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 .
Response to Amendment
Claims 4, 6, 11, 21-23, and 27-28 have been cancelled; and claims 1-3, 5, 7-10, 12-20, and 24-26 are currently pending.
Priority
Acknowledgment is made of applicant's claim for foreign priority under 35 U.S.C. 119(a)-(d).
Information Disclosure Statement
The information disclosure statements filed on 6/10/2026 has been acknowledged and a signed copy of the PTO-1449 is attached herein.
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.
Claims 1-2, 5, and 12-13 are rejected under 35 U.S.C. 103 as being unpatentable over Betz et al. (US 2016/0300155 A1, hereinafter “Betz”) in view of Schenkel et al. (US 2013/0087766 A1, hereinafter “Schenkel”).
In regards to claim 1, Betz discloses (See, for example, Figs. 3) a processing element for a quantum processing apparatus (See, for example Abstract), the processing element comprising:
a silicon substrate (See, for example, 16, See also Pars [0075], [0076]);
a dielectric material (7, See, for example, Par [0075]), wherein the silicon substrate and the dielectric material form an interface (interface between 7 and 16);
an electrode (121, 122) formed on the dielectric material (7) for isolating one or more electrons in the silicon substrate to form a quantum dot (171, 172, See, for example, Pars [0075]-[0078]);
a group IV atom having a nuclear spin located in the wavefunction of the one or more electrons, the nuclear spin of the group IV atom entangled with the one or more electrons (See, for example, Par [0101], naturally occurring 29Si atoms are inherently entangled with electrons in the quantum dots and are also inherently within the waveforms of the electrons in order to generate the disclosed differences in hyperfine fields of each quantum dot); and
a control arrangement for controlling a quantum property of the quantum dot and the nuclear spin to operate as a qubit (See, for example, Par [0079], “coupling between the dos 171, 172, can be controlled by a back-gate provided …”, See also, Pars [0159]-[0165], [0185]-[0195], [0202]-[0214], and [0259]-[0260]).
Betz is silent regarding the specific recitation of a control arrangement for controlling a quantum property of the quantum dot and the nuclear spin to operate as a qubit.
Schenkel while disclosing a scalable quantum computer teaches a control arrangement for controlling a quantum property of the quantum dot and the nuclear spin to operate as a qubit
(Controlling quantum dot: See Par [0009], this is structural teaching silicon substrate => buried oxide=> semiconductor (28Si) =>dielectric => top gate electrodes that electrostatically define and isolate electrodes in quantum dots.
Controlling Nuclear spin: See Par [0017], this teaches a two-step control chain:
The electrode- defined quantum dot traps an electron whose spin is controllable, and
The electron spin couples to the donor nuclear spin via hyperfine interaction.
The nuclear spin serves as quantum memory while the electron spin is the operational qubit interface.
Voltage-controlled exchange coupling between Qdot and nuclear spin: See Par [0020], this teaches that by varying the electrode voltage, the operator tunes how strongly the quantum dot electron “communicate” the donor electron (which in turn is hyperfine-coupled to the nuclear spin). Turning this coupling on and off is what enables two-qubit gate operations involving the nuclear spin.
Protecting the nuclear spin coherence: See Par [0023], which teaches active control of nuclear spin coherence by ionizing/de-ionizing the donor (via gate voltages), and the protocol for reading quantum information out of the nuclear spin back into the electron spin system).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify Betz by Schenkel because this help provide scalable inter-qubit coupling achieved through electrode-controlled Heisenberg exchange between adjacent quantum dots rather than direct donor-donor interaction.
In regards to claim 12, Betz discloses (See, for example, Figs. 3. 5 and 13) a method of operation of a plurality of quantum processing elements (See, Abstract), each quantum processing element comprising
a silicon substrate (16),
a dielectric material (7), wherein the silicon substrate (16) and the dielectric material (7) form an interface,
an electrode (121, 122) formed on the dielectric material (7) for isolating one or more electrons in the silicon substrate (16) to form a quantum dot (171, 172),
a group IV atom having a nuclear spin located in the wavefunction of the one or more electrons, the nuclear spin of the group IV atom entangled with the one or more electrons (See, for example, Par [0101], naturally occurring 29Si atoms are inherently entangled with electrons in the quantum dots and are also inherently within the waveforms of the electrons in order to generate the disclosed differences in hyperfine fields of each quantum dot), and
a control arrangement for controlling a quantum property of the quantum dot and the nuclear spin to operate the quantum dot and the nuclear spin as a qubit (See, for example, Par [0079], “coupling between the dos 171, 172, can be controlled by a back-gate provided …”, See also, Pars [0159]-[0165], [0185]-[0195], [0202]-[0214], and [0259]-[0260]),
the method comprising the step of:
applying a signal via the control arrangement to control a state of the qubit (See, for example, Par [0079], “coupling between the dos 171, 172, can be controlled by a back-gate provided …”, See also, Pars [0159]-[0165], [0185]-[0195], [0202]-[0214], and [0259]-[0260]).
Betz is silent regarding the specific recitation of a control arrangement for controlling a quantum property of the quantum dot and the nuclear spin to operate as a qubit.
