Η ΗΛΕΚΤΡΟΝΙΚΗ ΕΓΚΥΚΛΟΠΑΙΔΕΙΑ ΤΟΥ ΕΛΛΗΝΙΣΜΟΥ

5.3 C
Athens
Τρίτη, 11 Φεβρουαρίου, 2025

Η «παράξενη 5η κατάσταση της ύλης»

Η «παράξενη
5η κατάσταση της ύλης»

ΤΩΡΑ μιλάμε ανοικτά
για την «Παράξενη ύλη»…

Έναν «εξωτικό» «πέμπτο
τύπο ύλης»…

Η ουσία, που
ονομάζεται συμπύκνωμα Bose-Einstein / Bose-Einstein condensate (BEC), θεωρήθηκε
αρχικά από τους Albert Einstein και Satyendra Nath Bose, στις αρχές της
δεκαετίας του 1920, ως η πέμπτη κατάσταση της ύλης, μετά από:

– τα στερεά,
– τα υγρά,
– τα αέρια και
– το πλάσμα.

Είναι στην ουσία
ένα
supercooled gas / υπερψυγμένο αέριο.
ΠΗΓΗ: David C. Aveline, Jason R.
Williams, Ethan R. Elliott, Chelsea Dutenhoffer, James R. Kellogg, James M.
Kohel, Norman E. Lay, Kamal Oudrhiri, Robert F. Shotwell, Nan Yu & Robert
J. Thompson «Observation of Bose–Einstein condensates in an Earth-orbiting research lab», Nature,
αρ. 582, σελ. 193-197, 11 June 2020, Nature, DOI: 10.1038/s41586-020-2346-1. ΑΡΧΕΙΟΝ ΠΟΛΙΤΙΣΜΟΥ, 12.6.2020.

Strange matter
An exotic fifth type of matter has been created in one
of the coldest places in the universe – a device on board the International
Space Station.

The substance, called a Bose-Einstein condensate (BEC), was
initially theorised by Albert Einstein and Satyendra Nath Bose in the early
1920s as the fifth state of matter, following solids, liquids, gases and
plasma. It is a supercooled gas that no longer behaves as individual atoms and
particles, but rather an entity in a single quantum state.

The Cold Atom
Laboratory, a suitcase-sized device launched to the ISS in 2018, chills atoms
of rubidium and potassium in a vacuum chamber, using laser light to slow their
movement.

Magnetic fields then contain the resulting cloud of atoms, which is
cooled to nearly absolute zero at -273°C, producing a BEC.

SOURCE: New Scientist.



Abstract

Quantum mechanics governs the microscopic world, where low mass and
momentum reveal a natural wave–particle duality. 

Magnifying quantum behaviour
to macroscopic scales is a major strength of the technique of cooling and
trapping atomic gases, in which low momentum is engineered through extremely
low temperatures. 

Advances in this field have achieved such precise control
over atomic systems that gravity, often negligible when considering individual
atoms, has emerged as a substantial obstacle. In particular, although weaker
trapping fields would allow access to lower temperatures, gravity empties
atom traps that are too weak. Additionally, inertial sensors based on cold
atoms could reach better sensitivities if the free-fall time of the atoms after
release from the trap could be made longer. Planetary orbit, specifically the
condition of perpetual free-fall, offers to lift cold-atom studies beyond such
terrestrial limitations. 

Here we report production of rubidium Bose–Einstein
condensates
(BECs) in an Earth-orbiting research laboratory, the Cold Atom Lab. 

We observe subnanokelvin BECs in weak trapping potentials with free-expansion
times extending beyond one second, providing an initial demonstration of the
advantages offered by a microgravity environment for cold-atom experiments and
verifying the successful operation of this facility. 

With routine BEC
production, continuing operations will support long-term investigations of trap
topologies unique to microgravity, atom-laser sources, few-body physics and pathfinding techniques for atom-wave interferometry.
ΛΕΞΕΙΣπαραξενη κατασταση, 5η κατασταση της υλης, Λεκακης, Παραξενη υλη, εξωτικη υλη, πεμπτος τυπος υλης, συμπυκνωμα Bose-Einstein Αινσταιν, Μποζ, 1920, πεμπτη κατασταση της υλης, στερεα, υγρα, αερια, πλασμα, υπερψυξη, ψυξη
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