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10 videos · 4 h 42 min
Explainer · YouTube
Looking Glass Universe
A short, careful argument for why entangled particles cannot carry messages, using the same Alice-and-Bob setup as Part 5. The video speaks of the particles 'affecting' each other; treat that as one way of talking (Part 5 explains why it is interpretation-dependent) and focus on the proof that Bob's results stay random.
Explainer · YouTube
Looking Glass Universe
Mithuna Yoganathan, who did her PhD in quantum computing, takes a quarter of an hour over the question in the title. Use it as a gentle second pass, then test what you heard against this section's central puzzle: the pair has a complete description while neither particle has a state of its own.
Explainer · YouTube
Sabine Hossenfelder
Sabine Hossenfelder asks what Einstein actually said and what he was referring to, before her chapter 'Where does entanglement come in?' (4:19). Pair it with this section's last paragraph: whether Alice's measurement physically changes Bob's photon or only updates what is known depends on interpretation, and on every reading no message gets through.
Short · YouTube
Science Magazine
Science magazine's short report on the Micius satellite's record-distance entanglement, the 1,203-kilometre experiment in this section. Practise the Hype filter on its headline: 'spooky action' here means correlated results in the two ground stations, and no message travelled faster than light.
Lecture · Perimeter
Perimeter Institute for Theoretical Physics · Shohini Ghose · 2020
Physicist Shohini Ghose of Wilfrid Laurier University surveys the quantum technologies that grow out of superposition and entanglement, from quantum computers to secure communication. A clear public lecture given at Perimeter Institute in March 2020.
Explainer · Fermilab
Fermilab
Fermilab's Dr. Don Lincoln explains what the phrase 'quantum entanglement' means and how two objects can be linked by quantum effects. As you watch, keep two questions in mind: what exactly is correlated, and could anything in the setup carry a message? Part 5 of the lesson settles the second question with a two-line calculation.
Lecture · MIT
MIT OpenCourseWare · Allan Adams · 2013
A full MIT 8.04 lecture by Allan Adams. The first part previews quantum computing (the no-cloning theorem, met briefly in Part 5 and fully in Chapter 24, and the Deutsch–Jozsa algorithm of Chapter 23); the last part is devoted to the EPR experiment and Bell's inequality, the ideal bridge from this chapter to the next. Best watched after the lesson.
Lecture · MIT
MIT OpenCourseWare · Barton Zwiebach
A 13-minute segment of Barton Zwiebach's MIT 8.04 (Spring 2016) devoted to entanglement. Watch it next to this section's factoring argument and keep the definition in front of you: a joint state is entangled exactly when it cannot be written as one particle's state times the other's.
Lecture · Oxford
Artur Ekert
A short segment from the entanglement lecture of Artur Ekert's quantum-information course, posted on his own channel. It comes between 'Bell states' (3.4) and 'Quantum teleportation' (3.7), and its subject, shared randomness, is this section's 'perfect agreement, perfect randomness' in quantum-information language. Ekert is also the physicist who proposed turning such correlations into a secret key (Part 7).
Lecture · IQOQI Vienna
IQOQI Vienna · Christoph Lehner
An hour-long history-of-physics talk at Vienna's quantum-optics institute on Schrödinger's part in the making of the Einstein–Podolsky–Rosen paradox. Watch it after this section for the 1935 story at research depth, told from the side of the man who gave entanglement its name (Part 1).