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.
Claim Objections
Claim 12 objected to because of the following informalities: “transmon-type qubits” should read “transom-type qubits”. Appropriate correction is required.
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 1-14 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 and 13-14, “determining the fidelity of the two-qubit gate” renders the claim indefinite because it is unclear if the two-qubit gate is the qubit gate of the preamble.
Claims 2-12 are indefinite by virtue of dependency on claim 1.
Claim Rejections - 35 USC § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claims 1-14 are rejected under 35 U.S.C. 101 because the claimed invention is directed to an abstract idea without significantly more.
Claim 1
Step 1: Is the claim to a process, machine, manufacture, or composition of matter?
Yes. Claim 1 is drawn to a process (method).
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 1 recites the following abstract ideas:
determining a first target matrix and a corresponding first evolution matrix, based on the two-qubit gate and the environmental qubit gates, wherein the first target matrix is a diagonal matrix constructed based on a logic gate, and the first evolution matrix is a matrix obtained after time-dependent evolution - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
determining the fidelity of the two-qubit gate based on the number of the environmental qubit gates associated with the two-qubit gate, the first target matrix, and the first evolution matrix - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Step 2A, Prong Two: Does the claim recite additional elements that integrate the judicial exception into a practical application?
No. Claim 1 recites the following additional elements:
a qubit gate in a quantum chip - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
determining environmental qubit gates associated with a two-qubit gate in the quantum chip, wherein the two-qubit gate interacts with the environmental qubit gates in the quantum chip - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
Step 2B: Does the claim recite additional elements that amount ot significantly more than the judicial exception?
No. Claim 1 recites the following additional elements:
a qubit gate in a quantum chip - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
determining environmental qubit gates associated with a two-qubit gate in the quantum chip, wherein the two-qubit gate interacts with the environmental qubit gates in the quantum chip - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
Claim 2
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 2 recites the following abstract ideas:
when the two-qubit gate does not interact with the environmental qubit gates, the fidelity of the two-qubit gate is determined by a second target matrix and a second evolution matrix, the second target matrix is used for representing the logic gate, and the second evolution matrix comprises a plurality of block matrices obtained after time-dependent evolution - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
determining the first target matrix and the corresponding first evolution matrix comprises: adjusting the second target matrix based on the environmental qubit gates to obtain the first target matrix; and adjusting the second evolution matrix based on the environmental qubit gates to obtain the first evolution matrix - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Claim 3
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 3 recites the following abstract ideas:
adjusting the second target matrix based on the environmental qubit gates to obtain the first target matrix comprises: performing tensor processing on the second target matrix based on the environmental qubit gates to obtain the first target matrix - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Claim 4
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 4 recites the following abstract ideas:
adjusting the second evolution matrix based on the environmental qubit gates to obtain the first evolution matrix comprises: rotating the second evolution matrix based on the environmental qubit gates to obtain the first evolution matrix - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Claim 5
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 5 recites the following abstract ideas:
determining the fidelity of the two-qubit gate based on the number of the environmental qubit gates associated with the two-qubit gate, the first target matrix, and the first evolution matrix comprises: obtaining a first trace of a product between a conjugate transpose matrix of the first evolution matrix and the first evolution matrix; obtaining a second trace of a product between a conjugate transpose matrix of the first target matrix and the first evolution matrix; and determining the fidelity of the two-qubit gate based on the first trace, a square of the second trace, and the number of the environmental qubit gates associated with the two-qubit gate - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Claim 6
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 6 recites the following abstract ideas:
