Zenith Grant Awardee
Jonathan Oppenheim
University College London
Co-Investigators
Fernando Brandao, University College London; Michal Horodecki, University of Gdansk
Project Title
What are the laws of quantum thermodynamics?
Project Summary
The laws of thermodynamics govern much of the world around us: they tell us that a hot cup of tea in a cold room will cool down rather than heat up; they tell us that unless we are vigilant, our houses will become untidy rather than spontaneously tidy. But the laws of thermodynamics only apply to large objects, when many particles are involved. Can the laws of thermodynamics be applied to small systems, or perhaps even quantum systems? Tools from information theory can be used to do so, and this research aims to construct laws of thermodynamics for quantum systems. What\'s more, it appears that nature imposes fundamental limitations on microscopic devices and heat engines. A quantum heat engine will sometimes fail. We cannot extract energy optimally from a quantum system. This means that the present laws of thermodynamics are fundamentally incorrect if applied to small systems, and many of the standard laws need to be modified. The results if this research have wide applications in small systems, from nanoscale devices, to biological motors, to quantum technologies such as quantum computers, and to nanorobots drinking molecular amounts of tea.
Technical Abstract
Information theory can shed light on fundamental aspects of thermodynamics in the quantum regime. Our current laws of thermodynamics only apply in the thermodynamic limit, when many particles are involved. Can the laws of thermodynamics be applied in the opposite regime – to small systems, or perhaps even single quantum systems? Remarkably, tools from information theory can be used to do so, and this research aims to construct laws of thermodynamics for individual quantum systems. Attention will be focused on deriving second law (or laws) at the quantum scale. We now know that the second law for quantum systems takes on a very different form than it does at the macroscopic scale, imposing not just one constraint on what state transformations are possible, but an entire family of constraints. Some of these constraints are known, but some are yet to be discovered. It also appears that restrictions on which state transformations are possible depend in a very precise way, on how cyclic a thermodynamical process is. Understanding this is crucial if we wish to fully formulate laws of thermodynamics at the quantum scale.
QSpace Latest
PressRelease: Shining a light on the roots of plant “intelligence”
All living organisms emit a low level of light radiation, but the origin and function of these ‘biophotons’ are not yet fully understood. An international team of physicists, funded by the Foundational Questions Institute, FQxI, has proposed a new approach for investigating this phenomenon based on statistical analyses of this emission. Their aim is to test whether biophotons can play a role in the transport of information within and between living organisms, and whether monitoring biophotons could contribute to the development of medical techniques for the early diagnosis of various diseases. Their analyses of the measurements of the faint glow emitted by lentil seeds support models for the emergence of a kind of plant ‘intelligence,’ in which the biophotonic emission carries information and may thus be used by plants as a means to communicate. The team reported this and reviewed the history of biophotons in an article in the journal Applied Sciences in June 2024.