{"id":3090,"date":"2025-05-14T11:35:58","date_gmt":"2025-05-14T11:35:58","guid":{"rendered":"https:\/\/scienceblog.com\/horizon\/?p=3090"},"modified":"2025-05-14T11:35:58","modified_gmt":"2025-05-14T11:35:58","slug":"cracking-the-code-of-supersolid-light-and-what-it-means-for-future-quantum-tech","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/horizon\/3090\/cracking-the-code-of-supersolid-light-and-what-it-means-for-future-quantum-tech\/","title":{"rendered":"Cracking the code of supersolid light \u2013 and what it means for future quantum tech"},"content":{"rendered":"

EU-funded researchers have brought supersolid light to life in the lab and are now exploring how this strange new state of matter could power real-world technologies.<\/p>\n

By<\/em> Jonathan O\u2019Callaghan<\/p>\n

Can light ever be a solid? It turns out that, in the microscopic world of the quantum realm, maybe it can.<\/p>\n

In a recent groundbreaking EU-funded study published in Nature<\/a>, a team of researchers succeeded in creating supersolid light \u2013 a strange, hybrid state of matter that combines the structure of a solid with the frictionless flow of a superfluid.<\/p>\n

From theory to application<\/strong><\/p>\n

Now, their focus is shifting from theory to application as they explore how this discovery could pave the way for advances in quantum computing and photonic technologies, including the optical neural networks that power AI.<\/p>\n

Daniele Sanvitto, a prominent physicist specialising in light-matter interactions, led the research at Italy\u2019s National Research Council (CNR).<\/p>\n

\u201cWe actually found a supersolid phase in a state that combines light and matter,\u201d said Sanvitto, who is the director of research at the Institute of Nanotechnology (CNR NANOTEC) in Lecce, Italy, and is coordinating a four-year EU-funded research initiative called Q-ONE.<\/p>\n

Combining the expertise of scientists from leading research institutes in Italy, Austria and the USA, the team managed to create a state of light and matter that was simultaneously a crystal-like solid but also flowed like a liquid.<\/p>\n

This discovery was achieved by harnessing a hybrid particle known as an exciton-polariton, which combines properties of light (photon) and matter (exciton). With its help, the researchers are opening new scientific frontiers with potential applications that stretch far beyond the lab, in Europe and beyond.<\/p>\n

This major breakthrough in quantum physics also comes at a timely juncture. On 16 May we celebrate the International Day of Light, the anniversary of the first use of a laser in 1960 by the American physicist Theodore Maiman.<\/p>\n

Q-ONE\u2019s research into supersolids shows how far this field of research has come since then.<\/p>\n

Supersolid light<\/strong><\/p>\n

Most of us are familiar with the regular states of matter \u2013 solid, liquid and gas. But there are other exotic states that can be created too, such as superfluids, liquids that flow without resistance. Supersolids are another exotic state.<\/p>\n

\u201cIf a superfluid gets some ordered structure in space, like a crystal, then it\u2019s called supersolid,\u201d said Sanvitto. \u201cIt looks like a solid, but at the same time it can move, in principle, without friction.\u201d<\/p>\n

Eight years ago, Sanvitto and his team showed that light could flow like a fluid inside a semiconductor. Now, they have taken that research further by creating an ordered structure made from unusual light-matter particles.<\/p>\n

These are formed when photons \u2013 particles of light \u2013 strongly interact with electronic excitations in a semiconductor, creating hybrid entities known as\u00a0exciton-polaritons.<\/p>\n

Because they combine properties of both light and matter, they open up new possibilities for manipulating light in ways not previously possible.<\/p>\n

Supersolids \u2013 materials that behave both like a solid and a superfluid at the same time \u2013 have until now only been observed for ultra-cold atomic gases. But that is starting to change.<\/p>\n

\u201cWe\u2019re the first to show that supersolids can also form in solid state devices that do not require ultra-cold temperatures,\u201d said Sanvitto.<\/p>\n

