1. Schrödinger’s cat
Today there are many interpretations of quantum
mechanics with the Copenhagen interpretation being perhaps the most
famous to-date. In the 1920s, its general postulates were formulated by Niels
Bohr and Werner Heisenberg. The wave function has become the core term
of the Copenhagen interpretation, it is a mathematical function
containing information about all possible states of a quantum system in which it exists simultaneously.
As stated by the Copenhagen interpretation, the
state of the system and its position relative to other states can only
be determined by an observation (the wave function is used only to help
mathematically calculate the probability of the system being in one
state or another). We can say that after observation, the quantum
system becomes classical and immediately cease to exist in other states,
except for the state it has been observed.
This approach has always had its opponents (remember
for example Albert Einstein’s “God does not play dice“), but the
accuracy of the calculations and predictions prevailed. However, the
number of supporters of the Copenhagen interpretation is decreasing
and the major reason for that is the mysterious instant collapse of the
wave function during the experiments. The famous mental experiment
by Erwin Schrödinger with the poor cat was meant to demonstrate the
absurdity of this phenomenon.
Let us recap the nature of this experiment. A live
cat is placed inside a black box, together with a vial containing poison
and a mechanism that can release this poison at random. For instance, a
radioactive atom during its decay can break the vial. The precise time of atom’s decay is unknown. Only half-life, or the time during which the decay occurs with a probability of 50%, is known.
Obviously, for the external observer, the cat inside
the box exists in two states: it is either alive, if all goes well, or
dead, if the decay occurred and the vial was broken. Both of
these states are described by the cat’s wave function, which changes
over time. The more time has passed, the more likely that radioactive
decay has already happened. But as soon as we open the box, the wave
function collapses, and we immediately see the outcomes of this inhumane
experiment.
In fact, until the observer opens the box, the cat
will be subjected to the endless balance on the brink of being
between life and death, and its fate can only be determined by the
action of the observer. That is the absurdity pointed out by
Schrödinger.
2. Diffraction of electrons
According to the poll of the greatest physicists
conducted by The New York Times, the experiment with electron
diffraction is one of the most astonishing studies in the history of
science. What was its nature?
There is a source that emits a stream of electrons onto
photosensitive screen. And there is obstruction in the way of
these electrons, a copper plate with two slits. What kind of picture can
be expected on the screen if the electrons are imagined as small
charged balls? Two strips illuminated opposite to the slits.
In fact, the screen displays a much more complex pattern of
alternating black and white stripes. This is due to the fact that, when
passing through the slit, electrons begin to behave not as particles,
but as waves (just like the photons, or light particles, which can be
waves at the same time). These waves interact in space, either
quenching or amplifying each other, and as a result, a
complex pattern of alternating light and dark stripes appears on the
screen.
At the same time, the result of this experiment does
not change, and if electrons pass through the slit not as one single
stream, but one by one, even one particle can be a wave. Even a single
electron can pass simultaneously through both slits (and this is also
one of the main postulates of the Copenhagen interpretation of quantum
mechanics, when particles can simultaneously display both their “usual”
physical properties and exotic properties as a wave).
But what about the observer? The observer makes this
complicated story even more confusing. When physicists, during similar
experiments, tried to determine with the help of instruments which slit
the electron actually passes through, the image on the screen had
changed dramatically and become a “classic” pattern with two illuminated
sections opposite to the slits and no alternating bands displayed.
Electrons seemed not wanting to show their wave
nature under the watchful eye of observers. Did they manage to follow
their instinctive desire to see a clear and simple picture. Is this some
kind of a mystery? There is a more simple explanation: no observation
of a system can be carried out without physically impacting it. But we
will discuss this a bit later.
3. Heated fullerene
Experiments on the diffraction of particles have
been conducted not only for electrons, but for much larger objects. For
example, using fullerenes, large and closed molecules consisting of
dozens of carbon atoms (for example, fullerene of sixty carbon atoms is
very similar in shape to a football, a hollow sphere comprised of
pentagons and hexagons).
Recently, a group of scientists from the University of Vienna supervised
by Professor Zeilinger tried to introduce an element of observation in
these experiments. To do this, they irradiated moving fullerene
molecules with alaser beam. Then, warmed by an external source, the
molecules began to glow and inevitably displayed their presence in space
to the observer.
Together with this innovation, the behavior of
molecules has also changed. Prior to the beginning of such comprehensive
surveillance, fullerenes quite successfully avoided obstacles
(exhibited wave-like properties) similar to the previous example
with electrons passing through an opaque screen. But later, with the
presence of an observer, fullerenes began to behave as completely
law-abiding physical particles.
