Future quantum computers could be based on electrons floating above liquid helium, according to study by a RIKEN physicist and collaborators, appearing in Physical Review Applied.
Condensed Matter
Mar 28, 2024
0
141
During the manufacturing process, many medical devices or equipment for use on humans must be sterilized according to recognized standards. This includes gowns, surgical drapes, syringes and implantable medical devices. In ...
General Physics
Mar 4, 2024
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1
From televisions to X-ray machines, many modern technologies are enabled by electrons that have been juiced up by a particle accelerator. Now, the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility ...
General Physics
Feb 29, 2024
1
115
The next time you pick up balloons for your big party, remember the helium gas in those balloons is destined for the stars. Helium is so light that it easily escapes Earth's gravity, and all helium will eventually make its ...
Other
Jan 18, 2024
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8
By using a special combination of laser beams as a very fast stirrer, RIKEN physicists have created multiple vortices in a quantum photonic system and tracked their evolution. This system could be used to explore exotic new ...
Nanophysics
Nov 21, 2023
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42
Molecules immersed in liquid helium can probe superfluidity since their electronic, vibrational and rotational dynamics can provide valuable cues about the superfluid at the nanoscale. In a new report in Science Advances, ...
A team of scientists from the Department of Energy's Ames National Laboratory have developed a way to collect terahertz imaging data on materials under extreme magnetic and cryogenic conditions. They accomplished their work ...
Optics & Photonics
May 12, 2023
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46
An international team led by Lancaster University has discovered how electrons can slither rapidly to-and-fro across a quantum surface when driven by external forces.
Soft Matter
Mar 21, 2023
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254
To study how stars and planets are born we have to look at star cradles hidden in cool clouds of dust. Far-infrared telescopes are able to pierce through those clouds. Conventionally, niobium nitride bolometers are used as ...
Astronomy
Feb 17, 2023
0
126
Today it only takes one and a half hours to make a superconducting particle accelerator at the Department of Energy's SLAC National Accelerator Laboratory colder than outer space.
Superconductivity
Aug 31, 2022
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181
Helium exists in liquid form only at extremely low temperatures. The boiling point and critical point depend on the isotope of the helium; see the table below for values. The density of liquid helium at its boiling point and 1 atm is approximately 0.125 g/mL
Helium-4 was first liquefied on 10 July 1908 by Dutch physicist Heike Kamerlingh Onnes. Liquid helium-4 is used as a cryogenic refrigerant; it is produced commercially for use in superconducting magnets such as those used in MRI or NMR. It is liquefied using the Hampson-Linde cycle.[citation needed]
The temperatures required to liquefy helium are low because of the weakness of the attraction between helium atoms. The interatomic forces are weak in the first place because helium is a noble gas, but the interatomic attraction is reduced even further by quantum effects, which are important in helium because of its low atomic mass. The zero point energy of the liquid is less if the atoms are less confined by their neighbors; thus the liquid can lower its ground state energy by increasing the interatomic distance. But at this greater distance, the effect of interatomic forces is even weaker.[citation needed]
Because of the weak interatomic forces, helium remains liquid down to absolute zero; helium solidifies only under great pressure. At sufficiently low temperature, both helium-3 and helium-4 undergo a transition to a superfluid phase (see table below).[citation needed]
Liquid helium-3 and helium-4 are not completely miscible below 0.9 K at the saturated vapor pressure. Below this temperature a mixture of the two isotopes undergoes phase separation into a lighter normal fluid that is mostly helium-3, and a denser superfluid that is mostly helium-4. (This occurs because the system can lower its enthalpy by separating.) At low temperatures, the helium-4 rich phase may contain up to 6% of helium-3 in solution, which makes possible the existence of the dilution refrigerator, capable of reaching temperatures of a few mK above absolute zero.[citation needed]
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