Chiara Marletto | Beyond Quantum Computation: Constructor Theory

*The Foresight Institute* is a research organization and non-profit that supports the beneficial development of high-impact technologies. Since our founding in 1987 on a vision of guiding powerful technologies, we have continued to evolve into a many-armed organization that focuses on several fields of science and technology that are too ambitious for legacy institutions to support. From molecular nanotechnology, to brain-computer interfaces, space exploration, cryptocommerce, and AI, Foresight gathers leading minds to advance research and accelerate progress toward flourishing futures.

*Chiara Marletto, Oxford University*
*Beyond Quantum Computation: Constructor Theory*
The theory of the universal quantum computer has brought us rapid technological developments, together with remarkable improvements in how we understand quantum theory. There are, however, reasons to believe that quantum theory may ultimately have to be modified into a new theory: for instance, it will have to be merged with general relativity, to incorporate gravity; and some claim that it may be impossible to have quantum effects beyond a certain macroscopic scale. So what lies ahead of quantum theory, and of the universal quantum computer? To shed some light on these questions, we need a shift of logic in the way things are explained.

Specifically, one can adopt the approach where the basic assumptions are general principles about possible/impossible transformations, rather than dynamical laws and initial conditions. This approach is called constructor theory. Chiara Marletto describes its application to a handful of interconnected problems, within information theory, thermodynamics, and even quantum gravity. This ‘Physics of Can and Can’t' may be the first step towards the ultimate generalization of the universal quantum computer, which von Neumann called the 'universal constructor’.

Chiara Marletto is a Research Fellow at Wolfson College and the Physics Department, University of Oxford. Her research is in theoretical physics, with special emphasis on Quantum Theory of Computation, Information Theory, Thermodynamics, Condensed-Matter Physics and Quantum Biology. Some of her recent research has harnessed a recently proposed generalisation of the quantum theory of information - Constructor Theory — to address subtle issues at the foundations of the theory of control and causation in physics. These include applications to defining general principles encompassing classical, quantum and post-quantum theories of information; and to assessing the compatibility of essential features of living systems, such as the ability to self-reproduce and evolve, with fundamental laws of physics, in particular with Quantum Physics. They also include the definition of a new class of witnesses of quantum effects in systems that need not obey quantum theory, such as gravity; and a scale-independent definition of irreversibility, work and heat, based on constructor-theoretic ideas. Chiara' new book about her research, "The science of can and can’t”, will be published by Penguin.

[mickwilson]

Chiara presents as a rock-solid proposer of an explanatory theory, without oversell or attempting to squeeze all explanations into this framework. Her intellectual honesty is fabulously refreshing to me. Her responses in the Q&A are coherent, consistent and well-argued.

[williamlewis]

well-spoken and largely unambiguous ---- I am glad to have found this conversation . It is very heartwarming to hear you all express yourselves so clearly .

[Chewychaca]

This woman is absolutely breath taking

[aliservan]

Her book was released in hardback on 4th May. Can't wait to get my copy. ebook available soon.

[ylegoff]

"Exotic experience" is one way to put it. But Chiara's on the money: Worth the try.

[paulcassidy]

super great video. thanks to everyone at Foresight for making it and of course Dr. Marletto for her fantastic work and presentation + generosity in the detailed answers given to the questions. I'll be going back to uni soon to finish my BS in math & physics and Constructor Theory will be at the top of my list for potential thesis topics... so yeah super excited! keep up the great work!

[interstellarconveyance]

Thank you! I have been sitting on the sideline as a skeptic, this interview has certainly been very helpful in visualizing the concept. Have a beautiful day! ⚡🌌👽💞🌈⚡⚡⚡

[stephencarter]

That was a great Q&A!!
I especially liked the interaction between Dr.Marletto and Joshua beginning @ 58:39.

