SciTech Now Episode 522

In this episode of SciTech Now, Unlocking the secrets of our Universe; holographic principles; introducing computer science and engineering at a young age; and reacting to health emergencies with virtual reality.


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Coming up, unlocking the secrets of our Universe.

As Einstein described it, gravity results from a curvature in the geometry of space-time, but on a quantum level, forces are produced by an exchange of particles.

The programmers of the future.

The goal is for them to be able to show off, to be able to build an app with a group of their peers that can be deployed to an app store.

VR meets the ER.

It's set up to be an operating room scenario in order to train them in the event that something goes wrong in the middle of a surgery.

It's all ahead.

Funding for this program is made possible by...


I'm Hari Sreenivasan.

Welcome to our weekly program bringing you the latest breakthroughs in science, technology and innovation.

Let's get started.

How does gravity work in the quantum regime?

A holographic duality from string theory offers a powerful tool for unraveling the mystery.

Take a look.

Physicists have long set a theory that unifies quantum mechanics with Einstein's theory of gravity to understand the laws of physics at the largest and the smallest scales.

Could the link come from a holographic principle within string theory called the AdS/CFT correspondence?

Imagine watching a 3-D shark film with your 3-D glasses on.

♪♪ That was scary.

Take off your glasses and the screen looks very different.

All the information is encoded on the 2-D screen, yet we experience it differently in a higher dimension.

Some researchers think quantum gravity may work much the same way.

Gravity is a force that explains how objects interact with each other on a large scale, like how planets revolve around the Sun and why leaping sharks fall back into the water.

As Einstein described it, gravity results from a curvature in the geometry of space-time, but on a quantum level, forces are produced by an exchange of particles, and since gravity is far weaker than any other force, we haven't been able to detect a gravity particle, a graviton, that fits into our understanding of quantum mechanics.

Enter the AdS/CFT correspondence, a mathematical mapping similar to a hologram, that shows how a region of space-time with gravity emerges out of a purely quantum theory.

The AdS in AdS/CFT stands for Anti-de Sitter space.

It's the space-time region that pops up like a hologram from the conformal field theory, or CFT, that describes the particles at the gravity-free boundary of the AdS Universe.

No information is lost in the hologram.

AdS space is negatively curved.

It includes gravity and has one more dimension than CFT.

You can think of the AdS/CFT Universe as a sphere.

The 3-D AdS space-time sits inside the sphere, bounded by the 2-D gravity-free CFT.

The negative curvature of AdS space gives it a boundary, which is needed to make the holographic principle work.

The lower dimensional boundary allows for the correspondence to be a duality, two different ways of looking at a system, like seeing the shark with and without 3-D glasses.

The AdS/CFT correspondence is a strong-weak duality.

The individual particles on the weakly coupled AdS side correspond to bound states on the strongly coupled CFT side.

This means that strongly coupled materials on the CFT side that are too complex to study can be converted into questions about individual particles moving on the AdS side.

Or add a black hole on the AdS side and what you get on the CFT side is a soup of particles or plasma that physicists can learn about by studying the black holes.

And because no information is lost in the holographic principle, gravity on the AdS side maps to the quantum interactions of the CFT side, giving researchers a way to describe gravity on the quantum level.

Even though our Universe has a different geometry than the AdS/CFT picture, and no boundary, understanding quantum gravity in AdS/CFT could reveal deep insights about black holes and the laws of physics at all scales.

So next time you're watching a 3-D movie, remember how holographic principles are being used to unlock the secrets of our Universe.

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Thomas Lin is the editor in chief of and the editor of two math and science books, 'The Prime Number Conspiracy' and 'Alice and Bob Meet the Wall of Fire.'

He joins us now to discuss how holographic principles are unlocking the secret of our Universe.

First, let's talk about what the holographic principles are and then kind of what the secrets are and how they're intermingled.

So how do we use holograms here?

Sure, and just to set it up, the problem that this is being applied to is one of the most fundamental questions, one of the big open questions in physics, which is the question of quantum gravity, which is how does gravity work at the smallest scales, at the particle level?

And so, somehow, physicists have come up with a holographic principle that can give some insights into, possibly, how quantum gravity works.

And basically the hologram idea is kind of like, imagine you're watching a 3-D movie, and so you have the glasses on and you see things that seem to be jumping out at you and things are happening and it seems like it's real life.


And it's, like, a hologram, but you take your glasses off and it's a flat movie screen, and so all the information that you're seeing in 3-D with the glasses on is encoded on a 2-D surface.

And so that's the basic idea behind a physics correspondence called the AdS/CFT correspondence where, essentially, it's like a toy universe, where the inside of this universe has particles and black holes and gravity and things like that, but the surface, the 2-D surface, so to speak, doesn't, and the 2-D surface is directly mathematically mapped to what's happening on the inside, just like the 2-D screen in the movie is creating this 3-D hologram.

