DETAILED ACTION
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 .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 10/28/24 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-7, 11, 12, 15 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claims 1, 2, 5, 6, 7, 11, 12, 15, the phrase "such as" or “preferably”, “e.g.” renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. See MPEP § 2173.05(d).
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.
Claim 1, 3, 6-10, 12-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Grover et al., “Fast Lifetime-Preserving Readout for High-Coherence Quantum Annealers” in view of Abdo, US 20190156238
Regarding claim 1, Grover discloses a method for measuring a direction of current in a flux qubit (Abstract; “read out flux qubit in the persistent current basis”), the method comprising providing a probe signal to a resonator circuit, the resonator circuit having a resonance frequency, the probe signal transmitting through or reflecting from the resonator circuit (Fig. 1a; flux qubit to QFP to rf-SQUID to Resonator), wherein the resonator circuit comprises a SQUID comprising a first superconducting loop interrupted by a first Josephson junction and the first superconducting loop of the SQUID being coupled to the flux qubit via inductive coupling (Fig. 1a; Qubit to rf-SQUID, Resonator; Fig. 7; Qubit, Josephson junction); measuring the reflected probe signal that has reflected from the resonator circuit or, respectively, measuring the transmitted probe signal that has transmitted through the resonator circuit (Fig. 1a; Page 3-4; Readout Protocol; “measuring transmission through a feedline”); and, determining the direction of current in the flux qubit based on a difference, such as a phase difference, between the provided probe signal and the reflected probe signal or, respectively, between the provided probe signal and the transmitted probe signal (Page 8; “state discrimination relied on simple thresholding in the in-phase and quadrature plane”).
Grover is silent in a DC SQUID and a second Josephson junction, the first Josephson junction and second Josephson junction being connected in parallel and the conducting loop of the DC SQUID being directly coupled to the flux qubit. Abdo teaches a DC SQUID having a first and a second Josephson junction (Fig. 1; DC SQUID 102 having junctions 102-1, 102-1), the first Josephson junction and second Josephson junction being connected in parallel and the DC SQUID being directly coupled to a flux qubit (¶[0051]; qubit coupled to resonator 100 using nodes 106, 108). It would have been obvious to one of ordinary skill in the art before the filing date of the invention to incorporate the teaching of Abdo into Grover since the substitution would produce the predictable result of reading the qubit states.
Regarding claim 3, Abdo teaches wherein the method further comprises: using a flux generating circuit that is inductively coupled to the first superconducting loop of the resonator circuit, providing a magnetic flux to the first superconducting loop herewith controlling the resonant frequency of the resonator circuit; and/or, wherein the first Josephson junction has a first critical current value and the second Josephson junction has a second critical current value, wherein the first critical current value is equal to the second critical current value or wherein the first critical current value is different from the second critical current value (Abstract; critical currents are different). It would have been obvious to one of ordinary skill in the art before the filing date of the invention to incorporate the teaching of Abdo into Grover since the substitution would produce the predictable result of reading the qubit states.
Regarding claim 6, Grover teaches wherein the probe signal is provided to the resonator circuit via a probe line, the method comprising preventing noise signals arriving via the probe line from reaching the resonator circuit using a filter, such as a resonator filter (Fig. 6; probe signal is filtered using multiple filters). Grover is silent in wherein the filter is a bandpass filter. However, it would be within the level of ordinary skill in the art to substitute the bandpass filter so that the less desired frequencies are filtered out.
Regarding claim 7, Grover teaches further comprising after bandpass filtering the reflected or transmitted probe signal, amplifying the reflected or transmitted probe signal using a quantum-limited amplifier, such as a traveling-wave parametric amplifier (Fig. 6; probe signal amplified by amplifier after filtering).
Regarding claim 8, Grover discloses a system for measuring a direction of current in a flux qubit (Abstract; “read out flux qubit in the persistent current basis”) comprising: a resonator circuit having a resonance frequency (Fig. 1a; flux qubit to QFP to rf-SQUID to Resonator), the resonator circuit comprises a DC SQUID comprising a first superconducting loop interrupted by a first Josephson junction and connected via inductive coupling (Fig. 1a; Qubit to rf-SQUID, Resonator; Fig. 7; Qubit, Josephson junction); a probe signal provisioning system for providing a probe signal to the resonator circuit such that the probe signal transmits through or reflects from the resonator circuit (Fig. 1a; signal transmitted to Resonator); a measurement system for measuring the reflected probe signal that has reflected from the resonator circuit or, respectively, for measuring the transmitted probe signal that has transmitted through the resonator circuit (Fig. 1a; Page 3-4; Readout Protocol; “measuring transmission through a feedline”); and, a signal analysis system for determining a difference between the provided probe signal and the reflected probe signal or, respectively, between the provided probe signal and the transmitted probe signal (Page 8; “state discrimination relied on simple thresholding in the in-phase and quadrature plane”)..
Grover is silent in a DC SQUID and a second Josephson junction, the first Josephson junction and second Josephson junction being connected in parallel and the conducting loop of the DC SQUID being directly coupled to the flux qubit. Abdo teaches a DC SQUID having a first and a second Josephson junction (Fig. 1; DC SQUID 102 having junctions 102-1, 102-1), the first Josephson junction and second Josephson junction being connected in parallel and the DC SQUID being directly coupled to a flux qubit (¶[0051]; qubit coupled to resonator 100 using nodes 106, 108). It would have been obvious to one of ordinary skill in the art before the filing date of the invention to incorporate the teaching of Abdo into Grover since the substitution would produce the predictable result of reading the qubit states.
