Category: quantum physics

Yes, Virtual Particles Can Have Real, Observab…

Yes, Virtual Particles Can Have Real, Observable Effects

“Now that the effect of vacuum birefringence has been observed — and by association, the physical impact of the virtual particles in the quantum vacuum — we can attempt to confirm it even further with more precise quantitative measurements. The way to do that is to measure RX J1856.5-3754 in the X-rays, and measuring the polarization of X-ray light.

While we don’t have a space telescope capable of measuring X-ray polarization right now, one of them is in the works: the ESA’s Athena mission. Unlike the ~15% polarization observed by the VLT in the wavelengths it probes, X-rays should be fully polarized, displaying right around an 100% effect. Athena is currently slated for launch in 2028, and could deliver this confirmation for not just one but many neutron stars. It’s another victory for the unintuitive, but undeniably fascinating, quantum Universe.”

If you think about empty space at a quantum level, you’ll find that it isn’t so empty, after all. Due to the inherent effects of quantum uncertainty, particle/antiparticle pairs pop into and out of existence continuously, including electrically charged particles. If you look at the quantum vacuum in the presence of a strong enough external magnetic field, the positive and negative particles, even though they’re only virtual particles, will move differently, and therefore will affect the real particles that pass through them differently than if there were no magnetic field. This leads to a real, observable signal that can be seen in space: around neutron stars! 

Heisenberg first predicted this in 1936, and today, we know it’s true. Get the story of the first observable effect of vacuum birefringence today.

The Quantum Physics That Makes Fireworks Possi…

The Quantum Physics That Makes Fireworks Possible

“Fireworks might appear to be relatively simple explosive devices. Pack a charge into the bottom of a tube to lift the fireworks to the desired height, ignite a fuse of the proper length to reach the burst charge at the peak of its trajectory, explode the burst charge to distribute the stars at a high temperature, and then watch and listen to the show as the sound, light, and color washes over you.

Yet if we look a little deeper, we can understand how quantum physics underlies every single one of these reactions. Add a little bit extra — such as propulsion or fuel inside each star — and your colored lights can spin, rise, or thrust in a random direction. Make sure you enjoy your fourth of July safely, but also armed with the knowledge that empowers you to understand how the most spectacular human-made light show of the year truly works!”

Fireworks have been around for more than a millennium, and universally contain the same four stages: a lift charge, a fuse, a burst charge, and stars. Yet even though we don’t particularly think about it frequently, quantum physics underlies each and every one of these stages, and is absolutely required if we want to understand how the light and color we see arises from simply heating/igniting different elements, ions, and chemical compounds.

Come celebrate the Fourth of July with a little science knowledge about fireworks, no matter where in the world you’re located!

What Is The Smallest Possible Distance In The …

What Is The Smallest Possible Distance In The Universe?

“At present, there is no way to predict what’s going to happen on distance scales that are smaller than about 10-35 meters, nor on timescales that are smaller than about 10-43 seconds. These values are set by the fundamental constants that govern our Universe. In the context of General Relativity and quantum physics, we can go no farther than these limits without getting nonsense out of our equations in return for our troubles.

It may yet be the case that a quantum theory of gravity will reveal properties of our Universe beyond these limits, or that some fundamental paradigm shifts concerning the nature of space and time could show us a new path forward. If we base our calculations on what we know today, however, there’s no way to go below the Planck scale in terms of distance or time. There may be a revolution coming on this front, but the signposts have yet to show us where it will occur.”

If you went down to smaller and smaller distance scales, you might imagine that you’ll start to see the Universe more clearly and in higher resolution. You’ll be able to hone in on the fundamental properties of nature, and glean more information the deeper you go. This is true, but only up to a point. Beyond that, you start running into the inescapable quantum rules that govern the Universe, and that means there’s a fundamental scale at which our best laws of physics cannot be trusted any longer.

That scale is the Planck scale, and for distances, it corresponds to about 10^-35 meters. It really is a problem for physics, and it’s high time you understood why.

Could An Incompleteness In Quantum Mechanics L…

Could An Incompleteness In Quantum Mechanics Lead To Our Next Scientific Revolution?

“But in the quantum Universe, this notion of relativistic causality isn’t as straightforward or universal as it would seem. There are many properties that a particle can have — such as its spin or polarization — that are fundamentally indeterminate until you make a measurement. Prior to observing the particle, or interacting with it in such a way that it’s forced to be in either one state or the other, it’s actually in a superposition of all possible outcomes.

Well, you can also take two quantum particles and entangle them, so that these very same quantum properties are linked between the two entangled particles. Whenever you interact with one member of the entangled pair, you not only gain information about which particular state it’s in, but also information about its entangled partner.”