And so, you know, to sort of step back for a second, the problem is that physicists know how gravity works on a large scale.

Einstein came up with his theory of general relativity about a century ago and it describes perfectly the way planets move, the way all the things that we experience, in terms of gravity, work, but unfortunately, that description doesn't work at the particle level.

And so, at that level, we have a different theory, which is a bedrock of physics, called quantum mechanics, which describes particle interactions, but those two theories don't play well together, and we don't know how gravity works at that level.

So scientists have been looking for something to pull those two ideas together, saying, 'Well, gravity has got to... We have to have a rule that works in both cases, the big and the small.'



So it's both because they want to know how all the final forces work together in all scales.

It's also because without a theory of quantum gravity, we don't know what's happening inside black holes, and we don't know exactly how the Big Bang happened because these are moments where there's such intense gravity happening at such small scales that we have to understand how that's working with quantum gravity in order to understand what actually happened.

So AdS/CFT, is that just a framework for how to map these 2-D, 3-D ideas?

Exactly, exactly because AdS stands for Anti-de Sitter space, which is essentially the higher-dimensional universe with stuff in it, and the CFT part of that correspondence is a conformal field theory, which essentially is a quantum mechanics field theory, which describes particles but does not have gravity.

And so being able to map this 2-D boundary to a three-dimensional or a higher-dimensional universe that has gravity inside shows, in theory, how you could get gravity from the interactions of a field theory like quantum mechanics.

It's almost like we're creating a laboratory, just theoretically...

Yes. be able to even study how these things would interact because we technically don't have a world that would function like that anyway.

We're in the opposite of that.

Yes. You could say that.

So how close are we to figuring this out?

I mean, I'm assuming there are researchers and scientists all over the world playing around in this AdS/CFT world and trying to figure out how gravity is going to work on this tiny, tiny scale as it works in the bigger world.

In terms of actually connecting it to the real world, though, unfortunately, physicists have sort of hit a wall in a way because there's no real way to probe at that level.

There hasn't been any way to, for example, find empirical evidence for what a gravity particle might be, which would be called a graviton, but nobody has actually detected that yet, and there's no sense that we'll be able to detect that any time soon.

And so, right now, physics is in this interesting state where there's this huge particle collider out in Switzerland called the Large Hadron Collider, and they've confirmed some of the particles of the standard model, which people were sort of expecting, but they haven't found the other particles that are needed to make sense of things like dark matter and quantum gravity and all these other things that are still missing in terms of our understanding of the Universe.

And there's still, again, many, many missing pieces and, unfortunately, we can't yet find those pieces, and so physicists have to work in this theoretical realm with math and with tools like the AdS/CFT correspondence.

So best-case scenario, let's say we figure out quantum gravity, what do we do with that information?


So, again, this is one of the things we cover these fundamental areas of research for which there's no necessarily a direct application right away, right?

It's just about gaining knowledge about the Universe, which ultimately, though, leads to all the technology that we use today, all of the medical advances and treatments that allow us to live longer and healthier lives.

That all comes from basic science from decades and decades ago.


And so, we don't know yet.

I mean, we honestly do not know what the applications for something like that might be necessarily, but what we would know is, again, we would understand much more about how the Universe works, how the basic laws of physics work, what's happening inside black holes, which we have no idea right now about, how the Universe got started, and ultimately, knowing how quantum gravity works could potentially lead to other ways to take advantage of things at that tiny sort of particle level.

We're talking about changing or altering what we think of as space and time, altering what Einstein had at sort of his disposal?

That's a great question because essentially that's where physics is right now, right?

We have these two bedrock theories.

We've got Einstein's theory of general relativity, which works perfectly well at large scales.


You have quantum mechanics, which works perfectly well at tiny particle scales, but they don't work well together, and so physicists have to think, 'Well, maybe there's a more fundamental theory than either of these.

Maybe one is right and really works in both scales.

Maybe neither is the more fundamental theory, and maybe there are things like, maybe space-time is emergent, right?

Maybe it's not even fundamental, too.'

I mean, these are all different ideas that physicists have right now.

They have to work with them in order to try to get past this road block right now from where they are because, you know, it's been decades since the last major physics revolution, and there's a sense now that we need a new revolution to understand the underlying nature of reality.

The underlying nature of reality.

Nothing short of that.

Thomas Lin of Thanks so much.

Thank you so much.


In 2017, NASA's Fermi Gamma-ray Space Telescope connected gamma rays, the highest-energy form of light, with new cosmic messengers, gravitational waves and high-energy neutrinos.

For the first time, the discoveries linked these new signals to the one sky watchers have known for millennia: light.

