How Noise Turns Order into Chaos on a Quantum Chip ⚡ экспресс
About forty years of research into chaos in isolated quantum systems have led to the discovery of universal signatures—level repulsion and eigenstate thermalization. In dissipative open systems, these properties are only beginning to be studied. For the first time, dissipative quantum chaos has been experimentally detected by measuring complex spacing ratios (CSR) in many-body circuits on a superconducting quantum processor with high accuracy. Using gradient-based tomography, a 'donut'-shaped CSR distribution was obtained for chaotic dissipative circuits—a hallmark of level repulsion in open systems. For an integrable circuit, a sharp peak at zero is observed, indicating the absence of spectral correlations. As the depth of the integrable dissipative circuit increases, a crossover from integrability to chaos occurs, proving that the processor's intrinsic noise is a dissipative chaotic process. The results reveal universal spectral features of dissipative many-body systems and turn contemporary quantum computing platforms into testbeds for dissipative quantum phenomena.
The energy levels of a quantum system can be imagined as people trying to keep their distance. In an orderly regime, they crowd together predictably, but add chaos—and they scatter into a circle, forming a 'donut': a dense ring with an empty center. That's exactly the picture physicists saw for the first time when they ran two programs on a quantum chip—one orderly and one chaotic. Using spectroscopy (listening to the 'notes' of atoms), they measured the distances between levels. In the chaotic case, those levels indeed kept a respectful distance, creating a donut shape. But the main discovery happened when the orderly program was extended: the chip's internal noise—energy leakage causing an increase in entropy—itself turned order into chaos. It turns out that even tiny imperfections, considered a nuisance for computation, make any quantum processor a ready-made laboratory for studying chaos. As noted long ago by Richard Feynman and developed by David Deutsch, quantum computers can model subtle effects that aren't captured by the simple standard model of isolated systems.
🎯 Small energy losses, like in a cup of coffee cooling down or on a currency exchange, can generate chaos—and that's exactly what the quantum chip showed.
🎬 In the series 'Devs,' a quantum computer predicts the future through deterministic chaos; real chips are even more finicky—noise smears everything.