Signal Scientists make quantum time flow backward in stunning physics breakthrough

Summary

Physicists Luis Pedro García-Pintos, Yi-Kai Liu and Alexey V. Gorshkov, working across Los Alamos National Laboratory, NIST and the University of Maryland, published "Reshaping the Quantum Arrow of Time" in Physical Review X on February 19, 2026. The team developed quantum control protocols using a specially constructed "control Hamiltonian" that can emulate the effects of measurement and use feedback to cancel, amplify or overcompensate for measurement disturbances — allowing them to prevent the emergence of a quantum system's arrow of time or even cause it to appear to run in reverse. García-Pintos noted that at the microscopic level, the fundamental laws of physics are symmetrical under time reversal, meaning "the equations work just as well if you reverse time." The researchers used this capability to design a "quantum demon," analogous to the 19th-century Maxwell's demon thought experiment, that can extract energy from the monitoring process itself. The findings remain theoretical but could be tested experimentally, with potential applications in superconducting qubit systems, quantum computing and energy harvesting; the work was funded by the US Department of Energy's Office of Science, the Beyond Moore's Law project at Los Alamos, and the National Science Foundation.