Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Eos

H Gas: Captured at last?

Peter M. Bell

Published Feb 24, 1981• 0 citations
Publisher

Abstract

In the strange world of low‐temperature physics, few more unusual phenomena have been discovered than monatomic hydrogen gas. According to a recent report (New Scientist, Jan. 1981, p. 204), hydrogen atoms do not tend to pair up to form molecules under special low‐temperature‐cryogenic experimental conditions. The reasons for the existence of atomic hydrogen gas at ultra‐low temperature, and for its implications, lie in an understanding of its almost pure quantum mechanical properties. Practical uses of atomic hydrogen will await more knowledge of its properties, but right now, if available in sufficient abundance, atomic hydrogen could be used in maser clocks because it emits highly defined frequencies of microwave radiation at room temperature, and atomic hydrogen gas could be used as an energy conservative fuel, as it recombines to the diatomic molecule. For every recombination between two hydrogen atoms, 4.5 eV of energy are released, which calculates to be over 1 million watts of power per second for 10 grams of atomic hydrogen recombined. The large impulse relative to its light mass could be significant in applications of atomic hydrogen as a rocket fuel. Practical applications aside, the main interest in atomic hydrogen at this moment is in the insight into quantum mechanics that study of its properties may provide. Atomic hydrogen atoms ‘abound throughout the universe,’ even though not on Earth, and thus quantum effects in space, and the hydrogen‐rich planets as well, may be elucidated by results of these studies.

DOI
10.1029/eo062i008p00076-02

Related papers

Stabilization of atomic hydrogen

А.Ф. Сильвера, Yu Valraven

The authors succeeded in conserving gas in monatomic state for several hours at the ultimately permissible temperature in a strong magnetic field. Under such conditions hydrogen atoms unite themselves relatively slowly, therefore gas may be considered as stable. As it follows from experimental results, monatomic hydrogen remains gaseous up to 0.08 K - the ultralow temperature at which the investigations have been carried out. These data at least preliminarily confirm an assumption that atomic hydrogen remains gaseous at absolute zero temperature, as it is predicted by the quantum theory.

•Apr 1, 1983•0 citations

The quantum world of ultra-cold atoms

William D. Phillips, Christopher J. Foot

Introduction This chapter describes remarkable new experiments that have been made possible through recent advances in laser cooling of atoms. Cooling of atoms in a gas by laser light is in itself surprising and this technique is important in a range of applications. In particular the experiments described here take atoms that have been laser cooled and then use other methods to reach even lower temperatures, at which wonderful and fascinating quantum effects occur. As well as revealing new phenomena, these experiments explore the deep analogies between the roles played by light waves in lasers and matter waves. These techniques are widely accessible and enable skilled researchers in laboratories all over the world to explore exciting new physics. The key physics and techniques of laser cooling are described in depth in Chapter 6. What is “temperature”? We use the words “cold” and “hot” every day; for example to refer to the temperature of the air outside. But what do “cold” and “hot” mean for the air’s molecules? Broadly speaking, we can say that atoms in a hot gas move faster than those in a cold gas and that cooling, by taking energy out of the gas, slows the atoms down. In this description of the gas as a collection of atoms behaving like billiard balls, or little hard spheres, the lowest possible temperature occurs when the atoms stop moving but, as we shall see, this picture does not give an accurate description at very low energies, for which quantum effects become important. In this chapter we will look at the fascinating properties of atomic gases cooled to temperatures within one millionth of a degree Kelvin from absolute zero. We shall use the term “ultra-cold” to refer to such extremely low temperatures that have only recently been achieved in experiments on atomic gases. The techniques used to cool liquids and solids have a longer history and have made available a different set of possibilities (see Chapter 8). Note that most of this chapter refers to gases in which the individual particles are atoms, but the general statements about temperature scales apply equally well to gases of molecules, e.g. air, whose major constituents, oxygen and nitrogen, exist as diatomic molecules.

Cambridge University Press eBooks•Feb 13, 2006•0 citations

Hydrogen: a quantum gas at last

Tom W. Hijmans

The experimental observation of Bose-Einstein condensation in gas of rubidium atoms in 1995 had huge impact on the physics community with reports of a new state of matter making newspaper headlines all over the world. By comparison, it was in relative obscurity that Simo Jaakkola and his group at the University of Turku in Finland, in collaboration with researchers at the Kurchatov Institute in Moscow, recently observed the two-dimensional analogue of the effect (A I Safonov et al. 1998 Phys. Rev. Lett. 81 4545). Jaakkola observed two-dimensional Bose-Einstein condensation (2D BEG) in gas of specially prepared hydrogen atoms adsorbed on the surface of liquid helium. In Bose-Einstein condensation all the particles in system collapse into single quantum state that has many unusual and novel properties.

