Researchers Develop Quantum Control Protocols to Reshape Arrow of Time

New techniques can suppress or invert the flow of time in quantum systems, enabling energy extraction and improved state preparation.

Apr. 8, 2026 at 11:39am

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Researchers at Los Alamos National Laboratory have developed quantum control protocols that can manipulate the 'arrow of time' in quantum systems, allowing them to engineer time-reversed trajectories and counteract or amplify disturbances. This work opens up possibilities for extracting energy from quantum measurements and improving quantum state preparation, with potential applications in superconducting qubit systems.

Why it matters

The ability to control the flow of time in quantum systems could lead to significant advancements in quantum computing and energy harvesting. By suppressing or inverting the arrow of time, researchers can create new ways to prepare and control quantum states, as well as extract energy from the measurement process itself - potentially violating classical thermodynamic principles in a quantum context.

The details

The team's control protocols use measurement and feedback to engineer time-reversed stochastic trajectories in quantum systems, effectively causing the system to behave as if time is flowing backward. This is achieved by designing a control Hamiltonian that can emulate the effects of measurements and then using feedback to cancel, amplify or overcompensate for measurement disturbances. The researchers leveraged this capability to design a 'quantum demon' that can extract energy from the monitoring process, similar to the 19th-century thought experiment of Maxwell's demon.

  • The research was published in Physical Review X on April 8, 2026.

The players

Luis Pedro García-Pintos

A physicist at Los Alamos National Laboratory who led the research team that developed the quantum control protocols.

Los Alamos National Laboratory

A U.S. Department of Energy research laboratory that conducted the research on reshaping the quantum arrow of time.

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What they’re saying

“Unlike phenomena we observe around us, at the microscopic level most fundamental laws of physics see forward and backward movement in time as physically possible. In other words, those laws of physics are symmetrical under time reversal; the equations work just as well if you reverse time. For quantum systems, which operate at that microscopic level, the tools we've constructed can manipulate the perceived arrow of time, leading to surprising, novel ways to control quantum systems.”

— Luis Pedro García-Pintos, Physicist, Los Alamos National Laboratory

What’s next

The researchers plan to experimentally demonstrate the use of Hamiltonian measurement processes for quantum feedback control, particularly in superconducting qubit systems. They will also explore using the new techniques to design quantum state preparation protocols.

The takeaway

This breakthrough in quantum control could enable significant advancements in quantum computing and energy harvesting by providing new ways to prepare and manipulate quantum states, as well as extract energy from the measurement process itself - challenging classical thermodynamic principles in the quantum realm.