Sunday, June 11, 2023

4049 - QUANTUM TEMPERATURES?

 

-    4049  -  QUANTUM  TEMPERATURES?    What Happens When You Cool an Atom?   Getting to the very small enters the Quantum World where physics takes on strange behavior.  But, also, getting to the very cold enters the same unusual world of Quantum Mechanics.  Today science is exploring more of this world near temperatures of Absolute Zero,  (-273 degrees Centigrade).


----------------------------   4049   -    QUANTUM  TEMPERATURES?

-    From the point of view of physics temperature is a measurement of the average Kinetic Energy of atoms.  We call it “Thermal Energy”.  It is the average momentum and velocity of a bunch of atoms.  As you heat up any material its atoms vibrate and oscillate faster.  The hotter it gets the faster they oscillate.

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-    At some point, when certain materials reach a specific temperature the oscillating atoms will break bonds and change states.  Ice will turn into water and water will turn into steam.  The matter expands as the faster oscillating atoms require more space.

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-     Kinetic Energy is the product of momentum and velocity.  Momentum is the product of mass and velocity.  Therefore, the Kinetic Energy of the atoms is their mass times their velocity squared,  ( KE  =  m*v^2 ).

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-    The opposite is happening when a material cools down.  The vibrations slow and the average Kinetic Energy goes down as the temperature declines.  The colder it gets the slower the atoms vibrate.  There is a point where atoms slow down to where they come to a complete stop.  This point is called Absolute Zero, zero degrees Kelvin, - 273 degrees Centigrade.

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-     Near Absolute Zero is where we enter the Quantum world  and we learn that atoms and their fundamental particles never really stop.  There is Zero Point Energy and the classical Kinetic Energy calculations say zero.  However, we must use the new math of Quantum Mechanics to understand the behavior of sub-atomic particles as they approach Absolute Zero temperature.

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-    Particles have on positions at the sub-atomic scales.  They are oscillating waves. And, Energy is not continuous.  It comes is small bundles, or quanta of energy.  This quanta ,or fundamental limit of how small energy bundles can be, is called Planck’s Constant of Action.  It is equal to 6.626 * 10^-34 kilogram * meters^2 / second.

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-    This is a very small number.  At the smallest scales of the oscillating particle / wave dualities, these bundles of energy are still oscillating even at the temperature of zero Kelvin.  As the temperature lowers you remove energy until you can not remove anymore.  Physics is getting so close to this limit they no longer use degrees Kelvin as the measurement.  They use the number of Quanta that are left to be removed.

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-  To better understand Planck’s Constant of Acton, symbol “h”, let’s define the meaning of Action.

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--------------------  Momentum is the product of Mass and Velocity,  ( p = m * v ),   kilograms * meters / second

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--------------------  Kinetic Energy is  the product of Momentum and Velocity,

( KE = m * v^2) ,  kilogram * meters^2 / seconds^2.

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--------------------  Action is the product of Energy, or Work, and Time, ( A = E * t ) , kilogram * meters^2  / second. 

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-------------------  Planck’s Constant of Action, ( h =  6.626 * 10^-34 kilogram * meters^2 / second ).

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-  The vibration  energy of the Quanta is the 'Constant of Action' divided by time.

  Energy = Action / time,  ( E = A / t ).  The frequency of vibration is cycles of waves per second.   Frequency =  1 / time,  ( f = 1/ t) .  So, another way to show the formula for Energy is as the product of Action and Frequency,  ( E = h * f ).    Lowering the temperature lowers the energy and therefore lowers the frequency of vibration.

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-    So, the way to visualize this is the oscillating Quanta of Energies are moving back and forth in an oscillating wave.  As the temperatures get lower, Energy is removed, and the energy packets in the waves move back and forth at an ever slower rate.

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-     Physics laboratories around the world are getting ever closer to the slowest rate possible.  It is called the Ground State of Absolute Zero.  Here is a summary of how close labs have gotten this measurement.  Note that at every lower temperatures the measurements are in Quanta instead of Kelvin:

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------------------------  U.C.  Santa Barbara  ---------------  0.000135 Kelvin

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------------------------  Yale University  -------------------- 0.0000682  Kelvin

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-----------------------  Swiss Federal Institute  ------------  63 Quanta

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----------------------  Cal Tech University  ----------------  4 Quanta

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----------------------  National Institute of Standards -----  1 Quanta

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-  The challenge for the labs now is how long they can keep the temperatures at this level so they can study the quantum affects.  To date the Ground-State lifetimes are only lasting from 6 nanoseconds to 100 microseconds.  How the labs are achieving these temperatures is a whole other story.  If you want to learn.  They are using lasers to dampen the Quantum oscillations.

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June 11,  2023           QUANTUM  TEMPERATURES?        1254      4049

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--------------------- ---  Sunday, June 11, 2023  ---------------------------------

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