A Bose-Einstein condensate is a phase of matter formed by bosons cooled to temperatures very near to absolute zero. The first such condensate was produced by Eric Cornell and Carl Wieman in 1995 at the University of Colorado at Boulder, using a gas of rubidium atoms cooled to 170 nanokelvins (nK). Under such conditions, a large fraction of the atoms collapse into the lowest quantum state. Bose-Einstein condensate - Introduction. Bose-Einstein condensates are best known to laymen as extremely low temperature ...

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• Bose-Einstein condensate - Introduction
• Bose-Einstein condensate - Theory
• Bose-Einstein condensate - Discovery
• Bose-Einstein condensate - Unusual characteristics
• Bose-Einstein condensate - Current research

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An atomic clock is a type of clock that uses an atomic resonance frequency standard as its counter. Early atomic clocks were masers with attached equipment. Today's best atomic frequency standards (or clocks) are based on more advanced physics involving cold atoms and atomic fountains. National standards agencies maintain an accuracy of 10-9 seconds per day, and a precision equal to the frequency of the radio transmitter pumping the maser. The clocks maintain a continuous and stable time scale, International Atomic Time (TA ...

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• Atomic clock - Research

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Frequency reference masers use glowing chambers of ionized gas, most often caesium, because caesium is the element used in the official international definition of the second. Since 1967, the International System of Units (SI) has defined the second as 9,192,631,770 cycles of the radiation which corresponds to the transition between two energy levels of the ground state of the Caesium-133 atom. This definition makes the caesium oscillator (often called an atomic clock) the primary standard for time and frequency measurements (see caesium standard). Other physical quantities, like the volt and metre, rely on the definition o ...

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Atomic clock, Atomic clock - How they work, Atomic clock - Research

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Rubidium (L rubidus, deepest red) was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff in the mineral lepidolite through the use of a spectroscope. However this element had minimal industrial use until the 1920s. Historically, the most important use for rubidium has been in research and development, primarily in chemical and electronic applications. Rubidium is used for polarizing 3He. Polarized Rb polarizes 3He by hyperfine interaction. Polarized 3He cell ...

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Rubidium, Rubidium - Notable characteristics, Rubidium - Applications, Rubidium - History, Rubidium - Occurrence, Rubidium - Isotopes, Rubidium - Precautions, Rubidium - Biological Effects

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Doping fullerenes with electro positive metals takes place in an arc reactor or via laser evaporation. The metals can be transition metals like scandium, yttrium as well as lanthanides like lanthanum and cerium. Also possible are endohedral complexes with elements of the alkaline earth metals like barium and strontium and alkali metals like potassium and tetravalent metals like uranium, zirconium and hafnium. The synthesis in the arc reactor is however unspecific. Besides unfilled Fullerenes, endohedral metallofullerenes develop with differe ...

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Endohedral fullerenes, Endohedral fullerenes - Endohedral metallofullerenes, Endohedral fullerenes - Non-metal doped fullerenes

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Star lifting - Thermal-driven outflow. The simplest system for star lifting would increase the rate of solar wind outflow by directly heating small regions of the star's atmosphere, using any of a number of different means to deliver energy such as microwave beams, lasers, or particle beams — whatever proved to be most efficient for the engineers of the system. This would produce a large and sustained eruption similar to ...

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Star lifting, Star lifting - Methods for lifting material, Star lifting - Thermal-driven outflow, Star lifting - Huff-n-Puff, Star lifting - Centrifugal acceleration, Star lifting - Harvesting lifted mass, Star lifting - Stellar husbandry

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The collapse of the atoms into a single quantum state is known as Bose condensation or Bose-Einstein condensation. This phenomenon was predicted in the 1920s by Satyendra Nath Bose and Albert Einstein, based on Bose's work on the statistical mechanics of photons, which was then formalized and generalized by Einstein. The result of the efforts of Bose and Einstein is the concept of a Bose gas, governed by the Bose-Einstein statistics, which describes the statistical distribution of identical particles with integer spin, now know ...

