Tag Archives: quantum-physics

Five Things That Sound Completely Made Up (But Are Annoyingly Real)

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Following on from last Friday’s article, one of the side effects of learning about Hawking radiation is discovering that modern physics is less a collection of facts and more a collection of increasingly unsettling revelations. Every time you think you’ve found the weirdest thing in the universe, physics quietly says, “Hold my equations.”

Here are five examples.

1. Right now, you are hotter than a black hole.

Let’s begin with an insult to black holes. And that is that right now you are hotter than most, if not maybe all, the black holes in the universe

Despite their reputation as the ultimate cosmic monsters, most black holes are astonishingly cold. Hawking showed us that black holes possess a temperature, and the larger the black hole, the colder it becomes. Therefore, a black hole with roughly the mass of our Sun would have a Hawking temperature of only a tiny fraction of a degree above absolute zero.

Meanwhile, you are sitting there at around 310 Kelvin (37°C), radiating infrared energy into your surroundings like a particularly self-satisfied space heater. So, thermally speaking, you’re absolutely thrashing a stellar-mass black hole. That is the same object capable of swallowing stars is, from a temperature perspective, a pathetic overachiever. The universe’s most feared gravitational predator is colder than deep space and vastly colder than the cup of tea that is slowly cooling beside me.

Hawking radiation revealed that black holes aren’t just gravitational objects. They’re thermodynamic objects. And thermodynamics has a wonderful habit of humiliating our intuitions.

2. Space ain’t empty.

The phrase “empty space” is one of the most misleading expressions in science. You got it, empty space is most definitely not empty.

What looks like nothing is actually a restless sea of quantum fields. According to quantum field theory, even a perfect vacuum contains fluctuations, tiny disturbances that constantly appear and disappear throughout space. This isn’t a rare occurrence, it’s happening everywhere, right now, around you, and, amazingly, it’s happening inside you! Between every atom in your body! Creepy and weird or what!!

In fact, Hawking radiation exists because black holes interact with these quantum fluctuations near their event horizons, and without the vacuum’s constant activity, Hawking’s discovery wouldn’t work. Which brings us back to that unsettling conclusion that nature doesn’t seem particularly fond of “nothing.”

Give the universe an empty stage, it’s competing with the best improv stand-up comedians. It immediately starts improvising itself!

3. Black holes ain’t that heavy.

If black holes are gravity taken to the extreme, neutron stars are gravity’s terrifying warm-up act. A teaspoon of neutron star material would weigh around a billion tonnes

Now then. A neutron star forms when a massive star dies and its core collapses so completely that atoms themselves are crushed. Electrons and protons merge into neutrons and produce an object roughly the size of a city but containing more mass than our Sun.

The result of this is density on a scale that defies common sense. A single teaspoon of neutron star material would weigh roughly a billion tonnes. That’s not a billion kilograms. That’s a billion tonnes. The sort of weight that makes the phrase “pick it up carefully” somewhat academic.

If you somehow brought that teaspoon to Earth, it wouldn’t politely sit on a kitchen counter and reality would very quickly become an SEP (you know what that is, you’ve read the Hitchhikers Guide to the Galaxy, it’s when Ford and Arthur arrive at lords on a battered sofa at the beginning of Life, the Universe, and Everything, Ford, clocking Slartibartfast’s ship out of the corner of his eye has to explain to Arthur there’s an SEP over there, try and catch it unawares by glimpsing it from the corner of your eye). Somebody else’s problem.

And at this point, every Futurama fan is now thinking exactly the same thing. “Wait… isn’t this basically Nibbler?” To which science’s answer is both inconvenient and hilarious, and the answer is, “yeah, sort of.”

Nibbler’s species, the Nibblonians, are famously absurdly dense. In one episode, Nibbler casually produces poo that weighs thousands of pounds, despite  Nibbler himself being roughly the size of an enthusiastic housecat. For once, science fiction wasn’t completely making things up. A neutron star packs so much mass into such a tiny volume that a teaspoonful would weigh about a billion tonnes. Compared to that, Nibbler is practically watching his figure.

Somewhere in the universe, one suspects Nibbler is looking at a neutron star, nodding approvingly, and muttering, “Hmm… at last… a sensible-sized snack.”

