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 .
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1, 3-4, 8-9, 11-12, 16-17 and 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lisenfeld Enhancing the coherence of superconducting quantum bits with electric field, 2023 (IDS 5/30/24 Cite No. 2 under “Non-Patent Literature Documents”) in view of Kelly, Scalable in situ qubit calibration during repetitive error detection, 2016.
With respect to claim 1, Lisenfeld teaches “1. A system, comprising: a memory that stores computer executable components; and a processor that executes at least one of the computer executable components that: execute a quantum circuit to obtain measurements of a qubit” on p. 1
Moreover, TLS resonance frequencies may fluctuate in time due to interactions with thermally activated, randomly switching low energy TLS. This mechanism efficiently transforms thermal noise into the qubit’s environmental spectrum and causes fluctuations of the qubit’s resonance frequency and energy relaxation rate. For quantum processors, this implies fluctuations of their quantum volume (i.e., computational power). Recently, we have shown that the resonance frequencies of TLS located on thin-film electrodes and the substrate of a qubit circuit can be tuned by an applied DC-electric field. Accordingly, it becomes possible to tune defects that dominate qubit energy relaxation away from the qubit resonance, and this results in longer relaxation times T1. Here, we demonstrate this concept using a simple routine which maximizes the T1 time of a qubit by searching for an optimal electric field bias. The method was tested at various qubit resonance frequencies and increased the 30-minute averaged qubit T1 time by 23%. The ability to control the decohering TLS bath independently from the qubit will be particularly useful for quantum processors using fixed-frequency qubits, where spoilage of individual qubits due to resonance collision with a strongly coupled defect can be alleviated in situ
The response of TLS to the applied electric field is observed by measuring the qubit energy relaxation time T1 as a function of qubit frequency, which shows Lorentzian minima whenever sufficiently strongly interacting TLS are tuned into resonance
“and modulate, via a control two-level system (TLS) knob, a TLS landscape of a quantum processor between . . . executions of the quantum circuit” on p. 1
Moreover, TLS resonance frequencies may fluctuate in time due to interactions with thermally activated, randomly switching low energy TLS. This mechanism efficiently transforms thermal noise into the qubit’s environmental spectrum and causes fluctuations of the qubit’s resonance frequency and energy relaxation rate. For quantum processors, this implies fluctuations of their quantum volume (i.e., computational power). Recently, we have shown that the resonance frequencies of TLS located on thin-film electrodes and the substrate of a qubit circuit can be tuned by an applied DC-electric field. Accordingly, it becomes possible to tune defects that dominate qubit energy relaxation away from the qubit resonance, and this results in longer relaxation times T1. Here, we demonstrate this concept using a simple routine which maximizes the T1 time of a qubit by searching for an optimal electric field bias. The method was tested at various qubit resonance frequencies and increased the 30-minute averaged qubit T1 time by 23%. The ability to control the decohering TLS bath independently from the qubit will be particularly useful for quantum processors using fixed-frequency qubits, where spoilage of individual qubits due to resonance collision with a strongly coupled defect can be alleviated in situ
It appears Lisenfeld fails to explicitly teach “successive.” However, Kelly, Scalable in situ qubit calibration during repetitive error detection teaches “modulate. . . between successive executions of the quantum circuit” in the abstract:
Additionally, we show how parameter drift can be compensated for during computation by inserting a frequency drift and using our method to remove it. We remove both drift on a single qubit and independent drifts on all qubits simultaneously.
Page 7
Assuming the 1.1 MHz error detection rate, N = 48000 measurements for each ζ measurement, two measurements per update, and three qubit patterns to cycle between as in Fig. 4, frequency drift as fast as 0.3 Hz could be compensated for every qubit in a continuously running repetition code experiment.
Kelly and Lisenfeld are analogous art because they are from the same field of endeavor as the claimed invention.
It would have been obvious to one skilled in the art before the effective filing date of the invention to modify and modulate, via a control two-level system (TLS) knob, a TLS landscape of a quantum processor between . . . executions of the quantum circuit” to include “successive executions” as taught by Kelly.
The motivation would have been to “keep[] error rates low on all physical qubits throughout the course of a computation.” Kelly abstract.
Claim 9 and 17 are rejected for the same reason given above for claim 1.
