DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 06/21/2023, 11/01/2024, and 09/22/2025 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statements are being considered by the examiner.
Specification
The disclosure is objected to because of the following informalities:
Para. 00112: contains the following grammar issue: Please confirm.]]
Para. 00112:
|
F
T
is not in equation 5
Para. 00131: details that the second tunable-frequency qubit device is 314, when it should be 814
Para. 00131: details coupler device 806 and qubit devices 802 and 804 which do not exist in fig. 8 of the drawings
Para. 00136: capacitance
C
1
is listed but should be
C
12
Para. 00137: capacitance
C
2
is listed but should be
C
56
Para. 00138: capacitance
C
c
is listed but should be
C
34
Para. 00140: capacitance
C
36
is listed but should be
C
34
Para. 00144: superconducting circuit loop 614 does not exist in fig. 9 of the drawings
Para. 00148: symbols
n
k
and
E
c
k
are not in equation 20
Para. 00150: symbol
g
k
c
is not in equation 26
Para. 00157: contains a grammatical mistake by not capitalizing when
Appropriate correction is required.
The disclosure is also objected to because para. 0046 contains an embedded hyperlink and/or other form of browser-executable code. Applicant is required to delete the embedded hyperlink and/or other form of browser-executable code; references to websites should be limited to the top-level domain name without any prefix such as http:// or other browser-executable code. See MPEP § 608.01.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph:
(A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier. Such claim limitation(s) is/are:
control system configured to perform operations in claim 16
flux bias signal is configured to tune the transition frequency of the second tunable-frequency qubit device to the maximum transition frequency in claim 19
Because this/these claim limitation(s) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, they are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
If applicant does not intend to have these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
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.
Claim 14 is 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.
Claim 14 recites the limitation second tunable-frequency qubit devices. There is insufficient antecedent basis for this limitation in the claim.
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.
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.
Claims 1-3, 5-18 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Krinner et al., Demonstration of an all-microwave controlled-phase gate between far-detuned qubits. Physical Review Applied. 2020 Oct 1(“Krinner”) in view of Didier, Flux control of superconducting qubits at dynamical sweet spots. arXiv preprint arXiv:1912.09416v1 2019 Dec 19(“Didier”) and in view of McKay., et al. "Universal gate for fixed-frequency qubits via a tunable bus." Physical Review Applied 6.6 (2016)(“McKay”)
Regarding claim 1, Krinner teaches a quantum information control method comprising:
generating, by operation of a control system, a flux modulation signal configured to modulate a transition frequency of a first tunable-frequency qubit device in a superconducting quantum processing unit(Krinner, pg., 2, see also figs., 1a and 1b, “The superconducting device used in our experiment uses a frequency-tunable transmon qubit (qubit A)...[t]he first qubit is made tunable to provide more freedom in the choice of operation frequencies[of a first tunable-frequency qubit device in a superconducting quantum processing unit]” & Krinner, pg., 6, see also fig. 6, “We use a superconducting coil to thread flux through the superconducting quantum-interference device (SQUID) of qubit A to tune its frequency[generating, by operation of a control system, a flux modulation signal configured to modulate a transition frequency]”)
and applying a two-qubit quantum logic gate to a pair of qubits in the superconducting quantum processing unit(Krinner, pgs., 2-3, “Our gate exploits a Raman transition between the two-qubit states
f
,
g
and
|
g
,
e
which we refer to as fgge transition[to a pair of qubits in the superconducting quantum processing unit]... [w]hen driving the fgge transition for a duration that corresponds to a full round trip in the
f
,
g
-
|
g
,
e
manifold, the state
|
g
,
e
picks up a geometric phase of π...thereby realizing a controlled-phase gate[and applying a two-qubit quantum logic gate].”),
wherein applying the two-qubit quantum logic gate comprises communicating the flux modulation signal [to a flux bias control line] coupled to the first tunable-frequency qubit device, and the pair of qubits comprises a first qubit defined by the first tunable-frequency qubit device and a second qubit defined by the second qubit device(Krinner, pg., 2, see also figs., 1a and 1b, “The superconducting device used in our experiment uses a frequency-tunable transmon qubit (qubit A) and a fixed-frequency transmon qubit (qubit B)[and the pair of qubits comprises a first qubit defined by the first tunable-frequency qubit device and a second qubit defined by the second qubit device]” & Krinner, pg., 6, see also fig. 6, “We use a superconducting coil to thread flux through the superconducting quantum-interference device (SQUID) of qubit A to tune its frequency[communicating the flux modulation signal coupled to the first tunable-frequency qubit device]).1
While Krinner does teach transition frequency, the first tunable-frequency qubit device, the flux modulation signal, Krinner does not teach: such that a time average of the transition frequency of the first tunable-frequency qubit device over a duration of the flux modulation signal is on resonance with a transition frequency of a second qubit device in the superconducting quantum processing unit.
