(Press-News.org) This news release is available in German.
How does a classical temperature form in the quantum world? An experiment at the Vienna University of Technology has directly observed the emergence and the spreading of a temperature in a quantum system. Remarkably, the quantum properties are lost, even though the quantum system is completely isolated and not connected to the outside world. The experimental results are being published in this week's issue of "Nature Physics".
Quantum and Classical Physics: From the Microscopic to the Macroscopic World
The connection between the microscopic world of quantum physics and our everyday experience, which is concerned with much larger objects, still remains puzzling. When a quantum system is measured, it is inevitably disturbed and some of its quantum properties are lost.
A cloud of atoms, for example, can be prepared in such away that each atom is simultaneously located at two different places, forming a perfect quantum superposition. As soon as the location of the atoms is measured, however, this superposition is destroyed. All that is left are atoms sitting at some well-defined places. They behave just as classical objects would.
In this case, the transition from quantum behavior to classical behavior is initiated by the measurement – a contact with the outside world. But what happens, if a quantum system is not influenced from the outside at all? Can classical properties still emerge?
Disorder in the Quantum World
"We are studying clouds consisting of several thousand atoms", explains Tim Langen, lead author of the study from Professor Jörg Schmiedmayer's research team at Vienna University of Technology. "Such a cloud is small enough to effectively isolate it from the rest of the world, but it is large enough to study how quantum properties are lost".
In the experiment, the atom clouds are split into two halves. After a certain time the two halves are compared to each other. In that way, the scientists can measure the amount of quantum mechanical connection between the clouds. Initially, this connection is perfect; all atoms are in a highly ordered quantum state. But as the cloud is a large object consisting of thousands of particles, this order does not remain for long.
Loss of Quantum Properties Without Influence From Outside
As the atoms interact with each other, disorder begins to spread with a certain velocity. Atoms in the already disordered regions lose their quantum properties. A temperature can be assigned to them – just as in a classical gas. "The velocity with which the disorder spreads depends on the number of atoms", says Tim Langen. This defines a clear border between the regions which can be described by a classical temperature and regions where quantum properties remain unchanged.
After a certain time the disorder has spread over the whole cloud. The remarkable observation is that this loss of quantum properties happens just because of quantum effects inside the atom cloud, without any influence from the outside world. "So far, such a behavior had only been conjectured, but our experiments demonstrate that nature really behaves like this", Jörg Schmiedmayer points out.
Atomic Clouds: A World on its Own
In a way, the atomic cloud behaves like its own miniature universe. It is isolated from the environment, so its behavior is solely determined by its internal properties. Starting with a completely quantum mechanical state, the cloud looks "classical" after some time, even though it evolves according to the laws of quantum physics. That is why the experiment could not just help us to understand the behavior of large atom clouds, it could also help to explain, why the world that we experience every day looks so classical, even though it is governed by quantum laws.
INFORMATION:
Further Information:
Dipl.-Phys. Tim Langen
Institute of Atomic and Subatomic Physics,
Vienna Center for Quantum Science and Technology (VCQ)
Vienna University of Technology
Stadionallee 2, 1020 Wien
T: +43-1-58801-141874
tim.langen@tuwien.ac.at
Prof. Jörg Schmiedmayer
Institute of Atomic and Subatomic Physics,
Vienna Center for Quantum Science and Technology (VCQ)
Vienna University of Technology
Stadionallee 2, 1020 Wien
T: +43-1-58801-141801
hannes-joerg.schmiedmayer@tuwien.ac.at
schmiedmayer@AtomChip.org
Temperature in the quantum world
Scientists at the Vienna University of Technology manage to study the physics that connect the classical the quantum world
2013-09-09
ELSE PRESS RELEASES FROM THIS DATE:
All set for The EMBO Meeting 2013
2013-09-09
Heidelberg, 9 September 2013 – With only two weeks to go and almost a thousand participants registered, the preparations for The EMBO Meeting 2013 have reached their final stages. This year's conference takes place in Amsterdam from 21-24 September.
Kai Simons will deliver the opening keynote lecture and explain how intricate changes in membrane structure can influence how cells work. In further keynote lectures, Hans Clevers will discuss how stem cells are involved in self-renewal and disease and Sir Michael Stratton will talk about how genetic changes contribute to ...
Surprising underwater-sounds: Humpback whales also spend their winter in Antarctica
2013-09-09
Biologists and physicists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, found out that not all of the Southern Hemisphere humpback whales (Megaptera novaeangliae) migrate towards the equator at the end of the Antarctic summer. Part of the population remains in Antarctic waters throughout the entire winter. The scientists report this in a current issue of scientific journal PLOS ONE. This surprising discovery based on underwater recordings from the Antarctic acoustic observatory PALAOA. PALAOA is located near the research base Neumayer ...
'Young Chinese people disappointed with German companies'
2013-09-09
According to a study, young Chinese managers are unsatisfied with the career opportunities in international companies in their home country. "The promotion expectations of highly qualified Chinese employees are restricted by flat hierarchies and poor chances of permanent employment with which Western companies flexibly react to the needs of the globalised market", the sociologist Junchen Yan from Bielefeld explains. He will present the results of the study at the 32nd German Oriental Studies Conference (Deutscher Orientalistentag, DOT) in Münster in September. Owing to ...
More than 100,000 Americans quit smoking due to national media campaign
2013-09-09
An estimated 1.6 million smokers attempted to quit smoking because of the Centers for Disease Control and Prevention's "Tips From Former Smokers" national ad campaign, according to a study released by the CDC. As a result of the 2012 campaign, more than 200,000 Americans had quit smoking immediately following the three-month campaign, of which researchers estimated that more than 100,000 will likely quit smoking permanently. These results exceed the campaign's original goals of 500,000 quit attempts and 50,000 successful quits.
