Jeff Barrett @jeff Not recently active ActivityProfileFriends 0Groups 1Forums PersonalMentionsFavoritesFriendsGroups Show: — Everything — Updates Friendships New Groups Group Memberships Group Updates Topics Replies Posts Comments Jeff Barrett changed their profile picture 8 years, 9 months ago Jeff Barrett joined the group 2016 International Workshop on Quantum Observers 8 years, 9 months ago 2016 International Workshop on Quantum Observers View group