determining the fidelity of the two-qubit gate based on the first trace, the square of the second trace, and the number of the environmental qubit gates associated with the two-qubit gate comprises: determining the fidelity of the two-qubit gate based on the first trace, the square of the second trace, the number of the environmental qubit gates, and an adjacent integer of the number of the environmental qubit gates - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Claim 7
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 7 recites the following abstract ideas:
when the two-qubit gate does not interact with the environmental qubit gates, the fidelity of the two-qubit gate is determined at least by a second evolution matrix, and obtaining a first trace of a product between a conjugate transpose matrix of the first evolution matrix and the first evolution matrix comprises: determining a third trace of a product between a conjugate transpose matrix of the second evolution matrix and the second evolution matrix as the first trace - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Claim 8
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 8 recites the following abstract ideas:
wherein obtaining a second trace of a product between a conjugate transpose matrix of the first target matrix and the first evolution matrix comprises: determining the second trace based on the sum of block matrices on a diagonal line of the second evolution matrix - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Claim 9
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 9 recites the following abstract ideas:
determining an initial time for evolution and an evolution duration of the quantum chip; dividing the evolution duration into a plurality of equal sub-evolution durations; and determining time-dependent Hamiltonian corresponding to each of the plurality of sub-evolution durations of the quantum chip based on the first evolution matrix, the initial time, and each of the plurality of sub-evolution durations - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Claim 10
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 10 recites the following abstract ideas:
determining a final state of the quantum chip after evolving from an initial state for the evolution duration at least based on the time-dependent Hamiltonian corresponding to each of the plurality of sub-evolution durations of the quantum chip, each of the plurality of sub-evolution durations, and the number of the plurality of sub-evolution durations - This is an observation, evaluation, judgement, or opinion, i.e. a concept performed in the human mind. See MPEP 2106.04(a)(2), III and/or a mathematical concept, see MPEP 2106.04(a)(2), I.
Claim 11
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 11 recites the following abstract ideas:
The abstract ideas of claim 1.
Step 2A, Prong Two: Does the claim recite additional elements that integrate the judicial exception into a practical application?
No. Claim 11 recites the following additional elements:
a superconducting quantum chip - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
Step 2B: Does the claim recite additional elements that amount ot significantly more than the judicial exception?
No. Claim 11 recites the following additional elements:
a superconducting quantum chip - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
Claim 12
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 12 recites the following abstract ideas:
The abstract ideas of claim 1.
Step 2A, Prong Two: Does the claim recite additional elements that integrate the judicial exception into a practical application?
No. Claim 12 recites the following additional elements:
wherein the superconducting quantum chip comprises fluxonium-type qubits, or transmon-type qubits - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
Step 2B: Does the claim recite additional elements that amount ot significantly more than the judicial exception?
No. Claim 12 recites the following additional elements:
wherein the superconducting quantum chip comprises fluxonium-type qubits, or transmon-type qubits - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
Claim 13
The analysis for claim 13 is the as that for claim 1. Regarding portions of claim 13 not found in claim 1:
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 13 recites the following abstract ideas:
See analysis of claim 1
Step 2A, Prong Two: Does the claim recite additional elements that integrate the judicial exception into a practical application?
No. Claim 13 recites the following additional elements:
acquiring, by invoking a first interface, environmental qubit gates associated with a two-qubit gate in the quantum chip, wherein the first interface comprises a first parameter having a first parameter value corresponding to the two-qubit gate and the environmental qubit gates - The sending and/or receiving of data is an insignificant extra-solution activity in the form of mere data gathering.. See MPEP 2106.05(g).
outputting the fidelity of the two-qubit gate by invoking a second interface, wherein the second interface comprises a second parameter having a second parameter value representing the fidelity of the two-qubit gate - The sending and/or receiving of data is an insignificant extra-solution activity in the form of mere data gathering. See MPEP 2106.05(g).
Step 2B: Does the claim recite additional elements that amount ot significantly more than the judicial exception?
No. Claim 13 recites the following additional elements:
acquiring, by invoking a first interface, environmental qubit gates associated with a two-qubit gate in the quantum chip, wherein the first interface comprises a first parameter having a first parameter value corresponding to the two-qubit gate and the environmental qubit gates - The sending and/or receiving of data is an insignificant extra-solution activity in the form of mere data gathering. See MPEP 2106.05(g).
outputting the fidelity of the two-qubit gate by invoking a second interface, wherein the second interface comprises a second parameter having a second parameter value representing the fidelity of the two-qubit gate - The sending and/or receiving of data is an insignificant extra-solution activity in the form of mere data gathering. See MPEP 2106.05(g).
Claim 14
The analysis for claim 14 is the as that for claim 1. Regarding portions of claim 14 not found in claim 1:
Step 2A, Prong One: Does the claim recite an abstract idea, law of nature, or natural phenomenon?
Yes. Claim 14 recites the following abstract ideas:
See analysis of claim 1
Step 2A, Prong Two: Does the claim recite additional elements that integrate the judicial exception into a practical application?
No. Claim 14 recites the following additional elements:
from a quantum platform - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
returning the fidelity of the two-qubit gate to the quantum platform. - The sending and/or receiving of data is an insignificant extra-solution activity in the form of mere data gathering.. See MPEP 2106.05(g).
Step 2B: Does the claim recite additional elements that amount ot significantly more than the judicial exception?
No. Claim 14 recites the following additional elements:
from a quantum platform - merely reciting the words “apply it” (or an equivalent) with the judicial exception, or merely including instructions to implement an abstract idea on a computer, or merely using a computer as a tool to perform an abstract idea. See MPEP 2106.05(f).
returning the fidelity of the two-qubit gate to the quantum platform. - The sending and/or receiving of data is an insignificant extra-solution activity in the form of mere data gathering.. See MPEP 2106.05(g).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-8 and 11-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Goto (Goto, Hayato. "Double-transmon coupler: Fast two-qubit gate with no residual coupling for highly detuned superconducting qubits." Physical review applied 18.3 (2022): 034038.) in view of Kueng (Kung, Richard, et. al. “Supplemental Material: Comparing Experiments to the Fault-Tolerance Threshold”, September 1, 2016).
Note: Prior art is directly quoted to show mappings to claim limitations. Quotations from the prior art appear within quotes, e.g. “Quoted passage from prior art” and limitations from the claim are bolded and within square brackets ([bold]) to indicate that the portion of the quoted passage preceding the square brackets teaches the limitation within the brackets.
Regarding claim 1, Goto teaches
a method for determining fidelity of a qubit gate in a quantum chip (Appendix B: Average Fidelity and Rotation Angle of the CPHASE Gate, “The average fidelities in Fig. 3(d) are obtained using the formula in Ref. [76], which is an extension of the formula in Ref. [77]…[a method for determining fidelity of a qubit gate]”, §1, “Tunable couplers have recently become a key component for high-fidelity two-qubit gates in superconducting quantum computers…[in a quantum chip]”), comprising:
determining environmental qubit gates associated with a two-qubit gate in the quantum chip (Appendix B, Equation B1, reproduced below, where U’ is the environmental qubit gate and Uid is the two-qubit gate, “Suppose that we simulate the gate operation on four initial states, each of which is one of the four two-qubit basis vectors…[determining environmental qubit gates], “In the case of the CPHASE gate, we defined Uid …” [associated with a two-qubit gate in the quantum chip]), wherein
the two-qubit gate interacts with the environmental qubit gates in the quantum chip (Appendix B, “Suppose that we simulate the gate operation on four initial states, each of which is one of the four two-qubit bases vectors…[the two-qubit gate interacts with the environmental qubit gates in the quantum chip]”);
determining a first target matrix and a corresponding first evolution matrix, based on the two-qubit gate and the environmental qubit gates (See Equation B1, reproduced below. The first target matrix is Uid because it represents the ideal gate and U’ is a corresponding first evolution matrix because it represents the actual, evolved state), wherein
the first target matrix is a diagonal matrix constructed based on a logic gate (Appendix B, “In the case of the CPHASE gate, we define Uid as Uid=diag(eiθ0, eiθ1 , eiθ2, eiθ3), where diag(…) represents a diagonal matrix…” [the first target matrix is a diagonal matrix based on a logic gate]”) and
the first evolution matrix is a matrix obtained after time-dependent evolution (Appendix B, “Suppose that we simulate the gate operation on four initial states, each of which is one of the four two-qubit bases vectors |ψij>…the resultant vectors |ψ’ij>…U’ is defined as U’2j+j,2i’+j’ = <ψij|ψ’i’j’>”[the first evolution matrix is obtained after time-dependent evolution]; and
determining the fidelity of the two-qubit gate based on the number of the environmental qubit gates associated with the two-qubit gate, the first target matrix, and the first evolution matrix (Appendix B, see Equation B1 below, where some number of environmental qubit gates are associated with the two-qubit gate because that is what is being measured, the first target matrix is Uid and the first evolution matrix is U’).
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150
619
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Greyscale
Goto does not explicitly show how Equation B1 includes “based on the number of environmental qubit gates associated with the two-qubit gate”.
Kueng shows, see Equation (1) reproduced below, where the denominator is equal to d(d+1) where d is the system size.
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media_image2.png
63
263
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Greyscale
As noted above with respect to Goto, four qubits are considered in Equation B1, therefor d = 4 and d(d+1) = 20, providing the denominator of Equation B1.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to utilize d(d+1) in the denominator of Goto as taught by Kueng in order to provide a more generalizable form of the fidelity equation.
Regarding claim 2, Goto as modified teaches all of the limitations of claim 1.
The limitations “the fidelity of the two-qubit gate is determined by a second target matrix and a second evolution matrix, the second target matrix is used for representing the logic gate, and the second evolution matrix comprises a plurality of block matrices obtained after time-dependent evolution; and determining the first target matrix and the corresponding first evolution matrix comprises: adjusting the second target matrix based on the environmental qubit gates to obtain the first target matrix; and adjusting the second evolution matrix based on the environmental qubit gates to obtain the first evolution matrix” in claim 2 are contingent on “when the two-qubit gate does not interact with the environmental qubit gates”. Per MPEP 2111.04, II, the contingent limitations are not required under the broadest reasonable interpretation of the claim because they are contingent on a step that does not need to be performed / are contingent on a condition that does not necessarily occur.
Therefore, Goto as modified teaches all of the limitations of claim 2 under its broadest reasonable interpretation.
Beyond the technical rejection based on MPEP 2111.04, II detailed above, the prior art does not anticipate or render obvious the limitations of the claim. Goto or Goto as modified does not anticipate or render obvious the limitations and one of ordinary skill in the art would not have an obvious roadmap for arriving at the claimed invention.
Regarding claim 3, Goto as modified teaches all of the limitations of claim 2.
The limitations “adjusting the second target matrix based on the environmental qubit gates to obtain the first target matrix comprises: performing tensor processing on the second target matrix based on the environmental qubit gates to obtain the first target matrix” is a sub-limitation of the contingent limitations in claim 2. Per MPEP 2111.04, II, the contingent limitations are not required under the broadest reasonable interpretation of the claim because they are contingent on a step that does not need to be performed / are contingent on a condition that does not necessarily occur.
Therefore, Goto as modified teaches all of the limitations of claim 3 under its broadest reasonable interpretation.
Beyond the technical rejection based on MPEP 2111.04, II detailed above, the prior art does not anticipate or render obvious the limitations of the claim. Goto or Goto as modified does not anticipate or render obvious the limitations and one of ordinary skill in the art would not have an obvious roadmap for arriving at the claimed invention.
Regarding claim 4, Goto as modified teaches all of the limitations of claim 2.
