Quantum logic gates from time-dependent global magnetic field in a system with constant exchange
A. V. Nenashev, A. F. Zinovieva, А. В. Двуреченский, A. Yu. Gornov, Tatiana Zarodnyuk · Journal of Applied Physics · 2015
We propose a method that implements a universal set of one- and two-quantum-bit gates for quantum computation in a system of coupled electron pairs with constant non-diagonal exchange interaction. In our proposal, suppression of the exchange interaction is performed by the continual repetition of single-spin rotations. A small g-factor difference between the electrons allows for addressing qubits and avoiding strong magnetic field pulses. Numerical experiments were performed to show that, to implement the one- and two-qubit operations, it is sufficient to change the strength of the magnetic field by a few Gauss. This introduces one and then the other electron in a resonance. To determine the evolution of the two-qubit system, we use the algorithms of optimal control theory.