The study surveyed thousands of adult smokers ...
Breakthrough in cryptography could result in more secure computing
2013-09-09
New research to be presented at the 18th European Symposium on Research in Computer Security (ESORICS 2013) this week could result in a sea change in how to secure computations.
The collaborative work between the University of Bristol and Aarhus University (Denmark) will be presented by Bristol PhD student Peter Scholl from the Department of Computer Science.
The paper, entitled 'Practical covertly secure MPC for dishonest majority – or: Breaking the SPDZ limits', builds upon earlier joint work between Bristol and Aarhus and fills in the missing pieces of the jigsaw ...
New 10 second sourcing technology set to transform archaeology
2013-09-09
Researchers at the University of Sheffield have developed a method of sourcing obsidian artefacts that takes only 10 seconds – dozens of times faster than the current methods – with a handheld instrument that can be used at archaeological excavations.
Obsidian, naturally occurring volcanic glass, is smooth, hard, and far sharper than a surgical scalpel when fractured, making it a highly desirable raw material for crafting stone tools for almost all of human history. The earliest obsidian tools, found in East Africa, are nearly two million years old, and obsidian scalpels ...
Programmable glue made of DNA directs tiny gel bricks to self-assemble
2013-09-09
A team of researchers at the Wyss Institute of Biologically Inspired Engineering at Harvard University has found a way to self-assemble complex structures out of bricks smaller than a grain of salt. The new method could help solve one of the major challenges in tissue engineering: creating injectable components that self-assemble into intricately structured, biocompatible scaffolds at an injury site to help regrow human tissues.
The key to self-assembly was developing the world's first programmable glue. The glue is made of DNA, and it directs specific bricks of a water-filled ...
Amino acid with promising anti-diabetic effects
2013-09-09
More than 371 million people worldwide suffer from diabetes, of whom 90% are affected by lifestyle-related diabetes mellitus type 2 (type 2 diabetes).
In new experiments, researchers from the University of Copenhagen working in collaboration with a research group at the University of Cincinnati, USA, have demonstrated that the amino acid arginine improves glucose metabolism significantly in both lean (insulin-sensitive) and obese (insulin-resistant) mice.
"In fact, the amino acid is just as effective as several well-established drugs for type 2 diabetics," says postdoc ...
More research urgently needed on caffeine
2013-09-09
New Rochelle, NY, September 9, 2013–Studies have shown that caffeine users can become dependent on or addicted to caffeine and may have difficulty reducing their consumption, as can occur with other drugs of dependence. A comprehensive review of the current evidence on caffeine dependence is presented in an article in Journal of Caffeine Research, a peer-reviewed publication from Mary Ann Liebert, Inc., publishers. The article is available free on the Journal of Caffeine Research website at http://www.liebertpub.com/jcr.
Steven Meredith and Roland Griffiths, Johns Hopkins ...
Bomb-detecting lasers could improve security checkpoints
2013-09-09
EAST LANSING, Mich. -- Michigan State University research has put the possibility of bomb-detecting lasers at security checkpoints within reach.
In the current issue of Applied Physics Letters, Marcos Dantus, MSU chemistry professor and founder of BioPhotonic Solutions, has developed a laser that can detect micro traces of explosive chemicals on clothing and luggage.
"Since this method uses a single beam and requires no bulky spectrometers, it is quite practical and could scan many people and their belongings quickly," Dantus said. "Not only does it detect the explosive ...
LAST 30 PRESS RELEASES:
Exercise as an anti-ageing intervention to avoid detrimental impact of mental fatigue
UMass Amherst Nursing Professor Emerita honored as ‘Living Legend’
New guidelines aim to improve cystic fibrosis screening
Picky eaters by day, buffet by night: Butterfly, moth diets sync to plant aromas
Pennington Biomedical’s Dr. Leanne Redman honored with the E. V. McCollum Award from the American Society for Nutrition
CCNY physicists uncover electronic interactions mediated via spin waves
Researchers’ 3D-printing formula may transform future of foam
Nurture more important than nature for robotic hand
Drug-delivering aptamers target leukemia stem cells for one-two knockout punch
New study finds that over 95% of sponsored influencer posts on Twitter were not disclosed
New sea grant report helps great lakes fish farmers navigate aquaculture regulations
Strain “trick” improves perovskite solar cells’ efficiency
How GPS helps older drivers stay on the roads
Estrogen and progesterone stimulate the body to make opioids
Dancing with the cells – how acoustically levitating a diamond led to a breakthrough in biotech automation
Machine learning helps construct an evolutionary timeline of bacteria
Cellular regulator of mRNA vaccine revealed... offering new therapeutic options
Animal behavioral diversity at risk in the face of declining biodiversity
Finding their way: GPS ignites independence in older adult drivers
Antibiotic resistance among key bacterial species plateaus over time
‘Some insects are declining but what’s happening to the other 99%?’
Powerful new software platform could reshape biomedical research by making data analysis more accessible
Revealing capillaries and cells in living organs with ultrasound
American College of Physicians awards $260,000 in grants to address equity challenges in obesity care
Researchers from MARE ULisboa discover that the European catfish, an invasive species in Portugal, has a prolonged breeding season, enhancing its invasive potential
Rakesh K. Jain, PhD, FAACR, honored with the 2025 AACR Award for Lifetime Achievement in Cancer Research
Solar cells made of moon dust could power future space exploration
Deporting immigrants may further shrink the health care workforce
Border region emergency medical services in migrant emergency care
Resident physician intentions regarding unionization
[Press-News.org] Temperature in the quantum worldScientists at the Vienna University of Technology manage to study the physics that connect the classical the quantum world