DETAILED ACTION
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
2. This communication is in response to the Applicant’s submission filed 14 November 2023, where:
Claims 1-15 are pending.
Claims 1-15 are rejected.
Foreign priority is claimed to CN 202211457950.8, filed 16 November 2022. A certified copy of this paper has been filed 30 December 2023 Accordingly, receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
3. An information disclosure statement was submitted on 16 May 2025. The submission complies with the provisions of 37 CFR 1.97. Accordingly, the Examiner considered the information disclosure statement.
Drawings
4. The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they include the following reference character(s) not mentioned in the description:
reference 1041 in Fig. 1,
reference 1042 in Fig. 1,
reference 401 in Fig. 4, and
reference 512 in Fig. 5.
Corrected drawing sheets in compliance with 37 CFR 1.121(d), or amendment to the specification to add the reference character(s) in the description in compliance with 37 CFR 1.121(b) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Specification
5. The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed.
Claim Rejections - 35 U.S.C. § 101
6. 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.
7. Claims 1-11 are rejected under 35 U.S.C. § 101 because the claimed invention is directed to an abstract idea without significantly more.
Claim 1 recites a qubit processing method, which is a process, and thus one of the statutory categories of patentable subject matter. (35 U.S.C. § 101).
However, under Step 2A Prong One, the claim recites the limitations of “acquiring a relationship between a frequency of a tunable resonator and a flux bias applied to the tunable resonator;” and “determining a target flux bias corresponding to energy level splitting of the tunable resonator based on the relationship, the energy level splitting representing that the tunable resonator resonates with the qubit.” These activities of “acquiring” and “determining” contain limitations that can practically be performed in the human mind, including, for example, observations, evaluations, judgments, and opinions, and accordingly, are a mental process, (MPEP § 2106.04(a)(2) sub III), which is one of the groupings of abstract ideas. (MPEP § 2106.04(a)(2)).
Further, the broadest reasonable interpretation of the claimed “method” covers the embodiments of a simulation and/or a mathematical model, which is not inconsistent with the Applicant’s disclosure. (MPEP § 2111; see Specification ¶¶ 0034, 0035 & 0047).
In this respect, the activities of “acquiring” and “determining” recite a mathematical concept, (MPEP § 2106.04(a)(2) sub I), which is one of the groupings of abstract ideas. (MPEP § 2106.04(a)(2)). Thus, claim 1 recites an abstract idea.
Under Step 2A Prong Two, the claim as a whole is not integrated into a practical application, because the additional elements recited in the claim beyond the identified judicial exception include a “qubit,” and a “tunable resonator,” which are recited at a high-level of generality, and are therefore generic computer components used to implement the abstract idea, (MPEP § 2106.05(f)), that does not serve to integrate the abstract idea into a practical application. Also, the claim recites the limitations of “controlling a qubit to be biased at a preset frequency,” and “applying the target flux bias to the tunable resonator for a preset time period to initialize the qubit,” which are insignificant extra-solution activities of providing data from a memory, (MPEP § 2106.05(g)), that does not serve to integrate the abstract idea into a practical application. Therefore, claim 1 is directed to the abstract idea.
Finally, under Step 2B, the additional elements, taken alone or in combination, do not represent significantly more than the abstract idea itself. The additional elements recited in the claim beyond the identified judicial exception include a “qubit,” and a “tunable resonator,” which are recited at a high-level of generality, and are therefore generic computer components used to implement the abstract idea, (MPEP § 2106.05(f)), that does not amount to significantly more than the abstract idea. Also, the claim recites the limitations of “controlling a qubit to be biased at a preset frequency,” and “applying the target flux bias to the tunable resonator for a preset time period to initialize the qubit,” which are well-understood, routine, and conventional activities of reading information from memory, (MPEP § 2106.05(d) sub II.iv), that does not amount to significantly more than the abstract idea. Therefore, claim 1 is subject-matter ineligible.
Claim 8 recites a qubit processing method, which is a process, and thus one of the statutory categories of patentable subject matter. (35 U.S.C. § 101).
However, under Step 2A Prong One, the claim recites the limitations of “based on the flux bias through the multiple adjustments and the measured frequencies corresponding to the flux bias through the multiple adjustments, determining a relationship between the frequency of the tunable resonator and the flux bias applied to the tunable resonator,” and “determining a target flux bias corresponding to energy level splitting of the tunable resonator based on the relationship, the energy level splitting representing that the tunable resonator resonates with the qubit.” These activities of “determining” contain limitations that can practically be performed in the human mind, including, for example, observations, evaluations, judgments, and opinions, and accordingly, are a mental process, (MPEP § 2106.04(a)(2) sub III), which is one of the groupings of abstract ideas. (MPEP § 2106.04(a)(2)).
Further, the broadest reasonable interpretation of the claimed “method” covers the embodiments of a simulation and/or a mathematical model, which is not inconsistent with the Applicant’s disclosure. (MPEP § 2111; see Specification ¶¶ 0034, 0035 & 0047).
In this respect, the activities of “determining” also recite a mathematical concept, (MPEP § 2106.04(a)(2) sub I), which is one of the groupings of abstract ideas. (MPEP § 2106.04(a)(2)). Thus, claim 8 recites an abstract idea.
Under Step 2A Prong Two, the claim as a whole is not integrated into a practical application, because the additional elements recited in the claim beyond the identified judicial exception include a “qubit,” and a “tunable resonator,” which are recited at a high-level of generality, and are therefore generic computer components used to implement the abstract idea, (MPEP § 2106.05(f)), that does not serve to integrate the abstract idea into a practical application. Also, the claim recites the limitations of “acquiring flux bias applied to a tunable resonator through multiple adjustments and measured frequencies corresponding to the flux bias subjected to the multiple adjustments, the tunable resonator being a resonator coupled with a qubit,” and “initialization of the qubit being realized after the target flux bias is applied to the tunable resonator for a preset time period,” which are insignificant extra-solution activities of providing data from a memory, (MPEP § 2106.05(g)), that does not serve to integrate the abstract idea into a practical application. Therefore, claim 8 is directed to the abstract idea.
