1714
hours. Carol is still at the hairdresser’s. I found this great article on
perceptions of reality. Here it is.
**
**
The article below is selected and edited from today's: edgeDOTcom
Power
Over Nature
New
Phenomena That Will Change and Enrich Our Understanding of Fundamentals
A
Conversation With Frank Wilczek [3.31.16]
The
big story of the 20th and the 21st century is that we’re learning to control
the world better. With the development of quantum mechanics, we understand the
fundamental principles of what matter is and how it behaves that’s adequate for
all engineering purposes.
The
limitation is just our imagination and our ability to calculate the
consequences of the laws. We’re getting better at both of those as we gain
experience. We have more imagination. As computing develops, we learn how to
calculate the consequences of the laws better and better. There’s also a
feedback cycle: when you can understand matter better, you can design better
computers, which will enable you to calculate better. It's kind of an ascending
helix.
FRANK
WILCZEK, currently the Herman Feshbach Professor of Physics at MIT, has
received many prizes for his work in physics, including the Nobel Prize (2004)
for work he did as a graduate student at Princeton University.
POWER
OVER NATURE
What
I’ve been thinking about today specifically is something of a potential
breakthrough in understanding our fundamental theories of physics. We have
something called a standard model, but its foundations are kind of scandalous.
We have not known how to define an important part of it mathematically
rigorously, but I think I have figured out how to do that, and it’s very
pretty. I’m in the middle of calculations to check it out.
When
we think about next steps in physics, we have to diagnose what’s wrong, first of
all. Solving problems guides us into knowing what’s wrong and what is not
wrong. Knowing that you can fix this problem is very important. It’s important because,
in thinking about future theories, we want to build on our understanding of
existing theories. The fact that there are theories whose statuses are
questionable—we don’t know whether they’re respectable or not, whether they
really satisfy the properties that we want them to have—is limiting. Now we’ll
be able to assess them. Also, this technique that I’ve been developing not only
shows that theories exist, it opens up new ways of calculating their properties
so that it gives us a bigger toolbox of potential models to construct world
theories.
Who
does this falsify? It’s a funny situation where the theory of electroweak or
weak interactions has been successful when you calculate up to a certain
approximation, but if you try to push it too far, it falls apart. Some people
have thought that would require fundamental changes in the theory, and have tried
to modify the theory so as to remove the apparent difficulty. What I’ve shown
is that the difficulty is only a surface difficulty. If you do the mathematics
properly, organize it in a clever way, the problem goes away. It falsifies
speculative theories that have been trying to cure a problem that doesn’t
exist. It’s things like certain kinds of brane-world models, in which people
set up parallel universes where that parallel universe's reason for being was
to cancel off difficulties in our universe—we don’t need it. It's those kinds
of speculations about how the foundations might be rotten, so you have to do
something very radical. It’s still of course legitimate to consider
radical improvements, but not to cure this particular problem. You want to do
something that directs attention in other places.
What’s
new in the universe? Well, the Large Hadron Collider—LHC—just announced its
preliminary results from run two, which was the first time we’ve had results at
their new higher energy. The statistics are not yet sufficient to draw any firm
conclusion, but they have a suggestive new phenomenon, a heavier version of the
Higgs particle that, if it holds up, would be very significant. It would mean
probably a major expansion of the standard model, perhaps a whole new world of
interactions. At present, it may very well go away; the statistical
significance is unclear.
Things
like this happen frequently in the sense that there are hints of new phenomena
that don’t stand up to further investigation. For instance, almost two years
ago in March, there were B-modes—the supposed gravity waves from the early
universe—which would have been enormously significant as evidence for inflation and
a window into extraordinarily high-energy physics and the first manifestation
of quantum gravity we showed, but that went away. It turned out that what they
were measuring had a much more mundane explanation in terms of cosmic dust
scattering light and producing this effect. It doesn’t falsify the theories of
course; it just means that different kinds of evidence will have to be
gathered.
I
had occasion recently to look at an old lecture by Sidney Coleman called “Quantum
Mechanics in Your Face,” where he explained in great detail, and
beautifully, a profound test of quantum mechanics. It’s a situation where
you have three spins, or three polarized photons, and measure certain
properties. A classical theory would always give one result plus one for this
measurement, whereas the quantum mechanical theory gives minus one. It couldn’t
be a more dramatic difference.