This breakthrough makes it possible to explore real-world applications without the need for the complex and ultra-cold lab setups used for atomic condensates. This will potentially pave the way for new technologies in computing, sensing and more.<\/p>\n

\u201cIt\u2019s exciting because it means we can explore entirely new physical phenomena in a semiconductor chip.\u201d<\/p>\n

Quantum states<\/strong><\/p>\n

The Q-ONE researchers want to create and identify different quantum states of matter using polariton quantum neural networks.<\/p>\n

\u201cOur goal in the Q-ONE research is to harness the strong nonlinear properties of polaritons to build an artificial neural network that can not only identify but eventually create quantum states of light,\u201d said Sanvitto.<\/p>\n

The Q-ONE research team is not the only group exploring the intersection of quantum states and AI. Since 2010, Professor Barbara Pi\u0119tka, a physicist at the University of Warsaw, has also been leading a research group focused on exciton-polaritons.<\/p>\n

Pi\u0119tka is currently coordinating a four-year research project called PolArt, supported by the European Innovation Council. Her team is working closely with Sanvitto\u2019s team at the CNR in Italy, as well as with other leading researchers in the field from France, Italy, Poland and Singapore.<\/p>\n

Neural networks<\/strong><\/p>\n

Their work is specifically looking at ways to use exciton-polaritons with artificial neural networks.<\/p>\n

\u201cExciton-polaritons are our building block,\u201d said Pi\u0119tka. \u201cWe are using these particles, known as quasiparticles, to construct big neural networks.\u201d<\/p>\n

According to Pi\u0119tka, much of what they are doing has been made possible by work such as Sanvitto\u2019s, which has shown that exciton-polaritons can be used to construct advanced neural computation networks \u2013 computer networks that mimic the structure and function of the human brain and nervous system.<\/p>\n

One possibility explored by the PolArt team is to integrate them onto chips using crystals made from a material called perovskite. Compared to conventional computer chips that emulate neural networks, the polariton-based approach consumes significantly less energy and offers faster processing speeds.<\/p>\n

\u201cWe can perform a single operation using just a few photons,\u201d said Pi\u0119tka.<\/p>\n

Bigger, faster, better<\/strong><\/p>\n

Pi\u0119tka and her team are working to scale up their polariton-based neural networks to handle increasingly complex tasks.<\/p>\n

\u201cWe are building progressively larger networks that enable us to tackle more sophisticated challenges,\u201d she explains.<\/p>\n

This approach could eventually power faster, more efficient large language models. These advanced AI models have been designed perform well\u00a0while using fewer resources and are becoming increasingly embedded in our daily lives.<\/p>\n

\u201cThe bigger the network, the more advanced the task it can perform,\u201d said Pi\u0119tka.<\/p>\n

Leading role<\/strong><\/p>\n

According to Sanvitto, Europe is currently at the forefront of research into exciton-polaritons.<\/p>\n

\u201cThe competition is intense \u2013 especially with China investing heavily in science \u2013 but Europe is leading much of this field at the moment,\u201d he said.<\/p>\n

Pi\u0119tka agrees, noting that research into polariton neural networks remains largely concentrated in Europe.<\/p>\n

However, this leadership, thanks in part to funding from the EU, especially through the European Research Council and the European Innovation Council, is at risk of fading unless we increase investments in science.<\/p>\n

\u201cIt\u2019s crucial for Europe to continue investing in this research and more generally in fundamental science to stay ahead,\u201d said Sanvitto.<\/p>\n

Both teams have more work ahead \u2013 and high hopes. \u201cThe ultimate goal is to develop a network that processes data with maximum speed and efficiency,\u201d said Pi\u0119tka.<\/p>\n

Research in this article was funded by the European Innovation Council (EIC). The views of the interviewees don\u2019t necessarily reflect those of the European Commission. <\/em><\/p>\n

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