However, Didier teaches:
such that a time average of the transition frequency of the first tunable-frequency qubit device over a duration of the flux modulation signal is on resonance with a transition frequency of a second qubit device in the superconducting quantum processing unit(Didier, pg., 4, “When a tunable transmon is capacitively coupled to a fixed-frequency transmon, entangling gates can be realized by bringing the time-averaged transition frequency of the tunable transrnon in resonance[such that a time average of the transition frequency of the first tunable-frequency qubit device over a duration of the flux modulation signal is on resonance] with the desired transition frequency of the fixed-frequency transmon[with a transition frequency of a second qubit device in the superconducting quantum processing unit].”)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner with the teachings of Didier the motivation to do so would be to protect quantum gates from noise(Didier, pgs., 1-2, “Under flux modulation, the tunable qubit is sensitive to two kinds of flux noise: the additive flux noise on the DC bias and the multiplicative flux noise on the AC amplitude. Dynamical sweet spots are achieved at operating points insensitive to both additive and multiplicative flux noise... [w]e
show how to protect entangling gates on a wide range of operating points. We exp1icitly focus on
1
/
f
flux noise....”).
While Krinner in view of Didier does teach communicating the flux modulation signal coupled to the first tunable-frequency qubit device Krinner in view of McKay does not teach: to a flux bias control line
However, McKay teaches:
to a flux bias control line(McKay, pg., 2, “To interact the qubits via the tunable coupler we apply a sinusoidal fast-flux bias modulation of amplitude
δ
so that the total flux applied to the tunable bus is
ϕ
t
=
Θ
+
δ
c
o
s
(
ω
ϕ
t
)
[to a flux bias control line].”)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner in view of Didier with the teachings of McKay the motivation to do so would be to reduce noise with respect to directly tuning qubit devices(McKay, pg. 1, “Ideally we would like to combine the best aspects from
both approaches: the flexibility and scalability of tunable qubits with the coherence and fidelity of fixed-frequency qubits. This is possible by transferring tunability from the computational qubits to the coupling degree of freedom thereby reducing sensitivity to noise.”).
Regarding claim 2, Krinner in view of Didier and McKay teach the method of claim 1, wherein: the first tunable-frequency qubit device comprises:
a superconducting circuit loop and a flux bias element that applies a magnetic flux to the superconducting circuit loop(McKay, pgs., 2-4, see also figs. 1a, 2a and 2b, “The tunable bus circuit that we consider in this paper consists of several fixed-frequency qubits dispersively coupled to a frequency-tunable bus; a circuit schematic is shown in Fig. 1 (a)[ a superconducting circuit loop]...[t]o interact the qubits via the tunable coupler we apply a sinusoidal fast-flux bias modulation of amplitude
δ
so that the total flux applied to the tunable bus is
ϕ
t
=
Θ
+
δ
c
o
s
(
ω
ϕ
t
)
[ and a flux bias element that applies a magnetic flux to the superconducting circuit loop].”);
and communicating the flux modulation signal to the flux bias control line comprises communicating the flux modulation signal to the flux bias element such that the magnetic flux is modulated by the flux modulation signal((McKay, pgs., 2-4, see also figs. 1a, 2a and 2b, As figs. 2a and 2b detail:
PNG
media_image1.png
348
469
media_image1.png
Greyscale
Fig. 2a represents the optical image of the two-qubit, one bus device and fig. 2b represents the tunable bus (TB) that is tuned by a DC bias coil and a high-speed flux line
(HSFL)[ communicating the flux modulation signal to the flux bias element such that the magnetic flux is modulated by the flux modulation signal].).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner in view of Didier with the above teachings of McKay for the same rationale stated at Claim 1.