One of the most important ideas in classical physics are those of locality and causality: that objects in close proximity can affect one another through the forces they exert on one another, which are limited by the speed of light. But quantum mechanics turns much of that on its head, where locality doesn’t appear to be a fundamental property of reality at all. Yet one of the most remarkable ideas of all out there conjectures that quantum gravity, which contains fundamental non-localities, could be described by variables that completely explain what we view as non-locality in standard quantum physics.

Could this be right? Lee Smolin is giving a talk on that today, and I’ll be live-blogging it as it happens. Don’t miss this one-of-a-kind event!

Could An Incompleteness In Quantum Mechanics L…

Could An Incompleteness In Quantum Mechanics Lead To Our Next Scientific Revolution?

“But in the quantum Universe, this notion of relativistic causality isn’t as straightforward or universal as it would seem. There are many properties that a particle can have — such as its spin or polarization — that are fundamentally indeterminate until you make a measurement. Prior to observing the particle, or interacting with it in such a way that it’s forced to be in either one state or the other, it’s actually in a superposition of all possible outcomes.

Well, you can also take two quantum particles and entangle them, so that these very same quantum properties are linked between the two entangled particles. Whenever you interact with one member of the entangled pair, you not only gain information about which particular state it’s in, but also information about its entangled partner.”

One of the most important ideas in classical physics are those of locality and causality: that objects in close proximity can affect one another through the forces they exert on one another, which are limited by the speed of light. But quantum mechanics turns much of that on its head, where locality doesn’t appear to be a fundamental property of reality at all. Yet one of the most remarkable ideas of all out there conjectures that quantum gravity, which contains fundamental non-localities, could be described by variables that completely explain what we view as non-locality in standard quantum physics.

Could this be right? Lee Smolin is giving a talk on that today, and I’ll be live-blogging it as it happens. Don’t miss this one-of-a-kind event!

No, Quantum Tunneling Didn’t Break The S…

No, Quantum Tunneling Didn’t Break The Speed Of Light; Nothing Does

“You might think, based on what you just read about the speed of quantum tunneling being instantaneous, that this means that particles can travel infinitely fast, breaking the speed of light, through a quantum mechanical barrier of finite, non-zero thickness. That’s the misinterpretation that always crops up, and how people fool themselves (and unscrupulous news organizations try to fool you) into thinking they’re breaking the speed of light.

But all that’s happening here is a portion of the quantum particles found in the pulse tunnels through the barrier, while the majority of the particles does what tennis balls do: they bounce back, failing to arrive at the destination. If you can front-load which particles make it through the barrier, preferentially cutting off the particles in the back of the pulse, you’ll falsely measure a faster-than-light speed, even though no individual particle actually breaks the speed of light.”

For the first time, researchers have measured what the speed of quantum tunneling is, and found that it was consistent with an instantaneous transition. If you’re in a quantum configuration that keeps you bound, or on one side of a barrier, tunneling can enable you to become unbound, or arrive on the other side of the barrier. But that doesn’t mean you can physically travel a finite distance through that barrier instantaneously, or faster-than-light. You can’t.

Here’s the real story, with an extra bonus of how this story (and ones like it) get mis-reported all the time.

Regular

inthenoosphere:

“Everything we call real is made of things that cannot be regarded as real.”

— Niels Bohr

Regular

inthenoosphere:

“Everything we call real is made of things that cannot be regarded as real.”

— Niels Bohr

The Sun Wouldn’t Shine Without Quantum P…

The Sun Wouldn’t Shine Without Quantum Physics

“If it weren’t for the quantum nature of every particle in the Universe, and the fact that their positions are described by wavefunctions with an inherent quantum uncertainty to their position, this overlap that enables nuclear fusion to occur would never have happened. The overwhelming majority of today’s stars in the Universe would never have ignited, including our own. Rather than a world and a sky alight with the nuclear fires burning across the cosmos, our Universe would be desolate and frozen, with the vast majority of stars and solar systems unlit by anything other than a cold, rare, distant starlight.

It’s the power of quantum mechanics that allows the Sun to shine. In a fundamental way, if God didn’t play dice with the Universe, we’d never win the Powerball three times in a row. Yet with this randomness, we win all the time, to the continuous tune of hundreds of Yottawatts of power, and here we are.”

In the core of our Sun, where temperatures cross the threshold of 4 million K (and rise all the way up to 15 million K), nuclear fusion occurs, driving the energy output of our Sun. Yet if you looked at what was going on at a particle level, that first step towards fusion is where two protons collide to form a deuteron. Only, there are two immediate problems: a deuteron is made out of a proton and neutron, not two protons, and that the two protons don’t even have enough energy to overcome the electrostatic repulsion between them! Thankfully, the Universe is quantum in nature, meaning weak interactions do occur, changing a quark’s flavor type, and particle positions are defined by quantum wavefunctions, which can overlap.

In a very real way, it’s the power of quantum physics that enables the Sun to shine. This is the story of how.

Regular