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Helium II will "creep" along surfaces in order to find its own level - after a short while, the levels in the two containers will equalize. The Rollin film also covers the interior of the larger container; if it were not sealed, the helium II would creep out and escape.
Helium II will "creep" along surfaces in order to find its own level - after a short while, the levels in the two containers will equalize. The Rollin film also covers the interior of the larger container; if it were not sealed, the helium II would creep out and escape. A Rollin film, named after Bernard V Rollin, is a 30 nm -thick liquid film of Helium in the helium II state

Superfluidity is a phase of matter or description of heat capacity in which unusual effects are observed when liquids, typically of helium-4 or helium-3, overcome friction by surface interaction when at a stage, known as the "lambda point" for helium-4, at which the liquid's viscosity becomes zero. In the Physical sciences a phase is a Set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity Liquid is one of the principal States of matter. A liquid is a Fluid that has the particles loose and can freely form a distinct surface at the boundaries of Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. Friction is the Force resisting the relative motion of two Surfaces in contact or a surface in contact with a fluid (e The Lambda point is the Temperature (approximately 217 K) below which normal fluid Helium (helium I transitions to Superfluid helium II Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. Also known as a major facet in the study of quantum hydrodynamics, it was discovered by Pyotr Kapitsa, John F. Allen, and Don Misener in 1937 and has been described through phenomenological and microscopic theories. Quantum hydrodynamics is more than the study of Superfluidity. Pyotr Leonidovich Kapitsa ( Russian Пётр Леонидович Капица ( July 9, 1894 &ndash April 8, 1984) was an innovative John "Jack" Frank Allen ( May 5, 1908 &ndash April 22, 2001) was a Canadian -born Physicist. Don Misener (AD Misener was a Physicist. Along with Pyotr Leonidovich Kapitsa and John F Year 1937 ( MCMXXXVII) was a Common year starting on Friday (link will display the full calendar of the Gregorian calendar. The term phenomenology in Science is used to describe a body of knowledge which relates several different empirical observations of phenomena to each other

Contents

Background

Although the phenomenologies of the superfluid states of helium-4 and helium-3 are very similar, the microscopic details of the transitions are very different. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. Helium-4 atoms are bosons, and their superfluidity can be understood in terms of the Bose statistics that they obey. History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny In Particle physics, bosons are particles which obey Bose-Einstein statistics; they are named after Satyendra Nath Bose and Albert Einstein In Statistical mechanics, Bose - Einstein statistics (or more colloquially B-E statistics determines the statistical distribution of Specifically, the superfluidity of helium-4 can be regarded as a consequence of Bose-Einstein condensation in an interacting system. A Bose–Einstein condensate (BEC is a State of matter of Bosons confined in an external Potential and cooled to Temperatures very near to On the other hand, helium-3 atoms are fermions, and the superfluid transition in this system is described by a generalization of the BCS theory of superconductivity. In Particle physics, fermions are particles which obey Fermi-Dirac statistics; they are named after Enrico Fermi. In it, Cooper pairing takes place between atoms rather than electrons, and the attractive interaction between them is mediated by spin fluctuations rather than phonons. In Condensed matter physics, a Cooper pair is the name given to electrons that are bound together at low temperatures in a certain manner first described in 1956 by The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J In Quantum mechanics, spin is a fundamental property of atomic nuclei, Hadrons and Elementary particles For particles with non-zero spin In Physics, a phonon is a quantized mode of vibration occurring in a rigid crystal lattice, such as the Atomic lattice of a Solid See fermion condensate. A fermionic condensate is a Superfluid phase formed by Fermionic particles at low Temperatures It is closely related to the Bose-Einstein A unified description of superconductivity and superfluidity is possible in terms of gauge symmetry breaking. In Physics, spontaneous symmetry breaking occurs when a system that is symmetric with respect to some Symmetry group goes into a Vacuum state

Superfluids, such as supercooled helium-4, exhibit many unusual properties. A superfluid acts as if it were a mixture of a normal component, with all the properties associated with normal fluid, and a superfluid component. The superfluid component has zero viscosity, zero entropy, and infinite thermal conductivity. Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. In Thermodynamics (a branch of Physics) entropy, symbolized by S, is a measure of the unavailability of a system ’s Energy In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. (It is thus impossible to set up a temperature gradient in a superfluid, much as it is impossible to set up a voltage difference in a superconductor. In atmospheric sciences ( Meteorology, Climatology and related fields the temperature gradient (typically of air, more generally of any Fluid Electrical tension (or voltage after its SI unit, the Volt) is the difference of electrical potential between two points of an electrical Superconductivity is a phenomenon occurring in certain Materials generally at very low Temperatures characterized by exactly zero electrical resistance ) One of the most spectacular results of these properties is known as the thermomechanical or "fountain effect". If a capillary tube is placed into a bath of superfluid helium and then heated, even by shining a light on it, the superfluid helium will flow up through the tube and out the top as a result of the Clausius-Clapeyron relation. Capillary action, capillarity, capillary motion, or wicking is the ability of a substance to draw another substance into it Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 The Clausius-Clapeyron relation, named after Rudolf Clausius and Émile Clapeyron, is a way of characterizing the Phase transition between two phases of A second unusual effect is that superfluid helium can form a layer, a single atom thick, up the sides of any container in which it is placed.

