![[2-torial] Quantum information theory, Part 4: Quantum bird watching (continued) @ToposInstitute](https://i.ytimg.com/vi/gl2Ni8ksGsc/maxresdefault.jpg)
Uploaded July 2026 | Updated September 2026, 2 weeks ago
2-torial, May 20 2026
You can find accompanying notes and other information on this video at https://topos.institute/work/lectures/2-torials/2026-05-20_hosgood_quantum/
Tutor: Tim Hosgood
Tutee: Jason Brown
The elements of quantum information theory are not so complicated: some linear algebra over the complex numbers and a bit of classical probability theory. But it doesn't take long before you run into some intriguing problems that showcase how established experimental results contradict our classical intuition. In this 2-torial we will learn the very basics of quantum theory, see how a Mach–Zehnder interferometer gives a real-world implementation of a classically impossible construction and suggests that we should go all in on complex numbers, and finally how this all applies to the world of theoretical bird watching via the Quantum Zeno effect.
2-torial, May 20 2026
You can find accompanying notes and other information on this video at https://topos.institute/work/lectures/2-torials/2026-05-20_hosgood_quantum/
Tutor: Tim Hosgood
Tutee: Jason Brown
The elements of quantum information theory are not so complicated: some linear algebra over the complex numbers and a bit of classical probability theory. But it doesn't take long before you run into some intriguing problems that showcase how established experimental results contradict our classical intuition. In this 2-torial we will learn the very basics of quantum theory, see how a Mach–Zehnder interferometer gives a real-world implementation of a classically impossible construction and suggests that we should go all in on complex numbers, and finally how this all applies to the world of theoretical bird watching via the Quantum Zeno effect.
![[2-torial] Quantum information theory, Part 4: Quantum bird watching (continued)](https://i.ytimg.com/vi/gl2Ni8ksGsc/mqdefault.jpg "[2-torial] Quantum information theory, Part 4: Quantum bird watching (continued)
2-torial, May 20 2026
You can find accompanying notes and other information on this video at https://topos.institute/work/lectures/2-torials/2026-05-20_hosgood_quantum/
Tutor: Tim Hosgood
Tutee: Jason Brown
The elements of quantum information theory are not so complicated: some linear algebra over the complex numbers and a bit of classical probability theory. But it doesnt take long before you run into some intriguing problems that showcase how established experimental results contradict our classical intuition. In this 2-torial we will learn the very basics of quantum theory, see how a Mach–Zehnder interferometer gives a real-world implementation of a classically impossible construction and suggests that we should go all in on complex numbers, and finally how this all applies to the world of theoretical bird watching via the Quantum Zeno effect.")
![[Oxford Seminar] José Siqueira | Double functorial representation of indexed monoidal structures](https://i.ytimg.com/vi/glQUcRImOkw/mqdefault.jpg "[Oxford Seminar] José Siqueira | Double functorial representation of indexed monoidal structures
Oxford Seminar, 12th of June 2025
The data of a logical doctrine acts in two directions: that of the *substitution* operation, and that of *quantification*. Double Category Theory provides the tools to capture these two actions and their relationship concomitantly: in a double category of spans, re-indexing and acting on predicates can be packaged as tight and loose arrows respectively, and in there tight arrows always have conjoints. By mapping these conjoints into a double category of quintets, we obtain adjunctions internal to a 2-category. Moreover, by using the notion of adequate triple, the indexing category need only have certain pullbacks.
Adding a monoidal structure to the fibers (and the double pseudofunctor) allows us to capture both the Beck-Chevalley and Frobenius conditions. We will concern ourselves with the monoidal analogues of regular hyperdoctrines and similar structures (where the objects of predicates are not necessarily posets, but rather live in some 2-category), and show how they are equivalent to (lax symmetric monoidal) double pseudofunctors between spans and quintet double categories.")
![[DOTS Lectures] 4. Composing Moore Machines](https://i.ytimg.com/vi/jsM2jTuT_Zc/mqdefault.jpg "[DOTS Lectures] 4. Composing Moore Machines
Part of a lecture series on the Double Operadic Theory of Systems (DOTS) presented by David Jaz Myers.")
![[2-torial] David Jaz tells Brendan about a topos-theoretic interpretation for conceptual modelling](https://i.ytimg.com/vi/kFQpKp-ehZI/mqdefault.jpg "[2-torial] David Jaz tells Brendan about a topos-theoretic interpretation for conceptual modelling
Recorded at the Oxford Office on the 5th of December 2025.")
![[DOTS Lectures] 1. Categories of systems](https://i.ytimg.com/vi/kZ4muU5Wc_4/mqdefault.jpg "[DOTS Lectures] 1. Categories of systems
Part of a lecture series on the Double Operadic Theory of Systems (DOTS) presented by David Jaz Myers.")
![[Berkeley Seminar] Raph Levien | How Rust won: the quest for performant, reliable software](https://i.ytimg.com/vi/k_-6KI3m31M/mqdefault.jpg "[Berkeley Seminar] Raph Levien | How Rust won: the quest for performant, reliable software
Title: How Rust won: the quest for performant, reliable software
Abstract: For a long time, high performance has been in tension with reliability. In particular, languages designed for high performance were not memory safe, with real implications for unexpected crashes and security vulnerabilities. Rust is the first practical language to address this tension, building on affine types and other principles programming language theory, synthesized with an attention to low level systems programming. Rust’s success emerged not just from a clever idea, but consistently excellent execution and the formation of a strong community around the language. This talk will discuss several aspects of what Rust got right, as well as the rocky journey of ideas from academic theory to real world impact.
Slides: https://docs.google.com/presentation/d/1SoDsm_m_pb_gS6Y98HghhzBviYZxp3F2XawhIppJQQo/edit?usp=sharing
https://topos.institute/events/berkeley-seminar/")
![[DOTS Lectures] 11. A general representability theorem for Systems Theory Pt. 1](https://i.ytimg.com/vi/kpmhI1oHGnM/mqdefault.jpg "[DOTS Lectures] 11. A general representability theorem for Systems Theory Pt. 1
Part of a lecture series on the Double Operadic Theory of Systems (DOTS) presented by David Jaz Myers.
Some material from these lectures can be found in Davids book on categorical systems theory:
https://www.davidjaz.com/Papers/DynamicalBook.pdf")