The
experiment is done and quantum mechanics wins. When Sidney explained this in
his inimitable style, it brought tears to my eyes and brought back a whole
flood of memories. The reason I was watching this is that recently, with a
brilliant student named Jordan Cotler, I had been working on a variant of that
kind of experiment where instead of looking at three photons at the same time,
you look at one photon at three different times. It turns out that some of the
properties that are most peculiar in quantum mechanics of entanglement between
different particles can also be a property of entangling histories of single
particles.
I
love the whole notion of entangling histories, where different possibilities
for what things might have happened get to interfere with each other, and the
whole notion of what the past is gets mixed up, gets the same weirdness that is
characteristic of Einstein-Podolsky-Rosen effects and Bell's paradox. All these
things not only affect particles in different places, but also can
affect things as they develop in time.
At
some level, the idea that physical reality is much richer than what we perceive
is something that everybody knows. We know nowadays that we see much more in
whole new worlds when we use microscopes or telescopes than we see when we use
the naked eye.
There
are many ways we can enhance our perception of the world using different kinds
of gadgets. We can slow down motion by taking rapid pictures and slowing it
down. We can also nowadays understand the microworld by calculating. We have a
very precise, rigorous, and successful theory of how the world works based on
very different ideas than are encountered in everyday life. We can present
those ideas in visual form if we’re creative, using data visualization
techniques to bring these other worlds into human perception that was built to
do something quite different.
The
particular thing that I got obsessed with recently is the mismatch between our
perception of the most important way we interact with the external world, that
is, our perception of light—our vision—and the underlying physical reality. We
sample with our eyes a very narrow range of the electromagnetic spectrum—basically,
one octave out of an infinite keyboard that, moreover, is not just discrete
notes but a continuum. We have a reliable, well-tested theory of what light is:
electromagnetic radiation. We can compare the reality of what light is to our
perception of it. What we see is, as I said, a very narrow band of frequencies.
But even within that narrow band, we do a paltry kind of sampling. We sample
three different averages of the intensities. This is called trichromatic
vision. The most common colorblindness is seeing only two averages.
There
are many forms of electromagnetic radiation that are physically different yet
look the same to us. There is information that we’re missing, which has two
dramatic consequences. First of all, it means that there’s a lot of the visual
world—the world we think we know—that we’re missing out on. Secondly, our
ability to use that portal to convey information is relatively limited
physically. There is much more bandwidth intrinsic to the visible portal than we
exploit.
On
the other hand, there are creatures that do a much better job of this. There is
something called a mantis shrimp, which is a champion in the animal world. It’s
a very successful species of underwater, shrimplike animal that exists in
hundreds of varieties. All of them have this feature where instead of
seeing three averages in the spectrum, they see a dozen or up to sixteen,
depending on the variety. They also see down to the ultraviolet, they see some
infrared. They have a much richer portal into color information than we do.
It
occurred to me—and this may be one of the best ideas I ever had—that we can
restore some of that information using modern technology and modern ideas about
how information can be conveyed, namely, by encoding different aspects of the
missing information as time-dependent modulation of the channels we have. So,
open new channels by modulating in ways that are recognizable and that keep the
image, the channels we have.
We
can start to perhaps see like mantis shrimp, and that will both enrich our
perception of the external world and also open up new possibilities for
visualization. In quantum mechanics, we learn that the wave functions—the
primary description of reality—live in high-dimensional spaces. If you have the
wave function for two particles, it lives in a six-dimensional space. That is
very hard to visualize.
Chemists
could find it very useful if they were able to get a better visualization of
things like that, or people dealing with complex datasets that depend on many
factors; those naturally live in many dimensional spaces, and it would be very
useful to be able to visualize those. Opening up extra channels, extra
dimensions of color perception, could be a very good thing. I've been working
on gadgets, tricks, software, and hardware to implement that.
It’s
been fun. It’s a new direction for me. My father was a kind of engineer, and I’ve
always had in the back of my mind that I’d love to do something useful.
Finally, I had an idea that plausibly could be useful, so I’m going for it.