Physics occasionally likes to remind us that density can be every bit as terrifying as size. And occasionally, it reminds us that Futurama was alarmingly well-informed.

4. Whatever is out there in the blackness, we can’t see it.

If Hawking radiation teaches humility, dark matter delivers the knockout punch. And that is most of the universe appears to be made up of something we can’t actually see.

For centuries we assumed that stars, planets, gas clouds and galaxies were the universe. Then astronomers started measuring how galaxies rotate, and the numbers didn’t add up.

Galaxies should have flown apart. But, instead, something invisible appeared to be providing extra gravity and holding everything together. Astronomers now call this missing ingredient dark matter.

And here’s one of those questions, you, my lovely readers, like to ask. What is dark matter?

The awkward answer is we still have absolutely no idea what it is. What we can infer is its existence from its gravitational effects. That is, we see the way it influences galaxies and bends light, but direct detection remains elusive. The evidence, however, says something is there. We just don’t know what.

Imagine discovering that most of your house consists of invisible rooms nobody can enter. That’s roughly where modern cosmology currently stands with dark matter.

5. What the hell is light doing?

And finally, quantum mechanics saves its strangest trick for last, and that is reality refuses to make up its mind until you look.

This is one of my favourites, and you can easily amaze your family and friends with it. This is the famous double-slit experiment, and it works like this.

If you fire particles through two narrow openings and don’t measure which slit they pass through, the resulting pattern suggests each particle behaves as if it travelled through both slits simultaneously.

Measure which slit it used and the pattern changes completely and the wave-like behaviour disappears and suddenly the particle acts as though it picked a side all along.

This doesn’t mean consciousness magically creates reality, despite what countless internet memes may suggest. What it does mean is observation and measurement play an extraordinarily deep role in quantum mechanics.

The universe, at its most fundamental level, appears less interested in giving definite answers than we would like, and it behaves more like a collection of probabilities than a collection of certainties.

Which is either fascinating or deeply irritating, depending on how much sleep you’ve had.

As I said, you can amaze your friends with this one, and I first saw this demonstrated in a physics class in high school many, many moons ago. All you need is a laser pointer and a couple of perfectly parallel holes in a piece of cardboard. Copy and paste this into google and it will show you how:

Can you do your own double slit experiment with cardboard and a laser pointer?

Let’s link these all together.

At first glance, these facts seem unrelated.  One is about black holes. One is about empty space. One is about neutron stars. One is about dark matter. One is about quantum mechanics.

But they all point toward the same uncomfortable conclusion. Reality is under no obligation whatsoever to resemble common sense.

Black holes glow. Nothingness isn’t empty. Matter can become unimaginably dense. Most of the universe appears invisible. And particles sometimes behave as if they’ve forgotten how choosing works.

Hawking radiation sits right in the middle of this collection of cosmic absurdities. It exists because gravity, quantum mechanics, thermodynamics, and information theory all collide at the edge of a black hole.

And every time physicists dig deeper into that collision, the universe responds with another fact that sounds fake, isn’t fake, and somehow makes everything even stranger.

I tell ya. You simply cannot win with Physics. Sort one thing out and it throws a spanner in the works.

Some of you asked: “How Do You Know So Much?” And honestly? Obsession, mostly. And I won’t shut up.

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Hi folks, quick interim post.

A few of you have been asking how I know so much about this stuff and how I write my articles. So, I thought I’d give you a little insight.

Truth is, I don’t know everything, obviously no one does, and although I’m not a professional physicist, I am a very well-read and well-studied amateur.

I got into it via my father, whose interest started with radio propagation when he was in the RAF. He was always fascinated with physics and space travel, planetary science, and in particular, anything to do with the possibilities of FTL communications.

In 1996 I bought my first tiny house in a small market town a few miles south of Norwich, and my dad lived around the corner. At the time I was working shifts in a factory, a week of days a week of nights, then I would get a week off.

During this time and for most of the rest of the nineties, my dad was always over and making use of my computer knowledge and internet and he introduced me to sites, such as Warp Drive When, and Breakthrough Propulsion Physics and other fun stuff. And it wasn’t long before I was hooked, and within a couple of years my knowledge had far surpassed my father’s.