The limitations “adjusting the second evolution matrix based on the environmental qubit gates to obtain the first evolution matrix comprises: rotating the second evolution matrix based on the environmental qubit gates to obtain the first evolution matrix” is a sub-limitation of the contingent limitations in claim 2. Per MPEP 2111.04, II, the contingent limitations are not required under the broadest reasonable interpretation of the claim because they are contingent on a step that does not need to be performed / are contingent on a condition that does not necessarily occur.
Therefore, Goto as modified teaches all of the limitations of claim 4 under its broadest reasonable interpretation.
Beyond the technical rejection based on MPEP 2111.04, II detailed above, the prior art does not anticipate or render obvious the limitations of the claim. Goto or Goto as modified does not anticipate or render obvious the limitations and one of ordinary skill in the art would not have an obvious roadmap for arriving at the claimed invention.
Regarding claim 5, Goto as modified teaches all of the limitations of claim 1, wherein determining the fidelity of the two-qubit gate based on the number of the environmental qubit gates associated with the two-qubit gate, the first target matrix, and the first evolution matrix comprises:
obtaining a first trace of a product between a conjugate transpose matrix of the first evolution matrix and the first evolution matrix (Appendix B, Equation B1, “
t
r
U
'
†
U
'
[a first trace of a product between a conjugate transpose matrix of the first evolution matrix and the first evolution matrix]”);
obtaining a second trace of a product between a conjugate transpose matrix of the first target matrix and the first evolution matrix (Appendix B, Equation B1, “
t
r
U
i
d
'
†
U
'
[a second trace of a product between a conjugate transpose matrix of the first target matrix and the first evolution matrix]”; and
determining the fidelity of the two-qubit gate based on the first trace, a square of the second trace, and the number of the environmental qubit gates associated with the two-qubit gate (Appendix B, Equation B1).
Regarding claim 6, Goto as modified teaches all of the limitations of claim 5, wherein determining the fidelity of the two-qubit gate based on the first trace, the square of the second trace, and the number of the environmental qubit gates associated with the two-qubit gate comprises:
determining the fidelity of the two-qubit gate based on the first trace, the square of the second trace, the number of the environmental qubit gates, and an adjacent integer of the number of the environmental qubit gates (see rejection of claim 1, Kueng shows, see Equation (1) reproduced above, where the denominator is equal to d(d+1) where d is the system size, where (d+1) is an adjacent integer of the number of the environmental qubit gates which is represented by “d”).
Regarding claim 7, Goto as modified teaches all of the limitations of claim 5.
The limitations “the fidelity of the two-qubit gate is determined at least by a second evolution matrix, and obtaining a first trace of a product between a conjugate transpose matrix of the first evolution matrix and the first evolution matrix comprises: determining a third trace of a product between a conjugate transpose matrix of the second evolution matrix and the second evolution matrix as the first trace” in claim 7 are contingent on “when the two-qubit gate does not interact with the environmental qubit gates”. Per MPEP 2111.04, II, the contingent limitations are not required under the broadest reasonable interpretation of the claim because they are contingent on a step that does not need to be performed / are contingent on a condition that does not necessarily occur.
Therefore, Goto as modified teaches all of the limitations of claim 7 under its broadest reasonable interpretation.
Beyond the technical rejection based on MPEP 2111.04, II detailed above, the prior art does not anticipate or render obvious the limitations of the claim. Goto or Goto as modified does not anticipate or render obvious the limitations and one of ordinary skill in the art would not have an obvious roadmap for arriving at the claimed invention.
Regarding claim 8, Goto as modified teaches all of the limitations of claim 7.
The limitations “obtaining a second trace of a product between a conjugate transpose matrix of the first target matrix and the first evolution matrix comprises: determining the second trace based on the sum of block matrices on a diagonal line of the second evolution matrix” is a sub-limitation of the contingent limitations in claim 7. Per MPEP 2111.04, II, the contingent limitations are not required under the broadest reasonable interpretation of the claim because they are contingent on a step that does not need to be performed / are contingent on a condition that does not necessarily occur.
Therefore, Goto as modified teaches all of the limitations of claim 8 under its broadest reasonable interpretation.
