Many-worlds and Bell’s theorem

Schrodinger's cat in many worlds

Sean Carroll's February AMA episode is up on his podcast. As usual, there were questions about the Everett many-worlds interpretation of quantum mechanics (which I did a new primer on a few weeks ago). This time, there was a question related to the correlated outcomes in measurements of entangled particles that are separated by vast … Continue reading Many-worlds and Bell’s theorem

The entanglements and many worlds of Schrödinger’s cat

I recently had a conversation with someone, spurred by the last post, that led to yet another description of the Everett many-worlds interpretation of quantum mechanics, which I think is worth putting in a post. It approaches the interpretation from a different angle than I've used before. As mentioned last time, the central mystery of … Continue reading The entanglements and many worlds of Schrödinger’s cat

The nature of splitting worlds in the Everett interpretation

Schrodinger's cat in many worlds

This post is about an aspect of the Everett many-worlds interpretation of quantum mechanics. I've given brief primers of the interpretation in earlier posts (see here or here), in case you need one. Sean Carroll, as he does periodically, did an AMA on his podcast. He got a number of questions on the Everett interpretation, … Continue reading The nature of splitting worlds in the Everett interpretation

The rules of time travel?

In a somewhat whimsical podcast episode, Sean Carroll explores the physics and "rules" of time travel. Probably the first two thirds explore the physics. Carroll notes that if time travel under general relativity is at all possible, it would more likely involve a spaceship attempting to navigate some kind of closed timelike curve than stepping … Continue reading The rules of time travel?

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

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

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

Sean Carroll on the Many Worlds Interpretation of quantum mechanics

Related to the post last week on quantum mechanics, here is a talk that got mentioned in the discussion thread.  Warning: Carroll is a passionate advocate for the Many Worlds Interpretation, so don't expect a fair and balanced discussion.  The video is about an  hour long. http://www.youtube.com/watch?v=iXRLDatmbgA A couple of points.  Carroll notes that we … Continue reading Sean Carroll on the Many Worlds Interpretation of quantum mechanics