5 papers
Optimal Control of Coupled Josephson Qubits
A. K. Spoerl, T. Schulte-Herbrueggen, S. J. Glaser +4
Quantum optimal control theory is applied to two and three coupled Josephson charge qubits. It is shown that by using shaped pulses a CNOT gate can be obtained with a trace fidelit…
A new local invariant for quantum gates
Laura Koponen, Ville Bergholm, Martti M. Salomaa
In this paper we study the properties of two-qubit gates. We review the most common parameterizations for the local equivalence classes of two-qubit gates and the connections betwe…
Quantum circuits with uniformly controlled one-qubit gates
Ville Bergholm, Juha J. Vartiainen, Mikko Mottonen +1
Uniformly controlled one-qubit gates are quantum gates which can be represented as direct sums of two-dimensional unitary operators acting on a single qubit. We present a quantum g…
Transformation of quantum states using uniformly controlled rotations
Mikko Mottonen, Juha J. Vartiainen, Ville Bergholm +1
We consider a unitary transformation which maps any given state of an -qubit quantum register into another one. This transformation has applications in the initialization of a q…
Quantum Circuits for General Multiqubit Gates
Mikko Mottonen, Juha J. Vartiainen, Ville Bergholm +1
We consider a generic elementary gate sequence which is needed to implement a general quantum gate acting on n qubits -- a unitary transformation with 4^n degrees of freedom. For s…