Jordan-Wigner fermions and dynamic probes of quantum spin chains
Abstract:
With the help of the Jordan-Wigner transformation the spin-1/2 XY chains
can be reformulated in terms of noninteracting spinless fermions and as
a result many statistical-mechanics calculations can be performed rigorously,
i.e. without making any simplifying approximations. We are interested in
dynamic properties of such chains (time-dependent spin correlation functions,
dynamic structure factors, dynamic susceptibilities) which are of great
importance for interpretation of experimental data. We have worked out
a number of dynamic quantities explicitly as well as have performed a general
analysis of the two-fermion continua which are relevant for different dynamic
quantities.
This study has been performed within the STCU project #1673 `Dynamics of correlations in quantum spin chains'.