Quantum physics: What is really real? - nature.com

[Dr. Jai Maharaj]

Quantum physics: What is really real?

A wave of experiments is probing the root of quantum
weirdness.

By Zeeya Merali
Nature News & Comment
nature.com
Wednesday, May 20, 2015

[Caption] An experiment showing that oil droplets can be
propelled across a fluid bath by the waves they generate
has prompted physicists to reconsider the idea that
something similar allows particles to behave like waves.
Dan Harris/MIT

Owen Maroney worries that physicists have spent the
better part of a century engaging in fraud.

Ever since they invented quantum theory in the early
1900s, explains Maroney, who is himself a physicist at
the University of Oxford, UK, they have been talking
about how strange it is - how it allows particles and
atoms to move in many directions at once, for example, or
to spin clockwise and anticlockwise simultaneously. But
talk is not proof, says Maroney. "If we tell the public
that quantum theory is weird, we better go out and test
that's actually true," he says. "Otherwise we're not
doing science, we're just explaining some funny squiggles
on a blackboard."

It is this sentiment that has led Maroney and others to
develop a new series of experiments to uncover the nature
of the wavefunction - the mysterious entity that lies at
the heart of quantum weirdness. On paper, the
wavefunction is simply a mathematical object that
physicists denote with the Greek letter psi (?) - one of
Maroney's funny squiggles - and use to describe a
particle's quantum behaviour. Depending on the
experiment, the wavefunction allows them to calculate the
probability of observing an electron at any particular
location, or the chances that its spin is oriented up or
down. But the mathematics shed no light on what a
wavefunction truly is. Is it a physical thing? Or just a
calculating tool for handling an observer's ignorance
about the world?

The tests being used to work that out are extremely
subtle, and have yet to produce a definitive answer. But
researchers are optimistic that a resolution is close. If
so, they will finally be able to answer questions that
have lingered for decades. Can a particle really be in
many places at the same time? Is the Universe continually
dividing itself into parallel worlds, each with an
alternative version of ourselves? Is there such a thing
as an objective reality at all?

"These are the kinds of questions that everybody has
asked at some point," says Alessandro Fedrizzi, a
physicist at the University of Queensland in Brisbane,
Australia. "What is it that is really real?"

Debates over the nature of reality go back to physicists'
realization in the early days of quantum theory that
particles and waves are two sides of the same coin. A
classic example is the double-slit experiment, in which
individual electrons are fired at a barrier with two
openings: the electron seems to pass through both slits
in exactly the same way that a light wave does, creating
a banded interference pattern on the other side (see
'Wave–particle weirdness'). In 1926, the Austrian
physicist Erwin Schrödinger invented the wavefunction to
describe such behaviour, and devised an equation that
allowed physicists to calculate it in any given
situation1. But neither he nor anyone else could say
anything about the wavefunction's nature.

Ignorance is bliss

From a practical perspective, its nature does not matter.
The textbook Copenhagen interpretation of quantum theory,
developed in the 1920s mainly by physicists Niels Bohr
and Werner Heisenberg, treats the wavefunction as nothing
more than a tool for predicting the results of
observations, and cautions physicists not to concern
themselves with what reality looks like underneath. "You
can't blame most physicists for following this 'shut up
and calculate' ethos because it has led to tremendous
developments in nuclear physics, atomic physics, solid-
state physics and particle physics," says Jean Bricmont,
a statistical physicist at the Catholic University of
Louvain in Belgium. "So people say, let's not worry about
the big questions."

But some physicists worried anyway. By the 1930s, Albert
Einstein had rejected the Copenhagen interpretation - not
least because it allowed two particles to entangle their
wavefunctions, producing a situation in which
measurements on one could instantaneously determine the
state of the other even if the particles were separated
by vast distances. Rather than accept such "spooky action
at a distance", Einstein preferred to believe that the
particles' wavefunctions were incomplete. Perhaps, he
suggested, the particles have some kind of 'hidden
variables' that determine the outcome of the measurement,
but that quantum theories do not capture.

Experiments since then have shown that this spooky action
at a distance is quite real, which rules out the
particular version of hidden variables that Einstein
advocated. But that has not stopped other physicists from
coming up with interpretations of their own. These
interpretations fall into two broad camps. There are
those that agree with Einstein that the wavefunction
represents our ignorance - what philosophers call psi-
epistemic models. And there are those that view the
wavefunction as a real entity - psi-ontic models.

