{
  "patent_number": "US 20080238531",
  "country": "US",
  "title": "How to Connect Quantum Computer Bits with a Superconducting Circuit",
  "original_title": "Systems, devices, and methods for controllably coupling qubits",
  "summary": "This patent describes a superconducting circuit called an rf-SQUID that can precisely turn on, turn off, or change the way two quantum computer bits (qubits) interact with each other.",
  "what_it_does": "This system provides a way to controllably link two quantum bits, or qubits, using a special superconducting loop called an rf-SQUID (Claim 1). This rf-SQUID has a 'compound Josephson junction' and is connected to both a first qubit and a second qubit through magnetic fields (mutual inductance). A separate 'magnetic flux inductor' is also connected to the Josephson junction (Claim 1). By adjusting the magnetic field produced by this inductor, the system can control how the two qubits interact, allowing for different 'coupling states' such as anti-ferromagnetic coupling, ferromagnetic coupling, or even no coupling at all (Claim 3, Claim 5). For example, if you want two qubits in a quantum computer to perform a calculation together, this system could turn on their interaction, and then turn it off when they need to operate independently.",
  "what_it_does_not_cover": [
    "Does not cover qubit coupling systems that do not use an rf-SQUID as the intermediate coupling device.",
    "Does not cover coupling mechanisms that do not rely on mutual inductance between the rf-SQUID and the qubits.",
    "Does not cover control methods for qubit coupling that do not involve a magnetic flux inductor adjusting flux through a compound Josephson junction.",
    "Does not cover qubits that are not superconducting, as the claims specifically mention 'superconducting flux qubit' (Claim 2) and 'superconducting material' (Claim 1).",
    "Does not cover direct coupling between qubits without an intermediate tunable coupler."
  ],
  "filed": "2008-01-22",
  "granted": null,
  "expires": "2028-01-22",
  "status": "active",
  "holder": "Individual",
  "holder_url": "https://patentbrief.org/company/individual",
  "inventors": [
    {
      "name": "Richard G. Harris",
      "url": "https://patentbrief.org/inventor/richard-g-harris"
    }
  ],
  "times_cited": 57,
  "tags": [
    "quantum_computing",
    "semiconductors",
    "telecommunications",
    "software"
  ],
  "abstract": "A coupling system may include an rf-SQUID having a loop of superconducting material interrupted by a compound Josephson junction; and a first magnetic flux inductor configured to selectively provide a mutual inductance coupling the first magnetic flux inductor to the compound Josephson junction, wherein the loop of superconducting material positioned with respect to a first and second qubits to provide respective mutual inductance coupling therebetween. The coupling system may further include a second magnetic flux inductor configured to selectively provide a second magnetic flux inductor mutual inductance coupling the second magnetic flux inductor to the compound Josephson junction. A superconducting processor may include the coupling system and two or more qubits. A method may include providing the first, the second and the third mutual inductances.",
  "url": "https://patentbrief.org/patent/us/20080238531/systems-devices-and-methods-for-controllably-coupling-qubits",
  "markdown_url": "https://patentbrief.org/patent/us/20080238531/systems-devices-and-methods-for-controllably-coupling-qubits/md",
  "google_patents_url": "https://patents.google.com/patent/US20080238531",
  "relatedPatents": [
    {
      "patentNumber": "11295225",
      "countryCode": "US",
      "title": "How D-Wave Clears Magnetic Noise in Quantum Computers",
      "url": "https://patentbrief.org/patent/us/11295225/superconducting-quantum-processor-and-method-of-operating-same"
    },
    {
      "patentNumber": "9256834",
      "countryCode": "US",
      "title": "How Quantum Computers Use Special Devices to Control Qubits",
      "url": "https://patentbrief.org/patent/us/9256834/quantum-computers-having-partial-interferometric-quantum-gates"
    },
    {
      "patentNumber": "20230229951",
      "countryCode": "US",
      "title": "How to Build a Room-Temperature Quantum-Like Computer with Regular Electronics",
      "url": "https://patentbrief.org/patent/us/20230229951/quantum-analog-computing-at-room-temperature-using-conventional-electronic-circu"
    },
    {
      "patentNumber": "12008436",
      "countryCode": "US",
      "title": "Solving Big Math Problems with Small Quantum Computers",
      "url": "https://patentbrief.org/patent/us/12008436/machine-learning-mapping-for-quantum-processing-units"
    },
    {
      "patentNumber": "20240296359",
      "countryCode": "US",
      "title": "How Quantum Computers Learn to Sort Data",
      "url": "https://patentbrief.org/patent/us/20240296359/classification-using-quantum-neural-networks"
    }
  ]
}