Our universe is expanding, and its future, according to cosmologists, is empty, cold de Sitter space. Understanding its quantum nature is like trying to read a book by looking only at its cover. The holographic principle suggests that all information about what happens inside a volume can be encoded on its boundary, like a picture on a film. But until now, there was no concrete 'microscope' to show how quantum threads at the boundary weave into the volumetric spacetime.
In the new work, physicists built such a microscope. They took a chain of special, 'non-Hermitian' fermions — particles that behave unusually, like actors playing roles without a clear script. Using the cMERA method (continuous multiscale entanglement renormalization ansatz), they showed that when these particles entangle at the boundary, the geometry of the de Sitter world emerges by itself from their connections. Short geodesic lines inside this world turned out to be like taut strings: near the horizon they become light rays, and far away they bend smoothly, like the trajectories of massive particles.
This image is not just a metaphor. The authors showed that such a 'lightened' network architecture exactly reproduces the logarithmic growth law of entanglement entropy characteristic of non-Hermitian systems. In other words, the famous Ryu-Takayanagi formula for holographic entropy has found a simple explanation: the number of threads crossing the boundary of a region is directly related to its information capacity. Thus, for the first time, a direct correspondence emerged between the discrete network at the boundary and the continuous de Sitter world inside.
De Sitter space is not just an abstraction. This is most likely what our universe will look like billions of years from now, when dark energy has dragged all galaxies so far apart that they can no longer see each other.
In Peter Watts's novel 'Blindsight,' alien ships use holographic principles to encode information — now we see that something similar might underlie reality itself.