Non-abelian symmetries in tensor networks: the open source tensor library QSpace

I will introduce the open-source tensor library QSpace that can deal with abelian and non-abelian symmetries in quantum tensor network simulations on a generic footing. QSpace is coded in C++ and as of now embedded into Matlab. QSpace v1 was initiated in 2006 for abelian U(1) symmetries. By 2012 QSpace v2 it had progressed to general continuous non-abelian symmetries, specifically SU(N) and Sp(2N). Major efficiency updates have been included in QSpace v3.* (2015-19) together with the implementation also of SO(N) and SO(2N+1). Based on its very history, QSpace has been extensively scrutinized and tested in the past in more than 75 research publications in a wide range of collaborations. Upon repeated request, QSpace v4 is finally going open source as a powerful versatile tool to deal with abelian and non-abelian symmetries in tensor network states.