Regarding claim 3, Krinner in view of Didier and McKay teach the method of claim 1, wherein: the second qubit device comprises
a fixed-frequency qubit device(McKay, pgs., 2-4, see also figs. 1a, 2a and 2b, “The tunable bus circuit that we consider in this paper consists of several fixed-frequency qubits[a fixed-frequency qubit device] dispersively coupled to a frequency-tunable bus; a circuit schematic is shown in Fig. 1 (a)),
the superconducting quantum processing unit comprises a fixed-frequency coupler device coupled between the first tunable-frequency qubit device and the fixed-frequency qubit device, and the first tunable-frequency qubit device and the fixed-frequency qubit device are coupled by the fixed-frequency coupler device during the application of the two-qubit quantum logic gate(Krinner, pgs., 2-3, see also fig., 1, “The superconducting device used in our experiment uses a frequency-tunable transmon qubit (qubit A)[between the first tunable-frequency qubit device] and a fixed frequency transmon qubit (qubit B)[ and the fixed-frequency qubit devices]... [t]he two qubits... are capacitively coupled with a coupling strength
J
2
π
=
42(1) Mhz[a fixed-frequency coupler device]...[t]he coupling is mediated by virtual states, which are coupled to
f
,
g
and
|
g
,
e
via... the direct qubit-qubit coupling J [see Fig. 1(c)][ and the first tunable-frequency qubit device and the fixed-frequency qubit device are coupled by the fixed-frequency coupler device during the application of the two-qubit quantum logic gate]” ).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner in view of Didier with the above teachings of McKay for the same rationale stated at Claim 1.
Regarding claim 5, Krinner in view of Didier and McKay teach the method of claim 1, wherein the first tunable-frequency qubit device further comprises a qubit drive line(Krinner, pgs., 2-3, see also fig. 2, “The coupling between
f
,
g
and
|
g
,
e
is activated by a strong microwave tone
Ω
A
t
=
Ω
f
g
g
e
c
o
s
(
ω
f
g
g
e
t
)
applied to the drive line of qubit A[a qubit drive line] at a frequency corresponding to the energy difference between the two states....”), and applying the two-qubit quantum logic gate to the pair of qubits comprises:
generating, by operation of the control system, a microwave drive signal; and communicating the microwave drive signal to the first tunable-frequency qubit device on the qubit drive line(Krinner, pgs., 2-3, see also figs. 1[generating, by operation of the control system] and 2, “The coupling between
f
,
g
and
|
g
,
e
is activated by a strong microwave tone
Ω
A
t
=
Ω
f
g
g
e
c
o
s
(
ω
f
g
g
e
t
)
applied to the drive line of qubit A[a microwave drive signal; and communicating the microwave drive signal to the first tunable-frequency qubit device on the qubit drive line] at a frequency corresponding to the energy difference between the two states....”).
Regarding claim 6, Krinner in view of Didier and McKay teach the method of claim 1, wherein the first tunable-frequency qubit device comprises a tunable-frequency transmon device(Krinner, pgs., 2-3, see also fig., 1, “The superconducting device used in our experiment uses a frequency-tunable transmon qubit (qubit A)[a tunable-frequency transmon device]....”).
