Category: quantum

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.

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Friend: Is your cat alive?

Schrödinger:

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.

Ask Ethan: What Is An Electron?

“Please will you describe the electron… explaining what it is, and why it moves the way it does when it interacts with a positron. If you’d also like to explain why it moves the way that it does in an electric field, a magnetic field, and a gravitational field, that would be nice. An explanation of charge would be nice too, and an explanation of why the electron has mass.”

When we, as physicists, speak about fundamental particles, we refer to the smallest constituents of matter and energy that cannot be divided any farther. There are two classes of such particles, fermions (which can be matter or antimatter) and bosons (which are neither), and they behave in rather unintuitive ways, since they’re quantum in nature. But even though there are many properties of quantum particles that are inherently uncertain, there are some that are intrinsic and perfectly well-known. These are the properties that define each type of particle and allow us to discern them from all others.

Here is, to the best of our knowledge, what the electron truly is, along with some fundamental questions we still have yet to answer about them!

Ask Ethan: What Is An Electron?

“Please will you describe the electron… explaining what it is, and why it moves the way it does when it interacts with a positron. If you’d also like to explain why it moves the way that it does in an electric field, a magnetic field, and a gravitational field, that would be nice. An explanation of charge would be nice too, and an explanation of why the electron has mass.”

When we, as physicists, speak about fundamental particles, we refer to the smallest constituents of matter and energy that cannot be divided any farther. There are two classes of such particles, fermions (which can be matter or antimatter) and bosons (which are neither), and they behave in rather unintuitive ways, since they’re quantum in nature. But even though there are many properties of quantum particles that are inherently uncertain, there are some that are intrinsic and perfectly well-known. These are the properties that define each type of particle and allow us to discern them from all others.

Here is, to the best of our knowledge, what the electron truly is, along with some fundamental questions we still have yet to answer about them!

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.