With respect to claim 3, Lisenfeld teaches “3. The system of claim 1, wherein the at least one of the computer executable components further: discretely changes parameters of the control TLS knob between the . . . executions of the quantum circuit” on p. 2:
. . ., at each qubit operation frequency
there is a preferable electric field bias where most of the
dominating TLS are tuned out of qubit resonance and the T1
time is maximized. In the following, we describe a simple routine
by which an optimal E-field bias can be automatically determined
First, the qubit T1-time is measured for a range of applied
electric fields. Hereby, the T1-time is obtained from exponential fits
to the decaying qubit population probability after it was excited
by a microwave pulse, measured using the common protocol
shown in the inset of Fig. 1d. Figure 2a shows the resulting electric
field dependence of T1 (black data points), measured at various
qubit resonance frequencies (rows I to III). These data are then
smoothed by a nearest-neighbor average (gray curve) to average
out individual dips and peaks in order to amplify broader maxima
that promise a more stable improvement.
Next, the E-field is set to the value where the maximum T1-time
occurred
. . .
Finally, a second pass is performed, sweeping the E-field
in finer steps around its previously determined optimum value
until the obtained T1 time is close to the maximum value that was
observed in the previous sweep.
(Examiner finds the changed electric fields teach changing parameters of TLS knob).
It appears Lisenfeld fails to explicitly teach “successive.”
However, Kelly, Scalable in situ qubit calibration during repetitive error detection teaches “successive executions” in the abstract:
Additionally, we show how parameter drift can be compensated for during computation by inserting a frequency drift and using our method to remove it. We remove both drift on a single qubit and independent drifts on all qubits simultaneously.
Page 7
Assuming the 1.1 MHz error detection rate, N = 48000 measurements for each ζ measurement, two measurements per update, and three qubit patterns to cycle between as in Fig. 4, frequency drift as fast as 0.3 Hz could be compensated for every qubit in a continuously running repetition code experiment.
Kelly and Lisenfeld are analogous art because they are from the same field of endeavor as the claimed invention.
It would have been obvious to one skilled in the art before the effective filing date of the invention to modify “executions” in Linsenfeld to include “successive executions” as taught by Kelly.
The motivation would have been to “keep[] error rates low on all physical qubits throughout the course of a computation.” Kelly abstract.
Claim 11 and claim 19 are rejected for the same reason given above for claim 3.
With respect to claim 4, Linsenfeld teaches “The system of claim 3, wherein the at least one of the computer executable components further: select, based on a metric, subsets of the measurements to determine subsets of the parameters of the control TLS knob” on p. 2:
As it is evident from Fig. 1e, at each qubit operation frequency
there is a preferable electric field bias where most of the
dominating TLS are tuned out of qubit resonance and the T1
time is maximized. In the following, we describe a simple routine
by which an optimal E-field bias can be automatically determined.
First, the qubit T1-time is measured for a range of applied
electric fields. Hereby, the T1-time is obtained from exponential fits
to the decaying qubit population probability after it was excited
by a microwave pulse, measured using the common protocol
shown in the inset of Fig. 1d. Figure 2a shows the resulting electric
field dependence of T1 (black data points), measured at various
qubit resonance frequencies (rows I to III). These data are then
smoothed by a nearest-neighbor average (gray curve) to average
out individual dips and peaks in order to amplify broader maxima that promise a more stable improvement.
(Examiner finds optimal E-field bias teaches the subset of the parameters of the control TLS knob; Examiner finds T1-time is the metric);
“and execute the quantum circuit using the subsets of the parameters” on p. 2
. . . Afterwards, the optimization routine searches for the electric field which maximizes the qubit’s coherence time by taking data as shown in Fig. 2a. The result is then checked by monitoring the T1-time at the found optimal E-field during another 30 min (blue data in Fig. 2b). Evidently, during most of this time, acquired T1 times after optimization are higher than the reference values that were obtained at zero applied electric field.
(Examiner finds “at the found optimal E-field” teaches the execution of the subset).
Claim 12 is rejected for the same reason given above for claim 4.
With respect to claim 8, Lisenfeld teaches “8. The system of claim 1, wherein the measurements from each of the . . .executions over the TLS landscape at different modulations are accumulated” on p. 2
First, the qubit T1-time is measured for a range of applied
electric fields. Hereby, the T1-time is obtained from exponential fits
to the decaying qubit population probability after it was excited
by a microwave pulse, measured using the common protocol
shown in the inset of Fig. 1d. Figure 2a shows the resulting electric
field dependence of T1 (black data points), measured at various
qubit resonance frequencies (rows I to III). These data are then
smoothed by a nearest-neighbor average (gray curve) to average
out individual dips and peaks in order to amplify broader maxima that promise a more stable improvement.
p. 4
In our experiments, the optimization routine took less than
10 min (to acquire about 60 values of qubit T1 at several E-fields
(Examiner finds Fig. 2a teaches illustrates an accumulation of measurements from each of the executions over the TLS landscape at different modulations).