Finally, under Step 2B, the additional elements, taken alone or in combination, do not represent significantly more than the abstract idea itself. The additional elements recited in the claim beyond the identified judicial exception include a “qubit,” and a “tunable resonator,” which are recited at a high-level of generality, and are therefore generic computer components used to implement the abstract idea, (MPEP § 2106.05(f)), that does not amount to significantly more than the abstract idea. Also, the claim recites the limitations of “acquiring flux bias applied to a tunable resonator through multiple adjustments and measured frequencies corresponding to the flux bias subjected to the multiple adjustments, the tunable resonator being a resonator coupled with a qubit,” and “initialization of the qubit being realized after the target flux bias is applied to the tunable resonator for a preset time period,” which are well-understood, routine, and conventional activities of reading information from memory, (MPEP § 2106.05(d) sub II.iv), that does not amount to significantly more than the abstract idea. Therefore, claim 8 is subject-matter ineligible.
Claim 2 depends from claim 1. The claim recites more details or specifics to the abstract idea of “acquiring a relationship” comprising “measuring a frequency of the tunable resonator after applying an initial flux bias to the tunable resonator to obtain a measured frequency corresponding to the initial flux bias,” “changing multiple times the flux bias applied to the tunable resonator based on the initial flux bias to obtain measured frequencies corresponding to the flux bias through the multiple changes,” and “based on the measured frequency corresponding to the initial flux bias and the measured frequencies corresponding to the flux bias through the multiple changes, simulating the relationship between the frequency of the tunable resonator and the flux bias applied to the tunable resonator,” and accordingly, are merely more specific to the abstract idea. Moreover, the activities of “measuring,” “changing the flux bias,” and “simulating the relationship” contain limitations that can practically be performed in the human mind, including, for example, observations, evaluations, judgments, and opinions, and accordingly, are a mental process, (MPEP § 2106.04(a)(2) sub III), which is one of the groupings of abstract ideas. (MPEP § 2106.04(a)(2)). Moreover, the activities of “measuring,” “changing the flux bias,” and “simulating the relationship” also are limitations that recite a mathematical concept, (MPEP § 2106.04(a)(2) sub I), which is one of the groupings of abstract ideas. (MPEP § 2106.04(a)(2)).
The additional elements of the claim does not serve to integrate the abstract idea into integrated into a practical application, (see MPEP § 2106.04(d)), nor do the additional elements amount to significantly more than the abstract idea, (MPEP § 2106.05 sub I; see also MPEP § 2106.05(a) – (h)), and thus, the claim recites no more than the abstract idea. Therefore, claim 2 is subject-matter ineligible.
Claim 3 depends from claim 1. Claim 9 depends from claim 8. The claims recite more details or specifics to the additional element of “applying” and “initializing” where (claims 3 and 9: “wherein the preset time period is tens to hundreds of nanoseconds), and accordingly, are merely more specific to the additional element. Therefore, claims 3 and 9 are subject-matter ineligible.
Claim 4 depends from claim 1. The claim recites more details or specifics to the abstract idea of “determining a target flux bias,” where “when a change curve showing the frequency changing along with the flux bias is adopted to represent the relationship, determining a position point where a number of the change curve changes from one to two,” and “determining a flux bias corresponding to the position point as the target flux bias,” and accordingly, are merely more specific to the abstract idea. The additional elements of the claim does not serve to integrate the abstract idea into integrated into a practical application, (see MPEP § 2106.04(d)), nor do the additional elements amount to significantly more than the abstract idea, (MPEP § 2106.05 sub I; see also MPEP § 2106.05(a) – (h)), and thus, the claim recites no more than the abstract idea. Therefore claim 4 is subject-matter ineligible.
Claim 5 depends from claim 1. Claim 10 depends from claim 8. The claims recite more details or specifics to the additional element of “a tunable resonator,” where (claims 5 & 10: wherein the tunable resonator is a superconducting quantum interference device”), and accordingly, are merely more specific to the additional element.” Therefore, claims 5 and 10 are subject-matter ineligible.
Claim 6 depends from claim 1. The claim recites more details or specifics to the abstract idea of “applying the target flux bias” comprising “under a condition that a plurality of qubits are coupled to the tunable resonator, applying the target flux bias to the tunable resonator for the preset time period,” and “performing batch initialization on the plurality of qubits,” and accordingly, is merely more specific to the abstract idea. The additional elements of the claim does not serve to integrate the abstract idea into integrated into a practical application, (see MPEP § 2106.04(d)), nor do the additional elements amount to significantly more than the abstract idea, (MPEP § 2106.05 sub I; see also MPEP § 2106.05(a) – (h)), and thus, the claim recites no more than the abstract idea. Therefore, claim 6 is subject-matter ineligible.
Claim 7 depends from claim 1. Claim 11 depends from claim 8. The claim recites more details or specifics to the additional element of a “qubit,” where (claims 7 & 11: “wherein the qubit is a Fluxonium qubit”), and accordingly, are merely more specific to the additional element. Therefore, claims 7 and 11 are subject-matter ineligible.
Claim Rejections – 35 U.S.C. § 103
8. 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.
9. 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.