Beyond the technical rejection based on MPEP 2111.04, II detailed above, the prior art does not anticipate or render obvious the limitations of the claim. Goto or Goto as modified does not anticipate or render obvious the limitations and one of ordinary skill in the art would not have an obvious roadmap for arriving at the claimed invention.
Regarding claim 11, Goto as modified teaches all of the limitations of claim 1, wherein
the quantum chip is a superconducting quantum chip (§1, “Tunable couplers have recently become a key component for high-fidelity two-qubit gates in superconducting quantum computers…[a superconducting quantum chip]”),
Regarding claim 12, Goto as modified teaches all of the limitations of claim 11, wherein
the superconducting quantum chip comprises fluxonium-type qubits, or transmon-type qubits (§II, “Figure 1 shows a diagram of the proposed coupler. This consists of two fixed-frequency transmons…[transom-type qubits]”).
Regarding claim 13, Goto as modified teaches (see rejection of claim 1)
A method for determining fidelity of a qubit gate in a quantum chip, comprising
acquiring, environmental qubit gates associated with a two-qubit gate in the quantum chip
wherein the two-qubit gate interacts with the environmental qubit gates in the quantum chip;
determining a first target matrix and a corresponding first evolution matrix based on the two-qubit gate and the environmental qubit gates, wherein
the first target matrix is a diagonal matrix represented based on a logic gate, and the first evolution matrix is a matrix obtained after time-dependent evolution;
determining the fidelity of the two-qubit gate based on the number of the environmental qubit gates interacting with the two-qubit gate, the first target matrix, and the first evolution matrix; and outputting the fidelity of the two-qubit gate.
Goto as modified further teaches
acquiring, by invoking a first interface, environmental qubit gates associated with a two-qubit gate in the quantum chip, wherein the first interface comprises a first parameter having a first parameter value corresponding to the two-qubit gate and the environmental qubit gates (Figure 3(d) of Goto, “The average CPHASE-gate fidelity FCPHASE corresponding to θCPHASE…[acquiring, by invoking a first interface, environmental qubit gates associated with a two-qubit gate in the quantum chip, wherein the first interface comprises a first parameter having a first parameter value corresponding to the two-qubit gate and the environmental qubit gates]” – θCPHASE, for example, can be considered the first parameter because it corresponds to both the two-qubit gate and the environmental qubit gate because it corresponds to fidelity)
outputting the fidelity of the two-qubit gate by invoking a second interface, wherein the second interface comprises a second parameter having a second parameter value representing the fidelity of the two-qubit gate (Appendix B, Equation B1, “F” represents the fidelity and is a second parameter and the second interface can be the FCPHASE axis of Figure 3(d)).
Regarding claim 14, Goto as modified according to claim 1 teaches a method for determining fidelity of a qubit gate in a quantum chip (see rejection of claim 1), comprising:
acquiring, from a quantum platform, environmental qubit gates associated with a two-qubit gate in the quantum chip (see rejection of claim 1, see Figure 3(d) of Goto, the platform that produces all results and calculations in Goto can be considered “the quantum platform”), wherein
the two-qubit gate interacts with the environmental qubit gates in the quantum chip; determining a first target matrix and a corresponding first evolution matrix based on the two-qubit gate and the environmental qubit gates, wherein the first target matrix is a diagonal matrix represented based on a logic gate, and the first evolution matrix is a matrix obtained after time-dependent evolution; determining the fidelity of the two-qubit gate based on the number of the environmental qubit gates associated with the two-qubit gage, the first target matrix, and the first evolution matrix (see rejection of claim 1); and
returning the fidelity of the two-qubit gate to the quantum platform (see Figure 3(d) of Goto).