First, gravitational waves and gamma rays were emitted from emerging neutron stars.

Fermi saw the first-ever light detected from a gravitational wave event.

Then, just weeks later, Fermi connected a high-energy neutrino seen by the IceCube experiment at the South Pole to a black hole-powered galaxy which fires a jet of matter that emits both neutrinos and gamma rays.

This is no overnight success story.

The origins of both these breakthroughs span more than a century.

As the 19th century closed, scientists worked to understand many new phenomena, including radioactivity and new forms of light, X-rays and gamma rays.

Light was expected to need a medium called the aether in order to move through space, which meant its speed should change when measured in different directions on the moving Earth, yet no changes were seen.

Solving this puzzle led to Einstein's special theory of relativity, which assumed light in a vacuum moves at a constant speed that nothing can exceed.

His theory formed a theoretical basis for particle physics, which in 1912, incorporated an unexpected source -- a rain of particles from space called cosmic rays.

Einstein's general theory of relativity, his theory of gravity, regarded space-time as the fabric of the cosmos.

Space-time tells matter how to move and matter tells space-time how to curve.

As scientists probed the subatomic realm, one type of radioactive decay suggested the presence of a new lightweight particle dubbed the neutrino.

Later, Einstein and Nathan Rosen showed that accelerating masses can create gravitational waves that ripple across space-time.

Following World War II, technological advances permitted new kinds of observations.

In the mid-'50s, neutrinos were detected for the first time.

Richard Feynman showed that gravitational waves must move matter, which means they're detectable.

In a few years, the first efforts to do so began.

The 1960s brought the first gamma rays seen in space, the first neutrinos detected from the Sun's interior, and something new, later called gamma rays bursts, or GRBs, was caught by satellites looking for banned tests of nuclear weapons.

In 1971, Rainer Weiss conceived of a way to detect gravitational waves using lasers, one of the roots of LIGO.

1987 delivered the brightest supernova in nearly 400 years.

Three experiments caught neutrinos from the star's collapse.

Instruments on balloons saw gamma rays from radioactive elements in the explosion's debris.

The 1990s and 2000s brought new satellites for exploring the gamma-ray universe, the construction and first operation of LIGO and AMANDA, a neutrino detector built under the ice at the South Pole.

In 2005, NASA's Swift satellite showed that short gamma ray bursts likely come from merging neutron stars.

Soon after, NASA launched Fermi, providing our best-ever view of the gamma-ray sky.

AMANDA morphed into IceCube, which was completed in 2010.

It monitors a cubic kilometer of ice under the South Pole for neutrinos.

The same year, LIGO shut down for years of upgrades.

IceCube reported than two dozen high-energy neutrinos, likely arrivals from beyond our galaxy.

In 2015, the upgraded LIGO saw the first gravitational waves, the source: merging black holes over a billion light-years away.

And in 2017, gamma-ray counterparts accompanied both a gravitational wave event and a cosmic neutrino source.

Multi-messenger astronomy and its promise of greater insight into the most powerful processes in the Universe has arrived.


Students at Canyon High School in California are introducing computer science and engineering to students at a younger age, giving them real-world experience, but also allowing their creativity to shine.

This segment is part of American Graduate: Getting to Work, a public media initiative made possible by the Corporation for Public Broadcasting.

Common applications such as Facebook, Twitter and smartphone apps are things that are used across generations, cultures and worldwide locations, but who's responsible for building these computer and technology-based apps?

In today's ever-changing workforce, computer science and engineering is in high demand and constantly looking for new, talented employees.

Computer science is an exponentially growing industry and there is a large deficit of programmers, so it is very necessary now that we are motivating more people in our generation to go into computer science because so many programmers are needed now, and the number of programmers that we will need in the future will only grow as technology continues to develop.

With this high demand for programmers and engineers, schools have had to figure out how to introduce this technical field to students at a younger age.

Enter Career Technical Education, a program of courses that schools use to help students careers and become career-ready.

Here at Canyon High School, the computer science pathway gives high school students real-world experience and practice.

In the computer science pathway, students have several opportunities.

The goal of the capstone course is for them to be able to show off, to be able to build an app with a group of their peers that can be deployed to an app store such as Google Play or iTunes.

We have professionals that come in and speak to our classes.

One professional recently talked about internship opportunities that can be made available to high school students.

The CTE computer science pathway not only provide courses for students to grow their technical skills, but also allows them to let their creativity shine.

The most unique thing about our program is the long-term goal to work with the art department to be able to create real-world environment where programmers and artists work together, like you'd find in a large corporation, to allow students to really show off.

Even if students don't end up pursuing a career in programming, the skills learned in these classes are very valuable.

Boss and scientific director of quality, Jessica Lee, uses her experiences from computer science classes in her current career.

