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R. Barrett and P. P. Delsanto
emit simultaneously. This light is coherent, and therefore readily produces
interference effects.
In the above experiment, the cat is clearly not a quantum particle, and the
radioactive particle that triggered the Geiger counter just as clearly is. The
boundary between the classical and quantum domains is continually being
raised. In 2010, Andrew Cleland and his team at the University of California,
succeeded in placing a “paddle” 30 microns long containing trillions of atoms
into a quantum state [9]. By cooling the paddle below 0.1° K, they placed
it into its “ground” state, where the available thermal energy is too small to
allow any excitations to higher energy states to occur. They then added the
smallest possible unit of vibrational energy. This created a situation where
the paddle was in a superposition of two states, one with zero energy and the
other with one unit of vibrational energy. “This is analogous to Schrödinger’s cat
being dead and alive at the same time,” said Cleland. When the experimenters
measured the energy, the wave function collapsed, and the paddle had to
“choose” whether to remain in the excited state, or pass its energy to the
measuring device. The paddle was large enough to be visible.
There are a number of interpretations of the Schrödinger Cat experiment,
some of which involve live and dead cats in various universes. The philosophical implications of the thought experiment are profound, involving as they
do a live animal, and notions of life and death. Let us consider for a moment
replacing Schrödinger’s cat with a virus. Depending on one’s definition of
life, a virus is considered by many to be a living creature. Viruses range in
size from 0.004 to 0.1 microns, and are thus much smaller than Cleland’s
paddle. Quantum effects should surely apply to them. Bacterial cells range
from about 1 to 10 microns in length and from 0.2 to 1 micron in width.
Bacteria are most certainly alive, and are also smaller than the paddle, so we
can expect quantum effects to be relevant to them. We begin to see some of
the challenges thrown to philosophers by Quantum Mechanics.
In the next Chapter, we shall present the next great challenge to Common
Sense , and the other half of the revolution in physics that took place in the
twentieth Century, namely, the Theory of Relativity.
References
1. Maxwell JC (1865) A dynamical theory of the electromagnetic field. Royal
Society, Great Britain
2. Pirandello L (1933) Uno, Nessuno, Centomila One, None, and a Hundred
Thousand, Trans. English by S Putnam (1933), published on Project Gutenberg.
Accessed 22 July 2020
R. Barrett and P. P. Delsanto
emit simultaneously. This light is coherent, and therefore readily produces
interference effects.
In the above experiment, the cat is clearly not a quantum particle, and the
radioactive particle that triggered the Geiger counter just as clearly is. The
boundary between the classical and quantum domains is continually being
raised. In 2010, Andrew Cleland and his team at the University of California,
succeeded in placing a “paddle” 30 microns long containing trillions of atoms
into a quantum state [9]. By cooling the paddle below 0.1° K, they placed
it into its “ground” state, where the available thermal energy is too small to
allow any excitations to higher energy states to occur. They then added the
smallest possible unit of vibrational energy. This created a situation where
the paddle was in a superposition of two states, one with zero energy and the
other with one unit of vibrational energy. “This is analogous to Schrödinger’s cat
being dead and alive at the same time,” said Cleland. When the experimenters
measured the energy, the wave function collapsed, and the paddle had to
“choose” whether to remain in the excited state, or pass its energy to the
measuring device. The paddle was large enough to be visible.
There are a number of interpretations of the Schrödinger Cat experiment,
some of which involve live and dead cats in various universes. The philosophical implications of the thought experiment are profound, involving as they
do a live animal, and notions of life and death. Let us consider for a moment
replacing Schrödinger’s cat with a virus. Depending on one’s definition of
life, a virus is considered by many to be a living creature. Viruses range in
size from 0.004 to 0.1 microns, and are thus much smaller than Cleland’s
paddle. Quantum effects should surely apply to them. Bacterial cells range
from about 1 to 10 microns in length and from 0.2 to 1 micron in width.
Bacteria are most certainly alive, and are also smaller than the paddle, so we
can expect quantum effects to be relevant to them. We begin to see some of
the challenges thrown to philosophers by Quantum Mechanics.
In the next Chapter, we shall present the next great challenge to Common
Sense , and the other half of the revolution in physics that took place in the
twentieth Century, namely, the Theory of Relativity.
References
1. Maxwell JC (1865) A dynamical theory of the electromagnetic field. Royal
Society, Great Britain
2. Pirandello L (1933) Uno, Nessuno, Centomila One, None, and a Hundred
Thousand, Trans. English by S Putnam (1933), published on Project Gutenberg.
Accessed 22 July 2020