# US 12,191,051 B2 · Coherent interconnects between superconducting qubits and microwave-optical transducers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,051 B2 - Document ID: US12191051B2 - Status: Granted - Kind: B2 - Application number: 18/329,743 - Filed: 2023-06-06 - Published: 2024-12-12 - Granted: 2025-01-07 - Earliest claimed: 2023-06-06 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Timothy Phung; Moein Malekakhlagh; Jason S. Orcutt - Web page: https://patentgrep.com/patent/US12191051B2 ## CPC - H01B 12/02: characterised by their form - G06N 10/00: Quantum computing, i.e. information processing based on quantum-mechanical phenomena - G06N 10/40: Physical realisations or architectures of quantum processors or components for manipulating qubits, e.g. qubit coupling or qubit control - H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K}) - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS ## Abstract Systems and techniques that facilitate enabling transfer of a quantum state between a quantum device and a microwave resonator of a microwave optical transducer. In various embodiments, a system can comprise a quantum device, a microwave optical transducer including a microwave resonator, and a coherent interconnect. In various embodiments, the coherent interconnect can be between the quantum device and the microwave optical transducer that can enable bi-directional transfer of a quantum state between the quantum device and the microwave resonator. In various embodiments, the microwave optical transducer can be separately packaged from the quantum device. With various embodiments, the coherent interconnect can be a superconducting coaxial cable. ## Claims ### Claim 1 A system, comprising: a quantum device; a microwave optical transducer including a microwave resonator; and a coherent interconnect between the quantum device and the microwave optical transducer that enables bi-directional transfer of a quantum state between the quantum device and the microwave resonator, wherein the microwave optical transducer is separately packaged from the quantum device. ### Claim 2 (depends on 1) The system of claim 1, wherein the coherent interconnect is a superconducting coaxial cable. ### Claim 3 (depends on 2) The system of claim 2, wherein the superconducting coaxial cable includes a length up to 10 centimeters. ### Claim 4 (depends on 1) The system of claim 1, wherein the quantum device is a transmon qubit. ### Claim 5 (depends on 4) The system of claim 4, wherein the quantum device is connected to a flux-tunable element that modulates the coupling between the quantum device and the coherent interconnect. ### Claim 6 (depends on 5) The system of claim 5, wherein the flux-tunable element is a transmon qubit. ### Claim 7 (depends on 5) The system of claim 5, wherein the flux-tunable element is a radio frequency superconducting quantum interference device (RF-SQUID). ### Claim 8 (depends on 1) The system of claim 1, wherein the coherent interconnect includes a DC SQUID connected in series to the coherent interconnect to permit frequency tuning of mode frequencies of the coherent interconnect. ### Claim 9 A device, comprising: a flux-tunable qubit; a microwave optical transducer; and a coherent interconnect including a cable coupling the flux-tunable qubit to the microwave optical transducer to enable bi-directional transfer of a quantum state between the microwave optical transducer and the flux-tunable qubit wherein the microwave optical transducer is separately packaged from the flux-tunable qubit. ### Claim 10 (depends on 9) The device of claim 9, wherein the coherent interconnect comprises a flux-tunable coupler. ### Claim 11 (depends on 10) The device of claim 10, wherein the cable includes a flux-tunable SQUID to facilitate frequency tuning of mode frequencies of the device. ### Claim 12 (depends on 11) The device of claim 11, wherein the microwave optical transducer is flux-tunable. ### Claim 13 (depends on 11) The device of claim 11, wherein the microwave optical transducer is not flux-tunable. ### Claim 14 (depends on 9) The device of claim 9, wherein the cable includes a flux-tunable SQUID to facilitate frequency tuning of mode frequencies of the device, and the microwave optical transducer is not flux-tunable. ### Claim 15 (depends on 9) The device of claim 9, wherein the cable is not flux tunable. ### Claim 16 (depends on 9) The device of claim 9, wherein the cable is flux tunable. ### Claim 17 A method comprising: enabling bi-directional transfer of a quantum state between a quantum device and a microwave resonator of a microwave optical transducer via a coherent interconnect connected between the quantum device and the microwave optical transducer, wherein the quantum device is separately packaged from the microwave optical transducer. ### Claim 18 (depends on 17) The method of claim 17, further comprising: tuning the quantum device to be in resonance with a mode of a cable of the coherent interconnect, and activating coupling to transfer the quantum state to the mode of the cable. ### Claim 19 (depends on 18) The method of claim 18, further comprising: tuning the mode of the cable to be in resonance with the microwave resonator that is part of the microwave optical transducer. ### Claim 20 (depends on 18) The method of claim 18, further comprising: tuning the microwave resonator of the microwave optical transducer to be in resonance with the mode of the cable.