All Segments
Sean Carroll: Many-Worlds Interpretation of Quantum Mechanics
8 segments available
This is a clip from a conversation with Sean Carroll from Nov 2019. Check out Sean's new book on quantum mechanics titled Something Deeply Hidden: https://amzn.to/2C6aCaf New full episodes are released once or twice a week and 1-2 new clips or a new non-podcast video is released on all other days. You can watch the full conversation here: https://www.youtube.com/watch?v=iNqqOLscOBY (more links below) Podcast full episodes playlist: https://www.youtube.com/playlist?list=PLrAXtmErZgOdP_8GztsuKi9nrraNbKKp4 Podcasts clips playlist: https://www.youtube.com/playlist?list=PLrAXtmErZgOeciFP3CBCIEElOJeitOr41 Podcast website: https://lexfridman.com/ai Podcast on Apple Podcasts (iTunes): https://apple.co/2lwqZIr Podcast on Spotify: https://spoti.fi/2nEwCF8 Podcast RSS: https://lexfridman.com/category/ai/feed/ Note: I select clips with insights from these much longer conversation with the hope of helping make these ideas more accessible and discoverable. Ultimately, this podcast is a small side hobby for me with the goal of sharing and discussing ideas. I did a poll and 92% of people either liked or loved the posting of daily clips, 2% were indifferent, and 6% hated it, some suggesting that I post them on a separate YouTube channel. I hear the 6% and partially agree, so am torn about the whole thing. I tried creating a separate clips channel but the YouTube algorithm makes it very difficult for that channel to grow. So for a little while, I'll keep posting clips on this channel. I ask for your patience and to see these clips as supporting the dissemination of knowledge contained in nuanced discussion. If you enjoy it, consider subscribing, sharing, and commenting. Sean Carroll is a theoretical physicist at Caltech and Santa Fe Institute specializing in quantum mechanics, arrow of time, cosmology, and gravitation. He is the author of several popular books and is a host of a great podcast called Mindscape. Subscribe to this YouTube channel or connect on: - Twitter: https://twitter.com/lexfridman - LinkedIn: https://www.linkedin.com/in/lexfridman - Facebook: https://www.facebook.com/lexfridman - Instagram: https://www.instagram.com/lexfridman - Medium: https://medium.com/@lexfridman - Support on Patreon: https://www.patreon.com/lexfridman
Segments Timeline
The Observer's Role in Quantum Mechanics
Sean Carroll discusses the philosophical implications of quantum mechanics, particularly the distinction between what is observed and what is real. He expresses skepticism about the fundamental role of observers in the laws of physics, suggesting that while measurement seems important in textbook interpretations, better interpretations like the many-worlds interpretation provide a more coherent understanding.
"so coming back to the textbook definition of quantum mechanics this idea that we I don't think we talked about can you this one of the most interesting philosophical points we talked at the human leve..."
Many-Worlds Interpretation Explained
Carroll elaborates on the many-worlds interpretation of quantum mechanics, explaining that observers are quantum systems themselves and that measurement leads to entanglement rather than collapse. He describes how this interpretation, proposed by Hugh Everett III, simplifies the understanding of quantum mechanics by suggesting that all possible outcomes exist in separate, non-interacting worlds.
"possibility so what do you do about the fact that in the textbook interpretation of quantum mechanics this idea of measurement or looking at things seems to play an important role well you you come up..."
The Nature of Quantum Worlds
In this segment, Carroll explores the implications of the many-worlds interpretation regarding the number of worlds created during quantum events. He discusses the finite dimensionality of Hilbert space and how the universe's expansion might limit the number of distinct worlds, emphasizing the vastness of possibilities within quantum mechanics.
"just he did therapy more than anything else you know he said like it's okay you know you don't need all these extra rules all you need to do is believe the Schrodinger equation the cost is there's a w..."
Understanding Quantum Branching
Carroll addresses the concept of branching in the many-worlds interpretation, explaining how the universe splits rather than duplicates during quantum events. He clarifies that this perspective avoids concerns about energy conservation, framing the universe's branching as a natural consequence of quantum mechanics rather than a violation of physical laws.
"just a very very big number in one of their talk somebody asked well if it's a if it's finite so actually I'm not sure exactly the logic you used to derive this but is there you know going to be a you..."
Controversies in Quantum Mechanics
Sean Carroll discusses the controversies surrounding the many-worlds interpretation of quantum mechanics. He highlights the distinction between simplicity in theory and the challenges of mapping that theory onto reality, noting that many physicists prefer interpretations that align more closely with observable phenomena.
"horizon approaches some fixed distance away from us and you can then argue that within that horizon there's only a finite number of things that can possibly happen the finite dimensional hilbert space..."
Exploring Alternative Interpretations
In this segment, Carroll outlines various alternative interpretations of quantum mechanics, including hidden variable theories and spontaneous collapse theories. He contrasts these with the many-worlds interpretation, noting that while they may be more complex, they often resonate more with our direct experiences of reality.
"copies of the world or splitting I think it's better to think of in quantum mechanics in many worlds the universe splits rather than new copies because people otherwise worry about things like energy ..."
The Debate on Quantum Reality
Carroll delves into the ongoing debate about the nature of the wave function in quantum mechanics, discussing epistemic versus ontological interpretations. He emphasizes the importance of understanding what the wave function represents and how different interpretations can lead to varying conclusions about reality.
"words to the underlying mathematics so one of my favorite things about many worlds is I mean I love that there's something controversial in science and for some reason it makes people actually not lik..."
The Simplicity of Many-Worlds
Sean Carroll articulates why he finds the many-worlds interpretation compelling, citing its simplicity and lack of classical baggage. He argues that it allows for a more straightforward application of quantum mechanics to modern physics, particularly in understanding complex phenomena like gravity and space-time.
"in fact all of the work in sort of elaborating many-worlds quantum mechanics is in the this effort to map it on to the world that we see so it's perfectly legitimate to be bugged by that right to say ..."