4. Cooling measurement
One of the famous laws in the world of quantum
physics is the Heisenberg uncertainty principle which claims that it is
impossible to determine the speed and the position of a quantum object
at the same time. The more accurate we are at measuring the momentum of a
particle, the less precise we are at measuring its position. But the
validity of quantum laws operating on tiny particles usually remains
unnoticed in our world of large macroscopic objects.
Recent experiments by Professor Schwab in the U.S.
are even more valuable in this respect, where quantum effects have been
demonstrated not at the level of electrons or fullerene molecules (their
characteristic diameter is about 1 nm), but on a little more tangible
object, a tiny aluminum strip.
This strip was fixed on both sides so that its
middle was in a suspended state and it could vibrate under external
influence. In addition, a device capable of accurately recording strip’s
position was placed near it.
As a result, the experimenters came up with two
interesting findings. First, any measurement related to the position of
the object and observations of the strip did affect it, after each
measurement the position of the strip changed. Generally speaking , the
experimenters determined the coordinates of the strip with high
precision and thus , according to the Heisenberg’s principle, changed
its velocity, and hence the subsequent position.
Secondly, which was quite unexpected, some
measurements also led to cooling of the strip. So, the observer can
change physical characteristics of objects just by being present there.
5. Freezing particles
As it is well known, unstable radioactive particles
decay not only for experiments with cats, but also on their own. Each
particle has an average lifetime which, as it turns out, can increase
under the watchful eye of the observer.
This quantum effect was first predicted back in the 1960s, and its brilliant experimental proof appeared in the article published in 2006 by the group led by Nobel laureate in Physics Wolfgang Ketterle of the Massachusetts Institute of Technology.
This quantum effect was first predicted back in the 1960s, and its brilliant experimental proof appeared in the article published in 2006 by the group led by Nobel laureate in Physics Wolfgang Ketterle of the Massachusetts Institute of Technology.
In this paper, the decay of unstable excited
rubidium atoms was studied (photons can decay to rubidium atoms in their
basic state). Immediately after preparation of the system, excitation
of atoms was observed by exposing it to a laser beam. The observation
was conducted in two modes: continuous (the system was constantly
exposed to small light pulses) and pulse-like (the system was irradiated
from time to time with more powerful pulses).
The obtained results are perfectly in line with
theoretical predictions. External light effects slow down the decay of
particles, returning them to their original state, which is far from the
state of decay. The magnitude of this effect for the two studied modes
also coincides with the predictions. The maximum life of unstable
excited rubidium atoms was extended up to 30-fold.
Quantum mechanics and consciousness
Electrons and fullerenes cease to show their wave
properties, aluminum plates cool down and unstable particles freeze
while going through their decay, under the watchful eye of the observer
the world changes. Why cannot this be the evidence of involvement of our
minds in the workings of the world? So maybe Carl Jung and Wolfgang
Pauli (Austrian physicist and Nobel laureate, the pioneer of quantum
mechanics) were correct after all when they said that the laws of
physics and consciousness should be seen as complementary?
We are only one step away from admitting that the
world around us is just an illusory product of our mind. Scary, isn’t
it? Let us then again try to appeal to physicists. Especially when in
recent years, they favor less the Copenhagen interpretation of quantum
mechanics, with its mysterious collapse of the wave function, giving
place to another quite down to earth and reliable term decoherence.
Here’s the thing, in all these experiments with the
observations, the experimenters inevitably impacted the system. They lit
it with a laser and installed measuring devices. But this is a common
and very important principle:you cannot observe the system or measure
its properties without interacting with it. And where there is
interaction, there will be modification of properties. Especially when a
tiny quantum system is impacted by colossal quantum objects. So the
eternal Buddhist observer neutrality is impossible.
This is explained by the term “decoherence”, which
is an irreversible, from the point of view of thermodynamics, process of
altering the quantum properties of the system when it interacts with
another larger system. During this interaction the quantum system loses
its original properties and becomes a classic one while “obeying ” the
large system. This explains the paradox of Schrödinger’s cat: the cat is
such a large system that it simply cannot be isolated from the rest of
the world. The mere design of this mental experiment is not quite
correct.
In any event, compared to the reality of
consciousness as an act of creation, decoherence represents a much more
convenient approach. Perhaps even too convenient. Indeed, with this
approach, the entire classical world becomes one big consequence of
decoherence. And as the authors of one of the most prominent books in
this field stated, such an approach would also logically lead to
statements like “there are no particles in the world” or ” there is no
time on a fundamental level”.
Is it the creator-observer or powerful decoherence?
We have to choose between the two evils. But remember, now scientists
are increasingly convinced that the basis of our mental processes is
created by these notorious quantum effects. So, where the observation
ends and reality begins, is up to each of us.
Source: Earth. We Are One
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