Tuesday, July 23, 2024

The Multisensory Multiplex Measures More Than You Think


This title means absolutely nothing, but it's unsettling to think "time" is as malleable as it is. 

Physicists develop highly robust time crystal
Feb 2024, phys.org

It's made of indium gallium arsenide, in which the nuclear spins act as a reservoir for the time crystal. The crystal is continuously illuminated so that a nuclear spin polarization forms through interaction with electron spins. And it is precisely this nuclear spin polarization that then spontaneously generates oscillations, equivalent to a time crystal.

A periodic time crystal was demonstrated in 2022 in a Bose-Einstein condensate but lived for just a few milliseconds. This one lasted for 40 minutes, or 10 million times longer. 

via TU Dortmund University: A. Greilich et al, Robust continuous time crystal in an electron–nuclear spin system, Nature Physics (2024). DOI: 10.1038/s41567-023-02351-6



The intricate dance of time and touch: Insights from the somatosensory cortex
Feb 2024, phys.org

The perception of time is intricately intertwined with touch, emerging within the tactile sensory representation.

Optogenetic intervention influenced perceived intensity in rats trained to assess vibration intensity while disregarding duration. Conversely, optogenetic intervention influenced perceived duration in animals trained to evaluate vibration duration while disregarding intensity.

"Since both percepts involve an overlapping set of neurons, we describe the two signals as 'multiplexed' in the somatosensory cortex.

via International School of Advanced Studies SISSA: Sebastian Reinartz et al, Direct contribution of the sensory cortex to the judgment of stimulus duration, Nature Communications (2024). DOI: 10.1038/s41467-024-45970-0


White House wants Moon to have its own time zone
Apr 2024, BBC News

The White House wants US space agency Nasa to develop a new time zone for the Moon - Coordinated Lunar Time (LTC).

Because of the different gravitational field strength on the Moon, time moves quicker there relative to Earth - 58.7 microseconds every day.

This might not seem like much, but it can have a significant impact when trying to synchronise spacecraft.

Time is currently measured on Earth by hundreds of atomic clocks stationed around our planet which measure the changing energy state of atoms to record time to the nanosecond. If they were placed on the Moon, over 50 years they would be running one second faster.


Image viewing experiments challenge theory of universal internal clock
Apr 2024, phys.org

The Universal Internal Clock (does not exist)

  • 170 volunteers participated
  • In the first two experiments, volunteers looked at photographs with varying degrees of size and clutter, and were asked how long they believed they had been looking at the images.
  • In the second two experiments, volunteers also estimated how memorable the photos were.
  • The took a memory test the following day.

  • Volunteers tended to overestimate the amount of time they viewed cluttered scenes, while underestimating the amount of time they viewed tidy areas.
  • Perception of time varied depending on the memorability of an image.
  • Volunteers were more accurate in their assessment of how much time had passed for the most memorable images
  • Experiments suggest that time perception is influenced by sensory perception.

via George Mason University: Alex C. Ma et al, Memorability shapes perceived time (and vice versa), Nature Human Behaviour (2024). DOI: 10.1038/s41562-024-01863-2


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