Superconducting Switch for Fast On-Chip Routing of Quantum Microwave Fields

Abstract

A switch capable of routing microwave signals at cryogenic temperatures is a desirable component for state-of-the-art experiments in many fields of applied physics, including but not limited to quantum information processing, communication and basic research in engineered quantum systems. Conventional mechanical switches provide low insertion loss but disturb operation of dilution cryostats and the associated experiments by heat dissipation. Switches based on semiconductors or microelectromechanical systems have a lower thermal budget but are not readily integrated with current superconducting circuits. Here we design and test an on-chip switch built by combining tunable transmission-line resonators with microwave beam-splitters. The device is superconducting and as such dissipates a negligible amount of heat. It is compatible with current superconducting circuit fabrication techniques, operates with a bandwidth exceeding 100 MHz, is capable of handling photon fluxes on the order of 10 5 µs −1 , equivalent to powers exceeding −90 dBm, and can be switched within approximately 6 − 8 ns. We successfully demonstrate operation of the device in the quantum regime by integrating it on a chip with a single-photon source and using it to route non-classical itinerant microwave fields at the single-photon level.

Micromachined Integrated Quantum Circuit Containing a Superconducting Qubit

“…[22]. More sophisticated on-chip input/output circuitry, such as quantum limited amplifiers [23][24][25], circulators [26,27], and switching elements [28,29], will also be required for practical quantum information processing. This integration will likely be accompanied by through-wafer metalized vias to prevent cross-talk.…”

Erratum: Micromachined Integrated Quantum Circuit Containing a Superconducting Qubit [Phys. Rev. Applied 7 , 044018 (2017)]

“…[21]. More sophisticated on-chip input/output circuitry, such as quantum limited amplifiers [22][23][24], circulators [25,26], and switching elements [27,28], will also be required for practical quantum information processing. We anticipate that the techniques demonstrated here can be successfully employed toward integrating these elements into increasingly complex MMIQCs.…”

Single-Shot Quantum Nondemolition Detection of Individual Itinerant Microwave Photons

“…This choice is justified noting that we use a source with negligible two-photon emission, as demonstrated by the g ð2Þ < 0.1 measured in Ref. [31]. As our readout circuit is separated in frequency from the detection, we avoid spurious power input at the detection frequency.…”

“…1(a) for a sketch inspired by optical frequency realizations, Fig. 1 We connect the input of our detector to the output of a single-photon source embedded in an on-chip switch [31]. The single-photon source is realized as a transmon strongly coupled to its output port with an emission linewidth of Γ=ð2πÞ ¼ 1.77 MHz.…”