168 research outputs found
Measurement of a Vacuum-Induced Geometric Phase
Berry's geometric phase naturally appears when a quantum system is driven by
an external field whose parameters are slowly and cyclically changed. A
variation in the coupling between the system and the external field can also
give rise to a geometric phase, even when the field is in the vacuum state or
any other Fock state. Here we demonstrate the appearance of a vacuum-induced
Berry phase in an artificial atom, a superconducting transmon, interacting with
a single mode of a microwave cavity. As we vary the phase of the interaction,
the artificial atom acquires a geometric phase determined by the path traced
out in the combined Hilbert space of the atom and the quantum field. Our
ability to control this phase opens new possibilities for the geometric
manipulation of atom-cavity systems also in the context of quantum information
processing.Comment: 5 + 6 page
A STUDY OF STATIC AND DYNAMIC CHARACTERISTICS OF MULTIFUNCTIONAL SIGNAL CONVERTERS
The issues of continuity, accuracy, speed and reliability of signal conversion, which are the main problems of quality control and management of production processes, remain relevant. Research shows that in practice there are different signal variables, the study of which is highly formalized in a number of modeling tasks and basic classification studies, in particular transients in converters, its sources and elements requires a unified mathematical approach, that is, visual, highly formalized modeling and research based on it. The paper presents a graph model of multifunctional signal converters that provide microprocessor and electronic devices with signals in the form of secondary voltage
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
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