10. Claims 1-6, 8-10, and 12-15 are rejected under 35 U.S.C. 103 as being unpatentable over US Published Application 201220269970 to Zhou et al. [hereinafter Zhou] in view of US Published Application US20180260732 to Bloom et al. [hereinafter Bloom].
Regarding claim 1, Zhou teaches [a] qubit processing method (Zhou, claim 17, teaches a “method implemented by a quantum circuit . . . comprising: a qubit, a resonant cavity, and a feeder [(that is, a qubit processing method)]”), comprising:
controlling a qubit to be biased at a preset frequency (Zhou, Fig. 2, teaches a quantum circuit with a flux bias line applied to a tunable resonator and qubit [Examiner annotations in dashed-line text boxes]:
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Zhou ¶ 0038 teaches “a change status of the frequency of the qubit with a pulse amplitude of the initialization signal. If a modulation pulse shown by a line 32 in FIG. 3 is applied to the z line in FIG. 2, the frequency of the qubit generates a vibration near a sweet spot (which is an optimal operating point) [(that is, controlling a qubit to be biased at a preset frequency)]”);
acquiring a relationship between a frequency of a tunable resonator and a flux bias applied to the tunable resonator (Zhou ¶ 0047 teaches “ꞷq of the qubit and magnetic flux added to the z line in FIG. 3 are simplified as:
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where Ec is the electrostatic energy of the qubit, Ej is the energy of the SQUID, d is related to the symmetry of the two junctions [of the SQUID], and Φ0 is a magnetic flux quantum. The parameters are all fixed values after a qubit is given. When the initialization signal Φ vibrates in the form of Φ = Acos(ꞷt+ Φ), A is the modulation amplitude, ꞷ is the modulation frequency, Φ is the modulation phase, and t is time [(that is, the “energy of the SQUID” and “flux bias Φ = Acos(ꞷt+ Φ)” of the initialization solution is acquiring a relationship between the frequency of the tunable resonator and the flux)]”), the tunable resonator being a resonator coupled with the qubit (Zhou ¶ 0037 teaches “the feeder 13 is a magnetic flux bias line, which can generate magnetic flux in a double-junction region of the SQUID 112 to adjust the frequency and an energy level of the qubit 11 [(that is, the tunable resonator being a resonator coupled with a qubit)]”;
[Examiner notes that the broadest reasonable interpretation of a “tunable resonator” covers the teachings of a SQUID of Zhou, which is not inconstant with the Applicant’s disclosure. (MPEP § 2111; see, e.g., Specification ¶ 0033)]);
* * *
and applying the target flux bias to the tunable resonator for a preset time period to initialize the qubit (Zhou, Fig. 3, teaches an initialization signal directed to a qubit [Examiner annotations in dashed-line text boxes]:
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Zhou ¶ 0038 teaches “a line 31 represents a change status of the frequency of the qubit with a pulse amplitude of the initialization signal. If a modulation pulse shown by a line 32 in FIG. 3 is applied to the z line in FIG. 2, the frequency of the qubit generates a vibration near a sweet spot (which is an optimal operating point) and the vibration generates a sideband with a frequency of ωq+ω, where ωq represents the frequency of the qubit, and ω represents a modulation frequency of the initialization signal [(that is, applying the target flux bias to the tunable resonator for a preset time period to initialize the qubit)]”).
Though Zhou teaches equivalent state exchanges occur when an energy level of a sideband generated by the vibration and an energy level of the resonant cavity meet an approach condition, Zhou, however, does not explicitly teach –
* * *
determining a target flux bias corresponding to energy level splitting of the tunable resonator based on the relationship,
the energy level splitting representing that the tunable resonator resonates with the qubit; and
* * *
But Bloom teaches –
* * *
determining a target flux bias corresponding to energy level splitting of the tunable resonator based on the relationship (Bloom ¶ 0060 teaches a “system assigns energy level transition frequencies of single or multi-photon transitions in the qubit”; Bloom ¶ 0064 teaches that “[e]xample success criteria can include: (A) Fitted transition frequencies for the 0 to 1 energy splitting and the 0-2 energy splitting are compared to design intent within a conformance window [(that is, determining a target flux bias corresponding to energy level splitting of the tunable resonator based on the relationship)]”;
[Examiner notes that the plain meaning of the term “energy level splitting” is, in relation to superconducting flux qubits, is the difference in energy between lowest-energy states of the qubit, from zero to the flux quantum (Φ0), or target flux bias. The splitting is a result of energy level splitting in a quantum system under an external perturbation, such as the magnetic flux. The broadest reasonable interpretation of “energy level splitting” is to superconducting flux qubit energy level states corresponding to a flux bias that covers the teachings of Bloom, which is not inconsistent with the Applicant’s disclosure. (MPEP § 2111; see Specification ¶¶ 0036-37)]),
the energy level splitting representing that the tunable resonator resonates with the qubit (Bloom ¶ 0034 teaches “device characteristics can be physical attributes of the device, for example, the resonance frequency [(that is, resonates with the qubit)] between the two lowest energy levels of a qubit [(that is, the energy level splitting representing that the tunable resonator resonates with the qubit)]”); and
* * *
Zhou and Bloom are from the same or similar field of endeavor. Zhou teaches a resonant cavity being coupled to the qubit, and a feeder being coupled to the qubit, the feeder feeds an initialization signal to the qubit. Bloom teaches qubit devices including a superconducting quantum interference device (SQUID) loop capacitively coupled to a neighboring resonator device.
Thus, it would have been obvious to a person having ordinary skill in the art as of the effective filing date of the Applicant’s invention to modify Zhou pertaining to a qubit coupled to a resonant cavity with the energy splitting levels of Bloom.