Regarding claim 7, Krinner in view of Didier and McKay teach the method of claim 1, wherein the flux modulation signal is defined by a flux modulation amplitude and a flux modulation frequency(Didier, pg., 2, “We now consider a bichrornatic modulation, characterized by the parking flux
ϕ
d
c
, the modulation amplitude
ϕ
a
c
[is defined by a flux modulation amplitude], the modulation frequency
f
m
[and a flux modulation frequency]... [u]nder this flux modulation, the time evolution of the qubit frequency is conveniently expressed in terms of a Fourier series[wherein the flux modulation signal]....”), and the method comprises,
prior to generating the flux modulation signal, determining, by operation of the control system, a value of the flux modulation frequency and a value of the flux modulation amplitude of the flux modulation signal(Didier, pgs., 2-3, see also fig. 1, “The dynamical sweet spots are found by looking for the sets of pulse parameters (
ϕ
d
c
,
ϕ
a
c
,
α
,
θ
) for which the dephasing rate, Eq. (5) vanishes. Using the symmetries of the time-averaged frequency, it is sufficient to consider
α
∈
[
0
,
π
2
]
and
θ
∈
[
0
,
π
]
. For a given set of
ϕ
d
c
and
ϕ
a
c
, the angle
α
is swept between 0 and
π
2
to find the intersection between the roots of the polynomials
∂
P
(
x
)
∂
ϕ
d
c
and
∂
P
(
x
)
∂
ϕ
a
c
on the real interval [-1, 1][as detailed by fig. 1][ prior to generating the flux modulation signal, determining, by operation of the control system, a value of the flux modulation frequency and a value of the flux modulation amplitude of the flux modulation signal]” ).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner with the above teachings of Didier for the same rationale stated at Claim 1.
Regarding claim 8, Krinner in view of Didier and McKay teach the method of claim 7, wherein the superconducting quantum processing unit comprises a third qubit device, the third qubit device is operably coupled to the first tunable-frequency qubit device(McKay, pgs. 2-3, see also fig. 1, “The tunable bus circuit that we consider in this paper consists of several fixed-frequency qubits[a third qubit device, the third qubit device is operably] dispersively coupled to a frequency-tunable bus[coupled to the first tunable-frequency qubit device]; a circuit schematic is shown in Fig. 1 (a).”),
and the value of the flux modulation frequency does not activate an interaction between the first tunable-frequency qubit device and the third qubit device(McKay, pgs., 3-4, As fig. 3c details:
PNG
media_image2.png
259
343
media_image2.png
Greyscale
When the flux drive strength i.e.,
ϕ
0
is less than 0.12, Qubit 2 does not shift at all[and the value of the flux modulation frequency does not activate an interaction between the first tunable-frequency qubit device and the third qubit device]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner in view of Didier with the above teachings of McKay for the same rationale stated at Claim 1.
Regarding claim 9, Krinner in view of Didier and McKay teach the method of claim 7, wherein the value of the flux modulation frequency is not equal to a subharmonic of the difference between the time average of the transition frequency of the first tunable-frequency qubit device and the transition frequency of the second qubit device(Didier, pgs., 4-5, see also figs. 1 and 4, “
∆
-
is the time-averaged detuning between the two states used in the coherent exchange. Explicitly,
∆
-
=
f
-
01
-
f
F
01
...is plotted as a function of the time-averaged frequency in Fig. 4(b)[of the difference between the time average of the transition frequency of the first tunable-frequency qubit device and the transition frequency of the second qubit device]...[t]he modulation frequency is chosen to activate an iSWAP or a CZ gate between the tunable transmon and a fixed-frequency transmon[wherein the value of the flux modulation frequency is not equal to a subharmonic].”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner with the above teachings of Didier for the same rationale stated at Claim 1.
