# US 2020/0401649 A1 · Systems and methods for removing unwanted interactions in quantum devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0401649 A1 - Document ID: US20200401649A1 - Status: Published application - Kind: A1 - Application number: 17/007,395 - Filed: 2020-08-31 - Published: 2020-12-24 - Earliest claimed: 2014-03-12 - Assignees: D-Wave Systems Inc. - Applicants: D-Wave Systems Inc. - Inventors: Trevor Michael Lanting - Web page: https://patentgrep.com/patent/US20200401649A1 ## CPC - G06F 17/00: Digital computing or data processing equipment or methods, specially adapted for specific functions (information retrieval, database structures or file system structures therefor G06F16/00) - G06F 15/82: data or demand driven - G06N 10/40: Physical realisations or architectures of quantum processors or components for manipulating qubits, e.g. qubit coupling or qubit control - G06N 10/60: Quantum algorithms, e.g. based on quantum optimisation, quantum Fourier or Hadamard transforms - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS ## Abstract Systems, devices, articles, methods, and techniques for advancing quantum computing by removing unwanted interactions in one or more quantum processor. One approach includes creating an updated plurality of programmable parameters based at least in part on a received value for the characteristic magnetic susceptibility of the qubit in the at least one quantum processor, and returning the updated plurality of programmable parameters. Examples programmable parameters include local biases, and coupling values characterizing the problem Hamilton. Also, for example, a quantum processor may be summarized as including a first loop of superconducting material, a first compound Josephson junction interrupting the first loop of superconducting material, a first coupler inductively coupled to the first loop of superconducting material, a second coupler inductively coupled to the first loop of superconducting material, and a second loop of superconducting material proximally placed to the first loop of superconducting material inductively coupled to the first coupler and the second coupler. ## Claims ### Claim 1 A quantum processor, comprising: a flux qubit; a first coupler inductively coupled to the flux qubit; and a compensator circuit inductively coupled to the first coupler, the compensator circuit operable to compensate at least in part for a magnetic susceptibility of the flux qubit. ### Claim 2 (depends on 1) The quantum processor of claim 1, wherein the compensator circuit comprises a loop of superconducting material that superconducts below a critical temperature. ### Claim 3 (depends on 2) The quantum processor of claim 2, further comprising: a tunable inductance interrupting the loop of superconducting material. ### Claim 4 (depends on 3) The quantum processor of claim 3, wherein the tunable inductance comprises a compound Josephson junction. ### Claim 5 (depends on 4) The quantum processor of claim 4, wherein the tunable inductance comprises a plurality of compound Josephson junctions. ### Claim 6 (depends on 1) The quantum processor of claim 1, wherein a magnetic susceptibility of the compensator circuit is opposite to a magnetic susceptibility of the flux qubit. ### Claim 7 (depends on 1) The quantum processor of claim 1, further comprising a second coupler inductively coupled to the flux qubit, wherein the compensator circuit is inductively coupled to the first coupler and the second coupler. ### Claim 8 (depends on 7) The quantum processor of claim 7, further comprising a third coupler inductively coupled to the flux qubit. ### Claim 9 (depends on 8) The quantum processor of claim 8, further comprising a fourth coupler inductively coupled to the flux qubit. ### Claim 10 (depends on 7) The quantum processor of claim 7, further comprising a global signal line inductively coupled to the flux qubit and the compensator circuit, wherein at least one of the first coupler and the second coupler couples the flux qubit to one or more additional flux qubits, and wherein each of the flux qubit and the one or more additional flux qubits are coupled to the global signal line. ### Claim 11 (depends on 10) The quantum processor of claim 10, wherein each of the first coupler and the second coupler provides controllable communicative coupling between the flux qubit and one of the one or more additional flux qubits and the global signal line. ### Claim 12 (depends on 1) The quantum processor of claim 1, further comprising a flux source coupled to the flux qubit to effect changes in a qubit bias and a tunneling rate. ### Claim 13 (depends on 1) The quantum processor of claim 1, wherein the flux qubit comprises a first loop of superconducting material that superconducts below a critical temperature and a first compound Josephson junction interrupting the first loop of superconducting material. ### Claim 14 (depends on 13) The quantum processor of claim 13, wherein the first compound Josephson junction comprises two superconducting parallel paths, each superconducting parallel path interrupted by at least one Josephson junction. ### Claim 15 (depends on 1) The quantum processor of claim 1, further comprising a global signal line inductively coupled to the flux qubit and the compensator circuit. ### Claim 16 (depends on 15) The quantum processor of claim 15, wherein the global signal line includes a persistent current compensation line. ### Claim 17 (depends on 15) The quantum processor of claim 15, wherein the global signal line includes an annealing signal line that carries an annealing signal to evolve the quantum processor during quantum annealing computation. ### Claim 18 (depends on 15) The quantum processor of claim 15, wherein a first product of the coupling of the global signal line to the compensator circuit and a magnetic susceptibility of the compensator circuit has an equal magnitude and an opposite sign to a second product of the coupling of the global signal line to the flux qubit and the magnetic susceptibility of the flux qubit.