Category: quantum physics

No, We Still Can’t Use Quantum Entanglement To Communicate Faster Than Light

“There’s an awful lot that you can do by leveraging the bizarre physics of quantum entanglement, such as by creating a quantum lock-and-key system that’s virtually unbreakable with purely classical computations. But the fact that you cannot copy or clone a quantum state — as the act of merely reading the state fundamentally changes it — is the nail-in-the-coffin of any workable scheme to achieve faster-than-light communication with quantum entanglement.

There are a lot of subtleties associated with how quantum entanglement actually works in practice, but the key takeaway is this: there is no measurement procedure you can undertake to force a particular outcome while maintaining the entanglement between particles. The result of any quantum measurement is unavoidably random, negating this possibility. As it turns out, God really does play dice with the Universe, and that’s a good thing. No information can be sent faster-than-light, allowing causality to still be maintained for our Universe.”

You might think that if you have two entangled quantum particles, you can separate them by a large distance, make an observation of some physical property at one location, measure your member of the entangled pair, and use that existing entanglement to send information about what you observed instantaneously to anywhere in the Universe. It’s a brilliant and clever idea, and it turns out it’s absolutely forbidden by the laws of physics.

What’s really going on with quantum entanglement, and why can’t it send information faster than light? Find out today.

No, Scientists Will Never Be Able To Remove The Empty Space From Atoms

“It might be a delightful science fiction dream to remove the empty space from atoms, decreasing the volume that matter occupies by factors of millions, trillions or even more. However, it isn’t that the electrons orbiting the nucleus inherently occupy an extremely large volume of space, but rather that the quantum properties inherent to particles — masses, charges, interaction strength, and quantum uncertainty — all combine to create the atoms that exist in our Universe.

Even if we had a stable, heavier counterpart of the electron, or the ability to compress matter to arbitrarily dense states, we’d run into a quantum threshold where the atomic nuclei at the centers of atoms would spontaneously fuse, preventing stable configurations of multiple atoms from existing at all. The fact that our atoms are mostly empty space permits the existence of molecules, chemistry, and life.

Removing the empty space from atoms might be a fun thought experiment, but atoms are the size they are because of the rules of the Universe. Our existence is dependent on that empty space being present, but with the constants of nature having the values they do, don’t worry. It cannot be any other way.”

What you’ve heard is true: atoms really are mostly empty space. Ever since that discovery more than a century ago, people have imagined what it might be like if it were possible to remove the empty space from these atoms, and what sort of interesting things we’d be able to create if we could do so. As it turns out, though, there are good fundamental reasons why the empty space can’t be removed, and dire consequences we face when we try the only two things we can think of.

Come learn the science of why we’ll never be able to remove the empty space from atoms.

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

Niels Bohr

mysteriousquantumphysics:

“What we observe as material bodies and forces are nothing but shapes and variations in the structure of space.”

— Erwin Schrödinger (via mysteriousquantumphysics)

This One Experiment Reveals More About Reality Than Any Quantum Interpretation Ever Will

“So you fire a beam of electrons at a barrier with two slits in it, and look at where the electrons arrive on the screen behind it. Although you might have expected the same result you got for the pebble-experiment earlier, you don’t get it. Instead, the electrons distinctly and unambiguously leave an interference pattern on the screen. Somehow, the electrons are acting like waves.

What’s going on? Are these electrons interfering with each other? To find out, we can change the experiment again; instead of firing a beam of electrons, we can send one electron through at a time. And then another. And then another. And then another, until we’ve sent thousands or even millions of electrons through. When we finally look at the screen, what do we see? The same interference pattern. Not only are the electrons acting like waves, but each individual electron behaves as a wave, and somehow manages to create an interference pattern only by interacting with itself.”

It’s been around for more than 200 years, but the double-slit experiment remains one of the best concrete ways to probe the quantum nature of reality. By tinkering with the apparatus and how it’s set up, you can determine how nature behaves under a wide variety of conditions, and wow, is it ever surprising and unintuitive. Instead of arguing over unanswerables like which philosophical interpretation is most pleasing, why not look at something real? 

These are the questions we’re actually answering, and you won’t find anything more profound than the answers that nature provides us with.

Can We Test Gravitational Waves For Wave-Particle Duality?

“Although we have every reason to believe that gravitational waves are simply the quantum analog of electromagnetic waves, we have, unlike the electromagnetic photon, not yet risen to the technological challenges of directly detecting the gravitational particle that’s the counterpart of gravitational waves: the graviton.

Theorists are still calculating the uniquely quantum effects that should arise and are working together with experimentalists to design tabletop tests of quantum gravity, all while gravitational wave astronomers puzzle over how a future-generation detector might some day reveal the quantum nature of these waves. Although we expect gravitational waves to exhibit wave-particle duality, until we detect it, we cannot know for certain. Here’s hoping that our curiosity compels us to invest in it, that nature cooperates, and that we find out the answer once and for all!”

One of the revolutionary discoveries of the quantum world was that every particle that we know of also behaves as a wave. Photons are the quanta associated with light, and every light wave is made up of a discrete number of photons. Particles like electrons also can behave as waves; if you send them through a double slit, even one-at-a-time, they’ll produce an interference pattern.

So what about gravitational waves? We’ve seen the wave part; could we ever test them for the “particle” part of that? Find out today!

This Is Why Two Higgs Bosons Don’t Have The Same Mass As One Another

“In this quantum Universe, every particle will have properties that are inherently uncertain, as many of the measurable properties are changed by the act of measurement itself, even if you measure a property other than the one you wish to know. While we might talk about photon or electron uncertainties most commonly, some particles are also unstable, which means their lifetime is not pre-determined from the moment of their creation. For those classes of particles, their inherent energy, and therefore their mass, is inherently variable, too.

While we might be able to state the mass of the average unstable particle of a particular variety, like the Higgs boson or the top quark, each individual particle of that type will have its own, unique value. Quantum uncertainty can now be convincingly extended all the way to the rest energy of an unstable, fundamental particle. In a quantum Universe, even a property as basic as mass itself can never be set in stone.”

Create an electron, and there will be a certain set of properties that you’ll know for certain, irrespective of any quantum uncertainty. You’ll know its mass, its electric charge, its intrinsic angular momentum, and many other properties as well. But that’s because the electron itself is a fundamentally stable particle: it’s lifetime is infinite, with no uncertainty. This isn’t true for many of the particles of the Standard Model, though, with the heaviest particles like the Higgs boson, the W and Z bosons, and the top quark having the shortest lifetime. Well, there’s also an energy-time uncertainty relation, and that means that the shorter your lifetime is, the bigger your inherent uncertainty in your energy is. Now, combine that with the knowledge that E = mc^2, and what do you get? 

An inherently uncertain mass. Yes, it’s true: every top quark you create has a unique mass that’s different from every other top quark. Come find out the science behind this remarkable property of nature!

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 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 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.