35 research outputs found
Microwave-controlled generation of shaped single photons in circuit quantum electrodynamics
Large-scale quantum information processors or quantum communication networks
will require reliable exchange of information between spatially separated
nodes. The links connecting these nodes can be established using traveling
photons that need to be absorbed at the receiving node with high efficiency.
This is achievable by shaping the temporal profile of the photons and absorbing
them at the receiver by time reversing the emission process. Here, we
demonstrate a scheme for creating shaped microwave photons using a
superconducting transmon-type three-level system coupled to a transmission line
resonator. In a second-order process induced by a modulated microwave drive, we
controllably transfer a single excitation from the third level of the transmon
to the resonator and shape the emitted photon. We reconstruct the density
matrices of the created single-photon states and show that the photons are
antibunched. We also create multipeaked photons with a controlled amplitude and
phase. In contrast to similar existing schemes, the one we present here is
based solely on microwave drives, enabling operation with fixed frequency
transmons
Quantum wave mixing and visualisation of coherent and superposed photonic states in a waveguide
Superconducting quantum systems (artificial atoms) have been recently
successfully used to demonstrate on-chip effects of quantum optics with single
atoms in the microwave range. In particular, a well-known effect of four-wave
mixing could reveal a series of features beyond classical physics, when a
non-linear medium is scaled down to a single quantum scatterer. Here we
demonstrate a phenomenon of the quantum wave mixing (QWM) on a single
superconducting artificial atom. In the QWM, the spectrum of elastically
scattered radiation is a direct map of the interacting superposed and coherent
photonic states. Moreover, the artificial atom visualises photon-state
statistics, distinguishing coherent, one- and two-photon superposed states with
the finite (quantized) number of peaks in the quantum regime. Our results may
give a new insight into nonlinear quantum effects in microwave optics with
artificial atoms.Comment: 6 pages, 5 figures; accepted versio