Regarding claim 10, Krinner in view of Didier and McKay teach the method of claim 7, wherein the value of the flux modulation frequency is greater than a threshold frequency value that activates interactions between the first tunable-frequency qubit device and the second qubit device(Didier, pgs., 4-5, see also fig. 1 and 4, As fig. 4(b) details: “Sideband k=-1 for p=2 and
0.2
ϕ
0
≤
ϕ
d
c
... [wherein the value of the flux modulation frequency is greater than a threshold frequency value]The modulation frequency is chosen to activate parametric entangling gates between the tunable transmon of Fig. 1 and a fixed-frequency transmon[that activates interactions between the first tunable-frequency qubit device and the second qubit device]....”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner with the above teachings of Didier for the same rationale stated at Claim 1.
Regarding claim 11, Krinner in view of Didier and McKay teach the method of claim 1, wherein the superconducting quantum processing unit comprises a tunable-frequency coupler device coupled between the first tunable-frequency qubit device and the second qubit device(Krinner, pgs., 2-3, see also fig. 1, “The superconducting device used in our experiment uses a frequency-tunable transmon qubit (qubit A)[the first tunable-frequency qubit device] and a fixed frequency transmon qubit (qubit B)[and the second qubit device]... [t]he two qubits... are capacitively coupled with a coupling strength
J
/
2
π
=42(1) MHz [see figs. 1(a) and 1(b)]... [t]he coupling is mediated by virtual states... via the drive
Ω
f
g
g
e
and the direct qubit-qubit coupling J[a tunable-frequency coupler device coupled between]”),
the flux modulation signal is defined by a flux modulation amplitude and a flux modulation frequency(Didier, pg., 2, “We now consider a bichrornatic modulation, characterized by the parking flux
ϕ
d
c
, the modulation amplitude
ϕ
a
c
[is defined by a flux modulation amplitude], the modulation frequency
f
m
[and a flux modulation frequency]... [u]nder this flux modulation, the time evolution of the qubit frequency is conveniently expressed in terms of a Fourier series [the flux modulation signal]....”), and the method comprises,
prior to generating the flux modulation signal,determining, by operation of the control system, a value of the flux modulation frequency and a value of the flux modulation amplitude of the flux modulation signal(Didier, pgs., 2-3, see also fig. 1, “The dynamical sweet spots are found by looking for the sets of pulse parameters (
ϕ
d
c
,
ϕ
a
c
,
α
,
θ
) for which the dephasing rate, Eq. (5) vanishes. Using the symmetries of the time-averaged frequency, it is sufficient to consider
α
∈
[
0
,
π
2
]
and
θ
∈
[
0
,
π
]
. For a given set of
ϕ
d
c
and
ϕ
a
c
, the angle
α
is swept between 0 and
π
2
to find the intersection between the roots of the polynomials
∂
P
(
x
)
∂
ϕ
d
c
and
∂
P
(
x
)
∂
ϕ
a
c
on the real interval [-1, 1][as detailed by fig. 1][ prior to generating the flux modulation signal, determining, by operation of the control system, a value of the flux modulation frequency and a value of the flux modulation amplitude of the flux modulation signal]”),
and the value of the flux modulation frequency does not activate an interaction(Didier, pg., 5, “Under modulation when the central sideband weight tends to its maximum value, the other sideband weights vanish and the qubit behaves closely to an undriven qubit...[a]t a dynamical sweet spot with a time-averaged frequency sufficiently away from the TLS[two level systems] frequency, the qubit is affected by neither slow flux noise nor by the TLS[and the value of the flux modulation frequency does not activate an interaction]”)
between the first tunable-frequency qubit device and the tunable-frequency coupler device(Krinner, pgs., 2-3, see also fig. 1, “The superconducting device used in our experiment uses a frequency-tunable transmon qubit (qubit A)[between the first tunable-frequency qubit device]... [t]he two qubits... are capacitively coupled with a coupling strength
J
/
2
π
=42(1) MHz [see figs. 1(a) and 1(b)]... [t]he coupling is mediated by virtual states... via the drive
Ω
f
g
g
e
and the direct qubit-qubit coupling J[and the tunable-frequency coupler device]”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner with the above teachings of Didier for the same rationale stated at Claim 1.