Physics World•Feb 1, 1999•2 citations

Gravitational and matter-wave spectroscopy of atomic hydrogen at ultra-low energies

Sergey Vasiliev, Janne Ahokas, Jarno Järvinen +4 more

We propose experiments with atomic hydrogen gas at ultra-low temperatures T < 100 μ K when the thermal energy of atoms is comparable with the changes of their potential energy in the Earth gravity field. At these conditions we suggest implementing a gravitational spectroscopy for studies of quantum properties of ultra-cold atomic hydrogen and its interactions with matter and gravity, similar to experiments with ultra-cold neutrons (Nesvizhevsky et al. Nature 415 , 297 2002 ). A magnetic trap used for reaching the Bose-Einstein Condensation (Fried et al. Phys. Rev. Lett. 81 , 3811 1998 ) can be used for cooling a large number of H atoms below 1 mK. Evaporative cooling over the trap barrier allows effective cooling of the vertical degree of freedom of the trapped atoms. Releasing these ultra-slow atoms from the trap onto the cold surface of superfluid helium will allow studies of quantum bounces and stationary gravitational states of H atoms in the potential well created by this surface and the field of Earth gravity. Experimental study of properties of gravitational quantum states of hydrogen and quantum reflection of ultracold hydrogen from surface would be of major importance for designing similar experiments with antihydrogen, which are currently prepared in CERN.

Hyperfine Interactions•Feb 4, 2019•8 citations

Atomic hydrogen: the quantum gas

Jook T. M. Walraven

It was a complete surprise when Isaac Silvera and his colleagues at the University of Amsterdam observed the existence of a remarkably stable gas of hydrogen atoms in 1979. They found that a gas of the so-called “atom of atoms” could be confined for several minutes in a cryogenic test cell close to absolute zero, provided that the walls were coated with a film of liquid helium. Until then, if researchers wanted to study monoatomic hydrogen for any length of time they had to use a discharge source to replace those hydrogen atoms that recombined to form molecular hydrogen. But most important, Silvera's experiments marked the first experimental investigation of a dilute quantum gas.

Physics World•Jul 1, 1995•5 citations

Hydrogen—The First Atom

Cynthia Kolb Whitney

The hydrogen atom is the gateway atom for the development of the quantum mechanics of all atoms, and hence all molecules, and hence all nanostructures. A more conservative analysis of the hydrogen atom just identifies the approximations that caused the classical analysis to go badly, and removes those approximations. The basic approach to the hydrogen atom that can be characterized as follows: take account of all processes that can be identified, and look for a natural balance between them. There exist other research areas awaiting further application of this approach. Hydrogen atoms, and all other atoms as well, are presently envisioned as having infinitely many ‘excited states’ that are described via the multiple solutions of Schrodinger’s differential equation for the atom. These excited states are presently understood as conditions that an individual atom possesses. The ionization potential of helium is very high–the highest among all elements. It invites the interpretation that electrons very much like to form a pair.

