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Seen and heard

Physics World February 2022

Physics World

 
Quanta Physics World  February 2022

Seen and heard

Weird and wonderful stories from the world of physics

(Courtesy: Schokraie et al./PLOS ONE 7 e45682 /CC BY 2.5 )

Entangled tale

Imagine being able to survive when chilled to near absolute zero. That’s what tiny organisms called tardigrades can do, but could these cute-looking “water bears” have another low-temperature trick up their sleeve? To find out, an international team of physicists chilled a tardigrade to below 10 mK and then used it as the dielectric in a capacitor that itself was part of a superconducting transmon qubit (arXiv:2112.07978). The researchers then entangled the qubit – tardigrade and all – with another superconducting qubit before warming up the tardigrade and bringing it out of its latent state of life called cryptobiosis. Some physicists, however, remain unconvinced. “This is not entanglement in any meaningful sense,” Rice University physicist Douglas Natelson noted on his blog. Whether or not the team achieved quantum entanglement, they definitely did set a record for the extreme conditions that a complex lifeform can survive, with the tardigrade spending 420 hours at temperatures below 10 mK and pressures of 6 × 10−6 mbar. 

Having a wobbly

Scaling the Matterhorn, which rises to 4470 m above sea level, is on the to-do list of thousands of climbers. But when an international team of scientists set out to take a closer look at his perfectly shaped Alpine peak in 2019, they were in for a shock. After installing several seismometers at different locations, they found that the Matterhorn is not quite the huge, immovable mass that it appears to be. The mountain is in fact constantly on the move, swaying gently back and forth about once every two seconds (Earth and Planetary Science Letters 10.1016/j.epsl.2021.117295). The researchers say that this subtle vibration, which has a fundamental frequency of 0.42 Hz, is stimulated by seismic energy in the Earth originating from oceans, earthquakes and – surprisingly – human activity. It’s enough to give you the shakes.

Interstellar setback

What kind of propulsion system would make interstellar travel possible? One option is the “Bussard collector” or “ramjet propulsion”, which was dreamt up in the 1960s by the US nuclear physicist Robert Bussard. It involves capturing protons in interstellar space and then using them for a nuclear fusion reactor. Peter Schattschneider, a physicist at the Technical University of Vienna, and Albert Jackson from private firm Triton Systems LLC in the US, have now analysed the technique and say that the basic principle of magnetic particle trapping does in fact work (Acta Astro. 191 227). The duo found that particles can be collected in the proposed magnetic field and guided into a fusion reactor. In theory, considerable acceleration can be achieved – up to relativistic speeds. Trouble is, to achieve a thrust of 10 million newtons – equivalent to twice the main propulsion of the Space Shuttle – the “magnetic funnel” to guide the particles would have to be about 150 million kilometres long. That’s roughly the distance between the Sun and the Earth. Half a century after it was cooked up, the prospect of the ramjet drive taking us on an interstellar journey is still probably best filed under science fiction.

 

(Courtesy: Google)

Hawking doodle do

To mark the 80th birthday of the late Stephen Hawking on 8 January, Google teamed up with the Hawking estate to release a two-minute video “Doodle” to celebrate the legendary physicist who died in March 2018. The animation recounts Hawking’s diagnosis with a neurodegenerative disease at 21 and his pioneering work on black holes as well as some inspirational quotes from the man himself (youtu.be/Isim0ysZ6X4). “We think he would have loved the Doodle and been very entertained to see his long, distinguished life expressed so creatively in this briefest history of all, a two-minute animation,” the Hawking estate noted. Meanwhile, the UK’s Science Museum Group announced that a new display will open on 10 February in London featuring several of Hawking’s most treasured possessions including his wheelchair, PhD thesis, as well as a blackboard filled with “academic doodles”.