Hi all,
Next week, there are two seminars planned on Tuesday:
(1) Daniele Oriti will talk about “Spacetime as a quantum many-body system and a few foundational issues”. The talk will take place in HIT E41.1 at 11:15
(2) Maite Arcos will talk about “A resource theory of gambling”. The talk will take place in HIT E41.1 at 13:30.
See below for the abstracts.
Best,
Ladina
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Title:
Spacetime as a quantum many-body system and a few foundational issues
Abstract:
Rather than the result of quantizing a classical gravitational theory, quantum gravity can be understood as the theory of spacetime microstructure, viewing the universe as a peculiar quantum many-body system and spacetime itself as emergent. I outline basic features of quantum gravity states and processes, common to a number of related quantum gravity formalisms (group field theory, canonical loop quantum gravity, simplicial quantum gravity, spin foam models). I emphasize their purely combinatorial and algebraic language, discrete geometric interpretation, how entanglement is a seed of topological and geometric properties, how they encode holographic and information-transmission properties, and how a pre-geometric, discrete notion of quantum causality can be implemented. The above features imply that quantum information concepts and tools play a key role in defining the structure of quantum spacetime.
I also sketch how the problem of spacetime emergence, and the extraction of continuum cosmological physics, can be addressed, on the basis of the above quantum structures, in the context of the group field theory framework.
Finally, I discuss briefly a few foundational issues that a framework like this poses, concerning the very definition of the fundamental quantum dynamics, the construction of relational spatiotemporal observables, the interpretation and use of the quantum formalism.
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Title:
A resource theory of gambling
Abstract:
The Kelly betting scheme is a classic problem in information theory: an agent repeatedly bets on uncertain outcomes in order to maximise their long-term wealth growth. While widely celebrated, Kelly’s strategy has also been heavily criticised in economics, where expected utility theory is usually taken as the more fundamental framework for decision-making under uncertainty.
In this talk, I will present a finite-regime and single-shot generalisation of Kelly gambling. This perspective allows us to quantify what it means for a gambler to possess more information than the odds-maker. Using tools from hypothesis testing and decision theory, we compute the optimal finite-bet strategies that maximise the probability of achieving a target rate of return. We will see that Rényi divergences characterise the fundamental risk–reward trade-offs, providing a hierarchy that interpolates between long-term growth and single-shot success probabilities. The optimal strategies coincide with those maximising expected utility and those minimising type-I/II errors, thereby unifying economic and information-theoretic viewpoints.
I will also describe a distributed extension in which multiple agents receive correlated side information about an unknown state and act strategically. Remarkably, the structure of optimal strategies persists in this multi-agent game and sets the stage for quantum generalisations.