%0 Journal Article %D 2010 %T Simulating sparse Hamiltonians with star decompositions %A Andrew M. Childs %A Robin Kothari %X We present an efficient algorithm for simulating the time evolution due to a sparse Hamiltonian. In terms of the maximum degree d and dimension N of the space on which the Hamiltonian H acts for time t, this algorithm uses (d^2(d+log* N)||Ht||)^{1+o(1)} queries. This improves the complexity of the sparse Hamiltonian simulation algorithm of Berry, Ahokas, Cleve, and Sanders, which scales like (d^4(log* N)||Ht||)^{1+o(1)}. To achieve this, we decompose a general sparse Hamiltonian into a small sum of Hamiltonians whose graphs of non-zero entries have the property that every connected component is a star, and efficiently simulate each of these pieces. %8 2010/03/18 %G eng %U http://arxiv.org/abs/1003.3683v2 %! Theory of Quantum Computation %R 10.1007/978-3-642-18073-6_8