Ask Ethan: Where Does Quantum Uncertainty Come From? (Synopsis)

"In the future, maybe quantum mechanics will teach us something equally chilling about exactly how we exist from moment to moment of what we like to think of as time." -Richard K. Morgan

It’s absolutely true that, in quantum mechanics, there are certain pairs of properties that we simply can’t measure simultaneously. Measure the position of an object really well, and its momentum becomes more uncertain. Measure its energy, and its time becomes more uncertain. And measure its voltage, and the free charge becomes more uncertain. Although this is disconcerting to some, it’s a fundamental part of the quantum nature of the Universe.

An illustration between the inherent uncertainty between position and momentum at the quantum level. Image credit: E. Siegel / Wikimedia Commons user Maschen.

But there’s also more to it than that! Not only are pairs inherently uncertain, but each component has some built-in uncertainty that you can never take away. Moreover, it arises from a simple fact that isn’t true classically: the order of operations -- whether you measure position or momentum first -- makes a fundamental difference in what you get out. This quantum commutation relation is where so much of the fundamental quantum weirdness in our Universe comes from.

A modern high field clinical MRI scanner. MRI machines are the largest medical or scientific use of helium today, and make use of quantum transitions in subatomic particles. Image credit: Wikimedia Commons user KasugaHuang.

It’s also why we have technologies like atomic clocks, hydrogen masers, and MRI machines! Come find out where quantum uncertainty arises from, and why it matters, on this week’s Ask Ethan!


More like this

“Oh Beautiful for smoggy skies, insecticided grain, For strip-mined mountain's majesty above the asphalt plain. America, America, man sheds his waste on thee, And hides the pines with billboard signs, from sea to oily sea.” -George Carlin When you think of helium, you very likely think of balloons…
"For the first time, astronomers have outlined and named the network of galaxies that includes the Milky Way, adding a line to our cosmic address and further defining our place in the universe." -Douglas Quenqua There’s been a longstanding puzzle in astrophysics that’s finally coming to a head. For…
In chapter 2 of How to Teach Physics to Your Dog, there's a footnote about the ubiquity of uncertainty principle analogies in the mass media: To give you an idea of the breadth of subjects in which this shows up, in June 2008, Google turned up citations of the Heisenberg Uncertainty Principle in (…
It's been a while since I did a "Basic Concepts" post. They tend to take a good bit of effort, and things have been hectic enough at work that I haven't had the energy. To make up for the blizzard of basketball-related stuff over the last week (with more to come), here's a look at the concept of…

Cool to see the QCD animation of how particle/antiparticle pairs pop up, how connected 'holes' show up and how the Vacuum starts to be shake up. Curious if these tremblings differ very much from Gravity waves?!

By Elle H.C. (not verified) on 12 Aug 2017 #permalink

Uncertainty is a principle to live by

Voltage and charge have a different product from the others?

This is news to me.

By D. C. Sessions (not verified) on 12 Aug 2017 #permalink