In undergrad, I took a computer science class in Java programming, and I actually liked it so much that I became the tutor for the class, and what I liked about it was the logical thought process involved in programming language, the if-then statements, and I find that even though I'm not a computer scientist now, I still use a lot of that logical thought process in my problem solving at work.

Not only does computer science guide students to engineering and programming careers, but it also translates into other fields.

Christian Jimenez, director of Front End Engineering from tech start-up company GoodRX, believes that the skills learned from computer science can be applied in other areas.

It helped me a lot with math because there's like... like, math is very logical, and I think computer science is very logical.

It tells you how to follow rules and how to take the order of these rules, and they're just conditions, and with these conditions, you can solve a problem.

But even in writing, writing has a structure, and you can get very creative with how you use that structure, but there are rules that bind the structure.

Just as the workforce is continuously evolving, technology must continue to develop as well.

Our generation is quite literally the future, and the future consists of more and more computing in the workplace because it's unlikely that we'd go from something as powerful as a computer back to pen and paper anytime soon.

So the advice that I would give to starting programmers or people who are interested in the field in general is, like, don't be discouraged.

I know a lot of people go online, and they see all these people who are doing amazing things.

Like, you just have to take it one step at a time.

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VR meets the ER.

Virtual reality is no longer just for video games.

The medical industry is using the technology to teach students how to react during health emergencies.

Let's see how researches at the University of Texas at San Antonio are using the VR system.

The student using the virtual reality, VR in the ER, can be able to expand their skills, which is never seen before.

For example, like learning biology, and usually, you can see the biological cells and you never can see inside of the cell, the structures and signaling pathways and proteins and genes.

In the virtual reality, you can build all those around it.

And another example is by training, and we have biologically, by medical, we have the application called Open Heart Simulator just to similar to the Fly Simulator, so this is for medical student for training.

Mando Rodriguez is a research solutions engineer here at UTSA.

He's going to show us virtual reality, how it can be used to train doctors in operating rooms using some of the equipment, Mando, that they would use in an open-heart surgery situation.

How is this going to utilize the virtual reality?

Well, this particular simulation is set up to be an operating room scenario.

This is set up for perfusionists in order to train them in the event that something goes wrong in the middle of a surgery.

Any number of things can go wrong with a heart-lung machine.

They can have an air bubble inside of the tube, blood pressure can drop, oxygen levels can drop, so that's what this VR trainer is made specifically for.

Over here, I'm checking to see that the hoses are properly connected.

Things can happen where the hoses are not properly connected.

I would need to go down here.


I connect the hose.

Any number of things can happen where the hose can come loose.

Silly thing to happen, but yeah.

That can happen, and an air bubble can be inside of one of these hoses.

Oxygen levels can drop, so this is what the simulator is designed to basically replicate.

Scenarios that go wrong aren't going to happen when you shadow a doctor is what I'm saying.

You don't want them to go wrong when you shadow a doctor.

So what I'm saying is if a med student was shadowing a doctor in the middle of a surgery, they don't want something to go wrong there, but here, you can safely replicate something going wrong and having them come in and, you know, save the day, you know, get an air bubble out of the tube, make sure that the oxygen pump is working properly, make sure blood pressure is correct.

You can make...If something like that were to happen here, you could replicate that over and over again without any actual risk to any patients.

You get a better idea of exactly what's going on in an object.

Then you have a lot of 3-D models where when you're looking at the computer screen, you can't really see a lot of the contours or results that are popping up.

So a lot of the simulations I do for finite element include a lot of 3-D models, so being able to see it in more than just the two-dimension computer screen, you get a better idea of what's going on in your simulation.

One of the most exciting projects going on at UTSA is the Google Labster on the Daydream, and the Bill Gates Foundation donated 20 sets of the VRs, so it's going to be coming in live in next semester.

The importance of having technology like this at UTSA to train the future leaders of our country and of our world, just tell me a little bit about, from your perspective, why this is so important that we have this here.

Why it's important?

Well, it can be pretty costly and sometimes you need high-end PCs.

You need this equipment.

You need good monitors and everything to... You don't always have that available, so you can just come into our lab here and, you know, it's here, freely available for anybody to use for any sort of projects that they're doing, and that's a lot better than, you know, going off and shelling out $400 or $500 just to, 'Gee, I don't know if this is going to work right,' and maybe have to switch to something else.

It's easier to come down here and just, you know, prototype and test here using our equipment and determine which one of these pieces of technology work best for you.

And that wraps it up for this time.

For more on science, technology and innovation, visit our website.

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You can also subscribe to our YouTube channel.

Until then, I'm Hari Sreenivasan.

Thanks for watching.

Funding for this program is made possible by... ♪♪ ♪♪ ♪♪ ♪♪ ♪♪