I’m a serial learner, once I get my teeth into a subject I don’t stop. It’s an obsessive trait I’ve had all my life, and only in recent years have I discovered it’s due to OCD/ADHD/Autism. Every one of us is on the spectrum somewhere, for me and my particular place on it, it has turned me into a compulsive seeker of knowledge.

As for the articles themselves, I bang out a rough draft of what I know on the subject matter I have chosen, and then I do my research. I know quite a lot of useless stuff, how it works, when it was first performed etc.  Once my draft is complete, I then start the research to make sure I’ve got the science correct, haven’t missed anything, and check timelines and people etc. I have a ton of books on the subjects I write about, and I have also subscribed to several scientific journals over the years and have those, Nature, Science, JBIS and a few others. And of course, I have the internet.

With the Quantum Teleportation article, I remember the experiments and I remember the time, and as I said in my article, I was genuinely so excited at the time I wouldn’t shut up about it. As I said above, once the draft is written, I then google it to make sure I’ve got all the awesome dudes who participated, as readers can be ruthless if I make a mistake, miss someone out, or get something wrong.

I then do a second phase over the whole thing and rewrite it before I re-read it out loud to myself, as this is the best way to pick up errors in the narration, typos, dodgy grammar etc.

Once I’m satisfied with it, I send the final draft to some very old friends from school, get them to read it and to see if it makes sense to them. With their feedback, I tweak the final article and it’s ready to go. This is also why some typos and wrong words still get through occasionally.

And that’s it. Physics is a subject that I love, and I love it so much, I want to share it with everybody else, so they will love it too.

When I resurrected this WordPress site after a four-year hiatus, I wanted to write about general sciency stuff. A bit of physics here, a bit of astronomy there, and a bit of paleoanthropology (my first love, don’t get me started on it, honestly, I won’t shut up for days!) in between.

As physics has consumed most of my adult life though, that is the direction my writings have naturally taken, and going forward, apart from the odd article in the other sections from time to time, physics is where it looks like it’s staying.

One last thing before you go. I love receiving your messages, and I have to admit I was a bit overwhelmed at how engaged some of you guys are, flattered at how many new readers are joining, and I’m genuinely thrilled at the messages I have received. Mostly via social media, which is why I added the email address to the home page.

If you want to get in touch to suggest future articles, point out mistakes, or even have a go (I’ve had a couple of those), please do. At present I am able to reply to everyone who gets in touch, unless they’re a complete arsehole.

Thank you for your time. You are AWESOME!

Mal
hello@malandally.co.uk

The Black Hole Glow: A Journey into Hawking Radiation

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Howdy my loyal readers. I’d like to start my saying thank you for the messages I’ve received asking if there is anything else they should know about black holes, and as they are a common theme through most of my articles, I’m going to indulge you with this one, on how Stephen Hawking discovered that the darkest objects in the universe may slowly evaporate away

By any reasonable definition, black holes should be simple. They pull things in. Nothing gets out. End of story. Yet in 1974, Stephen Hawking discovered something astonishing, and that was, black holes are not completely black. Given enough time, they glow, lose mass, shrink, and may eventually disappear altogether. That prediction is now known as Hawking radiation and remains one of the most profound (you’ve heard my ear worm already) insights in the history of physics.

This was a problem nobody expected, although I’m pretty sure Stephen Hawking had an inkling. You see, Black holes emerge naturally from Einstein’s theory of General Relativity. According to the classical picture, they are regions of space where gravity becomes so powerful that nothing, not even light, can escape once it crosses the event horizon. I know, I know, this is old news to you guys, I’ve stated it several times in previous articles.

For decades, physicists assumed black holes could only grow. Matter falls in. Energy falls in. Nothing comes out. Yeah? Then along came Stephen Hawking, and he combined Einstein’s gravity with quantum mechanics and arrived at an answer nobody could have anticipated. Black holes should emit a faint thermal glow. And this implication was extraordinary. Simply put, it meant that Black Holes could die.

As humoungously massive as it is, the Universe is never truly empty, and to understand Hawking radiation, we need to start with a strange feature of quantum mechanics, and that is what appears to be empty space isn’t actually empty.

According to quantum field theory, the vacuum of space is filled with fluctuating quantum fields. That is, teeny tiny disturbances constantly occur throughout space, causing particle-like excitations to briefly appear and disappear. Something that physicists call vacuum fluctuations.