Regarding claim 12, Krinner in view of Didier and McKay teach the method of claim 1, comprising, prior to generating the flux modulation signal, performing a calibration process for the two-qubit quantum logic gate, wherein performing the calibration process comprises determining values of device parameters of the superconducting quantum processing unit(Didier, pgs., 2-3, see also fig. 1, “The dynamical sweet spots are found by looking for the sets of pulse parameters (
ϕ
d
c
,
ϕ
a
c
,
α
,
θ
) for which the dephasing rate, Eq. (5) vanishes. Using the symmetries of the time-averaged frequency, it is sufficient to consider
α
∈
[
0
,
π
2
]
and
θ
∈
[
0
,
π
]
. For a given set of
ϕ
d
c
and
ϕ
a
c
, the angle
α
is swept between 0 and
π
2
to find the intersection between the roots of the polynomials
∂
P
(
x
)
∂
ϕ
d
c
and
∂
P
(
x
)
∂
ϕ
a
c
on the real interval [-1, 1][as detailed by fig. 1][ prior to generating the flux modulation signal, performing a calibration process for the two-qubit quantum logic gate determining values of device parameters of the superconducting quantum processing unit]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner with the above teachings of Didier for the same rationale stated at Claim 1.
Regarding claim 13, Krinner in view of Didier and McKay teach the method of claim 12, wherein determining values of the device parameters comprises determining values of at least one of a range of operating frequencies and anharmonicities of the first tunable-frequency qubit device(Didier, pgs., 2-3, see also fig. 1, “The dynamical sweet spots are found by looking for the sets of pulse parameters (
ϕ
d
c
,
ϕ
a
c
,
α
,
θ
) for which the dephasing rate, Eq. (5) vanishes. Using the symmetries of the time-averaged frequency, it is sufficient to consider
α
∈
[
0
,
π
2
]
and
θ
∈
[
0
,
π
]
. For a given set of
ϕ
d
c
and
ϕ
a
c
, the angle
α
is swept between 0 and
π
2
to find the intersection between the roots of the polynomials
∂
P
(
x
)
∂
ϕ
d
c
and
∂
P
(
x
)
∂
ϕ
a
c
on the real interval [-1, 1][as detailed by fig. 1].” & Didier, pgs., 2-3, see also fig. 1, As fig. 1 details: “The tunable transmon is characterized by a maximum frequency
f
m
a
x
=
5
G
H
z
, a minimum frequency
f
m
i
n
=
4.2
G
H
z
, and an anharmonicity
η
m
a
x
=200MHz[determining values of at least one of a range of operating frequencies and anharmonicities of the first tunable-frequency qubit device]” ).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner with the above teachings of Didier for the same rationale stated at Claim 1.
Regarding claim 14, Krinner in view of Didier and McKay teach the method of claim 12,wherein the calibration process comprises: while the first and second tunable-frequency qubit devices are on resonance with each other, measuring values of a coupling strength of the first and second tunable- frequency qubit devices(Krinner, pgs., 2-3, see also fig. 1, “The superconducting device used in our experiment uses a frequency-tunable transmon qubit (qubit A)[the first tunable-frequency qubit device]... [t]he two qubits... are capacitively coupled with a coupling strength
J
/
2
π
=42(1) MHz [see figs. 1(a) and 1(b)]... [t]he coupling is mediated by virtual states... via the drive
Ω
f
g
g
e
and the direct qubit-qubit coupling J[and second tunable-frequency qubit devices]...[o]n resonance... [w]e next measure the coupling strength
g
f
g
g
e
[are on resonance with each other, measuring values of a coupling strength of the first and second tunable- frequency qubit devices]....”)
to determine an operating value and a parking value of a magnetic flux applied on the tunable-frequency coupler device(Didier, pg., 3, “While most of this range is available at all parking flux for p=2, most of the flexibility is obtained at the maximum and minimum of the band for p=3...[a] convenient configuration is to park the qubit at an extremum of the frequency band[to determine an operating value and a parking value of a magnetic flux applied on the tunable-frequency coupler device]....”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner with the above teachings of Didier for the same rationale stated at Claim 1.
