Landauer's principle tested in the quantum many-body regime
Landauer's principle — that erasing one bit of information must dissipate at least kT ln 2 of heat — has mostly been confirmed in simple, single-bit systems. A new experiment pushes the information–heat bound into a far more demanding setting: a complex, out-of-equilibrium quantum many-body system.
A quantum field simulator
The work, reported in Nature Physics, was carried out by a collaboration spanning TU Vienna, FU Berlin, the University of British Columbia, Crete and Pavia. Rather than manipulating a single particle, the team used a one-dimensional quantum field simulator built from tunnel-coupled ultracold Bose gases. Such a platform behaves as a continuous quantum field with many interacting degrees of freedom, giving experimenters a controllable stand-in for the kind of many-body physics that is otherwise hard to probe directly.
Information meets dissipation
By preparing and manipulating states of this field, the researchers examined the link between entropy change and dissipated heat that lies at the heart of Landauer's principle. Confirming the bound in a many-body, out-of-equilibrium regime matters because real computing and quantum devices are not isolated single bits — they are large, interacting systems. Showing that the information–heat relationship still holds there extends the reach of Landauer's principle well beyond its original proof-of-concept tests.
Why it matters
The result strengthens the bridge between information theory and thermodynamics in the quantum domain, and offers a new experimental handle on how entropy is produced when complex quantum systems are driven out of equilibrium — a question that touches both fundamental physics and the ultimate energy cost of computation.
Source: Nature Physics (2025); preprint on arXiv:2407.21690; plain-language summary at Phys.org.