The motivation to do so is because “a calibration process can provide technical advantages for operating a quantum computing system. For instance, the calibration process may provide reliable results by applying well-defined criteria for pass/fail during calibration of superconducting qubits.” (Bloom ¶ 0295).
Regarding claim 2, the combination of Zhou and Bloom teaches all of the limitations of claim 1, as set out above in detail.
Zhou teaches -
wherein acquiring the relationship between the frequency of the tunable resonator and the flux bias applied to the tunable resonator comprises:
measuring a frequency of the tunable resonator (Zhou ¶ 0032 teaches “reading line 14 and the resonant cavity 12 are configured to read a state of the qubit 11. Specifically, when the qubit 11 is in different states, the frequency of the resonant cavity 12 presents different characteristics. The reading line 14 can learn the state of the qubit 11 by reading the frequency of the resonant cavity 12 [(that is, measuring a frequency of the tunable resonator)]”) after applying an initial flux bias to the tunable resonator to obtain a measured frequency corresponding to the initial flux bias (Zhou ¶ 0039 & Fig. 2 teaches “the initialization signal is determined according to a product of a modulation amplitude of the initialization signal and a trigonometric function, variables of the trigonometric function including a modulation frequency of the initialization signal, a modulation phase of the initialization signal, and time. For example, the initialization signal can be represented by:
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Φ represents the initialization signal [(that is, applying an initial flux bias to the tunable resonator)], A represents a modulation amplitude of the initialization signal, ꞷ represents a modulation frequency of the initialization signal, φ represents a modulation phase of the initialization signal, and t represents time”);
changing multiple times the flux bias applied to the tunable resonator based on the initial flux bias to obtain measured frequencies corresponding to the flux bias through the multiple changes (Zhou ¶ 0037 & Fig. 2 teaches the “feeder 13 is a magnetic flux bias line, which can generate magnetic flux in a double-junction region of the SQUID 112 to adjust the frequency and an energy level of the qubit 11; Zhou ¶ 0043 teaches “Through experiments, an initialization signal is applied to a qubit, a modulation frequency and a modulation order of the initialization signal are adjusted, and a probability that the qubit is in a state 1 is then measured. It is found that if an operating point of the qubit is close to a sweet spot, an initialization effect achieved by using second-order modulation, fourth-order modulation, or higher-even-number-order modulation is better (that is, the probability that the qubit is in the state 1 is lower) [(that is, “modulation order adjustment” is changing multiple times the flux bias applied to the tunable resonator based on the initial flux bias to obtain measured frequencies corresponding to the flux bias through the multiple changes)]); and
based on the measured frequency corresponding to the initial flux bias and the measured frequencies corresponding to the flux bias through the multiple changes (Zhou ¶ 0030 teaches “the qubit 11 is a frequency-adjustable qubit. That is, the frequency of the qubit is adjustable. The frequency of the qubit is adjusted by applying a specific signal to the qubit. For example, the qubit 11 is a frequency-adjustable superconducting qubit”; Zhou ¶ 0043 teaches “[t]hrough experiments, an initialization signal is applied to a qubit, a modulation frequency and a modulation order of the initialization signal are adjusted, and a probability that the qubit is in a state 1 is then measured. It is found that if an operating point of the qubit is close to a sweet spot, an initialization effect achieved by using second-order modulation, fourth-order modulation, or higher-even-number-order modulation is better (that is, the probability that the qubit is in the state 1 is lower) [(that is, “modulation signal adjustment” is based on the measured frequency corresponding to the initial flux bias and the measured frequencies corresponding to the flux bias through the multiple changes)]”), simulating the relationship between the frequency of the tunable resonator and the flux bias applied to the tunable resonator (Zhou ¶ 0043 teaches “determining the modulation order can be obtained through . . . simulation experiments [(that is, by “modulation order” pertains to simulating the relationship between the frequency of the tunable resonator and the flux bias applied to the tunable resonator)]”).
Regarding claim 3, the combination of Zhou and Bloom teaches all of the limitations of claim 1, as described above in detail.
Zhou teaches -
wherein the preset time period is tens to hundreds of nanoseconds (Zhou ¶ 0061 teaches that a “qubit, which originally consumes about 10 microseconds to decay, decays to a ground state in the order of hundreds of nanoseconds, and an initialization time is shortened by two orders of magnitude [(that is, the preset time period is tens to hundreds of nanoseconds)]”).
Regarding claim 4, the combination of Zhou and Bloom teaches all of the limitations of claim 1, as described above in detail. 0 → 1
Zhou teaches -
wherein determining the target flux bias corresponding to energy level splitting of the tunable resonator based on the relationship comprises:
when a change curve showing the frequency changing along with the flux bias is adopted to represent the relationship, determining a position point where a number of the change curve changes from one to two (Zhou, Fig. 3, teaches a change status depicted by a line [Examiner annotations in dashed-line text boxes]:
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Zhou ¶ 0038 & Fig. 3 teaches “line 31 represents a change status of the frequency of the qubit with a pulse amplitude of the initialization signal [(that is, when a change curve showing the frequency changing along with the flux bias is adopted to represent the relationship)]. If a modulation pulse shown by a line 32 in FIG. 3 is applied to the z line in FIG. 2, the frequency of the qubit generates a vibration near a sweet spot (which is an optimal operating point) [(that is, determining a position point)] and the vibration generates a sideband with a frequency of ωq+ω, where ωq represents the frequency of the qubit, and ω represents a modulation frequency of the initialization signal (that is, the foregoing modulation pulse). When the frequency or an energy level of the sideband approaches a frequency or an energy level of the resonant cavity, a population of states 1 of the qubit transfers to the resonant cavity [(that is, ”sweet spot” or “population of states” is determining a position point where a number of the change curve changes from one to two)]”); and
determining a flux bias corresponding to the position point as the target flux bias (Zhou, Fig. 3, teaches the “pulse amplitude of initialization signal [(that is, the “initialization signal” and “sweet spot” is determining a flux bias corresponding to the position point as the target flux bias)]”).
