Ars Technica’s series on quantum mechanics: How big is a particle?

A couple of weeks ago, I shared Ars Technica's first article in a series on quantum mechanics that promised to be math and philosophy free. So far, the author, Miguel Morales, has stuck to that promise. Today he published the third installment. This one focuses on the size of particle, and why that's far from … Continue reading Ars Technica’s series on quantum mechanics: How big is a particle?

Ars Technica has a new series on quantum mechanics (no math)

Miguel Morales at Ars Technica is beginning a new introductory guide on quantum mechanics, one he promises won't require any math. If you've watched some of us wrangle over the implications of QM and wondered just what the heck we were so worked up about, this looks like it will be a good series for … Continue reading Ars Technica has a new series on quantum mechanics (no math)

Mea culpa on quantum decoherence

Lately, I've been trying to gain a better understanding of quantum decoherence. This is the process of a quantum system in superposition interacting with the environment and, as a result, appearing to lose its quantum nature, notably by having interference between the elements of its superposition become undetectable. Decoherence is often used synonymously with the … Continue reading Mea culpa on quantum decoherence

The nature of quantum nonlocality

Quantum physics has been on my mind again lately, somewhat triggered by a recent conversation with Wyrd Smythe on his blog. I've always known quantum nonlocality has nuances, but stuff I read this week revealed some wrinkles I wasn't aware of. (Well, I was aware of them, but wasn't aware they pertained to nonlocality.) A … Continue reading The nature of quantum nonlocality

A PBS Space Time series on time and the block universe

Somewhat related to the previous post, I just saw this video from Matt O'Dowd discussing why the block universe is such a compelling concept. https://www.youtube.com/watch?v=EagNUvNfsUI&t=12s The second video in the series discusses the effect quantum mechanics might have on this concept. It reminds me why cosmologists seem to be more comfortable with the Many Worlds … Continue reading A PBS Space Time series on time and the block universe

Thoughts about quantum computing and the wave function

Qubit bloch sphere

The main difference between a quantum computer and a classical one is the qubit. Qubits are like classical bits, in that they hold binary values of either 1 or 0, on or off, true or false, etc. However, qubits, being quantum objects, can be in a superposition of both states at once. The physical manifestation … Continue reading Thoughts about quantum computing and the wave function

David Deutsch’s version of many worlds

Schrodinger's cat in many worlds

I've written about the bizarre nature of quantum physics many times, providing a lightning primer back in May on three major interpretations: Copenhagen, pilot-wave, and many worlds.  The many worlds interpretation (MWI) is often summarily dismissed by people, often along with visceral shudders or high doses of outrage.  I understand the discomfort.  When I first … Continue reading David Deutsch’s version of many worlds

The measurement problem, Copenhagen, pilot-wave, and many worlds

With quantum physics, we have a situation where a quantum object, such as a photon, electron, atom or similar scale entity, acts like a wave, spreading out in a superposition, until we look at it (by measuring it in some manner), then it behaves like a particle.  This is known as the measurement problem. Now, … Continue reading The measurement problem, Copenhagen, pilot-wave, and many worlds

Is entanglement decoherence from the outside, and decoherence entanglement from the inside?

A recent tweet by Sean Carroll has me thinking. https://twitter.com/seanmcarroll/status/1204128666273271808 Quantum decoherence is said to occur when a particular quantum system becomes entangled with its environment, that is to say, as information about the quantum system spreads throughout the environment, that system undergoes at least an apparent wave function collapse.  It stops behaving like a … Continue reading Is entanglement decoherence from the outside, and decoherence entanglement from the inside?