OK. This bizarre activity actually happens everywhere in the universe, and this includes some of the most extreme environments surrounding a black hole.

And this takes us to the famous story that everyone learns. And that is, the most common explanation of Hawking radiation goes something like this:

Near the event horizon, a particle and antiparticle appear as a pair. Now then, normally they would immediately annihilate each other, but if the pair forms close enough to the event horizon, gravity can separate them before they reunite. Which means, one particle escapes into space, while the other one falls back into the black hole. To a distant observer, the escaping particle looks like radiation emitted by the black hole itself.

And this is because, the particle that falls inward, effectively carries negative energy relative to faraway observers, thus reducing the black hole’s mass, so over immense stretches of time the black hole slowly evaporates.

It is an absolutely, beautiful explanation.

But, and there’s always a but, you know this by know, surely guys, there’s one problem.

This isn’t really how Hawking derived the result.

To look at the deeper truth, among physicists, this particle-pair story is considered a useful mental picture, but is not the actual mathematics (maths again, I know. Regular readers already know my issue with maths). Anyway, Hawking’s original calculation used quantum field theory in curved spacetime. And that is, the essential idea is subtle. Different observers can disagree about what counts as empty space. A vacuum for one observer may appear to contain particles to another observer. But, near a black hole’s event horizon, spacetime is distorted so severely that these differing perspectives become physically important

When Hawking compared the state of quantum fields before and after a black hole forms, he discovered that an observer far away would detect radiation emerging from the black hole. So, in other words, Hawking radiation is less about particles popping out of nowhere, and more about the deep relationship between quantum fields, spacetime, and observation itself.

One of Hawking’s greatest discoveries was that black holes possess temperature, and the temperature of a black hole is inversely proportional to its mass, so the heavier the black hole, the colder it becomes, and this leads to a surprising consequence.

A supermassive black hole containing millions or billions of solar masses is incredibly cold, and a tiny black hole is extraordinarily hot, and this relationship means, small black holes radiate far more efficiently than large ones.

Because Hawking radiation carries energy away, the black hole loses mass, and this results in the slow death of a black hole.

As it shrinks, something curious happens. The black hole gets smaller as its temperature rises, then radiation increases which causes the mass to decrease even faster, and therefore the process accelerates.

If the theory is correct, then the final phase could end up with an enormous burst of energy, however, what exactly happens during those final moments remains unknown.

If you got the time to watch one, don’t expect to watch one evaporate as the evaporation process is incredibly slow. A black hole with roughly the mass of our Sun would survive for approximately 10⁶⁷ years, and this is one hell of a lot of zeros, and an incredibly long time. Trillions upon trillions upon trillions of times longer than the current age of the universe. Told you it was a long time.

And what’s more, supermassive black holes live even longer! Fortunately for the universe, black hole death is not an urgent problem, and nothing to worry about. Not for a verrrrrry longtime, at least!

Before Hawking’s discovery, physicist Jacob Bekenstein, argued that black holes should possess entropy, a measure of information content (remember my last article? You did read it, didn’t you?), and Hawking’s calculations confirmed this. In fact, black holes possess staggering amounts of entropy. Even more surprisingly, that entropy scales with the surface area of the event horizon rather than the black hole’s volume!

This observation helped inspire one of the deepest concepts in modern theoretical physics, and that is the Holographic Principle (you know this, I mentioned it way back in my original Black Hole article). This principle suggests that information contained within a region of space may be fully encoded on its boundary surface. It may sound like science fiction, but it has become one of the central ideas in attempts to understand quantum gravity

There’s a problem though, and that is the Information Paradox, and that is the question that changed theoretical physics forever.

Let us suppose a black hole swallows, my laptop I’m writing this article on, books, planets, stars, people, and entire civilizations and the specific details seem to vanish behind the event horizon.

If the black hole later evaporates and only thermal Hawking radiation remains, where did the information go? And that, is what has become known as the Black Hole Information Paradox.

The paradox appears to pit two fundamental pillars of physics against one another. Again, you know this, I’ve mentioned it before. It pits General Relativity against Quantum Mechanics. And this is because quantum theory normally forbids information destruction. What’s surprising is, Hawking’s original result seemed to imply exactly that.  And that is why many physicists consider this one of the deepest unresolved problems in science.