Regarding claim 5, the combination of Zhou and Bloom teaches all of the limitations of claim 1, as described above in detail.
Zhou teaches -
wherein the tunable resonator is a superconducting quantum interference device (Zhou ¶ 0037 teaches a “superconducting quantum interference device (SQUID) 112 including two Josephson junctions . . . to adjust the frequency and an energy level of the qubit 11 [(that is, the tunable resonator is a superconducting quantum interference device)]”).
Regarding claim 6, the combination of Zhou and Bloom teaches all of the limitations of claim 1, as described above in detail.
Bloom teaches -
wherein applying the target flux bias to the tunable resonator for a preset time period to initialize the qubit comprises:
under a condition that a plurality of qubits are coupled to the tunable resonator, (Bloom ¶ 0015 teaches “quantum logic can be performed in a manner that allows large-scale entanglement within the quantum system. Control signals can manipulate the quantum states of individual qubits and the joint states of the multiple qubits. In some instances, information can be read out from the composite quantum system by measuring the quantum states of the individual qubits [(that is, “entanglement” is where under a condition that a plurality of qubits are coupled to the tunable resonator)]”; as noted, Bloom ¶ 0020 teaches “superconducting quantum circuit system 104 may include resonator devices coupled to the respective qubit devices, for instance, where each qubit device includes a superconducting quantum interference device (SQUID) loop [(that is, tunable resonator)] and is capacitively coupled to a neighboring resonator device. . . . In some examples, some of the circuit devices 105 are coupler devices that selectively operate on individual qubits or pairs of qubits. For example, the coupler devices may produce entanglement or other multi-qubit states over two or more qubits”) applying the target flux bias to the tunable resonator for the preset time period (Bloom ¶ 0152, 0154-55 teaches a “a 2× Pulsed RF signal generator with amplitude, frequency, and phase control, Pulsed RF signal receiver, tunable constant current source to set magnetic flux through SQUID loop [(that is, a tunable resonator)]. . . . Before beginning a loop of bring-ups for different flux settings, follow the normal bring-up procedure (2) for a starting flux value [(that is, applying the target flux bias to the tunable resonator)]. Strategy I: Terminate after 1 flux period [(that is, “flux period” is the preset time period)], adjust step size to achieve fixed delta in qubit frequency”); and
performing batch initialization on the plurality of qubits (Bloom ¶ 0042 teaches a “calibration process . . . to characterize and tune up components of the quantum computing system. . . . In some cases, multiple operations are combined, performed in parallel, or divided into additional operations [(that is, “combined” or “in parallel” is performing batch initialization on the plurality of qubits )]”).
Regarding claim 8, Zhou teaches [a] qubit processing method (Zhou, claim 17, teaches a “method implemented by a quantum circuit . . . comprising: a qubit, a resonant cavity, and a feeder [(that is, a qubit processing method)]”), comprising:
acquiring flux bias applied to a tunable resonator through multiple adjustments and measured frequencies corresponding to the flux bias subjected to the multiple adjustments, the tunable resonator being a resonator coupled with a qubit (Zhou, Fig. 2, teaches a quantum circuit with a flux bias line applied to a tunable resonator and qubit [Examiner annotations in dashed-line text boxes]:
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Zhou ¶ 0037 teaches “the feeder 13 is a magnetic flux bias line [(that is, acquiring flux bias)], which can generate magnetic flux in a double-junction region of the SQUID 112 [(that is, acquiring flux bias applied to a tunable resonator)] to adjust the frequency and an energy level of the qubit 11 [(that is, through multiple adjustments and measured frequencies corresponding to the flux bias subjected to the multiple adjustments, the tunable resonator being a resonator coupled with a qubit)]”;
[Examiner notes that the broadest reasonable interpretation of a “tunable resonator” covers the teachings of a SQUID of Zhou, which is not inconstant with the Applicant’s disclosure. (MPEP § 2111; see, e.g., Specification ¶ 0033)]);
based on the flux bias through the multiple adjustments and the measured frequencies corresponding to the flux bias through the multiple adjustments (Zhou ¶ 0030 teaches “the qubit 11 is a frequency-adjustable qubit. That is, the frequency of the qubit is adjustable. The frequency of the qubit is adjusted by applying a specific signal to the qubit. For example, the qubit 11 is a frequency-adjustable superconducting qubit”; Zhou ¶ 0043 teaches “[t]hrough experiments, an initialization signal is applied to a qubit, a modulation frequency and a modulation order of the initialization signal are adjusted, and a probability that the qubit is in a state 1 is then measured. It is found that if an operating point of the qubit is close to a sweet spot, an initialization effect achieved by using second-order modulation, fourth-order modulation, or higher-even-number-order modulation is better (that is, the probability that the qubit is in the state 1 is lower) [(that is, “modulation signal adjustment” is based on the flux bias through the multiple adjustments and the measured frequencies corresponding to the flux bias through the multiple adjustments)]”),
determining a relationship between the frequency of the tunable resonator and the flux bias applied to the tunable resonator (Zhou ¶ 0047 teaches “ꞷq of the qubit and magnetic flux added to the z line in FIG. 3 are simplified as:
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where Ec is the electrostatic energy of the qubit, Ej is the energy of the SQUID, d is related to the symmetry of the two junctions [of the SQUID], and Φ0 is a magnetic flux quantum. The parameters are all fixed values after a qubit is given. When the initialization signal Φ vibrates in the form of Φ = Acos(ꞷt+ Φ), A is the modulation amplitude, ꞷ is the modulation frequency, Φ is the modulation phase, and t is time [(that is, the “energy of the SQUID” and “flux bias Φ = Acos(ꞷt+ Φ)” of the initialization solution is determining a relationship between the frequency of the tunable resonator and the flux)]”); and
[determining a target flux bias] . . . initialization of the qubit being realized after the target flux bias is applied to the tunable resonator for a preset time period (Zhou, Fig. 3, teaches an initialization signal directed to a qubit [Examiner annotations in dashed-line text boxes]:
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Zhou ¶ 0038 teaches “a line 31 represents a change status of the frequency of the qubit with a pulse amplitude of the initialization signal. If a modulation pulse shown by a line 32 in FIG. 3 is applied to the z line in FIG. 2, the frequency of the qubit generates a vibration near a sweet spot (which is an optimal operating point) and the vibration generates a sideband with a frequency of ωq+ω, where ωq represents the frequency of the qubit, and ω represents a modulation frequency of the initialization signal [(that is, initialization of the qubit being realized after the target flux bias is applied to the tunable resonator for a preset time period)]”).
