Featured Research

from universities, journals, and other organizations

Quantum Systems Could Flout Physics Law

Date:
June 3, 2008
Source:
Weizmann Institute of Science
Summary:
Scientists have shown how quantum systems might disobey a hard and fast rule of physics: While an ensemble of small systems in a larger heat bath should eventually reach thermal equilibrium, repeated measuring of quantum systems could interfere with the process, causing them to heat further or lose energy to the heat bath.

Scientists in the Weizmann Institute’s Faculty of Chemistry, together with colleagues in Germany, have made a startling prediction: Simply 'taking the temperature' of certain quantum systems at frequent intervals might cause them to disobey a hard and fast rule of thermodynamics.

Related Articles


Thermodynamics tell us that the interaction between a large heat source (a heat bath) and an ensemble of much smaller systems must bring them – at least on average – progressively closer to thermal equilibrium. Now Prof. Gershon Kurizki, Dr. Noam Erez and doctoral student Goren Gordon of the Chemical Physics Department, in collaboration with Dr. Mathias Nest of Potsdam University, Germany, have shown that ensembles of quantum systems in thermal contact with a heat bath could present a drastic departure from this allegedly universal trend, a prediction they recently reported in Nature.

With complete disregard for this physical rule, the ensemble may, remarkably, heat up even when it is hotter than the bath or cool down when it is colder. The scientists showed that if the energy of these systems is measured repeatedly, both systems and bath will undergo temperature increase or decrease, and this change depends only on the rate of measurement – not on the actual results of these measurements.

How can these effects of quantum measurements be explained? As opposed to classical measurement, which may be completely nonintrusive, measuring quantum systems decouples them from their heat bath. This decoupling, followed by recoupling of the two when measurement ceases, introduces energy (at the expense of the measuring apparatus) into the systems and the bath alike, and thus heats them up. When this happens over a very short time interval, the systems cannot be discriminated from the bath.

For longer time intervals, the systems and bath start exchanging energy as coupled oscillators (analogous to connected springs). This energy exchange will cause the quantum systems to lose energy to the bath, thus lowering the temperature of the ensembles. Depending on whether the measurements are repeated at short or long intervals, it should be possible to heat up or cool down the systems.

The predicted effects may be the key to developing novel heating and cooling schemes for atomic, molecular and solid-state devices. Such schemes might allow ultrafast temperature control by optical measurements performed at an extremely high rate.


Story Source:

The above story is based on materials provided by Weizmann Institute of Science. Note: Materials may be edited for content and length.


Cite This Page:

Weizmann Institute of Science. "Quantum Systems Could Flout Physics Law." ScienceDaily. ScienceDaily, 3 June 2008. <www.sciencedaily.com/releases/2008/06/080602103359.htm>.
Weizmann Institute of Science. (2008, June 3). Quantum Systems Could Flout Physics Law. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2008/06/080602103359.htm
Weizmann Institute of Science. "Quantum Systems Could Flout Physics Law." ScienceDaily. www.sciencedaily.com/releases/2008/06/080602103359.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Newsy (Nov. 23, 2014) — Microsoft has robotic security guards working at its Silicon Valley Campus. Video provided by Newsy
Powered by NewsLook.com
Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

AFP (Nov. 21, 2014) — Toyota presented its hydrogen fuel-cell compact car called "Mirai" to US consumers at the Los Angeles auto show. The car should go on sale in 2015 for around $60.000. It combines stored hydrogen with oxygen to generate its own power. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Google Announces Improvements To Balloon-Borne Wi-Fi Project

Google Announces Improvements To Balloon-Borne Wi-Fi Project

Newsy (Nov. 21, 2014) — In a blog post, Google said its balloons have traveled 3 million kilometers since the start of Project Loon. Video provided by Newsy
Powered by NewsLook.com
Raw: Paralyzed Marine Walks With Robotic Braces

Raw: Paralyzed Marine Walks With Robotic Braces

AP (Nov. 21, 2014) — Marine Corps officials say a special operations officer left paralyzed by a sniper's bullet in Afghanistan walked using robotic leg braces in a ceremony to award him a Bronze Star. (Nov. 21) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins