Patent Application 17488203 - Qubit Detection Using Superconductor Devices - Rejection
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Patent Application 17488203 - Qubit Detection Using Superconductor Devices
Title: Qubit Detection Using Superconductor Devices
Application Information
- Invention Title: Qubit Detection Using Superconductor Devices
- Application Number: 17488203
- Submission Date: 2025-05-20T00:00:00.000Z
- Effective Filing Date: 2021-09-28T00:00:00.000Z
- Filing Date: 2021-09-28T00:00:00.000Z
- National Class: 505
- National Sub-Class: 170000
- Examiner Employee Number: 81033
- Art Unit: 1735
- Tech Center: 1700
Rejection Summary
- 102 Rejections: 1
- 103 Rejections: 6
Cited Patents
The following patents were cited in the rejection:
Office Action Text
Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Election/Restrictions Applicant’s election without traverse of Group III, claims 16-26 in the reply filed on 04/29/2025 is acknowledged. Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. Claim(s) 16-17, 19, 21 is/are rejected under 35 U.S.C. 102a1/a2 as being anticipated by Esteve (US 2003/0207766). Regarding claim 16, Esteve discloses a circuit (Fig 7, abstract), comprising: a first resonant circuit (box 110 including a qubit meets limitation of resonant circuit; para. 0056) having a first magnetic flux while the first resonant circuit (110) is in a first state (i.e., |0> state) and a second magnetic flux while the first resonant circuit is in a second State (i.e., |1> state) (Fig 7, para (0056), ..applying, from a source 122, radiofrequency pulses u(t) at or close to resonance, with the qubit of the box 110...a current source 125 is applied to the read out junction 105 in order to bring it close to its critical current..", para (0088)], *..Reading the state of the qubit according to the invention is optimized by choosing the magnetic flux [phi] induced through the superconducting loop so that the loop currents i0 and i1 associated with the |0> and |1> states, ascertained by the read pulse, are as different as possible.."); a detection circuit (105, 161) comprising: a superconducting component (105) located adjacent to and coupled with the first resonant circuit (110) (Fig 7, para (0056), “..a third Josephson junction 105, which is included in an S-type superconducting loop closing up onto the Cooper-pair box 110 and constituting the detecting element of the read circuit.."), wherein the superconducting component (105) is configured to: receive an input current (from current source 125) (Fig 7, para [0056], "..a current source 125 is applied to the read out junction 105 in order to bring it close to its critical current.."); operate in a superconducting state while a temperature of the superconducting component is below a superconducting threshold temperature and a current carried in the superconducting component is below a threshold current (implicit to maintaining superconductivity and switching between first and second qubits states via different loop currents, the “threshold current" being between the two loop current states i0 and i1) of the superconducting component (Fig 7, para [0088], ”..loop currents iO and i1 associated with the |O> and |1> states, ascertained by the read pulse, are as different as possible..”, para [0115], "The operating temperature of the circuit must be well below the transition energy of the qubit divided by the Boltzmann constant.."); and generate a flux-induced current based on a state of the first resonant circuit (110) (Fig 7, para [0088], "..Reading the state of the qubit according to the invention is optimized by choosing the magnetic flux [phi] induced through the superconducting loop so that the loop currents i0 and i1 associated with the {0> and |1> states, ascertained by the read pulse, are as different as possible..") such that: the superconducting component (105) carries a first current (i0), less than the threshold current, while the first resonant circuit (110) is in the first state (10) and has the first magnetic flux; and the superconducting component (105) carries a second current (i1) that exceeds the threshold current (“critical current") while the first resonant circuit (110) is in the second state and has the second magnetic flux, thereby transitioning the superconducting component (105) to a non-superconducting state while the first resonant circuit (110) is in the second state (Fig 7, para [0056], "..a current source 125 is applied to the read out junction 105 in order to bring it close to its critical current..”, para {0086}, "..During reading, the current must be close to the critical current of the read junction 105 so as to be able to have transition rates close to 0% and 100% for the two states of the qubit, respectively..", para [0088], “..Reading the state of the qubit according to the invention is optimized by choosing the magnetic flux (phi) induced through the superconducting loop so that the loop currents i0 and i1 associated with the |0> and |1> states, ascertained by the read pulse, are as different as possible..", para [0121], "The magnetic flux [phi] is adjusted by a variable current source 135..", note: the term "critical current” is recognized in the field of superconductor materials as a current above which the material loses superconductivity, additionally a current exceeding the threshold current would necessarily transition the