Modern research increasingly views Hawking radiation as an entanglement phenomenon. The radiation escaping from a black hole appears linked to degrees of freedom hidden behind the event horizon, and these quantum correlations may play a crucial role in preserving information.

This current line of thinking has driven decades of research involving Quantum information theory, string theory, holography (my old, now dead, dad was a big fan of holography), and quantum gravity, as well as many other areas.

Moving on, there is another remarkable discovery that Hawking radiation appears closely related to the Unruh Effect.

The what, I hear you say? Another topic for later? Sorry, yes (picture me doing an emoji grimace in apology as I type this), the Unruh Effect predicts that an accelerating observer can perceive empty space as containing thermal radiation. And that is what one observer sees as a vacuum, another observer sees as heat. Many physicists suspect both effects arise from the same underlying physics linking horizons, acceleration, and quantum fields.

Which brings us to the puzzles of tine scales. And that is, there is another challenge lurking inside Hawking’s theory.

When researchers trace Hawking radiation backward in time, some calculations appear to involve wavelengths smaller than the Planck scale (you know what that is), where known physics may stop working completely, and this issue is called the Trans-Planckian Problem. Which suggests we may need a deeper theory of nature to fully understand what is happening near the event horizon of a black hole.

Ah, who was that at the back, another question do I hear? Have we ever seen Hawking Radiation?

Surprisingly, the answer is…

No. We haven’t.

Despite being one of the most famous predictions in science, Hawking radiation has never been directly observed from a real astronomical black hole, and that is because the effect is simply too faint. Remember how long it would take to observe it? That is how faint it is. Even paint dries at the speed of light in comparison. (It doesn’t, bit that sounded cool, didn’t it!).

However, researchers have built laboratory systems that mimic the behaviour of event horizons using optical fibre, fluid systems, and Bose-Einstein condensates, and these analogue systems have produced Hawking-like radiation and, yes there’s another and, in recent experiments, even evidence of the associated back-reaction effects predicted by theory! Cool huh?

While these are not actual black holes, they do provide valuable support for the underlying physics, which leaves us with the final mystery.

And that is perhaps that the most important thing about Hawking radiation is not the radiation itself. There is a deeper lesson, that black holes sit at the intersection of humanity’s three greatest theories, General Relativity. Quantum Field Theory, and Thermodynamics. Unfortunately, those theories do not fit together perfectly, but Hawking radiation exposes the cracks.

Hawking radiation tells us that spacetime has temperature, that gravity may be linked to information, and that entropy and geometry are somehow connected. Oh, and that our deepest theories are still incomplete.

More than fifty years after Hawking’s discovery, physicists are still trying to understand what the phenomenon is really telling us.

The black hole’s faint glow may ultimately reveal not just how black holes die, but how reality itself is built! I’ve said this before at the end of my articles, and I’m going to say it again. How amazingly awesome is that!!

Quantum Teleportation: Not Star Trek, But Still Pretty Wild

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Hello my lovely readers, you may be few, but I love you all the same.

Having had a read through my previous articles since I started this whole bringing physics to the masses journey, I noticed there’s a nice progression developing: Gravity > Relativity > Entanglement > Bell’s Proof, a quick side step into the footy  (let’s not talk about that), which leads naturally onto this week’s article:

Quantum teleportation.

Now then, there’s a misconception about teleportation, and I’ve touched on it with my Star Trek allegories in previous articles.

When most of us hear the word teleportation, we probably all think of Captain James T. Kirk demanding that Scotty gets the malfunctioning transporter fixed pronto and beams him up (or Benjamin Sisko making the same demand of Chief O’Brien, or Captain Janeway…. Sorry, got a bit carried away, on with the article). Quantum teleportation is both less dramatic and far more profound (every time I type the word profound, I can hear Prof Brian Cox saying it in my head).

Unfortunately, scientists have not discovered a way to transport humans, objects, genesis devices, or even particles from one place to another. What they have discovered is a way to transport the quantum state of a particle, that is a complete description of its quantum properties, from one particle to another, potentially over vast distances.