Though Zhou teaches equivalent state exchanges occur when an energy level of a sideband generated by the vibration and an energy level of the resonant cavity meet an approach condition, Zhou, however, does not explicitly teach –
* * *
determining a target flux bias corresponding to energy level splitting of the tunable resonator based on the relationship,
the energy level splitting representing that the tunable resonator resonates with the qubit, . . . .
But Bloom teaches –
* * *
determining a target flux bias corresponding to energy level splitting of the tunable resonator based on the relationship (Bloom ¶ 0060 teaches a “system assigns energy level transition frequencies of single or multi-photon transitions in the qubit”; Bloom ¶ 0064 teaches that “[e]xample success criteria can include: (A) Fitted transition frequencies for the 0 to 1 energy splitting and the 0-2 energy splitting are compared to design intent within a conformance window [(that is, determining a target flux bias corresponding to energy level splitting of the tunable resonator based on the relationship)]”;
[Examiner notes that the plain meaning of the term “energy level splitting” is, in relation to superconducting flux qubits, is the difference in energy between lowest-energy states of the qubit, from zero to the flux quantum (Φ0), or target flux bias. The splitting is a result of energy level splitting in a quantum system under an external perturbation, such as the magnetic flux. The broadest reasonable interpretation of “energy level splitting” is to superconducting flux qubit energy level states corresponding to a flux bias that covers the teachings of Bloom, which is not inconsistent with the Applicant’s disclosure. (MPEP § 2111; see Specification ¶¶ 0036-37)]),
the energy level splitting representing that the tunable resonator resonates with the qubit (Bloom ¶ 0034 teaches “device characteristics can be physical attributes of the device, for example, the resonance frequency [(that is, resonates with the qubit)] between the two lowest energy levels of a qubit [(that is, the energy level splitting representing that the tunable resonator resonates with the qubit)]”), . . . .
Zhou and Bloom are from the same or similar field of endeavor. Zhou teaches a resonant cavity being coupled to the qubit, and a feeder being coupled to the qubit, the feeder feeds an initialization signal to the qubit. Bloom teaches qubit devices including a superconducting quantum interference device (SQUID) loop capacitively coupled to a neighboring resonator device.
Thus, it would have been obvious to a person having ordinary skill in the art as of the effective filing date of the Applicant’s invention to modify Zhou pertaining to a qubit coupled to a resonant cavity with the energy splitting levels of Bloom.
The motivation to do so is because “a calibration process can provide technical advantages for operating a quantum computing system. For instance, the calibration process may provide reliable results by applying well-defined criteria for pass/fail during calibration of superconducting qubits.” (Bloom ¶ 0295).
Regarding claim 9, the combination of Zhou and Bloom teaches all of the limitations of claim 8, as described above in detail.
Zhou teaches -
wherein the preset time period is tens to hundreds of nanoseconds (Zhou ¶ 0061 teaches that a “qubit, which originally consumes about 10 microseconds to decay, decays to a ground state in the order of hundreds of nanoseconds, and an initialization time is shortened by two orders of magnitude [(that is, the preset time period is tens to hundreds of nanoseconds)]”).
Regarding claim 10, the combination of Zhou and Bloom teaches all of the limitations of claim 8, as described above in detail.
Zhou teaches –
wherein the tunable resonator is a superconducting quantum interference device (Zhou ¶ 0037 teaches a “superconducting quantum interference device (SQUID) 112 including two Josephson junctions . . . to adjust the frequency and an energy level of the qubit 11 [(that is, the tunable resonator is a superconducting quantum interference device)]”).