Regarding claim 10, Grover is silent in wherein the first Josephson junction has a first critical current and the second Josephson junction has a second critical current that may be different from the first critical current. Abdo teaches wherein the first Josephson junction has a first critical current value and the second Josephson junction has a second critical current value, wherein the first critical current value is equal to the second critical current value or wherein the first critical current value is different from the second critical current value (Abstract; critical currents are different). It would have been obvious to one of ordinary skill in the art before the filing date of the invention to incorporate the teaching of Abdo into Grover since the substitution would produce the predictable result of reading the qubit states.
Regarding claim 12, Grover teaches a filter that is configured to prevent noise signals, that come from a probe line via which the probe signal is provided to the resonator circuit, from reaching the resonator circuit (Fig. 6; probe signal is filtered using multiple filters). Grover is silent in wherein the filter is a bandpass filter. However, it would be within the level of ordinary skill in the art to substitute the bandpass filter so that the less desired frequencies are filtered out.
Regarding claim 13, Grover teaches further comprising a quantum-limited amplifier that is configured to amplify the transmitted or reflected probe signal (Fig. 6; probe signal amplified by amplifier after filtering).
Regarding claim 14, Grover teaches wherein at least part of the system is in a cryogenic environment and wherein said at least part of the system in the cryogenic environment does not comprise a resistor (Fig. 6; cryogenic circulator).
Regarding claim 15, Grover teaches based on the difference between the probe signal and the reflected probe signal or, respectively, between the probe signal and the transmitted probe signal, such as a phase difference, determining the current direction in the flux qubit (Page 8; “state discrimination relied on simple thresholding in the in-phase and quadrature plane”).
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Grover et al., “Fast Lifetime-Preserving Readout for High-Coherence Quantum Annealers” in view of Abdo, US 20190156238 in view of Przybysz et al., CA 3088449
Regarding claim 9, Grover is silent in a flux generating circuit that is inductively coupled to the first superconducting loop of the resonator circuit and that is configured to provide a magnetic flux to the first superconducting loop for controlling the resonant frequency of the resonator circuit. Przybysz teaches a flux generating circuit that is inductively coupled to the first superconducting loop of the resonator circuit and that is configured to provide a magnetic flux to the first superconducting loop for controlling the resonant frequency of the resonator circuit (Fig. 2; signal line 232 to loop of 228). It would have been obvious to one of ordinary skill in the art before the filing date of the invention to incorporate the teaching of Przybysz into Grover for the benefit of controlling the state of the qubit.
Allowable Subject Matter
Claims 2, 4, 5, 11 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter:
Regarding claim 2, prior art does not disclose or suggest: “wherein the resonator circuit is controlled to be in a first state or in a second state, preferably based on a first flux signal or a second flux signal respectively, wherein in the first state the resonator circuit is insensitive to small flux variations so that it decouples from the flux qubit and wherein in the second state the resonator circuit is sensitive to small flux variations so that it is coupled to the flux qubit for determining the direction of the current in the flux qubit” in combination with all the limitations of claim 2.
Regarding claim 4, prior art does not disclose or suggest: “wherein the resonator circuit comprises a second superconducting loop that is interrupted by the second Josephson junction, the method comprising using a second flux generating circuit that is inductively coupled to the second superconducting loop of the resonator circuit, to provide a magnetic flux to the second superconducting loop for biasing the first superconducting loop with a bias current, preferably to provide a first magnetic flux value to the second superconducting loop so that the resonator circuit is insensitive to small flux variations and therefore decouples from the flux qubit, while the flux qubit is being operated, or to provide a second flux value to the second superconducting loop so that the resonator circuit is sensitive to small flux variations when a current direction of the flux qubits needs to be determined” in combination with all the limitations of claim 4.
Regarding claim 5, prior art does not disclose or suggest: “wherein due to an inductive coupling between the first superconducting loop and the flux qubit, the resonant frequency of the resonator circuit has a first value when the current in the flux qubit has a first direction, e.g. a clockwise direction, and has a second value, different from the first value, when the current in the flux qubit has a second direction, e.g. a counter-clockwise direction, and wherein the probe signal provided to the resonator circuit has a frequency lower than the first or second value and higher than the second or, respectively, first value” in combination with all the limitations of claim 5.
Regarding claim 11, prior art does not disclose or suggest: “wherein the resonator circuit comprises a second superconducting loop that is interrupted by the second Josephson junction, the system further comprising a second flux generating circuit that is inductively coupled to the second superconducting loop of the resonator circuit, and that is configured to provide a magnetic flux to the second superconducting loop, preferably that is configured to provide a first magnetic flux value to the second superconducting loop so that the resonator circuit is insensitive to flux and therefore decouples from the flux qubit, while the flux qubit is being operated, or to provide a second flux value to the second superconducting loop so that the resonator circuit is sensitive to flux when the current direction of the flux qubits needs to be determined” in combination with all the limitations of claim 11.
Conclusion
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/FEBA POTHEN/Examiner, Art Unit 2858
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