In other words, quantum teleportation does not move matter, it moves information.

And that distinction may reveal something fundamental about the nature of reality.

So, if it’s not Star Trek personnel being teleported, what is?

To understand quantum teleportation, we first need to understand a quantum state.

Again, as I mentioned previously, unlike a classical bit, which can be either 0 or 1, a quantum bit, or qubit to give it its correct term, can exist in a superposition of all states simultaneously: it can be zero, one, or both, at the same time. The state of a qubit contains all the information that can be known about it.

The remarkable achievement of quantum teleportation is that the exact state of one qubit can be recreated in another distant qubit without ever measuring and copying the original state. The original state disappears, and the new state appears elsewhere. There is nothing physical travelling between the two except for a teeny tiny amount of ordinary information.

Quantum teleportation relies on three extraordinary ingredients.

The first ingredient is quantum entanglement.

When two particles become entangled, they cease behaving as independent objects. Instead, they become part of a larger quantum system whose properties are linked regardless of the distance separating them. You know what’s coming, don’t you? Yep, you’ve got it, this is what our old mate Albert Einstein famously referred to as “Spooky action at a distance.”

You’ve read my previous article on Bell’s Inequalities, so you know this already, but I’m going to repeat myself again anyway.

Today, entanglement is one of the most experimentally verified phenomena in physics.

On to ingredient number two. The sender (traditionally called Alice, but who I have renamed Betty in honour of my dear old late Mum), performs what’s known as a Bell-state measurement on the particle she wants to teleport and her half of an entangled pair. This measurement destroys the original quantum state, this destruction is not a bug though, it’s a requirement.

Ingredient three is the classical communication.

Betty then sends Bob, the receiver, two ordinary classical bits describing the measurement result.

It is only after Bob receives those bits that he can perform the operation needed to reconstruct the original state on his entangled particle.

At that moment, the teleportation is complete.

Sound familiar? If you read my “Spooky Action at a Distance” series, it should. I’m about to reuse that same trick about entanglement and the speed limit on information. If you haven’t read it yet… well, what are you waiting for?

Now we have one of the biggest misconceptions concerning quantum teleportation. Why doesn’t it break the speed of light?

Because entanglement creates correlations that appear instantaneous, but usable information still cannot travel faster than light. Bob cannot reconstruct the teleported state until Betty’s classical message arrives. This keeps Einstein’s theory of relativity perfectly safe and intact. No matter how strange quantum teleportation appears, and I know I’m repeating myself here, it does not allow faster-than-light communication.

Let’s look at the rule that makes this all possible, which is a fundamental principle of quantum mechanics called the No-Cloning Theorem. This rule states that an unknown quantum state cannot be copied perfectly, essentially meaning teleportation doesn’t produce two versions of the same particle state, the original state is destroyed, and the distant state is created. Quantum teleportation is a transfer, not a duplication.

The theory of quantum teleportation was first proposed in 1993 by Charles Bennett, Gilles Brassard, Claude Crépeau, Richard Jozsa, Asher Peres, and William Wootters. Their groundbreaking paper showed how an unknown quantum state could be transferred using a combination of entanglement and classical communication. If you really want to have a deep dive into it, let me know and I’ll send you the paper. It took only four years for researchers to successfully demonstrate the effect experimentally using photons in 1997. I remember being really, REALLY, excited at the time, I still get goosebumps looking back to when I first heard the news.

What had once sounded like science fiction had become a laboratory reality.

To me, and I’m sure to many others, this has become one of the greatest ironies of modern physics. Poor Einstein, the phenomenon he disliked most of all, quantum entanglement, became the foundation of quantum teleportation. However, the universe turned out to be even stranger than Einstein imagined.

That’s where Bell came in with his theorem I tried to explain (and hopefully succeeded) in my previous article before the footy one.

For decades, some scientists hoped that hidden variables might explain away Einstein’s quantum weirdness. John Bell showed that certain predictions of quantum mechanics could be experimentally tested and the results repeatedly favoured quantum mechanics and ruled out large classes of local hidden-variable theories.

If it wasn’t for Bell, quantum teleportation might still be considered an interesting mathematical idea rather than a physical reality.

Ah, another question from you? How far have we been able to teleport?