The motivation to combine “successive” in Kelly with “executions” in Linsenfeld is given in claim 1 above.
Claim 16 is rejected for the same reason given above for claim 8.
Claim(s) 2, 10, and 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lisenfeld Enhancing the coherence of superconducting quantum bits with electric field, 2023 (IDS 5/30/24 Cite No. 2 under “Non-Patent Literature Documents”) in view of Kelly, Scalable in situ qubit calibration during repetitive error detection, 2016 as applied to claim 1 and claim 9 and claim 17 above and further in view of Li, Motional averaging in a superconducting qubit, Jan 2013.
With respect to claim 2, Lisenfeld teaches “supply a . . . modulation that continuously varies of the control TLS knob during the . . . executions of the quantum circuit.” See p. 1 quoted in claim 1 above.
It appears Lisenfeld fails to explicitly teach “during the successive executions of the quantum circuit.”
However, Kelly teaches "during the successive executions of the quantum circuit.” See abstract:
Additionally, we show how parameter drift can be compensated for during computation by inserting a frequency drift and using our method to remove it. We remove both drift on a single qubit and independent drifts on all qubits simultaneously.
And Page 7:
Assuming the 1.1 MHz error detection rate, N = 48000 measurements for each ζ measurement, two measurements per update, and three qubit patterns to cycle between as in Fig. 4, frequency drift as fast as 0.3 Hz could be compensated for every qubit in a continuously running repetition code experiment.
Kelly and Lisenfeld are analogous art because they are from the same field of endeavor as the claimed invention.
It would have been obvious to one skilled in the art before the effective filing date of the invention to modify “supply a . . . modulation that continuously varies of the control TLS knob during the . . . executions of the quantum circuit” in Lisenfeld to include “successive executions” as taught by Kelly.
The motivation would have been to “keep[] error rates low on all physical qubits throughout the course of a computation.” Kelly abstract.
It appears Lisenfeld et al. fails to explicitly teach “a periodic modulation” “based on a period of the periodic modulation.”
However, Li, Motional averaging in a superconducting qubit, Jan 2013 teaches periodic modulation in the abstract (“With
sinusoidal modulation a complex pattern of additional sidebands is observed”); p. 3 (“Sinusoidal modulation of frequency. To further explore these effects, we have used sinusoidal waves to modulate the qubit energy splitting”); Examiner finds sinusoidal teaches a type (species) of periodic modulation (genus).
Li and Lisenfeld et al. are analogous art because they are from the same field of endeavor as the claimed invention.
It would have been obvious to one skilled in the art before the effective filing date of the invention to modify “wherein the at least one of the computer executable components further: supply a . . . modulation that continuously varies of the control TLS knob during the successive executions of the quantum circuit . . .” in Lisenfeld/Kelly to include supplying periodic modulation as taught by Li and to modify “modulation that continuously varies of the control TLS knob during the successive executions of the quantum circuit” at taught by Lisenfeld/Kelly to include “during the successive executions of the quantum circuit” as taught by Li.
The motivation for both combinations would have been to improve dephasing times of existing superconducting qubits. See Li page 4 left column under “discussion”:
We anticipate, resting on the motional narrowing phenomenon, that the dephasing times of the existing superconducting qubits may be dramatically improved if one is able to accelerate the dynamics of the longitudinally coupled TLSs.
Claim 10 and claim 18 are rejected for the same reason given above for claim 2.
Claim(s) 5, 7, 13, 15, and 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lisenfeld Enhancing the coherence of superconducting quantum bits with electric field, 2023 (IDS 5/30/24 Cite No. 2 under “Non-Patent Literature Documents”) in view of Kelly, Scalable in situ qubit calibration during repetitive error detection, 2016 as applied to claims 1 and 9 and 17 above and further in view of Li, Motional averaging in a superconducting qubit, Jan 2013 as applied to claims 2 and 10 and 18 above and further in view of Preda Broadband pump-probe spectroscopy at 20-MHz modulation frequency, 2016.
With respect to claim 5, it appears Linsenfeld et al. fails to explicitly teach “The system of claim 2, wherein the period is determined by an experimental repetition rate at which the measurements are obtained . . .”
However, Preda teaches “wherein the period is determined by an experimental repetition rate at which the measurements are obtained” on p. 2970 (“ΔT∕T signals in pump-probe are typically very small and lie on a large background, so they require modulation transfer techniques for their measurement. These techniques consist of: (i) amplitude modulation of the pump through a mechanical chopper, or an acousto-optic or an electro-optic modulator, ideally at a frequency exactly locked to half the repetition rate of the laser, so as to benefit from the enhanced energy correlation of consecutive laser pulses”)
Preda and Linsenfeld et al. are analogous art because they are from the same field of endeavor as the claimed invention.
