4,652 research outputs found
Planar multilayer circuit quantum electrodynamics
Experimental quantum information processing with superconducting circuits is
rapidly advancing, driven by innovation in two classes of devices, one
involving planar micro-fabricated (2D) resonators, and the other involving
machined three-dimensional (3D) cavities. We demonstrate that circuit quantum
electrodynamics can be implemented in a multilayer superconducting structure
that combines 2D and 3D advantages. We employ standard micro-fabrication
techniques to pattern each layer, and rely on a vacuum gap between the layers
to store the electromagnetic energy. Planar qubits are lithographically defined
as an aperture in a conducting boundary of the resonators. We demonstrate the
aperture concept by implementing an integrated, two cavity-modes, one
transmon-qubit system
The reconfigurable Josephson circulator/directional amplifier
Circulators and directional amplifiers are crucial non-reciprocal signal
routing and processing components involved in microwave readout chains for a
variety of applications. They are particularly important in the field of
superconducting quantum information, where the devices also need to have
minimal photon losses to preserve the quantum coherence of signals.
Conventional commercial implementations of each device suffer from losses and
are built from very different physical principles, which has led to separate
strategies for the construction of their quantum-limited versions. However, as
recently proposed theoretically, by establishing simultaneous pairwise
conversion and/or gain processes between three modes of a Josephson-junction
based superconducting microwave circuit, it is possible to endow the circuit
with the functions of either a phase-preserving directional amplifier or a
circulator. Here, we experimentally demonstrate these two modes of operation of
the same circuit. Furthermore, in the directional amplifier mode, we show that
the noise performance is comparable to standard non-directional superconducting
amplifiers, while in the circulator mode, we show that the sense of circulation
is fully reversible. Our device is far simpler in both modes of operation than
previous proposals and implementations, requiring only three microwave pumps.
It offers the advantage of flexibility, as it can dynamically switch between
modes of operation as its pump conditions are changed. Moreover, by
demonstrating that a single three-wave process yields non-reciprocal devices
with reconfigurable functions, our work breaks the ground for the development
of future, more-complex directional circuits, and has excellent prospects for
on-chip integration
Robust concurrent remote entanglement between two superconducting qubits
Entangling two remote quantum systems which never interact directly is an
essential primitive in quantum information science and forms the basis for the
modular architecture of quantum computing. When protocols to generate these
remote entangled pairs rely on using traveling single photon states as carriers
of quantum information, they can be made robust to photon losses, unlike
schemes that rely on continuous variable states. However, efficiently detecting
single photons is challenging in the domain of superconducting quantum circuits
because of the low energy of microwave quanta. Here, we report the realization
of a robust form of concurrent remote entanglement based on a novel microwave
photon detector implemented in the superconducting circuit quantum
electrodynamics (cQED) platform of quantum information. Remote entangled pairs
with a fidelity of are generated at Hz. Our experiment
opens the way for the implementation of the modular architecture of quantum
computation with superconducting qubits.Comment: Main paper: 7 pages, 4 figures; Appendices: 14 pages, 9 figure
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