Well, it’s actually a great deal further than you probably think. Quantum states have been teleported using photons, atoms, electrons, superconducting circuits, and solid-state quantum systems.

Researchers have demonstrated space-based teleportation using China’s Micius satellite over distances exceeding 1,000 kilometres. And more recent experiments have teleported quantum information between different physical systems and over telecom-compatible networks designed to support future quantum communications. Just this year, researchers reported teleporting a photon’s state between physically separate quantum dots connected across a 270-metre free-space link, another step toward practical quantum networking.

Looking to the future of this amazing technology, scientists believe quantum teleportation will one day become one of the foundational technologies of a future quantum internet.

Instead of simply sending data, future quantum networks may distribute entanglement between thousands or millions of devices. Quantum teleportation could be used to transfer qubits between quantum computers. It could also be used to construct ultra-secure communication links, enable distributed quantum computing, and build true global-scale quantum networks.

Can you imagine quantum processors in London, New York, and Tokyo acting like pieces of a single giant computer? Well folks, that’s the long-term vision.

Ok, ok, I know you’re desperate to ask the question everyone asks. Could we teleport a person?

Well, in principle, quantum mechanics doesn’t obviously forbid it, but in practice, it is almost unimaginably difficult.

A human body contains roughly 10²⁸ atoms, each participating in an immensely complex web of quantum interactions. Capturing every detail required to reconstruct a person would involve a truly humongously astronomical quantity of information. Oh, there’s also another problem.

Don’t forget the no-cloning theorem in the rules above. The original transported person would have to be destroyed during the process, which raises a somewhat disturbing philosophical question. If a perfect copy appears elsewhere while the original is destroyed, did the person actually travel? Or were they killed while an identical replacement appeared at the other end.

That is a question that science currently has no answer for.

And here we can link back to black holes and wormholes. Deep developments in modern theoretical physics suggest that quantum teleportation may connect to mysteries far beyond communication technology.

Researchers studying black holes discovered unexpected relationships between entanglement, information, spacetime, and wormholes.

There’s the famous proposal, known as ER = EPR, yep, that one from another of my previous articles, which suggests that entanglement and wormholes may be two descriptions of the same underlying phenomenon. Although this is still speculative, these ideas hint that teleportation may reveal something truly profound (there goes Prof B. Cox again. I didn’t know it was possible to have one person saying a single word as an earworm) about the structure of the universe itself.

And then we get to the biggest mystery of them all. Perhaps the most extraordinary aspect of quantum teleportation is that nobody fully understands why reality allows it.

The mathematics works flawlessly and the experiments work repeatedly. And the technology is rapidly advancing.

Yet the deeper philosophical question remains.

Why should information be able to move through the universe in this way?

Quantum teleportation sits at the crossroads of quantum mechanics, information theory, computing, cosmology, and philosophy. Beginning as a clever theoretical idea in 1993, today it is helping scientists build the foundations of the quantum internet.

Who knows, tomorrow, it may help explain nothing less than the nature of space, time, and reality itself! Wouldn’t that truly be profound!

Quantum Entanglement Part One – Spooky Action at a Distance

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Just a quick note before we start: I got a bit carried away with this one. What was meant to be one article on quantum entanglement turned into something closer to a small dissertation, so I’ve split it into two parts rather than dumping the whole lot on you in one sitting which will also give me an extra week do the research and get Part Two much more readable.

This week, Part One: entanglement itself, what Einstein got wrong (and sort of right), and why it doesn’t break the universe. Next Friday, Part Two: what entanglement actually builds, and how deep the rabbit hole goes. Right, on with the show…

Hello, my lovely readers, how about today we take a friendly deep dive into the universe’s strangest connection: Quantum Entanglement.

At some point in your life, you were probably told the universe works like a well-behaved machine. Things move, collide, push, and pull. Causes lead neatly to effects. Objects exist whether or not you’re looking at them.

Then quantum physics came along and politely, but firmly, said:

“Er… Excuse me? I like your thinking, but that’s not quite right.”

And at the heart of that disruption is something both beautiful and unsettling, something the physics boffins call quantum entanglement. The term was first coined by Erwin Schrödinger, you know, the guy with the cat in the box you’re always hearing about?

Einstein famously mocked it as “spooky action at a distance.” He thought it was a flaw, but it actually turned out to be a feature.

