Abstract:We introduce and experimentally characterize a general purpose device for
signal processing in circuit quantum electrodynamics systems. The device is a
broadband two-port microwave circuit element with three modes of operation: it
can transmit, reflect, or invert incident signals between 4 and 8 GHz. This
property makes it a versatile tool for lossless signal processing at cryogenic
temperatures. In particular, rapid switching (less than or equal to 15 ns)
between these operation modes enables several multiple… Show more
“…[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.…”
We present a device demonstrating a lithographically patterned transmon integrated with a micromachined cavity resonator. Our two-cavity, one-qubit device is a multilayer microwave integrated quantum circuit (MMIQC), comprising a basic unit capable of performing circuit-QED (cQED) operations. We describe the qubit-cavity coupling mechanism of a specialized geometry using an electric field picture and a circuit model, and obtain specific system parameters using simulations. Fabrication of the MMIQC includes lithography, etching, and metallic bonding of silicon wafers. Superconducting wafer bonding is a critical capability that is demonstrated by a micromachined storage cavity lifetime of 34.3 µs, corresponding to a quality factor of 2 million at single-photon energies. The transmon coherence times are T1 = 6.4 µs, and T Echo 2 = 11.7 µs. We measure qubit-cavity dispersive coupling with rate χqµ/2π = −1.17 MHz, constituting a Jaynes-Cummings system with an interaction strength g/2π = 49 MHz. With these parameters we are able to demonstrate cQED operations in the strong dispersive regime with ease. Finally, we highlight several improvements and anticipated extensions of the technology to complex MMIQCs.
“…[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.…”
We present a device demonstrating a lithographically patterned transmon integrated with a micromachined cavity resonator. Our two-cavity, one-qubit device is a multilayer microwave integrated quantum circuit (MMIQC), comprising a basic unit capable of performing circuit-QED (cQED) operations. We describe the qubit-cavity coupling mechanism of a specialized geometry using an electric field picture and a circuit model, and obtain specific system parameters using simulations. Fabrication of the MMIQC includes lithography, etching, and metallic bonding of silicon wafers. Superconducting wafer bonding is a critical capability that is demonstrated by a micromachined storage cavity lifetime of 34.3 µs, corresponding to a quality factor of 2 million at single-photon energies. The transmon coherence times are T1 = 6.4 µs, and T Echo 2 = 11.7 µs. We measure qubit-cavity dispersive coupling with rate χqµ/2π = −1.17 MHz, constituting a Jaynes-Cummings system with an interaction strength g/2π = 49 MHz. With these parameters we are able to demonstrate cQED operations in the strong dispersive regime with ease. Finally, we highlight several improvements and anticipated extensions of the technology to complex MMIQCs.
“…[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.…”
We present a device demonstrating a lithographically patterned transmon integrated with a micromachined cavity resonator. Our two-cavity, one-qubit device is a multilayer microwave integrated quantum circuit (MMIQC), comprising a basic unit capable of performing circuit-QED (cQED) operations. We describe the qubit-cavity coupling mechanism of a specialized geometry using an electric field picture and a circuit model, and finally obtain specific system parameters using simulations. Fabrication of the MMIQC includes lithography, etching, and metallic bonding of silicon wafers. Superconducting wafer bonding is a critical capability that is demonstrated by a micromachined storage cavity lifetime 34.3 µs, corresponding to a quality factor of 2 million at single-photon energies. The transmon coherence times are T1 = 6.4 µs, and T Echo 2 = 11.7 µs. We measure qubit-cavity dispersive coupling with rate χqµ/2π = −1.17 MHz, constituting a Jaynes-Cummings system with an interaction strength g/2π = 49 MHz. With these parameters we are able to demonstrate cQED operations in the strong dispersive regime with ease. Finally, we highlight several improvements and anticipated extensions of the technology to complex MMIQCs.
“…As the imbalance in the bridge determines its transmission, changing δ allows the circuit to act as a switch or a multiplying element [37,38]. The bridge circuit's tunable inductors are realized with series arrays of superconducting quantum interference devices (SQUIDs), formed by the parallel arrangement of two Josephson junctions.…”
We report on the design and performance of an on-chip microwave circulator with a widely (GHz) tunable operation frequency. Nonreciprocity is created with a combination of frequency conversion and delay, and requires neither permanent magnets nor microwave bias tones, allowing on-chip integration with other superconducting circuits without the need for high-bandwidth control lines. Isolation in the device exceeds 20 dB over a bandwidth of tens of MHz, and its insertion loss is small, reaching as low as 0.9 dB at select operation frequencies. Furthermore, the device is linear with respect to input power for signal powers up to hundreds of fW (≈10 3 circulating photons), and the direction of circulation can be dynamically reconfigured. We demonstrate its operation at a selection of frequencies between 4 and 6 GHz.
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