3 research outputs found
Realization of efficient quantum gates with a superconducting qubit-qutrit circuit
Building a quantum computer is a daunting challenge since it requires good
control but also good isolation from the environment to minimize decoherence.
It is therefore important to realize quantum gates efficiently, using as few
operations as possible, to reduce the amount of required control and operation
time and thus improve the quantum state coherence. Here we propose a
superconducting circuit for implementing a tunable system consisting of a
qutrit coupled to two qubits. This system can efficiently accomplish various
quantum information tasks, including generation of entanglement of the two
qubits and conditional three-qubit quantum gates, such as the Toffoli and
Fredkin gates. Furthermore, the system realizes a conditional geometric gate
which may be used for holonomic (non-adiabatic) quantum computing. The
efficiency, robustness and universality of the presented circuit makes it a
promising candidate to serve as a building block for larger networks capable of
performing involved quantum computational tasks.Comment: 27 pages including technical supplementary information, 9 figures,
comments are most welcom
The superconducting circuit companion -- an introduction with worked examples
This tutorial aims at giving an introductory treatment of the circuit
analysis of superconducting qubits, i.e., two-level systems in superconducting
circuits. It also touches upon couplings between such qubits and how microwave
driving and these couplings can be used for single- and two-qubit gates, as
well as how to include noise when calculating the dynamics of the system. We
also discuss higher-dimensional superconducting qudits. The tutorial is
intended for new researchers with limited or no experience with the field but
should be accessible to anyone with a bachelor's degree in physics. The
tutorial introduces the basic methods used in quantum circuit analysis,
starting from a circuit diagram and ending with a quantized Hamiltonian, that
may be truncated to the lowest levels. We provide examples of all the basic
techniques throughout the discussion, while in the last part of the tutorial we
discuss several of the most commonly used circuits for quantum-information
applications. This includes both worked examples of single qubits and examples
of how to analyze the coupling methods that allow multiqubit operations. In
several detailed appendices, we provide the interested reader with an
introduction to more advanced techniques for handling larger circuit designs.Comment: Accepted as a tutorial in PRX Quantu