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Bose-Einstein condensate, Bose-Einstein condensate - Introduction, Bose-Einstein condensate - Theory, Bose-Einstein condensate - Discovery, Bose-Einstein condensate - Unusual characteristics, Bose-Einstein condensate - Current research

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Most research focuses on way to make the clocks smaller, cheaper, more accurate, and more reliable. These goals usually conflict. A lot of research currently focuses on various sorts of ion traps. Theoretically, a single ion suspended electromagnetically could be observed for very long periods, increasing the accuracy of the clock, while also reducing its size and power consumption. In practice, single-ion clocks have poor short term accuracy because the ion moves so much. Current research uses laser cooling of ions, with optic ...

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Atomic clock, Atomic clock - How they work, Atomic clock - Research

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There are 24 isotopes of rubidium known with naturally occurring rubidium being composed of just two isotopes; Rb-85 (72.2%) and the radioactive Rb-87 (27.8%). Normal mixes of rubidium are radioactive enough to expose photographic film in approximately 30 to 60 days. Rb-87 has a half-life of 48.8×109 years. It readily substitutes for potassium in minerals, and is therefore fairly widespread. Rb has been used extensively in dating rocks; Rb-87 decays to stable strontium-87 by emission of a negative beta particle. During fra ...

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Rubidium, Rubidium - Notable characteristics, Rubidium - Applications, Rubidium - History, Rubidium - Occurrence, Rubidium - Isotopes, Rubidium - Precautions, Rubidium - Biological Effects

Read more here: » Rubidium: Encyclopedia II - Rubidium - Isotopes

Most research focuses on way to make the clocks smaller, cheaper, more accurate, and more reliable. These goals usually conflict. A lot of research currently focuses on various sorts of ion traps. Theoretically, a single ion suspended electromagnetically could be observed for very long periods, increasing the accuracy of the clock, while also reducing its size and power. In practice, single-ion clocks have poor short term accuracy because the ion moves so much. Current research uses laser cooling of ions, with optical resonator ...

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Atomic clock, Atomic clock - How they work, Atomic clock - Research

Read more here: » Atomic clock: Encyclopedia II - Atomic clock - Research

In 1938, Pyotr Kapitsa, John Allen and Don Misener discovered that helium-4 became a new kind of fluid, now known as a superfluid, at temperatures below 2.17 kelvins (K) (lambda point). Superfluid helium has many unusual properties, including zero viscosity (the ability to flow without dissipating energy) and the existence of quantized vortices. It was quickly realized that the superfluidity was due to Bose-Einstein condensation of the helium-4 atoms, which are bosons. In fact, many of the properties of superfluid helium also appear in the g ...

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Bose-Einstein condensate, Bose-Einstein condensate - Introduction, Bose-Einstein condensate - Theory, Bose-Einstein condensate - Discovery, Bose-Einstein condensate - Unusual characteristics, Bose-Einstein condensate - Current research

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Further experimentation by the JILA team in 2000 uncovered a hitherto unknown property of Bose-Einstein condensate. Cornell, Wieman, and their coworkers originally used rubidium-87, an isotope whose atoms naturally repel each other making a more stable condensate. The JILA team instrumentation now had better control over the condensate so experimentation was made on naturally attracting atoms of another rubidium isotope, rubidium-85 (having negative atom-atom scattering length). Through a process called Feshbach resonance involving a ...

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Bose-Einstein condensate, Bose-Einstein condensate - Introduction, Bose-Einstein condensate - Theory, Bose-Einstein condensate - Discovery, Bose-Einstein condensate - Unusual characteristics, Bose-Einstein condensate - Current research

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Compared to more commonly-encountered states of matter Bose-Einstein condensates are extremely fragile. The slightest interaction with the outside world can be enough to warm them past the condensation threshold, forming a normal gas and losing their interesting properties. It is likely to be some time before any practical applications are developed. Nevertheless, they have proved to be useful in exploring a wide range of questions in fundamental physics, and the years since the initial discoveries by the JILA and MIT groups have seen ...

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Bose-Einstein condensate, Bose-Einstein condensate - Introduction, Bose-Einstein condensate - Theory, Bose-Einstein condensate - Discovery, Bose-Einstein condensate - Unusual characteristics, Bose-Einstein condensate - Current research

Read more here: » Bose-Einstein condensate: Encyclopedia II - Bose-Einstein condensate - Current research