Regarding claim 15, Krinner in view of Didier and McKay teach the method of claim 12, comprising, prior to generating the flux modulation signal, determining a gate time for the two-qubit quantum logic gate(Didier, pg., 5, see also fig. 5, “The infidelity of entaglining gates is plotted in Fig. 5 for p=2 and p=3 as a function of the fixed transmon frequency ....” & Didier, pg., 5, see also fig. 5, As fig. 5 details: “The gate parameters...gate time...are optimized without flux noise (dashed lines)[ prior to generating the flux modulation signal, determining a gate time for the two-qubit quantum logic gate]”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner with the above teachings of Didier for the same rationale stated at Claim 1.
Regarding claim 16, Krinner teaches a superconducting quantum processing unit(Krinner, pg., 2, see also figs., 1a and 1b, “The superconducting device used in our experiment uses a frequency-tunable transmon qubit (qubit A)....”) and for all other claim limitations they are rejected on the same basis as independent claim 1 since they are analogous claims.
Referring to dependent claims 17-18 and 20, they are rejected on the same basis as
dependent claims 2-3 and 5 since they are analogous claims.
Claims 4 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Krinner et al., Demonstration of an all-microwave controlled-phase gate between far-detuned qubits. Physical Review Applied. 2020 Oct 1(“Krinner”) in view of Didier, Flux control of superconducting qubits at dynamical sweet spots. arXiv preprint arXiv:1912.09416v1 2019 Dec 19(“Didier”) and in view of McKay., et al. "Universal gate for fixed-frequency qubits via a tunable bus." Physical Review Applied 6.6 (2016)(“McKay”) and further in view of Ferguson et al. US 2020/0279186 Al(“Ferguson”)
Regarding claim 4, Krinner in view of Didier and McKay teach the method of claim 1, wherein:
[the first tunable-frequency qubit device and the second tunable-frequency qubit device are coupled by the tunable-frequency coupler device] during the application of the two-qubit quantum logic gate(Krinner, pgs., 2-3, “When driving the fgge transition for a duration that corresponds to a full round trip in the
f
,
g
-
|
g
,
e
manifold, the state
|
g
,
e
picks up a geometric phase of π...thereby realizing a controlled-phase gate[during the application of the two-qubit quantum logic gate]).2
However, Krinner in view of Didier and McKay do not teach:
the second qubit device comprises a second tunable-frequency qubit device, the superconducting quantum processing unit comprises a tunable-frequency coupler device coupled between the first tunable-frequency qubit device and the second tunable-frequency qubit device, the first tunable-frequency qubit device and the second tunable-frequency qubit device are coupled by the tunable-frequency coupler device, the transition frequency of the second qubit device is a maximum transition frequency of the second tunable-frequency qubit device, and applying the two-qubit quantum logic gate comprises communicating a flux bias signal to a flux bias control line coupled to the second tunable-frequency qubit device, wherein the flux bias signal is configured to tune the transition frequency of the second tunable-frequency qubit device to the maximum transition frequency.
