An official website of the United States government
Here's how you know
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Simulated waiting times to reach 99% A starting from all B for circles (solid curve) and 2D lattices (dashed curve). Time periods represent the average number of updates per individual.