Apple Academic Press eBooks•May 10, 2020•0 citations
In the strange world of low‐temperature physics, few more unusual phenomena have been discovered than monatomic hydrogen gas. According to a recent report (New Scientist, Jan. 1981, p. 204), hydrogen atoms do not tend to pair up to form molecules under special low‐temperature‐cryogenic experimental conditions. The reasons for the existence of atomic hydrogen gas at ultra‐low temperature, and for its implications, lie in an understanding of its almost pure quantum mechanical properties. Practical uses of atomic hydrogen will await more knowledge of its properties, but right now, if available in sufficient abundance, atomic hydrogen could be used in maser clocks because it emits highly defined frequencies of microwave radiation at room temperature, and atomic hydrogen gas could be used as an energy conservative fuel, as it recombines to the diatomic molecule. For every recombination between two hydrogen atoms, 4.5 eV of energy are released, which calculates to be over 1 million watts of power per second for 10 grams of atomic hydrogen recombined. The large impulse relative to its light mass could be significant in applications of atomic hydrogen as a rocket fuel. Practical applications aside, the main interest in atomic hydrogen at this moment is in the insight into quantum mechanics that study of its properties may provide. Atomic hydrogen atoms ‘abound throughout the universe,’ even though not on Earth, and thus quantum effects in space, and the hydrogen‐rich planets as well, may be elucidated by results of these studies.
The authors succeeded in conserving gas in monatomic state for several hours at the ultimately permissible temperature in a strong magnetic field. Under such conditions hydrogen atoms unite themselves relatively slowly, therefore gas may be considered as stable. As it follows from experimental results, monatomic hydrogen remains gaseous up to 0.08 K - the ultralow temperature at which the investigations have been carried out. These data at least preliminarily confirm an assumption that atomic hydrogen remains gaseous at absolute zero temperature, as it is predicted by the quantum theory.
Introduction This chapter describes remarkable new experiments that have been made possible through recent advances in laser cooling of atoms. Cooling of atoms in a gas by laser light is in itself surprising and this technique is important in a range of applications. In particular the experiments described here take atoms that have been laser cooled and then use other methods to reach even lower temperatures, at which wonderful and fascinating quantum effects occur. As well as revealing new phenomena, these experiments explore the deep analogies between the roles played by light waves in lasers and matter waves. These techniques are widely accessible and enable skilled researchers in laboratories all over the world to explore exciting new physics. The key physics and techniques of laser cooling are described in depth in Chapter 6. What is “temperature”? We use the words “cold” and “hot” every day; for example to refer to the temperature of the air outside. But what do “cold” and “hot” mean for the air’s molecules? Broadly speaking, we can say that atoms in a hot gas move faster than those in a cold gas and that cooling, by taking energy out of the gas, slows the atoms down. In this description of the gas as a collection of atoms behaving like billiard balls, or little hard spheres, the lowest possible temperature occurs when the atoms stop moving but, as we shall see, this picture does not give an accurate description at very low energies, for which quantum effects become important. In this chapter we will look at the fascinating properties of atomic gases cooled to temperatures within one millionth of a degree Kelvin from absolute zero. We shall use the term “ultra-cold” to refer to such extremely low temperatures that have only recently been achieved in experiments on atomic gases. The techniques used to cool liquids and solids have a longer history and have made available a different set of possibilities (see Chapter 8). Note that most of this chapter refers to gases in which the individual particles are atoms, but the general statements about temperature scales apply equally well to gases of molecules, e.g. air, whose major constituents, oxygen and nitrogen, exist as diatomic molecules.
The experimental observation of Bose-Einstein condensation in gas of rubidium atoms in 1995 had huge impact on the physics community with reports of a new state of matter making newspaper headlines all over the world. By comparison, it was in relative obscurity that Simo Jaakkola and his group at the University of Turku in Finland, in collaboration with researchers at the Kurchatov Institute in Moscow, recently observed the two-dimensional analogue of the effect (A I Safonov et al. 1998 Phys. Rev. Lett. 81 4545). Jaakkola observed two-dimensional Bose-Einstein condensation (2D BEG) in gas of specially prepared hydrogen atoms adsorbed on the surface of liquid helium. In Bose-Einstein condensation all the particles in system collapse into single quantum state that has many unusual and novel properties.
We propose experiments with atomic hydrogen gas at ultra-low temperatures T < 100 μ K when the thermal energy of atoms is comparable with the changes of their potential energy in the Earth gravity field. At these conditions we suggest implementing a gravitational spectroscopy for studies of quantum properties of ultra-cold atomic hydrogen and its interactions with matter and gravity, similar to experiments with ultra-cold neutrons (Nesvizhevsky et al. Nature 415 , 297 2002 ). A magnetic trap used for reaching the Bose-Einstein Condensation (Fried et al. Phys. Rev. Lett. 81 , 3811 1998 ) can be used for cooling a large number of H atoms below 1 mK. Evaporative cooling over the trap barrier allows effective cooling of the vertical degree of freedom of the trapped atoms. Releasing these ultra-slow atoms from the trap onto the cold surface of superfluid helium will allow studies of quantum bounces and stationary gravitational states of H atoms in the potential well created by this surface and the field of Earth gravity. Experimental study of properties of gravitational quantum states of hydrogen and quantum reflection of ultracold hydrogen from surface would be of major importance for designing similar experiments with antihydrogen, which are currently prepared in CERN.
It was a complete surprise when Isaac Silvera and his colleagues at the University of Amsterdam observed the existence of a remarkably stable gas of hydrogen atoms in 1979. They found that a gas of the so-called “atom of atoms” could be confined for several minutes in a cryogenic test cell close to absolute zero, provided that the walls were coated with a film of liquid helium. Until then, if researchers wanted to study monoatomic hydrogen for any length of time they had to use a discharge source to replace those hydrogen atoms that recombined to form molecular hydrogen. But most important, Silvera's experiments marked the first experimental investigation of a dilute quantum gas.
The hydrogen atom is the gateway atom for the development of the quantum mechanics of all atoms, and hence all molecules, and hence all nanostructures. A more conservative analysis of the hydrogen atom just identifies the approximations that caused the classical analysis to go badly, and removes those approximations. The basic approach to the hydrogen atom that can be characterized as follows: take account of all processes that can be identified, and look for a natural balance between them. There exist other research areas awaiting further application of this approach. Hydrogen atoms, and all other atoms as well, are presently envisioned as having infinitely many ‘excited states’ that are described via the multiple solutions of Schrodinger’s differential equation for the atom. These excited states are presently understood as conditions that an individual atom possesses. The ionization potential of helium is very high–the highest among all elements. It invites the interpretation that electrons very much like to form a pair.