superconducting component to a non-superconducting state); and an impedance component (161) coupled to the superconducting component (105) on one end and configured, on another end, to be coupled to a second circuit (162, 126) (Fig 7, para [0123], “..resistor 161 which increases the impedance of the circuit located downstream. This circuit includes a low-pass filter 162 and then an amplifier 126 having a high input impedance."). Regarding claim 17, Esteve discloses the subject matter of claim 16, as described above, wherein the second circuit (162, 126) comprises a circuit that produces a first output while the superconducting component is in the superconducting state and a second output, different from the first output, while the superconducting component is in the non-superconducting state (Fig 7, para [0056], "..a current source 125 is applied to the read out junction 105 in order to bring it close to its critical current...reading is achieved by measuring the voltage V at the terminals of the read junction 105 using an amplifier circuit 126. The two states of the qubit correspond faithfully to the appearance or absence of a finite voltage..", note: the term “critical current” is recognized in the field of superconductor materials as a current above which the material loses superconductivity, thus appearance of a finite voltage for the second qubit state corresponds to current flowing through a non-zero resistance and thus a loss of superconductivity). Regarding claim 19, Esteve teaches the superconducting component 105 includes a loop located adjacent to and coupled with the resonant circuit 110 (para. 0056; fig. 7). Regarding claim 21, Esteve teaches the second magnetic flux is larger than the first magnetic flux; and the flux-induced current in the superconducting component while the first resonant circuit is in the second state is larger than the flux-induced current in the superconducting component while the first resonant circuit is in the first state (Fig 7, para [0086}, “..During reading, the current must be close to the critical current of the read junction 105 so as to be able to have transition rates close to 0% and 100% for the two states of the qubit, respectively..", para [0088], "..Reading the state of the qubit according to the invention is optimized by choosing the magnetic flux [phi] induced through the superconducting loop so that the loop currents i0 and i1 associated with the |0> and [1> states, ascertained by the read pulse, are as different as possible..”, note: it is implicit that the second magnetic flux, associated with the second current, would be greater than the first magnetic flux, associated with the first current, since a greater current, and thus greater magnetic flux, would be necessary to transition above the critical current of the read junction 105). Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claim(s) 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Esteve in view of Najafi (US 20190148848). Esteve teaches an apparatus as described above in claim 16, but fails to teach the resistive component is coupled in parallel to the superconducting component, the resistive component having a resistance that is smaller than a resistance of the superconducting component while the superconducting component is in the non-superconducting state such that at least a portion of the input current is redirected from the superconducting component to the second circuit while the superconducting component is in the non-superconducting state. Najafi, however, teaches a superconductor circuit (abstract) wherein resistive component is coupled in parallel to the superconducting component, the resistive component having a resistance that is smaller than a resistance of the superconducting component while the superconducting component is in the non-superconducting state such that at least a portion of the input current is redirected from the superconducting component to the second circuit while the superconducting component is in the non-superconducting state (para. 0039). Therefore, it would have been obvious to one of ordinary skill in the art to provide resistive component is coupled in parallel to the superconducting component, the resistive component having a resistance that is smaller than a resistance of the superconducting component while the superconducting component is in the non-superconducting state such that at least a portion of the input current is redirected from the superconducting component to the second circuit while the superconducting component is in the non-superconducting state in Esteve in order to provide a configuration known in the art as taught by Najafi. Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Esteve in view of Berggren (US 2020/0027502). Esteve teaches an apparatus as described above in claim 16, but fails to teach the superconducting component includes a wire that has an asymmetrical width such that a first portion of the wire has a first width and a second portion of the wire has a second width that is greater than the first width. Berggren is relevant to superconducting circuit components (abstract) and suggests including a superconducting wire (210) that has an asymmetrical width (218) such that a first portion of the wire (210) has a first width and a second portion of the wire has a second width that is greater than the first width to promote current crowding and improve switching efficiency between superconducting and non-superconducting states (Fig 2A, 2B, para [0044], "..constriction 218 can be formed as a narrowing of the superconductor material (e.g.. to form a nanowire) that results in a region with reduced critical current...switch from a superconducting state into the normal resistive state.."). It would have been obvious to a person of ordinary skill in the art at the time of the invention to provide the superconducting component of Esteve to include a wire that has an asymmetrical width such that a first portion of the wire has a first width and a second portion of the wire has a second width that is greater than the first width to promote current crowding and improve switching efficiency between superconducting and non-superconducting states as suggested by Berggren. Claim(s) 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Esteve in view of Wakana (US 20070158791). Esteve teaches an apparatus as described above in claim 16, but fails to teach the flux-induced current has a same direction as the input current. Wakana is relevant to superconducting circuits (abstract) and suggests applying a flux- induced current in a same direction as an input current to facilitate switching the superconducting state (Fig 14, para [0102], "..the switching of the superconducting junction J6 occurs because the circulating current and the current pulse caused the flux quantum flow in the same direction.."). It would have been obvious to a person of ordinary skill in the art at the time of the invention to provide the flux- induced current of Esteve to have a same direction as the input current to facilitate switching of the superconducting state as suggested | by Wakana. Claim(s) 23 is/are rejected under 35 U.S.C. 103 as being unpatentable over Esteve in view of Thomas (US 2019/0164959). Esteve teaches an apparatus as described above in claim 16, as described above, wherein the first resonant circuit (110) is a qubit (Fig 7, para [0056], "..applying, from a source 122, radiofrequency pulses u(t) at or close to resonance, with the qubit of the box 110..”) but fails to teach to specify wherein the qubit is a tansmon superconducting qubit. Thomas is relevant to quantum circuitry (abstract) and suggests that transmon superconducting qubits were known to be used for resonant readout and have less sensitivity to charge noise (Fig 15, para [0065], “..superconducting qubit implementations...Transmons...exhibit reduced sensitivity to charge noise.", para [0081], °..a readout ‘resonator 218 may be provided to each qubit...the qubit is implemented as a transmon.."). It would have been obvious to a person of ordinary skill in the art at the time of the invention to provide the resonant circuit qubit of Esteve as a transmon superconducting qubit to provide reduced sensitivity to charge noise as suggested by Thomas. Claim(s) 24 is/are rejected under 35 U.S.C. 103 as being unpatentable over Esteve in view of Blais (US 2004/0077503). Esteve teaches an apparatus as described above in claim 16, but fails to teach a second resonant circuit coupled to the first resonant circuit such that the second resonant circuit and first resonant circuit exhibit quantum entanglement. Blais is also related to coupling resonant and superconducting circuits and suggests coupling multiple resonant circuits (120-1 through 120-N) and qubits (310-1 through 310-N) via quantum entanglement (Fig 3, para [0063)). It would have been obvious to a person of ordinary skill in the art at the time of the invention to include a second resonant circuit coupled to the first resonant circuit of Esteve such that the second resonant circuit and first resonant circuit exhibit quantum entanglement to scale up to larger quantum computing circuits as suggested by Blais and because duplication of parts is prima facie obvious. MPEP 2144.04 (VI) (B). Claim(s) 25-26 is/are rejected under 35 U.S.C. 103 as being unpatentable over Esteve in view of Minev (US 2018/0069288). Esteve teaches an apparatus as described above in claim 16, but fails to teach: the (superconducting) detection circuit is formed on a first layer; and the first resonant circuit is formed on a second layer distinct from the first layer. Minev is also related to quantum computing circuitry (abstract) and suggests forming resonant qubit circuitry (412, 414, 415) in a different layer from other superconducting circuitry on a substrate (451, 452, 453) to facilitate manufacture of three dimensional circuitry and thus improve scalability (Fig 4A, 4B, para [0007], {(0066)). It would have been obvious to a person of ordinary skill in the art at the time of the invention to form the (superconducting) detection circuit of Esteve on a first layer; and the first resonant circuit formed on a second layer distinct from the first layer to facilitate manufacture of three dimensional circuitry and thus improve scalability as suggested by Minev and because integration of parts and rearrangement of parts is prima facie obvious. MPEP 2144.04 (V)(B) and MPEP 2144.04 (VI)(C). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to PAUL A WARTALOWICZ whose telephone number is (571)272-5957. The examiner can normally be reached Monday-Friday 9 am - 5 pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Keith Walker can be reached at 571-272-3458. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735