Nonholonomic quantum devices - art. no. 012308

We analyze the possibility and efficiency of nonholonomic control over quan tum devices with exponentially large number of Hilbert space dimensions. We show that completely controllable devices of this type can be assembled fr om elementary units of arbitrary physical nature, and can be employed effic iently for universal quantum computations and simulation of quantum-field d ynamics. As an example we describe a toy device that can perform Toffoli-ga te transformations and discrete Fourier transform on 9 qubits.