Landauer’s principle connects entropy and energy dissipation in non-equilibrium processes. An experiment now uses this principle to measure entropy production in a Bose gas to resolve contributions from correlations and dissipation.

When placed under a powerful laser field (i.e., under strong-field ionization), electrons can temporarily cross the so-called quantum tunneling barrier, an energy barrier that they would typically be unable to overcome. This quantum mechanics phenomenon, known as quantum tunneling, has been the focus of numerous research studies.

Precisely measuring the exact time that an electron spends inside a quantum tunneling barrier during strong-field ionization has so far proved challenging. In recent years, physicists have developed advanced experimental tools called attoclocks, which can measure the timing of ultrafast electron dynamics and could thus help to answer this long-standing research question.

Despite their potential for measuring the tunneling time of electrons, most attoclocks developed to date have had significant limitations and have been unable to yield reliable and conclusive measurements. In a recent paper published in Physical Review Letters, researchers at Wayne State University and Sorbonne University introduced a new attoclock technique that leverages the carrier-envelope phase (CEP), the offset between the peak of a laser’s pulse’s envelope and its oscillating field, to collect more precise tunneling time measurements.

The extraction of work (i.e., usable energy) from quantum processes is a key focus of quantum thermodynamics research, which explores the application of thermodynamics laws to quantum systems. Meanwhile, other quantum physics research has been investigating the non-Markovian dynamics of open quantum systems, which entail the influence of past states on the systems’ future evolution.

Researchers at the University of Nottingham and University of São Paulo have introduced a general and rigorous framework that bridges quantum thermodynamics and non-Markovian dynamics, showing that the latter could serve as a resource that can be exploited to enhance the extraction of work from quantum processes.

Their paper, published in Physical Review Letters, could open new possibilities for the future development of quantum technologies.

An international research collaboration featuring scientists from the FAMU-FSU College of Engineering and the National High Magnetic Field Laboratory has discovered a fundamental universal principle that governs how microscopic whirlpools interact, collide and transform within quantum fluids, which also has implications for understanding fluids that behave according to classical physics.

The study, which was published in the Proceedings of the National Academy of Sciences, revealed new insights into vortex dynamics within superfluid helium, a remarkable liquid that exhibits zero-resistance flow at temperatures approaching absolute zero. The research demonstrates that when these quantum vortices intersect and reconnect, they separate faster than their initial approach velocity, creating bursts of energy that characterize turbulence in both quantum and classical fluids.

“Superfluids offer a uniquely clear perspective on turbulence,” said FAMU-FSU College of Engineering Professor Wei Guo, a study co-author. “We’re beginning to understand the universal physics that connects quantum and classical worlds, and that’s an exciting frontier for both science and technology.”