Answer these please ,,'bout BEC-Bose einstein Condensate

Question

What is the significance of studying Bose-Einstein Condensate?

Does it able help our environment?

What is are photons and bosons..?

tnx(froM;Rosalie;12 years old)

Answer 1

Before discussing Bose-Einstein condensates, it is perhaps best to explore just why Einstein and Bose collaborated and first predicted such exotic phenomena. Furthermore, it seems prudent too briefly cover the statistical mathematics underlying their prediction. To avoid complex mathematics and to keep the arguments understandable, I have quoted from several commercial encyclopaedias.

Microsoft’s Encarta encyclopaedia, comments, ‘Statistical mechanics was developed in the 19th century, largely by the British physicist James Clerk Maxwell, the Austrian physicist Ludwig Boltzmann, and the American mathematical physicist J. Willard Gibbs. These scientists believed that matter is composed of many tiny particles (atoms and molecules) in constant motion. They knew that determining the motions of the particles by assuming each particle individually obeys Newtonian mechanics is unworkable, because any sample of matter contains an enormous number of particles. For example, the number of particles in a cubic metre (about 35 cubic feet) of air is about 25 trillion trillion (25 followed by 24 zeroes). Maxwell, Boltzmann, and Gibbs developed statistical techniques to average the microscopic dynamics of individual particles and obtain their macroscopic (large-scale) thermodynamic features. Through their calculations they discovered that temperature is a measure of the average kinetic energy of microscopic particles. They also found that entropy is proportional to the logarithm of the number of ways a given macroscopic system can be microscopically arranged.

Statistical mechanics had to be extended in the 1920s to incorporate the new principles of quantum theory. The nature of particles is different in quantum theory from what it is in classical physics, which is based on Newton's laws of motion. In particular, two classical particles are in principle distinguishable; just as two cue balls can be distinguished by placing an identifying mark on one, so in principle can classical particles. In contrast, two identical quantum particles are indistinguishable, even in principle, requiring new formulations of statistical mechanics. Furthermore, there are two quantum mechanical formulations of statistical mechanics corresponding to the two types of quantum particles—fermions and bosons. The formulation of statistical mechanics designed to describe the behaviour of a group of classical particles is called Maxwell-Boltzmann (MB) statistics. The two formulations of statistical mechanics used to describe quantum particles are Fermi-Dirac (FD) statistics, which applies to fermions, and Bose-Einstein (BE) statistics, which applies to bosons.

Two formulations of quantum statistical mechanics are needed because fermions and bosons have significantly different properties. Fermions—particles that have non-integer spin—obey the Pauli exclusion principle, which states that two fermions cannot be in the same quantum mechanical state. Some examples of fermions are electrons, protons, and helium-3 nuclei. On the other hand, bosons—particles that have integer spin—do not obey the Pauli exclusion principle. Some examples of bosons are photons and helium-4 nuclei. While only one fermion at a time can be in a particular quantum mechanical state, it is possible for multiple bosons to be in a single state.

The phenomenon of superconductivity dramatically illustrates the differences between systems of quantum mechanical particles that respectively obey Bose-Einstein statistics and Fermi-Dirac statistics. At room temperature, electrons, which have spin y, are distributed among their possible energy states according to FD statistics. At very low temperatures, the electrons pair up to form spin-0 Cooper electron pairs, named after the American physicist Leon Cooper. Since these electron pairs have zero spin, they behave as bosons, and promptly condense into the same ground state. A large energy gap between this ground state and the first excited state ensures that any current is “frozen in”. This causes the current to flow without resistance, which is one of the defining properties of superconducting materials.

Bose graduated in applied mathematics from the University of Calcutta and published a number of papers in fields as diverse as crystallography and unified field theory, while lecturing at the universities of Dhaka and Calcutta. His paper, “Planck's Law and the Hypothesis of Light Quanta”, published in 1924, in which he derived Planck's equation purely from quantum theory, using his model for the behaviour of a group of photons, was sent to Einstein. Highly impressed, Einstein entered into a collaboration with Bose, and further extended Bose's work on the behaviour of photons, which are particles of zero spin, resulting in what is now known as Bose-Einstein statistics. This behaviour, characterized by the ability of any number of particles to occupy the same energy state (degeneracy), applies to any group of particles of integral spin, or bosons, as they are now called. This is in marked contrast to the behaviour of fermions, or particles with nonintegral spin, such as electrons (spin 1/2), which are subject to the Pauli Exclusion Principle, preventing any two particles occupying the same quantum state. At low temperatures, a large number of bosons may occupy the same energy state, resulting in what is known as a Bose-Einstein condensation.’

Wikipedia, the free encyclopaedia, adds, 'A Bose–Einstein condensate (BEC) is a state of matter of bosons confined in an external potential and cooled to temperatures very near to absolute zero (0 K, −273.15 °C, or −459 °F ). Under such supercooled conditions, a large fraction of the atoms collapse into the lowest quantum state of the external potential, at which point quantum effects become apparent on a macroscopic scale.

This state of matter was first predicted by Satyendra Nath Bose in 1925. Bose submitted a paper to the Zeitschrift für Physik but was turned down by the peer review. Bose then took his work to Einstein who recognized its merit and had it published under the names Bose and Einstein, hence the hyphen.

Seventy years later, the first gaseous condensate was produced by Eric Cornell and Carl Wieman in 1995 at the University of Colorado at Boulder NIST-JILA lab, using a gas of rubidium atoms cooled to 170 nanokelvin (nK) (1.7×10−7 K). Eric Cornell, Carl Wieman and Wolfgang Ketterle at MIT were awarded the 2001 Nobel Prize in Physics in Stockholm, Sweden.'

Apart from being, an exotic physics phenomenon - I am not sure that the study of these condensates will have a direct environmental benefit. However, the theoretical 'spin-off' will impact upon a wide range of areas of physical study

For more information try: -

http://en.wikipedia.org/wiki/Bose%E2%80%...

Answer 2

I don't think that at this point, it's anything more than basic research.

http://en.wikipedia.org/wiki/Bose_einste...

  It's not going to help our environment anytime too soon.

Light comes in little chunks.  We call them photons.

http://en.wikipedia.org/wiki/Photon

Fundamental particles (like photons) may have an intrinsic angular momentum that we call spin.  This spin can only come in multiples of a certain amount, which we call h-bar.  h-bar is a very, very tiny amount of angular momentum.  If a particle's spin is an integer multiple of h-bar (0, h-bar, 2 h-bar, etc), we call it a boson.  If a particle's spin is a half-integer multiple (1/2 h-bar, 3/2 h-bar, 5/2 h-bar, etc), we call it a fermion.  It turns out that fermions and bosons behave completely differently in some circumstances.  Two fermions cannot exist in identical states.  This is why chemistry works--the electrons can't share states, so the energy levels stack up.  But bosons are perfectly happy sharing states--they can all pack into the ground state, which is what makes the BEC possible.