Why hotter clocks are more accurate
2021-05-07
(Press-News.org) A new experiment shows that the more energy consumed by a clock, the more accurate its timekeeping.
Clocks pervade every aspect of life, from the atomic clocks that underlie satellite navigation to the cellular clocks inside our bodies. All of them consume energy and release heat. A kitchen clock, for example, does this by using up its battery. Generally the most accurate clocks require the most energy, which hints at a fundamental connection between energy consumption and accuracy. This is what an international team of scientists from Lancaster, Oxford, and Vienna set out to test.
To do this, they built a particularly simple clock, consisting of a vibrating ultra-thin membrane, tens of nanometers thick and 1.5 millimeters long, incorporated into an electronic circuit. Each oscillation of the membrane generated one electrical tick. The ingenious aspect of this design is that it is powered simply by heating the membrane, while the complete flow of energy through the clock can be measured electrically.
The scientists found that the more heat they supplied, the more accurately the clock ran. In fact, the accuracy was directly proportional to the heat released. To make the clock twice as accurate, they needed to supply twice as much heat.
The experimental team consisted of Dr Edward Laird at Lancaster University, Professor Marcus Huber at Atominstitut, TUWien, Dr Paul Erker and Dr Yelena Guryanova at the Institute for Quantum Optics and Quantum Information (IQOQI), and Dr Natalia Ares, Dr Anna Pearson and Professor Andrew Briggs from Oxford.
Their study, published in Physical Review X, is the first time that a measurement has been made of the entropy - or heat loss - generated by a minimal clock.
Understanding the thermodynamic cost involved in timekeeping is a central step along the way in the development of future technologies, and understanding and testing thermodynamics as systems approach the quantum realm.
It also shows a similarity between the operation of a clock and a steam engine. With a steam engine there is fundamental constraint on how much heat we must supply to do a desired amount of work. This constraint is the famous Second Law of Thermodynamics which is central to modern engineering. What this experiment suggests is that clocks, like engines, are constrained by the Second Law, with their output being accurate ticks instead of mechanical work.
Dr Edward Laird of Lancaster University said: "The subject of thermodynamics, which incorporates the most fundamental principles of nature, tells us that there are two types of machine that we cannot operate without releasing heat. One is the mechanical engine, which releases heat to do work, and the other is the computer memory, which releases heat when it rewrites itself. This experiment - in conjunction with other work - suggests that clocks are also limited by thermodynamics. It also poses an intriguing question: are all possible clocks limited in this way, or is it just a property of the ones we have studied?"
Interestingly, many everyday clocks have an efficiency that is close to what the scientists' analysis predicts. For example, their formula predicts that a wristwatch whose accuracy per tick is one part in ten million must consume at least a microwatt of power. In fact, a basic wristwatch usually consumes only a few times this amount. The laws of thermodynamics, discovered in the nineteenth century, are still finding new applications today.
INFORMATION:
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2021-05-07
A research team from the Skoltech Center for Design, Manufacturing and Materials (CDMM) studied the effects of processing additives - aluminum hydroxide and zinc stearate - on the polymerization kinetics of thermosets used in pultrusion. The research was published in the Journal of Composite Materials.
Fiber-reinforced plastic (FRP) structural elements that have obvious advantages over conventional materials, such as steel, wood, and concrete, are widely used in civil, marine and road construction. FRP structures are manufactured using the pultrusion process, in which polymerization is achieved by continuously pulling ...
2021-05-07
A new University of Iowa study challenges the idea that gray matter (the neurons that form the cerebral cortex) is more important than white matter (the myelin covered axons that physically connect neuronal regions) when it comes to cognitive health and function. The findings may help neurologists better predict the long-term effects of strokes and other forms of traumatic brain injury.
"The most unexpected aspect of our findings was that damage to gray matter hubs of the brain that are really interconnected with other regions didn't really tell us much about how poorly people would do on cognitive tests after brain damage. On the other hand, people with damage to the densest white matter connections did much worse on those tests," explains Justin Reber, PhD, ...
2021-05-07
Training the artificial intelligence models that underpin web search engines, power smart assistants and enable driverless cars, consumes megawatts of energy and generates worrying carbon dioxide emissions. But new ways of training these models are proven to be greener.