There
are many practical applications of the information that’s in colors we don’t
see, so to speak. We see three averages, but you can have a more fine-grained
picture if you separate the different frequencies and have more channels of
information. One very practical thing that people use this information for is
sorting fruit that’s old and starting to go bad. Depending on the fruit, it
shows different characteristics that are difficult to see with the resources
our eyes give us naturally, but if you look at these extra pieces of
information, it stands right out.
Another
thing that’s, I don’t know if you call it practical, but it’s kind of cool, is
that many insects and butterflies see four or five dimensions, and many flowers
that want to make a good impression on butterflies or insects have displays in
those extra dimensions. They have extra structure in the ultraviolet, extra
structure that’s attuned to the particular capabilities of the insects that
they want to attract that we don’t see. We can enhance our perception to see
what they look like and see extra patterns. Gardens would look prettier,
rainbows would look prettier, different aspects of art objects could leap out;
it could be great fun.
The
fact is we don’t know exactly what the mantis shrimps do with this information,
and that’s a very active subject in biophysics. It's such a strange
phenomenon, and striking, how capable in their own environment and
successful these species are. They’re not that extraordinary: they’re not super
creatures, they’re not superhuman, certainly. What do they do with this
information? The most plausible idea is that they primarily use this
information to make sexual displays to show their fitness and to communicate with
other mantis shrimps. Part of the evidence for that is you just look at these
mantis shrimps; they look extremely colorful even to us, so you can only
imagine what they look like to each other.
Mantis
shrimps have very small brains, so they don’t do the kind of sophisticated
processing of the visual scene that we do. They don’t have as high a spatial
resolution either, so they see more colors, but the picture is fuzzier.
A
way of thinking of their experience as compared to ours is that we have a very
fine-grained picture of a three-dimensional space of color, whereas they have a
much coarser view of a twelve-dimensional space. We see lots of discrete
points, so to speak. On a computer display, when you see millions of different
colors, we can distinguish millions of different colors, but they’re all points
in a three-dimensional space. They are all manufactured in the computer screen
by combining red, green, and blue LEDs—or whatever the light source is—in
different proportions. Millions of colors are really three colors in different
proportions. The mantis shrimp has twelve base colors that you can put in
different proportions, but they almost certainly can’t resolve the fine
structure nearly as well. You could think of them as seeing big blobs in a
high-dimensional space, whereas we see fine points in a low-dimensional space.
The
surprise that I’m thinking about different things is no surprise. I have always
had this style of thinking about something—trying to skim off the cream and
then moving on to something else. I look for opportunities. I keep coming back
to the subjects that I've visited before if I don’t feel that I’ve exhausted
them. This thing that I mentioned before about what I was thinking about and am
excited about is making the foundations of the standard model more secure. This
problem that we’re addressing has been a worm in the rose for decades that has
been worrying people. Most people don’t want to think about it; they think it’s
somehow going to resolve itself.
It
looks very technical, but it’s been there and it’s been annoying for those of
us who care about logical consistency. That’s always been in the back of my
mind. It’s one thing to have something in the back of your mind, it’s another
thing to have a good idea about it.
I’m
still interested in these possibilities for unusual quantum statistics—anyons,
they’re called. Since I introduced them, they have been a very fertile source
of theoretical work, and are firmly embedded in theories that have a lot of
other success, but there is still no direct evidence for the primary concept. I
keep coming back to that, thinking about how we can design experiments that will
display these phenomena that are surely there, but subtle and hard to find.
That leads me to think about new kinds of microscopy that are intrinsically
sensitive to quantum effects, to the effects of entanglement. That’s how I came
to think about those entangled histories.
~ ~ ~
My
research has mostly been in rather abstract, advanced quantum field theory,
high-energy physics, cosmology, and low-temperature physics that is esoteric,
if you like. For many years I've also kept a lively interest in artificial
intelligence and what’s going on in neurobiology and computer science. I almost
became a professional in that when I was a student. If things had been slightly
different, I might have gone the other way. The work that I wound up
concentrating on is the tip of the iceberg of a lot of other potentials.
What’s
happening in physics depends on what you mean by physics. High-energy physics
and fundamental physics, in the sense of finding new interactions, has been
slow for quite a while. The standard model has held up much better than any of
us thought it would. It’s been much more difficult to get beyond the standard
model.