[NathanOkun]

If I understand you correctly here, you propose to change the method of defining the results of formulae and basic physical principles and laws from the "volumes" of the effective regions in the universe -- as defined by a n-dimensional graph of the inputs and the expected outputs of those principles -- into the BOUNDARIES of these "rules" giving where they allow results in our universe and where they do not. This would form the SURFACE of these volumes as a pair of green (OK) and red (IMPOSSIBLE for that rule) dots close together. For some rules, like quantum mechanical laws, these boundaries would be blurry shading from green to red due to the changing probabilities. To define what is actually possible and impossible, you take all; of these boundary regions of the laws that apply to some result and plot them all on the same graph, where only the place -- "volume" -- where they ALL OVERLAP will be the place where any results of use are possible. As you look at these many overlapping zone edges for any given problem to be solved, you will be able to see how the structure of the universe is shaped more easily. Kind of like a version of the Holographic Universe for each set of rules that apply to a desired solution. When you have enough of these boundary images, a more deep understanding of how the universe works may be possible to extrapolate. Is this correct?

[theokapanadze]

Excellent presentation and QA very enjoyable too❤

[deeliciousplum]

Exceptional talk. As someone who is so far removed from the ideas and the research that Chiara is sharing of, I can attest that the explanations as well the responses by Chiara are accessible and have provided me with so much to think of. Thank you Foresight Institute for hosting this event and a huge thank to Chiara Marletto for sharing your time with us. 🌸

[algonte]

New Physics theories imply getting into increasingly extreme conditions: extremely big, extremely small, extremely fast. But after dealing with extreme conditions they become useful inside the non-extreme (everyday) conditions: GPS, semiconductors, laser, etc. What will be the more extreme conditions that will unveil the new Physics theory and what everyday life changes will bring it?

[williamjmccartan]

Second watch, still great.

I just listened to Sean Carroll give a talk at the Sante Fe Institute this past week, it lines up with Chiara's understanding of quantum theory, the observer is irrelevant. It's all waves.

[lackushi]

Great video!!!! Language was the biggest barrier in this entire conversation. It just shows how incomplete all languages are at explaining reality!

[thegoodthebadandtheugly]

14:50 it’s not just “satisfactory unproblematic predictions” - it is also workable and useful predictions. Why the scientific method and science is better than any other dogmatic way of thinning and explaining our universe before is exactly because those other ways were not very useful ideologies.. post-justifications. We have to keep an eye that our new explanations don’t become not very useful ideologies and post-justifications / post-rationalisations and semantics

[charlesnelson]

I think it's very brave to be moving 'beyond' something which hasn't happened yet!

[nicoleorton]

This was very nice. Great discussion! Thank you Chiara and Allison.

[supermarcoa]

I find the construction theory here explained quite obscure. Apart the self-replicating machine which is just a technological issue, which can be clearly realized noways (it was maybe an issue at von neumann times where computers could just produce printed output). The explication as some bigger issues. For instance the thermodynamic examples (about the second law) illustrate exactly the opposite of what the girl is trying to claim. The laws of thermodynamics were found without the classical dynamical structure of physical theories (such as general relativity or electromagnetism) and they are working well, but just because Boltzmann at that time was ignorant about the real physical processes which cause these thermodynamic effects. When quantum mechanics was discovered we had a better picture of was going on and why the thermodynamic laws work in this way. Declaring that you you would like to describe things without an explication, just from an emergent point of view, basically because we have some difficulties doing in the usual way it seems to me quite short sighted. Gravity might be an emergent or effective phenomenology (and have been a huge literature in that sense), but I think that renouncing to understand in the hard way is not a step forward, just an admission of ignorance and of giving up in understanding how things really works, which is the main objective of physics. I hope they can in the future provide some prediction to test, verify or falsify their model, I'm frankly quite skeptical after listening this video. However remember that the scientific model provided us by Galileo, based on the dynamical analysis of nature, is the biggest engine of human progress (not only of physics).

[abies]

Would this be correct?
Turing's definition of a universal machine doesn't disallow self replication. It's just that all replicants are also the machine and are included in the set of possible machine states, which can be countably infinite. Programs can also avoid HALT forever under some conditions. The idea that quantum computing will break out of Turing's constraints and become independent of programming is based on the creation of new states, or something that defies the definition of a state?

[robertwilsoniii]

Only thing is that Google and Caltech recently demonstrated that an ER = EPR dynamical model works as a theory of quantum gravity and a unified theory of everything using their Sycamore quantum computer. But, their quantum computer can't do anything beyond what a Turing machine can do so there's still room for constructor theory.

But this wasn't known at the time of this upload, which makes sense. That discovery wasn't made until Nov. 30th 2022.