has served computers for decades.
While a classical computer has ‘bits’ made up of zeros and ones, a quantum computer has ‘qubits’ which can take on the value of zero or one, or even both simultaneously.
One of the major stumbling blocks for the development of quantum computers has been demonstrating they can beat classical computers.
Google, IBM, and Intel are among companies competing to achieve this.