The
LHC so far has just succeeded in verifying a standard model with unprecedented
accuracy—dotting the i’s and crossing the t’s with the discovery of the Higgs
particle. Maybe something new will show up. I hope so. There are very logical
and compelling extensions of the standard model based on low-energy
supersymmetry and unification that I've been fond of, which I pioneered thirty
years ago. The experiments so far have not caught up with that.
There
are beautiful ideas about extending the standard model using something called
axions, which could very well be the dark matter. It's a very attractive theory
that only gets more attractive as time goes on and the competition dies off.
The experiments to test this theory are very difficult, but some heroic people
have taken it on themselves to try to do this. Leslie Rosenberg is a brilliant
experimental physicist who has devoted his whole career for thirty years now or
more to developing the technology that’s needed to find axions, and he’s
getting very close. There are other ideas that are very clever and that are
relatively new, but also have a plausible chance. We’re getting there.
Dark
matter is an unfortunate name, but the phenomenon is the following. We have (we
think) very reliable laws for the gravitational force based on general
relativity, which is a generalization of Newton’s theory of gravity; it’s
famous—Einstein. There are many tests of it nowadays. It’s very successful, but
hard to modify in a consistent way. People have tried to modify it, but that
direction doesn’t seem very fruitful; however, if you apply the laws of gravity
to the study of astronomy, you find a whole series of phenomena that all point
in the same direction that are anomalous. You look at the way things are
moving, like how one galaxy moves around another, or how the stars at the edge
of a galaxy move around the center, and you find that they’re moving faster
than they should be if the forces they’re responding to are due to the matter
we see that they’re moving around. You can estimate the mass in stars and gas
clouds and all kinds of matter that we understand, and figure out how fast
particles or stars have to be moving in order to stay in orbit, and you compare
with observations and you find that things are moving faster.
The
explanation that stood the test of time is that there is another form of matter
that contributes a lot of extra mass, but it’s a form of matter that resists
detection, that our telescopes miss, that doesn’t emit cosmic rays, doesn’t
absorb light; it’s very transparent, very inert as far as ordinary matter,
including light, is concerned. That’s what’s called the dark matter—this extra
stuff.
Basically
every galaxy that’s been studied has turned out to have a dark matter halo
around it. In fact, it would be better to call the galaxy an impurity within
this dark matter cloud that surrounds it because, although it’s more diffuse
than the visible matter when you add it all up, because it occupies a much
bigger volume, it weighs about six times as much. It clumps, but not as much as
ordinary matter.
As
far as galaxy formation is concerned, ordinary matter looks to be an impurity
within the dark matter. So what is it? The first thing to say is that it may
seem outlandish to introduce as a hypothesis that there’s some new kind of
matter just to solve this problem. Wouldn’t it be better to modify gravity?
Maybe something profound is happening, not just another new particle, and that’s
still possible, but that has not turned out to be a fruitful idea because no
theory based on that has been mathematically consistent with observation. It
just hasn’t worked.
Now
that we understand fundamental interactions well—as far as ordinary matter is
concerned in a standard model—and have profound principles of quantum mechanics
and relativity, we think we know how things work. The possibility of the kinds
of matter that interact very feebly with ordinary matter doesn’t seem
outlandish at all. It’s easy for things like that to happen. In fact, we know
of an example: neutrinos.
Neutrinos
interact very feebly with ordinary matter. It was difficult to observe them at
all. At one time, it was thought that they could be the dark matter, and if
they had a slightly larger mass than they do, they would be the dark matter.
Now we know enough about neutrinos to rule them out. It could be some
neutrino-like particle, or it could be some other particle that doesn’t have
any of the standard fundamental interactions. We know how to construct such
consistent models that are even very attractive and solve problems that would
lead to candidates for what this dark matter is.
To
me, the most attractive of those ideas, partly because I had a lot to do with
inventing it, is something called axions. It’s a long story why axions were
introduced. Let me give you a very short version of it. It’s profound and
entertaining to the people who are likely to listen to this.