However, Ferguson teaches:
wherein: the second qubit device comprises
a second tunable-frequency qubit device, the superconducting quantum processing unit comprises a tunable-frequency coupler device coupled between the first tunable-frequency qubit device and the second tunable-frequency qubit device(Ferguson, paras. 0020-0034, see also fig. 2, “In the example of FIG. 2, the tunable current-mirror qubit 50 includes a plurality of SQUIDs 52[a second tunable-frequency qubit device; the first tunable-frequency qubit device]...[a]dditionally, the tunable current-mirror qubit 50 includes a plurality of capacitors, demonstrated in the example of FIG. 2 as
C
1
,
C
2
,
C
3
, and
C
4
, that interconnect nodes between respective pairs of SQUIDs 52[a tunable-frequency coupler device coupled between the first tunable-frequency qubit device and the second tunable-frequency qubit device]”),
the first tunable-frequency qubit device and the second tunable-frequency qubit device are coupled by the tunable-frequency coupler device [during the application of the two-qubit quantum logic gate](Ferguson, paras. 0020-0034, see also fig. 2, “Additionally, the tunable current-mirror qubit 50 includes a plurality of capacitors, demonstrated in the example of FIG. 2 as
C
1
,
C
2
,
C
3
, and
C
4
, that interconnect nodes between respective pairs of SQUIDs 52[the first tunable-frequency qubit device and the second tunable-frequency qubit device are coupled by the tunable-frequency coupler device].”),
the transition frequency of the second qubit device is a maximum transition frequency of the second tunable-frequency qubit device(Ferguson, paras. 0020-0034, see also fig. 2, “[T]o transition between the microwave excitation mode and the persistent current mode, the first input flux
α
is tuned from slightly greater than approximately zero amplitude...to a value approximately equal to a first amplitude
ϕ
corresponding to the superconducting flux quantum... the excited state is adiabatically transformed into the higher energy current state[the transition frequency of the second qubit device is a maximum transition frequency of the second tunable-frequency qubit device].”),
and applying the two-qubit quantum logic gate comprises communicating a flux bias signal to a flux bias control line coupled to the second tunable-frequency qubit device, wherein the flux bias signal is configured to tune the transition frequency of the second tunable-frequency qubit device to the maximum transition frequency(Ferguson, paras. 0020-0034, see also fig. 2, “In the example of FIG. 2, a first one of the SQUIDs 52, demonstrated at 72, is configured to receive a first input flux
α
[communicating a flux bias signal to a flux bias control line coupled to the second tunable-frequency qubit device], while the remaining SQUIDs 52 are configured to receive a second input flux
γ
... fluxes... can be independently controlled to control the mode of the tunable current-mirror qubit 50, such as to allow the tunable current-mirror qubit 50 to transition between at least two modes... to transition between the microwave excitation mode and the persistent current mode, the first input flux
α
is tuned from slightly greater than approximately zero amplitude...to a value approximately equal to a first amplitude
ϕ
corresponding to the superconducting flux quantum... the excited state is adiabatically transformed into the higher energy current state[wherein the flux bias signal is configured to tune the transition frequency of the second tunable-frequency qubit device to the maximum transition frequency].”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Krinner in view of Didier and McKay with the teachings of Ferguson the motivation to do so would be to implement a control and circuit mechanism to change the quantum states of qubits based upon different modes of excitation for computation and storage(Ferguson, para. 0004, “One example includes a tunable current-mirror qubit. The qubit includes a plurality of flux tunable elements disposed in a circuit loop. A first portion of the flux tunable elements can be configured to receive a first input flux and a remaining portion of the flux tunable elements can be configured to receive a second input flux to control a mode of the tunable current-mirror qubit between a microwave excitation mode to facilitate excitation or quantum state manipulation of the tunable current-mirror qubit via a microwave input signal and a noise-protected mode to facilitate storage of the quantum state of the tunable current-mirror qubit.”)
Referring to dependent claim 19, it is rejected on the same basis as
dependent claims 4 since they are analogous claims.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 10599990 B2(details a quantum information system through the use of multiple arrays tunable qubit devices)
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/Adam C Standke/
Primary Examiner
Art Unit 2129
1 Examiner Notes: The claim limitations that are not in bold and contained within square brackets (i.e., [ ]) are
claim limitations that are not taught by the prior art of Krinner.
2 Examiner Notes: The claim limitations that are not in bold and contained within square brackets (i.e., [ ]) are
claim limitations that are not taught by the prior art of Krinner in view of Didier and McKay.