⏳ Scientists Found a Way to Make Quantum Time Look Like It Runs Backward
At our everyday scale, time has a clear direction. Eggs break, coffee cools, and no one has ever un-spilled a glass of water.
But at the quantum scale, the story is stranger. Many fundamental equations work just as well forward or backward in time. The arrow of time appears when a system is measured — because measurement randomly disturbs its state.
Now researchers from Los Alamos National Laboratory, NIST, and the University of Maryland have developed a theoretical control method that can reshape that arrow.
Their idea is based on a “control Hamiltonian” — a precisely designed sequence of fields and pulses that mimics and counteracts the random disturbance caused by quantum measurement. With the right feedback, the system’s trajectory can be made to look as if it is moving backward rather than forward.
To be clear: this is not a time machine.
No one reversed time for people, objects, or the universe. The work shows that, in a monitored quantum system, the appearance of time’s direction can be weakened, blurred, or even inverted.
The team also used the framework to design a quantum version of Maxwell’s demon — a measurement-powered engine that could, in principle, extract useful energy from the act of observation itself. That energy might one day help drive quantum processes or be stored in a quantum battery.
The caveat: this is still mostly a theoretical result. Experimental tests are planned for superconducting qubits, where fast feedback and quantum Maxwell’s demon setups are already technically plausible.
Why it matters: better control over quantum measurement could help with quantum state preparation, more stable quantum computers, and new ways to manage energy at the smallest scales.
The big takeaway: the arrow of time may feel absolute in daily life — but in the quantum world, it can become something engineers may learn to control.
📄 Original paper: https://link.aps.org/doi/10.1103/l18s-9vmh 📖 Los Alamos summary: https://www.lanl.gov/media/news/0319-reshaping-quantum-arrow 📖 ScienceDaily summary: https://www.sciencedaily.com/releases/2026/06/260625014802.htm
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