9 papers
Second Quantization for the Kepler Problem
John C. Baez
The Kepler problem concerns a point particle in an attractive inverse square force. After a brief review of the classical and quantum versions of this problem, focused on their hid…
Motifs and Emergent Feedback in Labeled Graphs
John C. Baez, Adittya Chaudhuri
In fields ranging from business to systems biology, directed graphs with edges labeled by signs are used to model systems in a simple way: the nodes represent entities of some sort…
Dirichlet Species and Arithmetic Zeta Functions
John C. Baez
Though Joyal's species are known to categorify generating functions in enumerative combinatorics, they also categorify zeta functions in algebraic geometry. The reason is that any…
What is Entropy?
John C. Baez
This short book is an elementary course on entropy, leading up to a calculation of the entropy of hydrogen gas at standard temperature and pressure. Topics covered include informat…
Double Categories of Open Systems: the Cospan Approach
John C. Baez
This is an overview of double categories of "open systems": systems that can interact with their environment. We focus on the variable sharing paradigm, where we compose open syste…
Groupoid Cardinality and Random Permutations
John C. Baez
If we treat the symmetric group as a probability measure space where each element has measure , then the number of cycles in a permutation becomes a random variable. Th…