A more fundamental property than the disappearance of viscosity becomes visible if superfluid is placed in a rotating container. Instead of rotating uniformly with the container, the rotating state consists of quantized vortices. In Physics, a quantum Vortex is a Topological defect exhibited in Superfluids and Superconductors. That is, when the container is rotated at speed below the first critical velocity (related to the quantum numbers for the element in question) the liquid remains perfectly stationary. Speed is the rate of motion, or equivalently the rate of change in position often expressed as Distance d traveled per unit of In Physics, velocity is defined as the rate of change of Position. Quantum numbers describe values of conserved numbers in the dynamics of the Quantum system. A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. Once the first critical velocity is reached, the superfluid will very quickly begin spinning at the critical speed. The speed is quantized - i. e. it can only spin at certain speeds.

Applications

Recently in the field of chemistry, superfluid helium-4 has been successfully used in spectroscopic techniques, as a quantum solvent. Chemistry (from Egyptian kēme (chem meaning "earth") is the Science concerned with the composition structure and properties Spectroscopy was originally the study of the interaction between Radiation and Matter as a function of Wavelength (λ A quantum solvent is essentially a Superfluid (aka a quantum liquid) used to dissolve another Chemical species. Referred to as Superfluid Helium Droplet Spectroscopy (SHeDS), it is of great interest in studies of gas molecules, as a single molecule solvated in a superfluid medium allows a molecule to have effective rotational freedom - allowing it to behave exactly as it would in the "gas" phase. This page is about the physical properties of gas as a state of matter In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by

Superfluids are also used in high-precision devices, such as gyroscopes, which allow the measurement of some theoretically predicted gravitational effects (for an example see the Gravity Probe B article). A gyroscope is a device for measuring or maintaining orientation, based on the principles of Angular momentum. Gravity Probe B ( GP-B) is a Satellite -based mission which launched in 2004

Recently, superfluids have been used to trap light and slow its speed. In an experiment, performed by Lene Hau, light was passed through a superfluid and found to be slowed to 17 metres per second from its normal speed of 299,792,458 metres per second in vacuum. Lene Vestergaard Hau (born in Vejle Denmark, on November 13, 1959) is a Danish Physicist. [1] This does not change the absolute value of c, nor is it completely new: any medium other than vacuum, such as water or glass, also slows down the propagation of light in a certain fraction. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium

The Infrared Astronomical Satellite (IRAS), launched in January 1983 to gather infrared data was cooled by 720 litres of superfluid helium, maintaining a temperature of 1. Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study This article is about artificial satellites For natural satellites also known as moons see Natural satellite. The Infrared Astronomical Satellite ( IRAS) was the first-ever space-based Observatory to perform a survey of the entire Sky at Infrared Year 1983 ( MCMLXXXIII) was a Common year starting on Saturday (link displays the 1983 Gregorian calendar) Debt AIDS Trade in Africa (or DATA) is a Multinational non-government organization founded in January 2002 in London by U2 's Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature 6K (-271. 4 ­°C).

Recent discoveries

Physicists have recently been able to create a Fermionic condensate from pairs of ultra-cold fermionic atoms. Below is a list of famous Physicists Many of these from the 20th and 21st centuries are found on the list of recipients of the Nobel Prize in physics. Under certain conditions, fermion pairs form diatomic molecules and undergo Bose–Einstein condensation. Diatomic molecules are molecules made only of two Atoms of either the same or different Chemical elements The prefix di- means two in Greek A Bose–Einstein condensate (BEC is a State of matter of Bosons confined in an external Potential and cooled to Temperatures very near to At the other limit, the fermions (most notably superconducting electrons) form Cooper pairs which also exhibit superfluidity. In Condensed matter physics, a Cooper pair is the name given to electrons that are bound together at low temperatures in a certain manner first described in 1956 by This recent work with ultra-cold atomic gases has allowed scientists to study the region in between these two extremes, known as the BEC-BCS crossover. A scientist, in the broadest sense refers to any person that engages in a systematic activity to acquire Knowledge or an individual that engages in such practices

Additionally, supersolids might have also been discovered, in 2004, by physicists at Penn State University. A supersolid is a spatially ordered material (that is a Solid or Crystal) with Superfluid properties "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " The Pennsylvania State University (commonly known as Penn State) is a state-related, land-grant, space grant public research University When helium-4 is cooled, below about 200 mK under high pressures, a fraction (~1%) of the solid appears to become superfluid [1]. A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume.

See also

Notes

  1. ^ Lene Vestergaard Hau, S. Superdiamagnetism (or perfect diamagnetism) is a Phenomenon occurring in certain materials at Low temperatures characterised by the complete absence of A Bose–Einstein condensate (BEC is a State of matter of Bosons confined in an external Potential and cooled to Temperatures very near to Superconductivity is a phenomenon occurring in certain Materials generally at very low Temperatures characterized by exactly zero electrical resistance In Physics, a quantum Vortex is a Topological defect exhibited in Superfluids and Superconductors. A supersolid is a spatially ordered material (that is a Solid or Crystal) with Superfluid properties Superfluidity and superconductivity are of inherent interest because they are Macroscopic manifestations of quantum mechanics. Douglas Dean Osheroff (born August 1, 1945) is an American physicist E. Harris, Zachary Dutton, Cyrus H. Behroozi Light speed reduction to 17 metres per second in an ultracold atomic gas Nature 397, 594-598 (18 February 1999)

References

External links

Dictionary

superfluid

-noun

  1. (physics) A substance, such as liquid helium, that exhibits superfluidity

-adjective

  1. of, pertaining to, or exhibiting superfluidity
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