Navigation Links
Quantum engines must break down
Date:6/26/2013

Our present understanding of thermodynamics is fundamentally incorrect if applied to small systems and needs to be modified, according to new research from University College London (UCL) and the University of Gdańsk. The work establishes new laws in the rapidly emerging field of quantum thermodynamics.

The findings, published today in Nature Communications, have wide applications in small systems, from nanoscale engines and quantum technologies, to biological motors and systems found in the body.

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; they tell us how efficient the best heat engines can be.

The current laws of thermodynamics only apply to large objects, when many particles are involved. The laws of thermodynamics for smaller systems are not well understood but will have implications for the construction of molecular motors and quantum computers, and might even determine how efficient energy extracting processes such as photosynthesis can be.

In this study researchers used results from quantum information theory to adapt the laws of thermodynamics for small systems, such as microscopic motors, nanoscale devices and quantum technologies.

Small systems behave very differently to large systems composed of many particles. And when systems are very small, then quantum effects come into play. The researchers found a set of laws which determine what happens to such microscopic systems when we heat them up or cool them down. An important consequence of their laws is that there is more fundamental irreversibility in small systems, and this means that microscopic heat engines can not be as efficient as their larger counterparts.

"We see that nature imposes fundamental limitations to extracting energy from microscopic systems and heat engines. A quantum heat engine is not as efficient as a macroscopic one, and will sometimes fail," said Professor Oppenheim, a Royal Society University Research Fellow at UCL's Department of Physics and Astronomy and one of the authors of the research. "The limitations are due to both finite size effects, and to quantum effects."

The researchers investigated the efficiency of microscopic heat engines and found that one of the basic quantities in thermodynamics, the free energy, does not determine what can happen in small systems, and especially in quantum mechanical systems. Instead, several new free energies govern the behaviour of these microscopic systems.

In large systems, if you put pure energy into a system, then you can recover all this energy back to use to power an engine which can perform work (such as lifting a heavy weight). But the researchers found that this was not the case for microscopic systems. If you put work into a quantum system you generally cannot get it all back.

Professor Michal Horodecki of the University of Gdansk, and co-author of the paper, said: "Thermodynamics at the microscopic scale is fundamentally irreversible. This is dramatically different to larger systems where all thermodynamic processes can be made reversible if we change systems slowly enough."


'/>"/>

Contact: Rosie Waldron
r.waldron@ucl.ac.uk
020-767-99041
University College London
Source:Eurekalert

Related biology news :

1. Researchers use graphene quantum dots to detect humidity and pressure
2. Quantum dots deliver Vitamin D to tumors for possible inflammatory breast cancer treatment
3. Quantum communication: Each photon counts
4. High Brightness Tetrapod Quantum Dots Developed
5. Good news for nanomedicine: Quantum dots appear safe in pioneering study on primates
6. Clean energy research targets idle engines
7. Evolution of an outbreak: Complications from contaminated steroid injections
8. Breakthrough research of essential molecule reveals important targets in diabetes and obesity
9. University of Toronto breakthrough allows fast, reliable pathogen identification
10. Flu vaccines aimed at younger populations could break annual transmission cycle
11. Unique US-Chinese lab to head off H7N9 outbreak and future threats
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/29/2017)... CHICAGO , March 29, 2017  higi, the ... ecosystem in North America , today ... Partners and the acquisition of EveryMove. The new investment ... extensive set of tools to transform population health activities ... and lifestyle data. higi collects and secures ...
(Date:3/24/2017)... , March 24, 2017 The Controller General of ... Mr. Abdulla Algeen have received the prestigious international IAIR Award ... Continue Reading ... ... and Deputy Controller Abdulla Algeen (small picture on the right) have received ...
(Date:3/23/2017)... , Mar. 23, 2017 Research and Markets ... Market Analysis & Trends - Industry Forecast to 2025" report ... ... at a CAGR of around 8.8% over the next decade to ... report analyzes the market estimates and forecasts for all the given ...
Breaking Biology News(10 mins):
(Date:4/20/2017)... (PRWEB) , ... April 20, 2017 , ... ... light sources for advanced technology applications, announced today that Chief Executive Officer (CEO) ... , SEMI is the global industry association connecting the electronics manufacturing ...
(Date:4/20/2017)... philosopher Koert van Mensvoort - founder of the Next Nature Network ... - has written a ,Letter to Humanity, in support of International ... slave and victim to its own technology, but to employ technology to enhance ... ... founder of the Next Nature Network and Fellow of ‘Next Nature’ at the ...
(Date:4/19/2017)... ... April 18, 2017 , ... The ... a key device for generating monodisperse droplets of known diameters for research applications ... generating monodisperse solid particles by drying monodisperse droplets. , The VOAG requires ...
(Date:4/19/2017)... ... April 18, 2017 , ... Optofluidics today announced ... comes after the company changed focus to making analytical tools for biopharmaceutical quality ... new technology,” says CEO Robert Hart. Founders Bernardo Cordovez, Robert Hart and David ...
Breaking Biology Technology: