Cryogenics: Very Low Temperature Physics; Implications

[coldcreation]

Cryogenics: Ultra-Low Temperature Physics; Implications


Because the universe is thought to have never been colder than the observed 2.7 K of the microwave background radiation—an idea based on modern cosmology—it is believed that Bose-Einstein condensates, along with other phenomena that occur below 2.7 K (superfluid helium, helium-3/helium-4 phase separation, adiabatic demagnetization of paramagnetic molecules, Fermi melting point of helium-3, Bose melting point of bosonic atomic gases, etc.) exist nowhere else in the universe other than in the laboratories here on Earth.

I argue that this may be a crucial error. For example, there has been observed at least one place in the universe that is colder than 2.7 K.

The Boomerang Nebula is one of the Universe's peculiar places. In 1995, using the 15-metre Swedish ESO Submillimetre Telescope in Chile, astronomers revealed that it is the coldest place in the Universe found so far. With a temperature of -272 °C, it is only 1 kelvin warmer than absolute zero (the lowest limit for all temperatures). Even the -270 °C background glow from the Big Bang is warmer than this nebula. It is the only object found so far that has a temperature lower than the background radiation. [2]. The Boomerang Nebula is also listed as PGC 3074547

Boomerang Nebula PGC 3074547
(Image Credit: NASA, ESA and The Hubble Heritage Team (STScI/AURA))

A brief history:

Important contributions to physics were introduced by Einstein in 1907 regarding the application of the quantum theory to the theory of specific heats, and concerning the quantum theory of gases in 1924-25 when he completed work on a new type of statistics known as Bose-Einstein statistics in which the existence of a new state of matter (a new category of statistics) was predicted called Bose-Einstein Condensates—a remarkable phenomenon discovered only in the last few years. The implications of these fundamental ideas have not yet been fully interpreted, evaluated, developed or theoretically submitted to application in the quest to illuminate the mysteries of the large and small-scale structures of the universe.

According to the fundamental laws of quantum mechanical processes that govern conditions in the micro-universe what we usually term a particle can sometimes behave as a wave. This is well known. Waves may likewise behave as particles. This may not be as well known. L. de Broglie (1924) hypothesized the existence of matter waves and expressed their wavelength in terms of the of momentum of the particles p: where h is Planck's constant. The more slowly the particle moves the less its momentum and the longer the de Broglie wavelength. According to the kinetic theory of gases low particle (or wave) velocities correspond to low temperatures. If a sufficiently dense gas of cold atoms can be produced, the matter wavelengths of the particles will be of the same order of magnitude as the distance that separates them. It is at this point that the diverse waves of matter can 'feel' one another and co-ordinate their state. This is called Bose-Einstein condensation. It is often said that a "superatom" arises since the whole composite arrangement is described by one single wave function exactly as in a single atom. We can also speak of coherent light in the case of a laser in the same way as of coherent matter.

An Indian physicist, Bose, (in 1924) made significant theoretical calculations concerning particles of light. He sent his findings to Einstein who broadened the theory to a particular type of atom. Einstein expected that if a gas of such atoms were cooled to an extremely low temperature all the atoms would abruptly congregate in the lowest possible energy state. The development is comparable to when drops of liquid form from a gas, therefore the term condensation—or like tiny droplets of water that form on a cold window when warm air comes into contact with it (but certainly not the same).

In 1995 the 2001 Nobel Laureates succeeded in attaining this extreme state of matter, Bose-Einstein condensate (BEC). Eric A. Cornell and Carl E. Wieman then produced a pure condensate of about 2000 rubidium atoms at 20 nK (nanokelvin), i.e., 0.00000002 degrees above absolute zero. Collective excitations and vortex formations have since been observed in condensates. Manifestations of Bose-Einstein condensation have previously been observed in more complex systems: condensation of paired electrons in superconductors (where loss of all electrical resistance occurs) and superfluidity or suprafluidity (loss of internal friction in fluids); both of which manifestations occur at very low temperatures.

BEC has also been attained in the most ubiquitous element in the universe: Bose-Einstein Condensation of Atomic Hydrogen, Dale G. Fried, Thomas C. Killian, Lorenz Willmann, David Landhuis, Stephen C. Moss, Daniel Kleppner, and Thomas J. Greytak, Department of Physics and Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (Received 11 September 1998).

But there is more. Due to Poincaré resonances, dynamical processes at higher temperatures also lead to long-range correlations, despite the short-range character of forces between particles—an essential fact that leads to asymmetry and permits evolutionary patterns in agreement with the thermodynamic description of nature.

The primary aim of this thread is to discuss the latest developments in the field of cryogenics (particulary below 2.7 K), in the hopes of gaining a better understanding of nature.


This frosty discourse should reveal certain alignments between the scientific stance and the artist who advocates non-objectivity: a common naturalism together with a common belief in the individual’s subjective capacity to transform appearances or concepts (particularly in cosmology). This dialogue, however, should also reveal a crucial difference. In one case, it is believed that after an intensely hot energetic phase of annihilation and separation a process began where undifferentiated matter gravitationally collapsed as the temperature of the universe drops during expansion. And the other, where that may not be the case.

“Mathematics, rightly viewed, posses not only truth, but supreme beauty; a beauty cold and austere, like that of sculpture”
(Bertrand Russell)



“Life always gets harder toward the summit - the cold increases, the responsibility increases”
(Friedrich Nietzsche)



CC

[Moontanman]

While my knowledge on cryogenic studies is nil, it is indeed a fascinating subject. Has there been anything in the research that points toward a practical use for this research or as of yet any reason to predict new discoveries? I look forward to reading more about this.

[CraigD]

Originally Posted by coldcreation

Because the universe is thought to have never been colder than the observed 2.7 K of the microwave background radiation—an idea based on modern cosmology—it is believed that Bose-Einstein condensates, along with other phenomena that occur below 2.7 K (superfluid helium, helium-3/helium-4 phase separation, adiabatic demagnetization of paramagnetic molecules, Fermi melting point of helium-3, Bose melting point of bosonic atomic gases, etc.) exist nowhere else in the universe other than in the laboratories here on Earth.

I argue that this may be a crucial error. For example, there has been observed at least one place in the universe that is colder than 2.7 K.

I believe coldcreation is misinterpreting the description of the CMBR as having the spectrum of a black body at about 2.7 K. This characteristic does not imply that the CMBR is currently being emitted by solid, liquid, or gaseous matter with a temperature of 2.7 K. It is simply a convenient way of describing its spectrum with a single numeric value.

The description of the temperature of unusual objects such as the “coldest place in the universe” Boomerang Nebula calls for careful consideration of the definition of temperature, the average kinetic energy of the bodies - in the case of a gas like the Boomerang Nebula, atoms - of a system. It’s very low temperature – about 1 K – is calculated by estimating the mass and initial temperature of the outflowing gas that forms it, and dividing by its current, much greater observed volume. It represents the temperature of a small representational volume of space moving at the same velocity as the average of the gas within it – if the entire volume is considered, the temperature is very high – about a million K - due to the great speed of the outflowing gas – about 167000 m/s. (note that, in terms of mass and velocity , temperature is given by , where is the Avogadro number, the gas constant)

Even if only a small volume of the gas is considered, the temperature may still be higher than given by the first calculation, because individual atoms of the gas in even a small volume may have fairly high relative velocities. A artificially produced BEC requires that nearly all fast-moving atoms in it be slowed or expelled. Though I’ve encountered some discussion of the possibility of unusual low-temperature effects in expanding nebulae such as the Boomerang, such as superconductivity of Bose-Einstein condensation, to the best of my knowledge the idea is very speculative. Although one can make the argument that BECs of very small numbers of atoms may rarely, randomly form in any very low-density gas, I suspect that it’s not a significant effect in objects like protoplanetary nebulae, even very cold ones like the Boomerang.

[coldcreation]

Originally Posted by CraigD

I believe coldcreation is misinterpreting the description of the CMBR as having the spectrum of a black body at about 2.7 K. This characteristic does not imply that the CMBR is currently being emitted by solid, liquid, or gaseous matter with a temperature of 2.7 K. It is simply a convenient way of describing its spectrum with a single numeric value.

I don't think there is a misunderstanding. We both agree that the CMB is not being emitted by solid, liquid, or gaseous matter with a temperature of 2.7 K. It is a thermal spectrum with black-body form.

Originally Posted by CraigD

The description of the temperature of unusual objects such as the “coldest place in the universe” Boomerang Nebula calls for careful consideration of the definition of temperature, the average kinetic energy of the bodies - in the case of a gas like the Boomerang Nebula, atoms - of a system. It’s very low temperature – about 1 K – is calculated by estimating the mass and initial temperature of the outflowing gas that forms it, and dividing by its current, much greater observed volume. It represents the temperature of a small representational volume of space moving at the same velocity as the average of the gas within it – if the entire volume is considered, the temperature is very high – about a million K - due to the great speed of the outflowing gas – about 167000 m/s. (note that, in terms of mass and velocity , temperature is given by , where is the Avogadro number, the gas constant)

The actual temperature of the cloud itself is speculative in that the velocity of the particles remains unknown. In fact, is speculative that the gas is out-flowing. What is observed it that this reflecting cloud of dust and gas has bipolar quasi-symmetric lobes of material, not that the material is being ejected from a central star. The possibility exists that what is observed is an inflow of gas. In other words, there is no guarantee that a rapid expansion has cooled molecules in the nebular gas.

Generally, out-flowing gas would be quasi-spherical in structure. In this case, an apparently intact spherical star, internally powered by nuclear fusion, appears to be 'ejecting' material along its axis only: something that has no astrophysical explanation. The diffuse bow-tie shape of the Boomerang Nebula makes it very different from other planetary nebulae observed; which normally have gaseous lobes that look more like 'bubbles.' (Source).

Bipolar outflows are usually seen to occur from both very young stars, protostars, that are in the process of collapsing and forming, as well as from older stars toward the ends of their lives, from bloated red giants. (Source)

What may actually be occurring is the formation of a star by a cold accreting gas, rather than the formation of a proto-planetary disc through ejection of hot, cooling gaseous material.

The filaments observed in the gas alternatively resemble Birkeland currents: caused by the movement of a plasma perpendicular to a magnetic field. (See here, for example: Boomerang Nebula Comes Back—to Plasma. A cold nebula provides evidence of electrical activity at temperatures near absolute zero.).

Originally Posted by CraigD

Even if only a small volume of the gas is considered, the temperature may still be higher than given by the first calculation, because individual atoms of the gas in even a small volume may have fairly high relative velocities. A artificially produced BEC requires that nearly all fast-moving atoms in it be slowed or expelled. Though I’ve encountered some discussion of the possibility of unusual low-temperature effects in expanding nebulae such as the Boomerang, such as superconductivity of Bose-Einstein condensation, to the best of my knowledge the idea is very speculative. Although one can make the argument that BECs of very small numbers of atoms may rarely, randomly form in any very low-density gas, I suspect that it’s not a significant effect in objects like protoplanetary nebulae, even very cold ones like the Boomerang.

I would be interested to find out where you have encountered discussion of the possibility of unusual low-temperature effects in expanding nebulae such as Boomerang, related to superconductivity of Bose-Einstein condensation.


CC

[coldcreation]

Originally Posted by Moontanman

While my knowledge on cryogenic studies is nil, it is indeed a fascinating subject. Has there been anything in the research that points toward a practical use for this research or as of yet any reason to predict new discoveries? I look forward to reading more about this.

Good question.

In this article, The revolution that has not stopped, it is written:

"What has happened in the past year with Fermi gases has only been topped by the discovery of the first condensates in 1995," says Ketterle. "But this is just the beginning - research into Fermi gases is now connecting to a long list of intellectual challenges in condensed-matter physics, such as superfluidity, superconductivity, magnetism and so on."

...For instance, some groups are exploring the use of condensates to make quantum computers that can perform certain tasks much faster than is possible on a classical computer. However, there is a lot of competition from other approaches. "Condensates have lots of potential quantum bits," says Chris Monroe of the University of Michigan, "but it remains very difficult to address and control individual neutral atoms at the same level as ions."

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[coldcreation]

This is interesting: Dark Matter Halos as Bose-Einstein Condensates, Eckehard W. Mielke, Burkhard Fuchs, Franz E. Schunck (Submitted on 24 Aug 2006).

Galactic dark matter is modelled by a scalar field in order to effectively modify Kepler's law without changing standard Newtonian gravity. In particular, a solvable toy model with a self-interaction U(Phi) borrowed from non-topological solitons produces already qualitatively correct rotation curves and scaling relations. Although relativistic effects in the halo are very small, we indicate corrections arising from the general relativistic formulation. Thereby, we can also probe the weak gravitational lensing of our soliton type halo. For cold scalar fields, it corresponds to a gravitationally confined Boson-Einstein condensate, but of galactic dimensions.

And check this out: Relativistic Gross-Pitaevskii equation and the cosmological Bose Einstein Condensation, Takeshi Fukuyama, Masahiro Morikawa (2005-2006)

We do not know 96% of the total matter in the universe at present. In this paper, a cosmological model is proposed in which Dark Energy (DE) is identified as Bose-Einstein Condensation (BEC) of some boson field. Global cosmic acceleration caused by this BEC and multiple rapid collapses of BEC into black holes etc. (=Dark Matter (DM)) are examined based on the relativistic version of the Gross-Pitaevskii equation. We propose (a) a novel mechanism of inflation free from the slow-rolling condition, (b) a natural solution for the cosmic coincidence ('Why Now?') problem through the transition from DE into DM, (c) very early formation of highly non-linear objects such as black holes, which might trigger the first light as a form of quasars, and (d) log-z periodicity in the subsequent BEC collapsing time. All of these are based on the steady slow BEC process.

This model too seems to support the contention that BEC is not a new state of matter, but one that exists in other parts of the universe:

Bose-Einstein Condensation, Dark Matter and Acoustic Peaks, F. Ferrer (Oxford U.), J. A. Grifols (Barcelona, Autonoma U. and IFAE) (2004-2005

Scalar mediated interactions among baryons extend well above the Compton wavelength, when they are embedded in a Bose-Einstein condensate composed of the mediating particles. Indeed, this non-trivial environment results in an infinite-ranged interaction. We show that if the Dark Matter of the Universe is composed of such a condensate, the imprints of an interaction between baryonic and Dark Matter could be manifest as anomalies in the peak structure of the Cosmic Microwave Background.

And finally: Bose Einstein Condensation as Dark Energy and Dark Matter, Masako Nishiyama, Masa-aki Morita, Masahiro Morikawa (2004)

We study a cosmological model in which the boson dark matter gradually condensates into dark energy. Negative pressure associated with the condensate yields the accelerated expansion of the Universe and the rapid collapse of the smallest scale fluctuations into many black holes, which become the seeds of the first galaxies. The cycle of gradual sedimentation and rapid collapse of condensate repeats many times and self-regularizes the ratio of dark energy and dark matter to be order one.

It is the further study of these types of phenomena (e.g., BEC) that will lead to an increased understanding of how of matter in this cold universe have collected, grouped, interacted, changed, and evolved with time and temperature.



This is just the tip of the iceberg.






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