- Attachments : picture of atoms
- When atoms approach Absolute Zero temperatures their vibrations slow down and new properties emerge. New properties in magnetism, in superconductivity, and in superfluidity.
- A vacuum chamber of criss-crossing beams contains a very dilute gas of rubidium atoms. (Rb37). Each lattice site is an energy well in which one or more atoms can become trapped. Science has learned that there are particular excitation laser frequencies that can eject an atom from the well. The frequency needed depends on how many atoms are in the well.
- The right modulation is used until there is just one atom per well. The energy for an atom to move into an adjacent well is extremely high. A special optical microscope is used to confirm there is one atom in each lattice site. When there are more than one atom per site an atom is removed. When an atom is removed this reduces the entropy ( the degree of disorder, or randomness), and that, in turn, reduces the temperature.
- Temperatures have been achieved within 10^-9 to 10^-12 degrees Kelvin. This is 0.000000001 degrees above Absolute Zero.
- More research is on the horizon. The optical lattice, in principle, could be used to store and manipulate the quantum state of atoms. This opens the door to Quantum Computers.
- Another avenue is to repeat this lattice capture with Fermions. Electrons are Fermions. Rubidium atoms are Bosons. This would allow further research into superconductors and superfluids.
- Here are some of the strange things that happen when materials are cooled to Absolute Zero temperatures. A piece of metal will levitate above a magnet with no energy being consumed. Liquid helium will flow up the walls of a container defying gravity. Solid material will pass right through each other. Magic? No, Physics.
- Once you cool liquid helium to about 2 Kelvin you can set the liquid rotating, and it will keep spinning forever with no energy being consumed. It becomes a “ superfluid” with zero viscosity.
- This superfluid property is used in the Large Hadron Collider at CERN, Switzerland. The thousands of magnets that direct the proton beam around the 27 kilometer ring are cooled using superfluid helium. The superfluid keeps the entire ring within 0.1 Kelvin.
- When the magnets are super cooled they become superconductors, the metals loose all resistance to the flow of electricity. Therefore, very little power is required for the electro- magnets to carry huge amounts of current. Then the magnets can generate the intense magnetic fields needed to control the proton beam.
- Superconductivity and superfluidity are properties of the Quantum World. According to Quantum Mechanics a particle can exist in many places at once and can move in more than one direction at a time. This is the property of wave-particle duality. When you sum up the possible outcomes of the atom’s behavior the phase can be “+1” or “- 1”. These two different phases represent two different types of particles, Bosons and Fermions.
- Helium atoms are Bosons and their super cooled formations become a Bose-Einstein Condensation which gives rise to superfluidity. The fluid becomes a giant atom in its lowest possible quantum energy state. The lack of viscosity arises because there is a huge gap in energy between the lowest state and the next higher energy state. Viscosity is the dissipation of energy due to friction. In its lowest stat there is no way to lose energy so there is no viscosity.
- Superconductors display the same property except using electrons which are Fermions. If you swap Fermions you always get a phase change of “-1”. Now, this time you add up the possible states and you get zero. There is zero probability of finding Fermions in the same Quantum State. This property is what makes chemistry possible. An atom’s electrons can not occupy the same positions. They are forced to occupy rings further and further away from the nucleus. This builds the elements in the periodic table and the outer electrons freer from the protons can engage in bonding and chemical reactions.
- Electrons in superconductors also form Bose-Einstein Condensations by binding together in “ Cooper Pairs” and acquiring the characteristics of a Boson. In effect the electrons become a single giant particle that lacks electrical resistance Again, the electron-pair condensation is in the lowest possible energy state. It can not dissipate more energy, so the resistance is zero.
- If helium is reduced to below 1 Kelvin and above 25 atmospheres pressure it becomes a solid. But, these solids can pass through each other, like a ghost walking through a wall. The super-solid helium is another form of Bose-Einstein Condensation.
- In 2011 astronomers discovered that the core of Cassiopeia A , Neutron Star, was a “ superfluid”. This star is 11,000 lightyears from Earth. One teaspoon of the star material would weigh 6,000,000,000 tons. The Neutron Star is not just made of neutrons, some of the material is protons that carry the electric charge of a superconductor. This “cold” is not created by temperature; it is created by pressure. Gravity can produce the Bose-Einstein Condensation and Quantum States as well as our new technology. An announcement will be made shortly, stay tuned.
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707-536-3272, Thursday, January 19, 2012
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