It's
been a remarkable thing since the earliest days of modern physics—you broadly
consider since Newton’s day—that the fundamental laws have had the character
that if you run them backwards in time, they don’t change, whereas if you look
at a motion picture and run it backwards in time, it doesn’t look like the
natural world. If you took a picture of things that are small—the microworld—and
ran it backwards, it would be indistinguishable; the events would still satisfy
the laws of physics, and you would have a hard time telling which way was
forwards and which way was backwards.
The
fundamental laws have this very different character from the world we
ordinarily experience. Earlier, we talked about this theme that our perception
of reality is quite different from deep reality, and this is one of the most
outstanding examples.
The
laws of physics had this property that seemed totally gratuitous, unnecessary
to describe the world, in fact, kind of embarrassing. It’s a famous problem
called the “arrow of time.” How can it be that the fundamental laws look
the same forwards and backwards in time, and yet, the world doesn’t?
Interesting problem, but an equally interesting problem is why the laws have
that property.
It
was only in the late 20th century in which that problem got a reasonable answer. It
turns out that property where the fundamental laws look the same, to great
accuracy, forwards and backwards in time, is an accidental consequence of
deeper principles.
The
principles of relativity, quantum mechanics, and gate symmetry, which is
necessary to make those work together properly, together greatly constrain the
possible physical laws for the fundamental interactions. When you take all
those constraints into account, you find that the only things that are allowed
look almost the same forwards and backwards in time, and, in
fact, there are subtle microphysical phenomena that people got Nobel Prizes for
observing—obscure particle decays that don’t look the same forwards and backwards
in time, but for the most part, the fundamental laws do look the same. It was a
great triumph to understand that puzzle. The so-called time reversal symmetry
of physical laws is a consequence of other deep principles.
There
are certain interactions that are allowed by the fundamental principles that do
look different run forwards and backwards in time. There are, for instance,
some scattering processes where the probability that they happen in one
direction: A plus B go to C plus D, is different from the probability of C plus
D goes to A plus B; that’s the basic idea. It’s more complicated in detail, but
that’s the basic idea. There are very slight asymmetries in certain reactions
run backwards and forwards in time, but they’re very obscure and very small
asymmetries. It was a great triumph to understand that.
This
is a long shaggy-dog story, but it eventually does connect to the dark matter.
This wonderful result has a loophole. It turns out there is one kind of
interaction that would give a rather large asymmetry between forwards and
backwards in time—one fundamental interaction that, if it existed, would. It’s
not forbidden by any fundamental principles, so the puzzle has been narrowed
but not solved. We still have this one loophole.
Two
physicists named Helen Quinn and Roberto Peccei introduced an idea, a way of
expanding the laws of physics, introducing more symmetry—a new profound
principle in addition to relativity, quantum mechanics, and gate symmetry—that
would explain why that interaction doesn’t exist, either. What I noticed, and
also Steve Weinberg noticed, is that that kind of theoretical proposal leads to
the existence of a new kind of particle, which has very remarkable properties.
It’s extremely light, extremely feebly interacting with matter, and it turns
out that if you worked out how it gets produced in the Big Bang, it gets
produced in about the right amount to make the observed dark matter that
astronomers want.
That’s
the axion. I named it after a laundry detergent. It wasn’t very long after I
was an adolescent that I did this. There was a laundry detergent on the market
called Axion, and I thought that sounds like a particle. I learned that there
was no such particle, and I said to myself, "If I ever get the chance, I’m
going to make such a particle." It turned out that this particle cleaned
up—it cleans up a problem with an axial current—so I called it the axion, and
that got through physical review letters and became the name which is now
universally accepted. That was, gosh, almost forty years ago now.
First
of all, I should say that I saved the world from the Higglet. Weinberg had been
calling this thing the Higglet, so when we learned that we were both barking up
the same tree and compared notes, he very wisely and graciously agreed to use
axion, which became the standard name.
Just
in the axion story itself, it wasn’t obvious at first what its cosmological
consequences were. It was not introduced consciously to provide dark matter; it
just turned out that the theory did provide dark matter. That’s pretty
encouraging. I had a big role working that out and trying to think of
experiments that would observe this stuff.
Another
thing that I played with that has turned out to be very fruitful and connected
to axions is a remarkable thing in physics. The basic equations that we use to
describe particle physics interactions also turn out to describe things on a
very different scale like superconductivity, behavior of matter at low
temperatures, super fluidity. Various exotic quantum mechanical behaviors are
common to the super duper microworld and the world of materials, especially at
low temperatures. That’s a connection that I’ve been exploring for years, but
is now commonly appreciated and has become a very big deal.