Claim(s) 9-10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Goto (Goto, Hayato. "Double-transmon coupler: Fast two-qubit gate with no residual coupling for highly detuned superconducting qubits." Physical review applied 18.3 (2022): 034038.) in view of Kueng (Kueng, Richard, et. al. “Supplemental Material: Comparing Experiments to the Fault-Tolerance Threshold”, September 1, 2016) as applied to claim 1, further in view of Poulin (Poulin, David, et al. "Quantum simulation of time-dependent Hamiltonians and the convenient illusion of Hilbert space." Physical review letters 106.17 (2011): 170501.)
Note: Prior art is directly quoted to show mappings to claim limitations. Quotations from the prior art appear within quotes, e.g. “Quoted passage from prior art” and limitations from the claim are bolded and within square brackets ([bold]) to indicate that the portion of the quoted passage preceding the square brackets teaches the limitation within the brackets.
Regarding claim 9, Goto as modified teaches all of the limitations of claim 1, but does not teach
determining an initial time for evolution and an evolution duration of the quantum chip;
dividing the evolution duration into a plurality of equal sub-evolution durations; and
determining time-dependent Hamiltonian corresponding to each of the plurality of sub-evolution durations of the quantum chip based on the first evolution matrix, the initial time, and each of the plurality of sub-evolution durations.
Poulin teaches:
determining an initial time for evolution and an evolution duration of the quantum chip (see time-dependent Trotter-Suzuki expansion below, reproduced from page 2, column 2 of Poulin. “We being by breaking the total time evolution into short segments U(0,t) = …[an initial time for evolution and an evolution duration of the quantum chip], i.e. initial time “0” and duration “t”);
dividing the evolution duration into a plurality of equal sub-evolution durations (see Trotter-Suzuki expansion reproduced below, Δt being equal sub-evolution durations, the plurality being indicated by subscript “j”); and
determining time-dependent Hamiltonian corresponding to each of the plurality of sub-evolution durations of the quantum chip based on the first evolution matrix, the initial time, and each of the plurality of sub-evolution durations (see Equation 2, reproduced below, where each timestep will produce
H
X
p
t
p
, which is based on the initial time because U(0,t) is based on the initial time, where “p” indexes subsequent times, and each Hamiltonian will include/is based on the evolution matrix because it represents the evolution matrix, i.e. it represents the time-evolution of the quantum system).
PNG
media_image3.png
118
687
media_image3.png
Greyscale
Time-dependent Trotter-Suzuki expansion
PNG
media_image4.png
126
635
media_image4.png
Greyscale
Equation 2
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Goto to include determining an initial time for evolution and an evolution duration of the quantum chip; dividing the evolution duration into a plurality of equal sub-evolution durations; and determining time-dependent Hamiltonian corresponding to each of the plurality of sub-evolution durations of the quantum chip based on the first evolution matrix, the initial time, and each of the plurality of sub-evolution durations in order to provide an accurate simulation of essential physical features in Goto (Poulin, “Indeed, the essential physical features of many systems can be explained by variational states specified with a small number of parameters.”).
Regarding claim 10, Goto as modified teaches all of the limitations of claim 9, further comprising:
determining a final state of the quantum chip after evolving from an initial state for the evolution duration at least based on the time-dependent Hamiltonian corresponding to each of the plurality of sub-evolution durations of the quantum chip, each of the plurality of sub-evolution durations, and the number of the plurality of sub-evolution durations (Poulin, Conclusion, “As an application, we showed that the set of quantum states that can be reached from a product state with a polynomial-time evolution of an arbitrary time-dependent quantum Hamiltonian is an exponentially small fraction of the Hilbert space [determining a final state of the quantum chip after evolving from an initial state for the evolution duration]” – this is based on the time-dependent Hamiltonian corresponding to each of the plurality of sub-evolution durations of the quantum chip, each of the plurality of sub-evolution durations, and the number of the plurality of sub-evolution durations because, as shown in the rejection of claim 9, these components are used to determine the final state.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Castrillo (WO2020263304A1) discusses two-qubit gate fidelity.
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