Physicist creates fifth state of matter from their living room

When the UK government announced the national lockdown on the 23 March 2020 due to the Covid19 pandemic, the labs at the University of Sussex were forced to close their doors but the Quantum Systems and Devices group were determined to keep their experiments running. This was no easy feat with large intricate and complex laser and optics set-ups in state-of-the-art labs which couldn’t just be transported home.

A BEC consists of a cloud of hundreds of thousands of rubidium atoms cooled down to nanokelvin temperatures which is more than a billion times colder than freezing.  

At this point the atoms take on a different property and behave all together as a single quantum object. This quantum object has special properties which can sense very low magnetic fields. 

Professor Krüger said: “We use multiple carefully timed steps of laser and radio wave cooling to prepare rubidium gases at these ultralow temperatures. 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.”

Without being able to set foot in the labs, bar a few essential maintenance visits, the only way to continue working on their experiments was for the research team to access the labs using dedicated remote control and monitoring technology.

With teaching already online and lockdown imminent, the team rapidly made preparations to work from home.  In the days leading up to lockdown, equipment, chairs, and computers were being ferried to various homes, deliveries were diverted and protocols for the remote access and online control were put in place. It was a massive team effort.

Just in time before lockdown, the researchers set-up a 2D magnetic optical trap and have returned only a couple of times to carry out essential maintenance. Dr Gadge, was then able to make the complex calculations, optimising and running the sequence from her home by accessing the lab computers remotely.

To achieve this, the team had to develop various monitoring systems to keep track of every important parameter such as laser parameters, vacuum pressure, electric currents and temperatures. The degree of automation and monitoring achieved made it possible to run the complex sequence of various cooling stages remotely from home to reach temperatures leading to a BEC.

Gadge (pictured left) explained in more detail: “Bose-Einstein Condensates have unique properties that make them extremely sensitive to low magnetic fields, making them ideal sensors. Unprecedented sensitivities can be reached using these quantum objects. An extremely controlled laboratory environment with several complex systems consisting of precisely tuned lasers, ultra-high vacuum systems and advanced electronic components is required to achieve a Bose – Einstein Condensate.”

“Typically we start with hot (hundreds of degrees) rubidium atoms which are cooled to around less than a thousandth of a degree above absolute zero temperature in a ‘magneto-optical trap’ using lasers and magnetic fields. We further cool the atoms to just a few hundred to nanokelvin (less than a millionth degree above absolute zero) by a process of evaporative cooling using radio waves. We have developed a dedicated computer and electronics system to control the switching of all the experiment components and devices very precisely which can be managed remotely.”

Gadge continued; "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 10-15 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.”

“We’re hopeful of establishing a skeleton crew back in the labs with social distancing measures in place as soon as it is safe to do so and permitted but we will be able to have many of the team continuing to work from home on a rota basis thanks to the progress we have made with remote working.”

A blueprint for remote quantum technology

The research team believe the achievement could provide a blueprint for operating quantum technology in inaccessible environments such as space.

Peter Krüger, Professor of Experimental Physics at the University of Sussex, said: “We believe this may be the first time that someone has established a BEC remotely in a lab that didn’t have one before. We are all extremely excited that we can continue to conduct our experiments remotely during lockdown, and any possible future lockdowns. 

"But there are also wider implications beyond our team. 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 Quantum Systems and Devices Group has been working on having a second lab with a BEC running consistently over the past nine months as part of a wider project developing a new type of magnetic microscopy and other quantum sensors.

The research team uses atomic gases as magnetic sensors close to various objects including novel advanced materials, ion channels in cells, and the human brain.

Trapped cold quantum gases are controlled to create extremely accurate and precise sensors that are ideal for detecting and studying new materials, geometries and devices.

The research team are developing their sensors to be applied in many areas including electrical vehicle batteries, touch screens, solar cells and medical advancements such as brain imaging.