To appreciate the difference, consider a thought
experiment that Schrödinger described in a 1935 letter to
Einstein. Imagine that a cat is enclosed in a steel box.
And imagine that the box also contains a sample of
radioactive material that has a 50% probability of
emitting a decay product in one hour, along with an
apparatus that will poison the cat if it detects such a
decay. Because radioactive decay is a quantum event,
wrote Schrödinger, the rules of quantum theory state
that, at the end of the hour, the wavefunction for the
box's interior must be an equal mixture of live cat and
dead cat.

[Image]

"Crudely speaking," says Fedrizzi, "in a psi-epistemic
model the cat in the box is either alive or it's dead and
we just don't know because the box is closed." But most
psi-ontic models agree with the Copenhagen
interpretation: until an observer opens the box and
looks, the cat is both alive and dead.

But this is where the debate gets stuck. Which of quantum
theory's many interpretations - if any - is correct? That
is a tough question to answer experimentally, because the
differences between the models are subtle: to be viable,
they have to predict essentially the same quantum
phenomena as the very successful Copenhagen
interpretation. Andrew White, a physicist at the
University of Queensland, says that for most of his 20-
year career in quantum technologies "the problem was like
a giant smooth mountain with no footholds, no way to
attack it".

That changed in 2011, with the publication of a theorem
about quantum measurements that seemed to rule out the
wavefunction-as-ignorance models2. On closer inspection,
however, the theorem turned out to leave enough wiggle
room for them to survive. Nonetheless, it inspired
physicists to think seriously about ways to settle the
debate by actually testing the reality of the
wavefunction.

Continues at:

http://www.nature.com/news/quantum-physics-what-is-really-real-1.17585

Jai Maharaj, Jyotishi
Om Shanti

http://groups.google.com/group/alt.fan.jai-maharaj

[Dr. Jai Maharaj]

Dr. Jai Maharaj posted:

Forwarded post:

I hate the language science writers use. I believe they
create as many problems as they solve. Particles in two
places at once? QM make NO such prediction. Simultaneous
clockwise and anticlockwise spin? Again, QM makes NO such
prediction. What DOES it say? It says properties like
location and spin DO NOT EXIST until they are measured.
So we shouldn't be saying things like a particle can be
in two places at once nor the cat is both alive and dead
when the truth is that the particle isn't anywhere at
all, and the cat's fate doesn't exist. Until we make
measurements. I think people should stop falling back on
the old claim that QM is weird and strange. It's not.
It's just the way things are. It's the "classical" world
that is really strange. How the heck do particles take
form when they are observed? The reality consists of two
worlds: wave and particle. Well, yes it does. But not the
way people mean when they say that. There is the
Schrodinger world (waves) and the Newtonian world
(particles) and they are forever distinct and separate
EXCEPT when an experiment is conducted that asks
questions like "where are you?". Doesn't anyone notice
that we can only see particles in our experiments? Never
ever waves. They can't be directly observed which is why
we know so little about them. ALL experiments that have
been done, and even the ones that can be conceived at
this time, involve particles. Take the famous two-slit
experiment. We ask which slit did a photon go through?
Then we clumsily say "both" when the answer is closer to
"it didn't go at all". It used to be over there. Now it's
here. It didn't "travel" at all. This experiment purports
to the show the wave nature of light. But it doesn't. The
wave nature can neither be seen nor detected. Our
experiments, without fail ALWAYS come down to particles.
We conduct the dual-slit experiment by observing how
photons (particles) strike our sensor plate. We have no
sensor at all that can detect a wave (not even radio
"waves"). I'm not talking about water and sound and other
such waves. So we note that Schrodinger's equations look
a lot like a wave phenomenon but just because they look
like that DOES NOT MEAN that's what they actually are.
That's done by humans trying desperately trying to bring
some sense to what they perceive as a strange and
impossible world. We really should stop doing that. But
even more importantly stop telling kids that because by
the time they reach college physics they've already been
indoctrinated into all these self-fulfilling but untrue
concepts. And thus physics moves so slowly ... because we
have such a terrible time giving up the past, a terrible
time with change. QM is what it is. But I'm not sure the
question "what is it?" can or will ever be answered. Now,
because of entanglement I could be wrong. I'm human and
not college educated in physics or math but I love it all
the same. So if I'm wrong could someone explain how/why
in simple words? 8-)

Posted by Greg Robert

End of forwarded post.