Axions,
in particular, it turns out, are closely connected to the hottest subjects in
condensed matter physics—something called topological insulators.
I
wrote a paper for fun called "Two Applications of Axion
Electrodynamics," where I wrote down the behavior that you would get if
you had an axion-like field, which was an emergent consequence of condensed
matter behavior. And by God, what’s been discovered is these topological
insulators obey the equations of axion electrodynamics. That was like
twenty-five years ago. Every once in a while something percolates.
The
big development is like if you asked what causes an Ice Age. What causes an Ice
Age is that there’s a little bit more snow every year that melts, so the ice
accumulates over time. It’s very dramatic, but year by year you don’t necessarily
know this. The big story of the 20th and the 21st century is that we’re learning to control the world better.
With the development of quantum mechanics, we understand the fundamental
principles of what matter is and how it behaves that’s adequate for all
engineering purposes.
The
limitation is just our imagination and our ability to calculate the
consequences of the laws. We’re getting better at both of those as we gain
experience. We have more imagination. As computing develops, we learn how to
calculate the consequences of the laws better and better. There’s also a
feedback cycle: when you can understand matter better, you can design better
computers, which will enable you to calculate better. It's kind of an ascending
helix.
To
me, that is the big story. We understand things better, and that gives us more
and more power over nature.
Of
course, astronomy is another source. People are developing techniques that are
ways of orchestrating much larger masses of data than we could handle before
and instruments that are more sensitive. People, as they have also gotten a
standard model of cosmology, have been able to ask more sophisticated
questions, more profound questions about how it all began.
There
are easy targets for this question of what theories will die, which are
theories that have never had substantial backing in the scientific community—theories
like creationism, theories like denial of global warming. I don’t even know if
that’s a theory; it’s just crankiness.
A
field where there’s lots of crap is the whole field around consciousness, where
people have very woolly ideas about something they call consciousness. No one
means exactly the same thing about what it is. There is something called the
hard problem, which says that there’s something about consciousness that can’t
be explained in terms of a physical substrate. Those ideas are doomed, and they’re
very superficial to begin with.
It’s
a profound fact and wonderful fact—and it’s only happened in the 20th century as far as I’m
concerned—that the fundamental understanding of the world became very
beautiful, that our ideas of symmetry and what I call exuberance, where you can
get a lot more out than you put in, only became fully characteristic at the level
they are now in the 20thcentury. Not all the laws we know are beautiful, either. There are a
lot of loose ends. But what is quite remarkable to me is that the core of our
understanding is based on beautiful equations.
One
aspect of why the laws are beautiful is certainly that if they weren’t
beautiful, we wouldn’t have discovered them.
In
the case of the strong interactions, quantum chromodynamics (QCD) and the weak
interactions, in particular, the phenomena are so difficult to study. The
high-energy interactions, the short distances, the basic things that the theory
is about are very difficult to study directly. You can’t in practice follow the
model that people like Francis Bacon recommended and Newton, where you accumulate
a lot of data but don’t make hypotheses, you just summarize the data in
theories and try to make a simple explanation. That’s not practical when the
information is so difficult to acquire.
The
way we proceed now that’s been remarkably successful is to guess beautiful
equations, derive their consequences, and compare crucial consequences with
reality. That’s a different procedure. If we didn’t have beauty as a guide to
what the plausible equations are, we would be lost; we wouldn’t find them. That’s
how axions also arise—looking for a way to make the standard model more
beautiful to clarify why certain interactions don’t occur.
If you want to explain
something in this very unfamiliar world where there isn’t a lot of data and
where everyday experience is not reliable, what have you got to go on other
than aesthetic feeling for how things should fit together?
Selected and edited from EdgeDOTcom
“Power Over Nature” April 20, 2016 – Conversation with Frank Wilczek
** **
Duskish.