Regarding claim 12, Zhou teaches [a] quantum circuit (Zhou, Fig. 2, teaches a quantum circuit), comprising:
a qubit readout resonator (Zhou, Fig. 2, teaches a quantum circuit [Examiner annotations in dashed-line text boxes]:
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Zhou ¶ 0032 teaches “[t]he resonant cavity 12 is coupled to the reading line 14, and the resonant cavity 12 is further coupled to the qubit 11. For example, the resonant cavity 12 and the reading line 14 are inductively coupled to each other, and the resonant cavity 12 and the qubit 11 are capacitively coupled to each other. Optionally, a coupling strength between the resonant cavity 12 and the qubit 11 is approximately 100 MHz. The reading line 14 and the resonant cavity 12 are configured to read a state of the qubit 11 [(that is, “resonant cavity” is a qubit readout resonator)]”);
a qubit coupled with a readout line through the qubit readout resonator (Zhou ¶ 0032 teaches “For example, the resonant cavity 12 and the reading line 14 are inductively coupled to each other, and the resonant cavity 12 and the qubit 11 are capacitively coupled to each other [(that is, a qubit coupled with a readout line through the qubit readout resonator)]”), and used for being biased at a preset frequency (Zhou ¶¶ 0039-40 teaches “the initialization signal is determined according to a product of a modulation amplitude of the initialization signal . . . . For example, the initialization signal can be represented by:
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Φ represents the initialization signal, A represents a modulation amplitude of the initialization signal, ω represents a modulation frequency of the initialization signal [(that is, used for being biased at a preset frequency)], ϕ represents a modulation phase of the initialization signal, and t represents time”); and
a tunable resonator coupled with the readout line and coupled with the qubit, wherein the tunable resonator is configured to initialize the qubit by applying a target flux bias (Zhou ¶ 0037 teaches “the qubit 11 includes a coupling capacitor 111 and a superconducting quantum interference device (SQUID) 112 [(that is, a tunable resonator)] including two Josephson junctions. The resonant cavity 12 and the qubit 11 are capacitively coupled, and the resonant cavity 12 and the reading line 14 are inductively coupled”; Zhou ¶¶ 0039-40 teaches “the initialization signal is determined according to a product of a modulation amplitude of the initialization signal [(that is, the tunable resonator is configured to initialize the qubit by applying a target flux bias)]. . . . For example, the initialization signal can be represented by:
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Φ represents the initialization signal, A represents a modulation amplitude of the initialization signal, ω represents a modulation frequency of the initialization signal, ϕ represents a modulation phase of the initialization signal, and t represents time”);
[Examiner notes that the broadest reasonable interpretation of a “tunable resonator” covers the teachings of a SQUID of Zhou, which is not inconstant with the Applicant’s disclosure. (MPEP § 2111; see, e.g., Specification ¶ 0033)]) . . . .
Though Zhou teaches equivalent state exchanges occur when an energy level of a sideband generated by the vibration and an energy level of the resonant cavity meet an approach condition, Zhou, however, does not explicitly teach –
* * *
[a tunable resonator, wherein the tunable resonator is configured to initialize the qubit by applying a target flux bias] enabling energy level splitting of the tunable resonator for a preset time period, the energy level splitting representing that the tunable resonator resonates with the qubit.
But Bloom teaches –
* * *
[a tunable resonator, wherein the tunable resonator is configured to initialize the qubit by applying a target flux bias] enabling energy level splitting of the tunable resonator for a preset time period (Bloom ¶ 0060 teaches a “system assigns energy level transition frequencies of single or multi-photon transitions in the qubit”; Bloom ¶ 0064 teaches that “[e]xample success criteria can include: (A) Fitted transition frequencies for the 0 to 1 energy splitting and the 0-2 energy splitting [(that is, enabling energy level splitting of the tunable resonator)] are compared to design intent within a conformance window [(that is, “conformance window” is a preset time period)]”;
[Examiner notes that the plain meaning of the term “energy level splitting” is, in relation to superconducting flux qubits, is the difference in energy between lowest-energy states of the qubit, from zero to the flux quantum (Φ0), or target flux bias. The splitting is a result of energy level splitting in a quantum system under an external perturbation, such as the magnetic flux. The broadest reasonable interpretation of “energy level splitting” is to superconducting flux qubit energy level states corresponding to a flux bias that covers the teachings of Bloom, which is not inconsistent with the Applicant’s disclosure. (MPEP § 2111; see Specification ¶¶ 0036-37)]),
the energy level splitting representing that the tunable resonator resonates with the qubit (Bloom ¶ 0034 teaches “device characteristics can be physical attributes of the device, for example, the resonance frequency [(that is, resonates with the qubit)] between the two lowest energy levels of a qubit [(that is, the energy level splitting representing that the tunable resonator resonates with the qubit)]”).
Zhou and Bloom are from the same or similar field of endeavor. Zhou teaches a resonant cavity being coupled to the qubit, and a feeder being coupled to the qubit, the feeder feeds an initialization signal to the qubit. Bloom teaches qubit devices including a superconducting quantum interference device (SQUID) loop capacitively coupled to a neighboring resonator device.
Thus, it would have been obvious to a person having ordinary skill in the art as of the effective filing date of the Applicant’s invention to modify Zhou pertaining to a qubit coupled to a resonant cavity with the energy splitting levels of Bloom.
The motivation to do so is because “a calibration process can provide technical advantages for operating a quantum computing system. For instance, the calibration process may provide reliable results by applying well-defined criteria for pass/fail during calibration of superconducting qubits.” (Bloom ¶ 0295).
Regarding claim 13, the combination of Zhou and Bloom teaches all of the limitations of claim 12, as set out above in detail.
Zhou teaches -
further comprising:
a capacitor coupled with the qubit and the tunable resonator respectively (Zhou ¶ 0037 & Fig. 2 teaches “he equivalent circuit of the qubit 11 includes a coupling capacitor 111 and a superconducting quantum interference device (SQUID) 112 including two Josephson junctions [(that is, a capacitor coupled with the qubit and the tunable resonator respectively)]”), and configured to assist in initializing the qubit (Zhou ¶ 0037 teaches “[t]he resonant cavity 12 and the qubit 11 are capacitively coupled [(that is, the “capacitor” is configured to assist in initializing the qubit )]”).
Regarding claim 14, the combination of Zhou and Bloom teaches all of the limitations of claim 12, as described above in detail.
wherein the tunable resonator is a superconducting quantum interference device (Zhou ¶ 0037 teaches a “superconducting quantum interference device (SQUID) 112 including two Josephson junctions . . . to adjust the frequency and an energy level of the qubit 11 [(that is, the tunable resonator is a superconducting quantum interference device)]”).