It would have been obvious to one skilled in the art before the effective filing date of the invention to modify the period in Linsenfeld to include “wherein the period is determined by an experimental repetition rate at which the measurements are obtained” as taught by Preda.
The motivation would have been “to benefit from the enhanced energy correlation of consecutive laser pulses.” Id.
Claim 13 and claim 20 are rejected for the same reason given above for claim 5.
With respect to claim 7, Linsenfeld teaches 7. The system of claim 5, wherein the at least one of the computer executable components further: modulate the TLS landscape of one or more qubits of the quantum circuit” on p. 1
The method was tested at various qubit resonance frequencies and increased the 30- minute averaged qubit T1 time by 23%. The ability to control the decohering TLS bath independently from the qubit will be
particularly useful for quantum processors using fixed-frequency
qubits, where spoilage of individual qubits due to resonance
collision with a strongly coupled defect can be alleviated in situ on p. 4 right column:
Our simulations indicated that it is straight-forward to equip
each qubit in a processor with local gate electrodes, which will
allow one to simultaneously improve T1 of all qubits. We thus see
good opportunities for this technique to become a standard in
superconducting quantum processors.
“via one or more respective control TLS knobs” on
p. 1
The method was tested at various qubit resonance frequencies and increased the 30- minute averaged qubit T1 time by 23%. The ability to control the decohering TLS bath independently from the qubit will be
particularly useful for quantum processors using fixed-frequency
qubits, where spoilage of individual qubits due to resonance
collision with a strongly coupled defect can be alleviated in situ.
p. 3 left column (“When each qubit in a processor is coupled to a dedicated local gate electrode, the optimization routine can be applied. . .”);
“wherein parameters of the periodic modulation and the shape of modulation on the TLS landscape is independent between the one or more respective control TLS knobs” p. 1
The method was tested
at various qubit resonance frequencies and increased the 30-
minute averaged qubit T1 time by 23%. The ability to control the
decohering TLS bath independently from the qubit will be
particularly useful for quantum processors using fixed-frequency
qubits, where spoilage of individual qubits due to resonance
collision with a strongly coupled defect can be alleviated in situ.
on p. 3 (“When each qubit in a processor is coupled to a dedicated local gate electrode, the optimization routine can be applied. . .”); p. 4
However, even when tunable qubits are used, it is still necessary to mutually balance their individual resonance frequencies to avoid crosstalk and to maximize gate fidelities, and this will be greatly simplified if qubit coherence can be optimized at all frequencies by having independent control of the TLS bath. Also, to improve two-qubit gates that require qubit frequency excursions, one could adjust
our optimization procedure to minimize the number of TLS that
have resonances in the traversed frequency interval
Claim 15 is rejected for the same reason given above for claim 7.
Claim(s) 6 and 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lisenfeld, Enhancing the coherence of superconducting quantum bits with electric field, 2023 (IDS 5/30/24 Cite No. 2 under “Non-Patent Literature Documents”) in view of Kelly, Scalable in situ qubit calibration during repetitive error detection, 2016 as applied to claim 1 and claim 9 above and further in view of Li, Motional averaging in a superconducting qubit, Jan 2013 as applied to claim 2 and claim 10 above and further in view of as Preda applied to claim 5 and 13 above and further in view of Shaniv, Quantum lock-in force sensing using optical clock Doppler velocimetry, 2017.
With respect to claim 6 Linsenfeld et al. teaches “periodic modulation of the control TLS knob.” See claim 2 above.
It appears Linsenfeld et al. fails to teach “is non-commensurate relative to the experimental repetition rate”
However, Shaniv, Quantum lock-in force sensing using optical clock
Doppler velocimetry, 2017 teaches ““is non-commensurate relative to the experimental repetition rate” on p. 4
Since the experiment is repeated at a rate that is incommensurate with the force frequency, the phase x is sampled with uniformed probability in different repetitions of the experiment
Shaniv et al. are analogous art because they are from the same field of endeavor as the claimed invention.
It would have been obvious to one skilled in the art before the effective filing date of the invention to modify “The system of claim 5, wherein the periodic modulation of the control TLS knob” taught by to include “is non-commensurate relative to the experimental repetition rate” taught by Shaniv.
The motivation would have been to reduce bias by not sampling the same phase data. See Shaniv page 4 quoted above.
Claim 14 is rejected for the same reason given above for claim 6.
Conclusion
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/ALBERT M PHILLIPS, III/Primary Examiner, Art Unit 2159
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