Let me try and unpack what that really means, without getting lost in too much maths, (as, I’ve mentioned before, maths isn’t one of my strong points), but still going deeper than the usual surface explanations.

So, what is entanglement?

Imagine two particles created together, say, two photons born from the same event. From that moment on, their properties become linked. They are not just similar, and not just predictable. They are shared, which means if you measure something about one such as its orientation or “spin”, you instantly know the corresponding property of the other.

Even, and this is the truly mind blowing bit, if it’s on the other side of the galaxy.

Well, that doesn’t sound so weird, right? At first glance, it feels normal, I’ll go with the classic analogy, say you have two gloves, one left and one right and you put them in separate boxes. You send one to Norwich and the other one to Waitangi (I chose these two places as I live in Norwich and I googled what is the antipodal point of Norwich City UK; here’s a link for no reason: https://tinyurl.com/4ap8w4d3). When you open one you immediately know what the other one is. No mystery, right? Except this analogy quietly assumes something critical and that is the gloves already had definite identities before you looked.

Unfortunately, quantum particles don’t behave that way.

The twist is that reality isn’t really set until you look. In quantum mechanics, particles can exist in a superposition which is a blend of possibilities. Before measurement, an electron doesn’t have a definite “spin” like up or down, it simply exists in a cloud of probabilities. Are you still with me? I’m going to carry on regardless even if you’re not as you’ll get it at the end, I promise. If I can understand it, absolutely anyone can.

So, when two particles are entangled, it’s not that they secretly agreed in advance that is what they were going to do, it’s more like they didn’t fully decide until one of them was observed and then they both snapped into agreement instantly!

Einstein didn’t like this at all and that’s the part he just couldn’t accept, and was quite vocal about it for many years. He believed in two key ideas: locality, where nothing can influence something else faster than light, and realism: where physical properties exist whether we observe them or not.

Einstein’s big problem with entanglement was that it seems to violate both. So, in 1935, Einstein and colleagues proposed the EPR paradox (I’ll attempt to actually explain this a bit later).

“Quantum mechanics must be incomplete. Something deeper must be going on.”

He suspected hidden variables, unknown factors quietly determining outcomes behind the scenes.

This debate simmered on and on for decades, it sounded philosophical and almost untestable until in 1964, physicist John Bell made a breakthrough.

He showed that if Einstein was right, that is, if hidden variables governed everything, then there should be strict limits on how correlated entangled particles can be. Right?

These limits are called Bell inequalities.

Basically, (without attempting any heavy maths), Bell’s logic boiled down to this:

If particles carry pre-existing answers, and no influence travels faster than light, then their measurement correlations must stay within certain bounds.

Right? Get it? No? Me neither at first and it’ll take yet another blog post to explain it fully, so just go with it for now and I’ll have to tell you all about Bell Inequalities in a different post.

Anyway, back to where we were: quantum mechanics predicts something different. It predicts stronger correlations than classical physics allows.

Physicists tested Bell’s predictions with real experiments, over and over, by taking entangled particles, separating them, and measuring them in different ways.

The result showed that quantum mechanics wins. Every time. Without fail. The observed correlations broke Bell’s Inequality, they couldn’t be explained with hidden variables, and they couldn’t be explained by local interactions either. Furthermore, recent experiments have ruled out all the usual loopholes.

This means we are forced to accept something different and more radical; the universe isn’t both local and real in the classical sense, which means something about our everyday intuition is wrong.

Hang on just a minute, didn’t you say in your last article that you couldn’t have faster than light messaging? If one particle instantly affects another, why can’t we use this to send messages faster than light?

And the answer to that question is quite a simple one, you can’t control the outcome of your measurement. When you measure a particle, you can’t choose “spin up” versus “spin down”; you can only observe whatever happens. Which means you get a random result. While the correlation is instant, there’s no way to encode and transmit information. Nature gives you Einstein’s spooky connection but keeps communications firmly limited by relativity.

And there we have it, the end of Part One, a short one this week as all the extra fun stuff will be packed in to Part Two, which judging by my draft, will be a tad longer. Thanks again for reading, and stay tuned folks, if I pull my finger out and crack on I’ll have Part Two ready for this time next week.