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How physicists conceive time today + Stimulating the sense of touch with chemistry

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How physicists conceive time today and other unsolved questions about the many-faceted mystery of time
https://www.bial.com/com/bial-foundation/symposia/

RELEASE: Is it the case that “the distinction between the past, present and future is only a stubbornly persistent illusion,” as Einstein famously declared? In the session on The Arrow of Time, on April 7th, experts on physics, cosmology, parapsychology, and history of ideas will discuss theory and data confronting this question.

Under the theme “The mystery of time”, the 13th Symposium of the BIAL Foundation gathers some of the most prominent scientists and philosophers to engage in an interdisciplinary dialogue around the many aspects of time.

The first session on The Arrow of Time will take place on the morning of April 7th having Etzel Cardeña (Lund, SE) as moderator. Orfeu Bertolami (Porto, PT), Jimena Canales (Urbana-Champaign, USA), Daniel Sheehan (San Diego, USA) and Patricia Cyrus (Orlando, USA) will explore how physicists conceive time today, and how their theories are shaped by what we know about the perception of time.

Are space and time distinct entities? Is our sense of time simply illusory as Einstein stated? Is the `arrow of time´ unidirectional? How can we explain precognition via retrocausation within the current paradigm of physics? These are some fundamental and yet unsolved questions to be addressed in the first session of the Symposium dedicated to the physics of time.

Jimena Canales sums it all up in one sentence: “while some scientists have tried to incorporate elements of our experience of time into our explanations of the universe, others continue to claim that our sense of time is simply illusory”. The Mexican American writer and historian of science will explore the origins of this persistent dilemma by focusing on the relation of physics to philosophy, history and the humanities.

The keynote lecturer Bernard Carr has also an interdisciplinary approach. For the emeritus professor of mathematics and astronomy at Queen Mary University of London “the problem of time involves an overlap between physics, philosophy, psychology and neuroscience” and he emphasizes that “physics may need to expand to address issues usually regarded as being in the other domains”.

For his PhD, Bernard Carr studied the first second of the Universe, working under Stephen Hawking. In the 13th Symposium of the BIAL Foundation he will first review the mainstream physics view of time, as it arises in Newtonian theory, relativity theory and quantum theory. “I will then discuss the various arrows of time, the most fundamental of which is the passage of time associated with consciousness. I will argue that this goes beyond both relativity theory and quantum theory, so that one needs some new physical paradigm to accommodate it”, he states.

The Symposium “Behind and Beyond the Brain” will be held from April 6 to 9, 2022, at Casa do Médico, Porto, Portugal. The event will be organised in a hybrid format involving both in-person and virtual participants to be accessible to a wider audience. Registrations are open and available here.


Stimulating the sense of touch with chemistry
https://www.acs.org/content/acs/en/press...istry.html

RELEASE: Our eyes may be windows on the world, but our fingertips put us in touch with it. To recreate this tactile sense, current technology relies on tiny motors and electricity. However, the bumps and buzzes they generate are not that good at mimicking the real thing. Today, scientists report evidence that our skin can perceive subtle differences in chemistry — findings they hope could provide the basis for a new way to control touch and better integrate it into applications, such as virtual reality.

The researchers will present their results at the spring meeting of the American Chemical Society (ACS). ACS Spring 2022 is a hybrid meeting being held virtually and in-person March 20-24, with on-demand access available March 21-April 8. The meeting features more than 12,000 presentations on a wide range of science topics.

“When you touch an object, you're feeling its surface, and you can change how it feels by changing the friction between that surface and your finger. That’s where the chemistry comes in,” says Charles Dhong, Ph.D., the project’s principal investigator. “We think materials chemistry could open the door to recreating more nuanced sensations, whether you're designing a surface to feel a certain way, or creating feedback devices for virtual reality.”

Of the five senses, technology has embraced some more readily than others. Computer monitors, smart phone screens and virtual reality headsets offer detailed, even immersive, imagery. Audio devices, too, recreate voices, music and other sound in high fidelity. Progress in touch technology, however, has lagged behind, in part because it involves multiple types of sensations, such as temperature and pain. In addition, some efforts to recreate touch have included systems designed to simulate a sense of moving one’s body — a complex sensation.

Dhong’s research at the University of Delaware focuses on a specific type of touch: using the fingers to detect texture. Some methods for evoking this kind of fine touch are already available. A vibrator within a smartphone enables it to attract your attention without ringing. In a refreshable braille display for people with low vision or blindness, an actuator moves pins up to create bumps. This type of touch depends on a physical force, friction, which is the resistance that skin encounters as it brushes against an object. While attributes such as the contours of a surface influence friction, so does chemistry. The structure of the molecules within a substance and the properties of its surface also influence the sensation. Dhong and his colleagues suspected that by altering only chemistry-related features, they could change how a surface feels.

In past work, Dhong’s team asked people to touch single-molecule-thick layers of silane, a silicon-containing compound. None of the silane surfaces possessed detectable differences in smoothness. Even so, those who touched the surfaces could differentiate them based on chemical differences, including the substitution of one atom within each silane molecule for another, because of subtle changes in friction. “Recent research has shown that people can detect the physical differences between surfaces at a resolution as low as 13 nanometers,” Dhong says. “Now we are saying that the sense of touch can also identify chemical changes as small as swapping a nitrogen atom for a carbon atom.”

At the meeting, Dhong will present recent work focusing on polymers, the go-to molecules for synthetic materials. Polymers are distinguished not only by their chemical formulas, but also by a characteristic known as crystallinity, which describes how neatly the chain-like molecules are organized. The polymers in these experiments had identical formulas and molecular weights; only the degree of crystallinity differed.

In their experiments, the researchers focused on the perceived texture of thin layers of polymers. As with the silanes, they asked the subjects to slide their fingers across the polymer. This time, too, they found that people could differentiate between the polymers based only on variations in the friction resulting from subtle changes to the crystallinity of the molecules.

A new approach to controlling fine touch and the perception of texture could have many applications, says Dhong. It could, for example, make it possible to design new types of surfaces, or to better integrate this sense into virtual reality environments. Other applications could include improving devices, such as refreshable braille displays, as well as providing feedback to surgeons conducting surgery remotely, Dhong says.
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