Towards synthetic Euclidean quantum field theory Speaker(s): Tobias Fritz
Abstract: In a synthetic approach to geometry and physics, one attempts to formulate an axiomatic system in purely logical terms, abstracting away from irrelevant "implementation details". In this talk, I will explain how intuitionistic logic and topos theory provide a synthetic theory of space, and then cons... read more
Date: 08/04/2019  2:00 pm
Series: Mathematical Physics

Towards synthetic Euclidean quantum field theory Speaker(s): Tobias Fritz
Abstract: In this status report on current work in progress, I will sketch a generalization of the temporal type theory introduced by Schultz and Spivak to a logic of space and spacetime. If one writes down a definition of probability space within this logic, one conjecturally obtains a notion whose semantics... read more
Date: 30/07/2018  4:00 pm
Collection: Foundations of Quantum Mechanics

The Kitaev model and aspects of semisimple Hopf algebras via the graphical calculus Speaker(s): Tobias Fritz
Abstract: The quantum double models are parametrized by a finitedimensional semisimple Hopf algebra (over $mathbb{C}$). I will introduce the graphical calculus of these Hopf algebras and sketch how it is equivalent to the calculus of two interacting symmetric Frobenius algebras. Since symmetric Frobenius alg... read more
Date: 03/08/2017  11:00 am

Quantum logic is undecidable Speaker(s): Tobias Fritz
Abstract:
I will explain and prove the statement of the title. The proof relies on a recent result of Slofstra in combinatorial group theory and the hypergraph approach to contextuality. Based on http://arxiv.org/abs/1607.05870. Date: 25/10/2016  3:30 pm
Series: Quantum Foundations

What is Entropy? Speaker(s): Tobias Fritz
Abstract: Entropy comes up all over physics and mathematics in many different guises. However, as one tries to understand its conceptual meaning, entropy often evades the question by shifting into a different shape. Here, I will try to capture the beast by surrounding it from all sides. Assistance by the audi... read more
Date: 20/05/2015  2:00 pm
Series: Colloquium

Equality Speaker(s): Tobias Fritz
Abstract: Equality of two mathematical objects is a seemingly simple and wellunderstood concept. In this talk, I will do three things to explain why this is a misconception: I will survey different notions of equality, explain how revising the notion of equality has led to an emerging alternative foundation ... read more
Date: 21/05/2014  2:00 pm
Series: Colloquium

Resources Speaker(s): Tobias Fritz
Abstract: One of the main challenges that we face both as individual persons and as a species concerns the distribution and use of resources, such as water, time, capital, computing power or negatively valuedresources like nuclear waste. Also within theoretical physics, one
frequently deals with resources l... read more
Date: 15/05/2013  2:00 pm
Series: Colloquium

Is spacetime fundamentally discrete?
Abstract: Modelling continuum dynamics on
discrete space timeWe will discuss perfect discretizations which aim at mirroring exactly continuum physics on a given lattice. Such discretizations avoid typical artifacts like Lorentz violation, energy dissipation, particle doubling and in particular breaking of di... read more
Date: 24/10/2012  9:00 am
Collection: Experimental Search for Quantum Gravity 2007

New Directions in Categorical Logic for Classical, Probabilistic and Quantum Physics Speaker(s): Tobias Fritz
Abstract: I will
give an idea of what category theory is and how it can be successfully applied in mathematics and the mathematical sciences by means of example. The example is a notion from mathematical logic formalizing the intuitive concept of "property". The new categorytheoretical
definition of this n... read more
Date: 09/10/2012  3:30 pm
Series: Quantum Foundations

Bell's Theorem and Bayesian Networks Speaker(s): Tobias Fritz
Abstract: The standard approach to quantum nonlocality (Bell's Theorem) relies on the assumption of the existence of "free will". I will explain how to get rid of this mysterious assumption in favor of the independence of sources. From this new point of view, Bell's Theorem becomes a statement about Bayesian ... read more
Date: 07/02/2012  3:30 pm
Series: Quantum Foundations
