University of Colorado Boulder physicists have created a \u201ctime crystal\u201d visible to the human eye.\u00a0<\/p>\n
Nobel laureate Frank Wilczek first proposed the concept of a time crystal in 2012.<\/p>\n
While other crystals, like diamonds, are defined by a repeating lattice pattern in space, a time crystal has a similarly organized structure but in the dimension of time.\u00a0<\/p>\n
Its components wouldn\u2019t sit still, but would move and transform in a never-ending cycle.<\/p>\n
The material\u2019s design could enable various new technologies, including anti-counterfeiting measures, 2D barcodes, and optical devices.<\/p>\n
\u201cThey can be observed directly under a microscope and even, under special conditions, by the naked eye,\u201d said Hanqing Zhao, lead author and a graduate student in the Department of Physics at CU Boulder.<\/p>\n
Time crystal under the microscope<\/p>\n
Although once believed to be impossible<\/a> and a violation of a key law of thermodynamics, time crystals were first observed in a 2016 experiment<\/a>.\u00a0<\/p>\n A notable example<\/a> occurred in 2021 when physicists used Google\u2019s quantum computer to create a network of atoms that repeated their movements after being triggered by a laser.<\/p>\n This new creation is unique among them because it is the \u201cworld\u2019s first\u201d one to be visible to the human eye.<\/p>\n Zhao and his collaborator, Professor Ivan Smalyukh, used liquid crystals\u2014the same materials found in phone displays\u2014to achieve this feat.\u00a0<\/p>\n The researchers filled glass cells with liquid crystals, which are rod-shaped molecules that exhibit solid and liquid properties.<\/p>\n Shining a specific light on the samples makes the liquid crystals move in repeating patterns.<\/p>\n When viewed under a microscope, the creation\u2019s swirling patterns resemble \u201cpsychedelic tiger stripes\u201d and dance in a continuous, repeating cycle.<\/p>\n \u201cEverything is born out of nothing. All you do is shine a light, and this whole world of time crystals emerges,\u201d said Smalyukh.\u00a0<\/p>\n The researchers explained the mechanism behind the phenomenon.<\/p>\n When the molecules are squeezed, they bunch together to form \u201ckinks.\u201d These kinks can move around and, in the right conditions, behave just like atoms.<\/p>\n \u201cThey behave like particles and start interacting with each other,\u201d Smalyukh noted.\u00a0<\/p>\n Use in anti-counterfeiting measures<\/p>\n In this new study, researchers placed a liquid crystal<\/a> solution between two pieces of glass coated with dye molecules.\u00a0<\/p>\n While the sample was initially still, shining a specific light on it caused the dye molecules to change position.\u00a0<\/p>\n Like dancers in a ballroom, these molecules<\/a> break apart, spin, and come back together, over and over again.<\/p>\n This pattern was remarkably stable, remaining unbroken even when the temperature of the sample was changed.<\/p>\n \u201cThat\u2019s the beauty of this time crystal,\u201d Smalyukh said.<\/a> \u201cYou just create some conditions that aren\u2019t that special. You shine a light, and the whole thing happens.\u201d<\/p>\n The researchers suggest that these materials could create advanced anti-counterfeiting measures.\u00a0<\/a><\/p>\n For instance, embedding \u201ctime watermarks\u201d in currency could allow a simple light to reveal a unique, moving pattern that would be almost impossible to copy.<\/p>\n Furthermore, the physicists suggest that time crystals could be stacked to create more complex patterns. This structure could be a new way to store large digital data.<\/p>\n As the technology is further developed and tested, the team believes it can be used in ways other than mentioned in the current study.<\/p>\n