Tag: quantum mechanics

We often think of quantum mechanics as only affecting only the smallest scales of reality, with classical reality taking over at some intermediate level. But in his 1944 book, What is Life?, the quantum physicist Erwin Schrödinger suggested that “incredibly small groups of atoms, much too small to display exact statistical laws, do play a dominating role in the very orderly and lawful events within a living organism.” Schrodinger was a visionary – and perhaps very specifically in this case. Because it turns out we might need all the weirdness of quantum mechanics to explain birds

Brian Greene explains the basic idea of String Theory in under 3 minutes.

This video outlines virtual particles, quantum teleportation, Schrödinger’s cat theory, quantum entanglement and the sun re photons and quantum energy.

While you might not think about quantum mechanics being part of your everyday life, it turns out that it might play a role in some of the most familiar things, from the sunlight in the trees to the nose on your face!

I try to teach my wife (biologist) about the basics of quantum mechanics: wave functions, Schrodinger’s equation, superpositions, and the measurement problem.

Back in 2015, the two detectors that make up the experiment called LIGO detected gravitational waves generated by two merging black holes. And now, some researchers believe they can build instruments that can detect gravitational waves even LIGO can’t see — instruments that would be small enough to fit on a table top.

Though the device is yet to be built, researchers believe a device like this that’s as small as 1 meter long could reveal low frequency gravitational waves. The proposed device would use nanoscale diamonds with defects, called nitrogen-vacancy centers or NV centers.

Find out more about how this new tech will work and how it might help us study the quantum character of gravity in this Elements.

Ever heard of the term “wave function” in relation to quantum mechanics? What does it mean? How is it interpreted?

Hey everyone, I’m back with a new video! This time, we’re going back to basics and understanding exactly what a wave function is, as well as what it represents, in the world of quantum physics. This video is going to be the first in a series I’m going to call “Quantum Mechanics… But Quickly”. In this series, I want to discuss some fundamental quantum concepts, and explain them in as visual and intuitive a way as possible – without having to sit through an hour long lecture, or understanding complicated graduate level mathematics.

A physicist named Louis de Broglie once suggested something amazing. While scientists were busy debating whether light was a wave or a particle, de Broglie suggested that even matter – things with mass (e.g. electrons, protons, atoms, etc.) – could behave like waves. This idea was revolutionary due to the mountains of evidence scientists had up until that point that matter behaved like particles. However, the quantum world was soon to revolutionise everything we thought we knew about the universe. And as it turns out, de Broglie’s suggestion was right.

His suggestion of matter waves permeated into the work of Erwin Schrodinger. Combining the idea of matter waves with the principle of Conservation of Energy, Schrodinger came up with the equation we now know as the Schrodinger Equation. This ended up being the governing equation of quantum mechanics, and crucially contained a function known as the wave function. This wave function contained mathematical information about any quantum system we happened to be studying.

The key question, then, was about what the wave function actually related to. What did it correspond to in real life? How should we interpret it? Well, there are a few different interpretations of quantum mechanics and how it relates to our real-life universe. The most commonly accepted one is the Copenhagen interpretation. And this interpretation suggests that a wave function is directly related to the probability distribution of a system. Specifically, if we take a system’s wave function and square it (well, technically if we take its square modulus), then this will give us the probabilities of various results occurring when we make a measurement on a system. For example, the wave function of a system could tell us the probability of finding a particle at a certain position in space. Or it could tell us the probabilities of finding different spin states when measuring the spin of an electron, for example.

In this video, we discuss these examples in detail. Additionally, we briefly look at the consequences of wave functions having imaginary parts. Lastly, we look at how the Schrodinger Equation (or at least the time dependent Schrodinger Equation) governs how a wave function changes over time – apart from when we make a measurement on the system. This measurement causes a discontinuous and jarring change in the wave function, known as the “collapse of the wave function”. This collapse has caused many philosophical problems for physicists over the years, and it continues to do so to this day.

A quantum internet is in the works. The U.S. Department of Energy recently rolled out a blueprint describing research goals and engineering barriers on the way to quantum internet. The DOE’s latest blueprint for a quantum internet in the U.S. has four key milestones. The first is to make sure quantum information sent over current fiber optic cables is secure. Then to establish entangled networks across colleges or cities, then throughout states, and finally for the whole country. But what exactly is quantum internet? There is no real clear meaning beyond “sending quantum signals back and forth,” and there are a few ways to go about doing it. In February 2020, the Department of Energy announced they had sent two entangled photons over two separate 42 kilometer fiber optic loops and had verified they were still correlated when they returned. They hailed it as a milestone on the way to developing a national quantum internet.