Quantum information effects

We study the two dual quantum information effects to manipulate the amount of information in quantum computation: hiding and allocation. The resulting type-and-effect system is fully expressive for irreversible quantum computing, including measurement. We provide universal categorical constructions that semantically interpret this arrow metalanguage with choice, starting with any rig groupoid interpreting the reversible base language. Several properties of quantum measurement follow in general, and we translate (noniterative) quantum flow charts into our language. The semantic constructions turn the category of unitaries between Hilbert spaces into the category of completely positive trace-preserving maps, and they turn the category of bijections between finite sets into the category of functions with chosen garbage. Thus they capture the fundamental theorems of classical and quantum reversible computing of Toffoli and Stinespring.

Pandemic Among the Amish: A Look at the Effects of COVID-19 on Amish Communities in Lancaster, Pennsylvania, in the First Four Months

March 2020 will be remembered as one of the most unusual months in living memory. When COVID-19 spread across the country, its reach and impact affected every region and every person in some way. The "new normal" forced much of the world to face a new reality of stay-at-home orders, food shortages, and rising death rates. Initially, the pandemic hit congested urban centers hardest, but the effects of the coronavirus were also felt among the rural Amish communities of Lancaster County, Pennsylvania. This study offers a preliminary look at how the pandemic affected these communities, focusing on the following themes: sources of news and information; effects of government mandates; and impact of the virus on the day-to-day lives of the Amish during the first four months of the pandemic, from late March 2020 through late July 2020. Findings suggest that the Amish experienced a mix of fear and hope, skepticism and optimism, but also a resolve in their faith, which they felt assured would carry them through the uncertainties of the coming months.

Do We Live in a ‘Post-Truth’ Era?

Have we entered a ‘post-truth’ era? This article is an attempt to answer this question by (a) offering an explication of the notion of ‘post-truth’ from recent discussions, (b) deriving a testable implication from that explication, to the effect that we should expect to see decreasing information effects – that is, differences between actual preferences and estimated, fully informed preferences – on central political issues over time and then (c) putting the relevant narrative to the test by way of counterfactual modelling, using election year data for the period of 2004–2016 from the American National Election Studies’ Times Series Study. The implication in question turns out to be consistent with the data: at least in a US context, we do see evidence of a decrease in information effects on key, political issues – immigration, same-sex adoption and gun laws, in particular – in the period 2004–2016. This offers some novel, empirical evidence for the ‘post-truth’ narrative.