The Worst Prediction in Physics History? Dark Energy and the Vacuum Catastrophe

Physics Explained March 22, 2021
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Physics Explained is a channel that explores advanced topics in physics without skimping on the mathematical detail. There is a growing community of independent learners who are keen to explore modern ideas in physics with the aid of mathematical reasoning. This channel aims to tackle advanced topics head on whilst at the same time providing a historical narrative to help provide context to the ideas. A bit about my educational background: I have a PhD in theoretical physics, specialising in string theory. I now dedicate most of my my time to physics education. You can help support this channel via the Physics Explained Patreon account: https://www.patreon.com/physicsexplained

Video Description

In this video I would like to discuss one of the great unsolved problems in fundamental physics, the famous vacuum energy catastrophe (also known as the cosmological constant problem). What makes the problem so fascinating is that it weaves together two of the most successful theories of the 21st century, quantum field theory and general relativity, and demonstrates that something has gone catastrophically wrong in our attempt to understand the origin of our expanding universe. The reason that we know something has gone horribly wrong is because our most successful theory of physics predicts that the universe should be doubling in size every millionth of a trillionth of a trillionth of a trillionth of a second! But this is clearly not happening. In fact, our best experimental observations suggest that the universe is in fact doubling in size every ten billion years. So what has gone wrong? And why? In order to answer this question we are going to need to take a journey through some of the most exciting ideas in modern physics, from the smallest quantum fluctuations of the vacuum, to the mysterious dark energy which is driving the accelerated expansion of the universe. References: Introduction to Cosmology - Ian Morrison A Universe from Nothing - Lawrence Krauss Introduction to Cosmology - M.Pettini Introduction to Cosmology - Matts Roos Introduction to Cosmology - Barbara Ryden Lecture on Vacuum Energy - Leonard Susskind YouTube (https://www.youtube.com/watch?v=GgKGPyFL-TM) Introduction to Cosmology - University of Ohio Lecture notes (https://www.astronomy.ohio-state.edu/weinberg.21/A5682/index.html) The picture of our universe: a view from modern cosmology - Reid, Kittell, Arsznov, Thompson (https://arxiv.org/pdf/astro-ph/0209504.pdf) The Cosmological Constant Problem and (no) solutions to it - Wolfgang Hollick () The Cosmological constant problem (https://scipp.ucsc.edu/~haber/ph171/CosmoConstant15.pdf) Estimating the vacuum energy density - Erik Margan (https://www-f9.ijs.si/~margan/Articles/vacuum_energy_density.pdf) You can help support this channel via the Physics Explained Patreon account: https://www.patreon.com/physicsexplained You can follow me on instagram: https://www.instagram.com/physics_explained_ig You can follow me on Twitter: https://twitter.com/PhysicsExplain1