The Many Hidden Worlds of Quantum Mechanics

Fasten your seat belts and take off into the realm of multiple, maybe even infinite, worlds. Professor Carroll explains how quantum mechanics predicts the existence of a large numb...

Investigate the classical picture of reality, which is how physicists thought the world worked before quantum mechanics. Codified by Isaac Newton, classical physics evolved into a...

The widely accepted system of classical physics began to unravel in 1900 when Max Planck proposed an idea that later became known as the quantum. Elaborated by Einstein, this theor...

Transition from the old quantum theory to full-fledged quantum mechanics with the mathematically elegant concept of the wave function, derived by Erwin Schrödinger in 1925. Profess...

Quantum mechanics was disquieting to anyone trained in classical physics. To dispel this unease, Niels Bohr and Werner Heisenberg devised the "Copenhagen Interpretation." Delve int...

Consider exactly what Heisenberg meant by his uncertainty principle, which is often misstated, even by physicists. Go deeper into wave-particle duality, studying the famous double-...

Explore the fundamental quantum property of particles known as "spin," which can come in binary states, like the 0 and 1 bits in digital computing. For the purposes of quantum comp...

Focus on Einstein's objection to a specific feature of quantum mechanics called entanglement, which he termed, "spooky action at a distance." When two particles are entangled, no m...

Use concepts developed in the course so far to learn how physicist Hugh Everett arrived at a bold new approach to quantum mechanics. Called the Many-Worlds Interpretation, it holds...

Focus on decoherence, which does the same work in Many-Worlds as the collapse of the wave function in the Copenhagen Interpretation. Both explain what happens when a measurement is...

Many-Worlds theorist David Deutsch helped pioneer quantum computing, which he argues is an outgrowth on the Many-Worlds Interpretation. Investigate the principles behind quantum co...

The Many-Worlds view seems to defy common sense. Why can't we see the other worlds? And don't they violate the laws of physics and other rules of nature? Professor Carroll answers...

Address another objection to the Many-Worlds Interpretation: its testability. This refers to philosopher Karl Popper's famous falsifiability criterion, which discounts any theory t...

Yet another hurdle for Many-Worlds is the origin and nature of probability. The Copenhagen version of quantum mechanics is fundamentally probabilistic, rather than deterministic. T...

Given the mind-boggling implications of Many-Worlds, many physicists have sought plausible alternatives. In this lecture, consider the possibility of altering the Schrödinger equat...

Does the wave function tell the whole story? Explore the hidden variable theory, devised by Louis de Broglie and refined by David Bohm. According to this view, particles are guided...

Since quantum mechanics and consciousness are both mysterious, could they be connected in some way? Examine several arguments that relate quantum phenomena to the involvement of co...

How does the structure of observed reality emerge from the wave function in Many-Worlds? In other words, where do the worlds come from? This question relates to the "preferred basi...

Quantum theory accounts for a remarkable array of particles and forces-but not gravity. Learn why constructing a successful theory of quantum gravity has vexed physicists for nearl...

Starting with the basic ingredients of quantum theory-wave functions, Schrödinger's equation, and entanglement-and following the Many-Worlds approach, probe this question: What cir...

As space might be an emergent property of quantum entanglement, could the same be true of time? Divide a wave function into subsystems and watch how the rest of the universe become...

Get philosophical by probing a pair of profound questions that arise from the far-out implications of Many-Worlds. Are multiple branching worlds caused by our decisions? Is human f...

A theory in which every moral act entails an immoral one taking place in a branching universe is rife with ethical quandaries. Now, consider whether you could be moral in each of t...

Many-Worlds and competing theories on the foundations of quantum mechanics may seem essential for our understanding of reality, but they were long ignored by no-nonsense practicing...