Artificial intelligence models are used increasingly widely in today's world. Many carry out natural language processing tasks - such as language translation, predictive text and email spam filters. They are also used to empower smart assistants such as Siri and Alexa to 'talk' to us, and to operate driverless cars.
But to function ...
2021-05-07
To observe the swift neuronal signals in a fish brain, scientists have started to use a technique called light-field microscopy, which makes it possible to image such fast biological processes in 3D. But the images are often lacking in quality, and it takes hours or days for massive amounts of data to be converted into 3D volumes and movies.
Now, EMBL scientists have combined artificial intelligence (AI) algorithms with two cutting-edge microscopy techniques - an advance that shortens the time for image processing from days to mere seconds, while ensuring that the resulting images are crisp and accurate. The findings are published in Nature Methods.
"Ultimately, we were able to take 'the best of both worlds' in this approach," says Nils Wagner, one of the paper's two lead ...
2021-05-07
PHILADELPHIA-- A gene called GAS2 plays a key role in normal hearing, and its absence causes severe hearing loss, according to a study led by researchers in the Perelman School of Medicine at the University of Pennsylvania.
The researchers, whose findings are published online today in Developmental Cell, discovered that the protein encoded by GAS2 is crucial for maintaining the structural stiffness of support cells in the inner ear that normally help amplify incoming sound waves. They showed that inner ear support cells lacking functional GAS2 lose their amplifier abilities, causing severe hearing ...
2021-05-07
Depressive symptoms are more common in teenage girls than in their male peers. However, boys' mental health appears to be affected more if they suffer from obesity. Irrespective of gender, bullying is a considerably greater risk factor than overweight for developing depressive symptoms. These conclusions are drawn by researchers at Uppsala University who monitored adolescents for six years in a questionnaire study, now published in the Journal of Public Health.
Peer-review/Observational study/People
"The purpose of our study was to investigate the connection ...
2021-05-07
Nearly four-fifths of 16- and 17-year-olds have encountered pornographic content on the Internet
Pornography is a multibillion-dollar business. Pornographic content is virtually ubiquitous on the Internet, and surveys suggest that 25% of all searches lead to explicit content. Given the size of the market, it's not surprising that young people are drawn to such sites, which are only a couple of clicks away.
Professor Neil Thurman of the Department of Media and Communication (IfKW) at Ludwig-Maximilians-Universitaet (LMU) in Munich, in collaboration with statistician Fabian Obster (Universität der Bundeswehr München), has carried out a study on the use of pornographic sites by young people. Based on a survey involving a sample ...
2021-05-07
Great reed warblers normally migrate by night during its month-long migration from northern Europe to Sub-Saharan Africa. However, researchers have now discovered that during the few occasions when it continues to fly during daytime, it flies at extremely high altitudes (up to 6300 meters). One possible explanation for this unexpected and consistent behaviour could be that the birds want to avoid overheating. The study is published in Science.
Most of the many millions of songbirds that migrate every year between Europe and Africa fly by night and spend the daytime hours resting and eating. Some species, which normally only fly by night, occasionally fly for over 24 consecutive ...
2021-05-07
If you are reading this, chances are you have several other tabs open in your browser that you mean to get to eventually.
Internet browser tabs are a major source of friction on the internet. People love them. People hate them. For some users, tabs bring order and efficiency to their web browsing. For others, they spiral out of control, shrinking at the top of the screen as their numbers expand.
A research team at Carnegie Mellon University recently completed the first in-depth study of browser tabs in more than a decade. They found that many people struggle with tab overload, an underlying reason being that while tabs serve a variety of functions, ...
2021-05-07
ITHACA, N.Y. - An 18.5 million-year-old fossil found in Panama provides evidence of a new species and is the oldest reliable example of a climbing woody vine known as a liana from the soapberry family. The discovery sheds light on the evolution of climbing plants.
The new species, named Ampelorhiza heteroxylon, belongs to a diverse group of tropical lianas called Paullinieae, within the soapberry family (Sapindaceae). More than 475 species of Paullinieae live in the tropics today.
Researchers identified the species from fossilized roots that revealed features known to be unique to the wood of modern climbing vines, adaptations that allow them to twist, grow and climb.
The study, "Climbing ...
LAST 30 PRESS RELEASES:
[Press-News.org] Why hotter clocks are more accurate