You had supper at Smashburgers and Carol is now walking at Pine Hills Lake
where you are waiting for her at the earth dam parking lot. You have underlined
some of the above since earlier but I would like to point out just a couple of
points for you to think and consider on (as far as books and blog are
concerned). Let’s go up and mark them with italics. – Amorella
1926
hours. I’m good with it. I sent this article on to Doug a couple of hours ago. I’m
curious what his comments might be if he has any.
** **
Below - Selected and edited
from EdgeDOTcom “Power Over Nature” April 20, 2016 – Conversation with Frank
Wilczek
Point A:
(Amorella)
It
turns out that some of the properties that are most peculiar in quantum
mechanics of entanglement between different particles can also be a property of
entangling histories of single particles.
I
love the whole notion of entangling histories, where different possibilities
for what things might have happened get to interfere with each other, and the
whole notion of what the past is gets mixed up, gets the same weirdness that is
characteristic of Einstein-Podolsky-Rosen effects and Bell's paradox. All these
things not only affect particles in different
places, but also can affect things as they develop in time.
At
some level, the idea that physical reality is much richer than what we perceive
is something that everybody knows. We know nowadays that we see much more in
whole new worlds when we use microscopes or telescopes than we see when we use
the naked eye.
There are many ways we can
enhance our perception of the world using different kinds of gadgets. We can
slow down motion by taking rapid pictures and slowing it down. We can also
nowadays understand the micro-world by calculating. We have a very precise,
rigorous, and successful theory of how the world works based on very different
ideas than are encountered in everyday life. We can present those ideas in
visual form if we’re creative, using data visualization techniques to bring
these other worlds into human perception that was built to do something quite
different.
Above - Selected and edited
from EdgeDOTcom “Power Over Nature” April 20, 2016 – Conversation with Frank
Wilczek
Point A (Amorella)
** **
** **
Below - Selected and edited
from EdgeDOTcom “Power Over Nature” April 20, 2016 – Conversation with Frank
Wilczek
Point B
(Amorella)
We
know how to construct such consistent models that are even very attractive and
solve problems that would lead to candidates for what this dark matter is.
To
me, the most attractive of those ideas, partly because I had a lot to do with
inventing it, is something called axions. It’s a long story why axions were
introduced. Let me give you a very short version of it. It’s profound and
entertaining to the people who are likely to listen to this.
It's
been a remarkable thing since the earliest days of modern physics—you broadly
consider since Newton’s day—that the fundamental laws have had the character
that if you run them backwards in time, they don’t change, whereas if you look
at a motion picture and run it backwards in time, it doesn’t look like the
natural world. If you took a picture of things that are small—the microworld—and
ran it backwards, it would be indistinguishable; the events would still satisfy
the laws of physics, and you would have a hard time telling which way was
forwards and which way was backwards.
The
fundamental laws have this very different character from the world we
ordinarily experience. Earlier, we talked about this theme that our perception
of reality is quite different from deep reality, and this is one of the most
outstanding examples.
The
laws of physics had this property that seemed totally gratuitous, unnecessary
to describe the world, in fact, kind of embarrassing. It’s a famous problem
called the “arrow of time.” How can it be that the fundamental laws look
the same forwards and backwards in time, and yet, the world doesn’t?
Interesting problem, but an equally interesting problem is why the laws have
that property.
It
was only in the late 20th century in which that problem got a reasonable answer. It
turns out that property where the fundamental laws look the same, to great
accuracy, forwards and backwards in time, is an accidental consequence of
deeper principles.
The principles of relativity,
quantum mechanics, and gate symmetry, which is necessary to make those work
together properly, together greatly constrain the possible physical laws for
the fundamental interactions. When you take all those constraints into account,
you find that the only things that are allowed look almost the same forwards and
backwards in time, and, in fact, there are subtle microphysical phenomena that
people got Nobel Prizes for observing—obscure particle decays that don’t look
the same forwards and backwards in time, but for the most part, the fundamental
laws do look the same. It was a great
triumph to understand that puzzle. The so-called time reversal symmetry of
physical laws is a consequence of other deep principles.
Selected and edited
from EdgeDOTcom “Power Over Nature” April 20, 2016 – Conversation with Frank
Wilczek
Point B (Amorella
** **
Tonight
or tomorrow (Jill K. is coming to clean tomorrow) take the above underlined
sections and reduce them into your own words, then we will look on the other article
you read yesterday. Post. - Amorella
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