Large-size Behavior of the Entanglement Entropy of Free Disordered Fermions
Abstract
We consider a macroscopic system of free lattice fermions, and we are interested in the entanglement entropy (EE) of a large block of size L of the system, treating the rest of the system as the macroscopic environment of the block. Entropy is a widely used quantifier of quantum correlations between a block and its surroundings. We begin with known results (mostly one-dimensional) on the asymptotics form of EE of translation-invariant systems for large L, where for any value of the Fermi energy there are basically two asymptotics known as area law and enhanced (violated ) area law. We then show that in the disordered case and for the Fermi energy belonging to the localized spectrum of a one-body Hamiltonian, the EE obeys the area law for all typical realizations of disorder and any dimension. As for the enhanced area law, it turns out to be possible for some special values of the Fermi energy in the one-dimensional case
12:00
Topological Recursion: Introduction, Overview and Applications
Abstract
Non-constant ground configurations in the disordered ferromagnet and minimal cuts in a random environment.
Abstract
Combinatorial moment sequences
Abstract
We will look at a number of interesting examples — some proven, others merely conjectured — of Hamburger moment sequences in combinatorics. We will consider ways in which this positivity may be expected: for instance, in different types of combinatorial statistics on perfect matchings that encode moments of noncommutative analogues of the classical Central Limit Theorem. We will also consider situations in which this positivity may be surprising, and where proving it would open up new approaches to a class of very hard open problems in combinatorics.
14:00
Algorithmic Insurance
Abstract
As machine learning algorithms get integrated into the decision-making process of companies and organizations, insurance products are being developed to protect their providers from liability risk. Algorithmic liability differs from human liability since it is based on data-driven models compared to multiple heterogeneous decision-makers and its performance is known a priori for a given set of data. Traditional actuarial tools for human liability do not consider these properties, primarily focusing on the distribution of historical claims. We propose, for the first time, a quantitative framework to estimate the risk exposure of insurance contracts for machine-driven liability, introducing the concept of algorithmic insurance. Our work provides ML model developers and insurance providers with a comprehensive risk evaluation approach for this new class of products. Thus, we set the foundations of a niche area of research at the intersection of the literature in operations, risk management, and actuarial science. Specifically, we present an optimization formulation to estimate the risk exposure of a binary classification model given a pre-defined range of premiums. Our approach outlines how properties of the model, such as discrimination performance, interpretability, and generalizability, can influence the insurance contract evaluation. To showcase a practical implementation of the proposed framework, we present a case study of medical malpractice in the context of breast cancer detection. Our analysis focuses on measuring the effect of the model parameters on the expected financial loss and identifying the aspects of algorithmic performance that predominantly affect the risk of the contract.
Paper Reference: Bertsimas, D. and Orfanoudaki, A., 2021. Pricing algorithmic insurance. arXiv preprint arXiv:2106.00839.
Paper link: https://arxiv.org/pdf/2106.00839.pdf