Regarding claim 15, the combination of Zhou and Bloom teaches all of the limitations of claim 12, as described above in detail.
Zhou teaches -
wherein the preset time period is tens to hundreds of nanoseconds (Zhou ¶ 0061 teaches that a “qubit, which originally consumes about 10 microseconds to decay, decays to a ground state in the order of hundreds of nanoseconds, and an initialization time is shortened by two orders of magnitude [(that is, the preset time period is tens to hundreds of nanoseconds)]”).
11. Claims 7 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over US Published Application 201220269970 to Zhou et al. [hereinafter Zhou] in view of US Published Application US20180260732 to Bloom et al. [hereinafter Bloom], and Dmitriev et al., “A perspective on superconducting flux qubits,” Applied Phys. Letters (2021) [hereinafter Dmitriev].
Regarding claim 7, the combination of Zhou and Bloom teach all of the limitations of claim 1, as set out above in detail.
Though Zhou and Bloom teach flux qubits relying on radio frequency superconducting quantum interference devices (SQUIDs) as adjustable resonators, the combination of Zhou and Bloom, however, does not explicitly teach –
wherein the qubit is a Fluxonium qubit.
But Dmitriev teaches -
wherein the qubit is a Fluxonium qubit (Dmitriev, right column of p. 5, “B. Fluxonium,” first paragraph, teaches an “approach is to form the inductance using many JJs.45 Such a qubit, known as a fluxonium qubit, is a modification of rf-SQUID with a long JJ chain inductance).
Zhou, Bloom, and Dmitriev are from the same or similar field of endeavor. Zhou teaches a resonant cavity being coupled to the qubit, and a feeder being coupled to the qubit, the feeder feeds an initialization signal to the qubit. Bloom teaches qubit devices including a superconducting quantum interference device (SQUID) loop capacitively coupled to a neighboring resonator device. Dmitriev taches a modification of a rf-SQUID with a long JJ chain inductance for a fluxonium qubit.
Thus, it would have been obvious to a person having ordinary skill in the art as of the effective filing date of the Applicant’s invention to modify the combination of Zhou and Bloom pertaining to a qubit coupled to a resonant cavity including energy splitting levels with the fluxonium qubit of Dmitriev.
The motivation to do so is because an “increase in the number of [Josephson Junctions (JJs)] results in increasing inductance and decreasing EL, which helps to reduce the sensitivity to flux noise and to achieve long dephasing times.” (Dmitriev, right column of p. 5, “B. Fluxonium,” first paragraph).
Regarding claim 11, the combination of Zhou and Bloom teaches all of the limitations of claim 8, as described above in detail.
Though Zhou and Bloom teach flux qubits relying on radio frequency superconducting quantum interference devices (SQUIDs) as adjustable resonators, the combination of Zhou and Bloom, however, does not explicitly teach –
wherein the qubit is a Fluxonium qubit.
But Dmitriev teaches -
wherein the qubit is a Fluxonium qubit (Dmitriev, right column of p. 5, “B. Fluxonium,” first paragraph, teaches an “approach is to form the inductance using many JJs.45 Such a qubit, known as a fluxonium qubit, is a modification of rf-SQUID with a long JJ chain inductance).
Zhou, Bloom, and Dmitriev are from the same or similar field of endeavor. Zhou teaches a resonant cavity being coupled to the qubit, and a feeder being coupled to the qubit, the feeder feeds an initialization signal to the qubit. Bloom teaches qubit devices including a superconducting quantum interference device (SQUID) loop capacitively coupled to a neighboring resonator device. Dmitriev taches a modification of a rf-SQUID with a long JJ chain inductance for a fluxonium qubit.
Thus, it would have been obvious to a person having ordinary skill in the art as of the effective filing date of the Applicant’s invention to modify the combination of Zhou and Bloom pertaining to a qubit coupled to a resonant cavity including energy splitting levels with the fluxonium qubit of Dmitriev.
The motivation to do so is because an “increase in the number of [Josephson Junctions (JJs)] results in increasing inductance and decreasing EL, which helps to reduce the sensitivity to flux noise and to achieve long dephasing times.” (Dmitriev, right column of p. 5, “B. Fluxonium,” first paragraph).
Conclusion
12. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
(Sete et al., “Charge- and Flux-Insensitive Tunable Superconducting Qubit,” arXiv (2017)) teaches we propose a flux-tunable superconducting qubit that minimizes the dephasing due to magnetic flux noise by engineering controllable flux “sweet spots” at frequencies of interest. This is realized by using a SQUID with asymmetric Josephson junctions shunted by a super-inductor formed from an array of junctions.
(US Patent 12645968 to Sete et al.) teaches a superconducting quantum processing circuit includes a tunable qubit device. The tunable qubit device includes a circuit loop configured to receive, during operation of the tunable qubit device, a magnetic flux that controls a qubit frequency of the tunable qubit device. In some aspects, the circuit loop consists of: a single non-linear circuit element and one or more linear circuit elements. The single non-linear circuit element is a Josephson junction connected between a first circuit node and a second circuit node. The one or more linear circuit elements includes a linear inductor connected in parallel with the Josephson junction between the first circuit node and the second circuit node.
13. Any inquiry concerning this communication or earlier communications from the Examiner should be directed to KEVIN L. SMITH whose telephone number is (571) 272-5964. Normally, the Examiner is available on Monday-Thursday 0730-1730.
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, KAKALI CHAKI can be reached on 571-272-3719. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/K.L.S./
Examiner, Art Unit 2122
/KAKALI CHAKI/Supervisory Patent Examiner, Art Unit 2122
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