Jai Maharaj, Jyotishi
Om Shanti

http://bit.ly/1EM9nsg

[Dr. Jai Maharaj]

Forwarded post:

It's simple and real: Quantum theory is that part of the
theory of probability, which considers probabilities of
dot events in the 3 + 1 space-time [2]: AN WAVE FUNCTION
IS AS REAL AS FUNCTION OF PROBABILITY IS REAL SINCE AN
WAVE FUNCTION IS THE REPRESENTATION OF THE FUNCTION OF
THE DOT EVENT PROBABILITY IN THE 3+1 SPACE-TIME:
Probability theory is a well-developed theory. Its
consistency is proved centuries of experience. This
theory is multifaceted - some parts describe
probabilities of events of the insurance business, the
other - probabilities of events of artillery, others -
probabilities of events card games, etc. etc. So, it
turns out [2.pp.57-105] that the part of probability
theory, which describes dot events in 3+1 space-time, is
the quantum theory: As is known, the probability density
of a point event in the 3 + 1 space-time is not invariant
under the Lorentz transformations. A 3 + 1 vector of the
probability density is invariant under these
transformations. In [2.pp.52-62] it is proved that any
such vector is defined by a complex state function. In
[2.pp.65-68], it is proved that this function obeys the
Dirac-type equation with boson gauge fields. The Event-
Probability Interpretation of quantum mechanics is an
updated version of the Copenhagen interpretation. Unlike
the Copenhagen interpretation, which assumes the
continuous existence of elementary particles, this
interpretation considers such particles to be ensembles
of their related dot events connected by probabilities.
The Event-Probability Interpretation (EPI) is a
development of attempts by H. Bergson[3], A. N.
Whithead[4], M. Capek[6][5], E. C. Whipple Jr.[7], and J.
Jeans[8] to interpret elementary physical particles as
events. The experimental basis for EPI is the Double-Slit
Experiment. Elementary physical particles in vacuum
behave in accord with these probabilities. For example,
in accordance with the Double slit experiment [2.pp.71--
81], if a partition with two slits is placed between a
source of elementary particles and a detecting screen in
vacuum, then interference occurs. But if this system is
instead put into a cloud chamber, then the trajectories
of the particles will be clearly marked with drops of
condensate and any interference will disappear. It seems
that any physical particle exists only in those short
periods of time when some event occurs to it. And in the
other periods of time the particle does not exist, but
the probability for some event to occur to the particle
remains. Thus, if no event occurs between a creation
particle event of a particle and an event of detection of
it, then the particle does not exist during this period
of time. There exists only the probability of detection
of the particle at some point. But this probability obeys
the equations of the quantum theory, and we get
interference. But in a cloud chamber events of
condensation form a chain that traces the trajectory of
th? particle. In this case the interference disappears.
But this trajectory is not continuous--each two points of
this line are separated by a gap. The observed movement
of th? particle arises from the fact that a wave of
probability propagates between these points.
Consequently, the elementary physical particle represents
an ensemble of dot events associated with probabilities.
Charge, mass, energy, momentum, spins, etc. as they would
be seen when the particle is actually observed, are
governed by the distribution parameters of the
probabilities pertinent thereto. It explains all
paradoxes of quantum physics. Schrodinger's cat lives
easily without any superposition of states until the
micro event awaited by everyone occurs. Moreover, the
wave function disappears without any collapse at the
moment when event probability disappears as the event
occurs. References [1] Quznetsov G 2013 Logical
foundation of fundamental theoretical physics (Lambert
Academic Publ., [2] http://vixra.org/pdf/1111.0051v5.pdf
[3] H. Bergson, Creative Evolution, Greenwood press,
Wesport, Conn, 1975. [4] A. N. Whitehead, The Concept of
Nature. Cambridge Uni. Press, 1920.. [5] M. Capek, The
Philosophical Impact of Contemporary Physics, D. Van
Nostrand, Princeton, N.J., 1961. [6] M. Capek, "Particles
or events," in Physical Sciences and History of Physics,
edited by R. S. Cohen, and M. W. Wastors ky, Reidel,
Boston, Mass., 1984, p. 1. [7] E. C. Whipple jr., Nuovo
Cimento A 92, 11 (1986). [8] J. Jeans, The New Background
of Science, Macmillan, N. Y., 1933.

Posted by Gunn Quznetsov

End of forwarded post.

Jai Maharaj, Jyotishi
Om Shanti

http://tinyurl.com/JaiMaharaj