Schenkel while disclosing a scalable quantum computer teaches a control arrangement for controlling a quantum property of the quantum dot and the nuclear spin to operate as a qubit
(Controlling quantum dot: See Par [0009], this is structural teaching silicon substrate => buried oxide=> semiconductor (28Si) =>dielectric => top gate electrodes that electrostatically define and isolate electrodes in quantum dots.
Controlling Nuclear spin: See Par [0017], this teaches a two-step control chain:
The electrode- defined quantum dot traps an electron whose spin is controllable, and
The electron spin couples to the donor nuclear spin via hyperfine interaction.
The nuclear spin serves as quantum memory while the electron spin is the operational qubit interface.
Voltage-controlled exchange coupling between Qdot and nuclear spin: See Par [0020], this teaches that by varying the electrode voltage, the operator tunes how strongly the quantum dot electron “communicate” the donor electron (which in turn is hyperfine-coupled to the nuclear spin). Turning this coupling on and off is what enables two-qubit gate operations involving the nuclear spin.
Protecting the nuclear spin coherence: See Par [0023], which teaches active control of nuclear spin coherence by ionizing/de-ionizing the donor (via gate voltages), and the protocol for reading quantum information out of the nuclear spin back into the electron spin system).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify Betz by Schenkel because this help provide scalable inter-qubit coupling achieved through electrode-controlled Heisenberg exchange between adjacent quantum dots rather than direct donor-donor interaction.
In regards to claim 2, Betz discloses (See, for example, Figs. 3, 5 and 13) the group IV atom is a silicon-29 (29Si) atom (See, for example, Par [0101]).
In regards to claim 5, Betz discloses (See, for example, Figs. 3, 5 and 13) the group IV atom is an isotope of a group IV element having nuclear spin (See, “…that differences in random
hyperfine fields on each point 171, 172 can be used due to the random positions of the 29Si atoms naturally occurring in silicon. This is due to the non-zero nuclear spins of this isotope S (29Si) = 1/2. These hyperfine fields exhibit random temporal fluctuations with Gaussian distribution with standard deviation BZ = 20 T. Alternatively, external
micromagnets may be used.”, Par [0101]).
In regards to claim 13, Betz discloses applying a signal via the control arrangement to store information in the qubit (See, for example, Pars [0007], [0008], [0079], [0159]-[0165], [0185]-[0197], [0202]-[0214], [0234]-[0240] and [0259]-[0260])
Claim 3 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Betz in view of Schenkel as applied to claim 1 above, and further in view of Lidar.
In regards to claims 3 and 7, Betz discloses all limitations of claim 1 above except that the silicon substrate is an isotopically enriched 29Si substrate comprising less than
or equal to 800ppm of 29Si atoms.
Lidar discloses (See, for example, Fig. 2) the silicon substrate is an isotopically enriched 29Si substrate comprising less than or equal to 800ppm of 29Si atoms (See, Par [0073], where US Patent No. 6472681, herein incorporated by reference in its entirety. The quantum computer 250 comprises a silicon semiconductor substrate 4 into which a one-dimensional array of donor atoms of phosphorous-31 (31 P) is introduced to produce an arrayed nuclear spintronic system with a large electron wave function at the nuclei of donor atoms 31 P. The substrate is selected from materials that do not have nuclear spins, i.e. 28Si, 30Si, or both. A Si02 insulating layer 7 is placed over the silicon substrate 4, on which the A-gate 8 and J-gate 10 are placed. The A-gate is over the 31P donor atoms, and the J gate is between the 31P donor atoms. Varying the voltage on the A-gate controls the strength of the hyperfine interaction between the donor electrons around the 31P donor atoms and the nuclear spins of the 31P donor atoms. Changing the voltage on the J-gate turns on and off electron-mediated coupling between nuclear spins of adjacent31P donor atoms. The quantum state of 250 is the direction of the nuclear spin of the 31P donor atom. An alternative to using 31P as a donor atom includes the use of 29Si, which is an example of a spin 1/2 particle (i.e. The silicon substrate is an isotopically enriched 28Si substrate)).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify Betz by Lidar because this would help implement the capability to perform many quantum logical operations in parallel.
In regards to claim 7, Betz discloses all limitations of claim 1 above except that the group IV atom is implanted in the silicon substrate.
Lidar discloses, in Par [0073] and Fig. 2, a quantum computer 250 from known art. (See U.S. Patent No. 6,472,681, herein incorporated by reference in its entirety). The quantum computer 250 comprises a silicon semiconductor substrate 4 into which a one-dimensional array of donor atoms of phosphorous-31 (31 P) is introduced to produce an arrayed nuclear spintronic system with a large electron wave function at the nuclei of donor atoms 31 P. The substrate is selected from materials that do not have nuclear spins, i.e. 28Si, 30Si, or both. A Si02 insulating layer 7 is placed over the silicon substrate 4, on which the A-gate 8 and J-gate 10 are placed. The A gate is over the 31P donor atoms, and the J-gate is between the 31P donor atoms. Varying the voltage on the A-gate controls the strength of the hyperfine interaction between the donor electrons around the 31P donor atoms and the nuclear spins of the 31P donor atoms. Changing the voltage on the J-gate turns on and off electron-mediated coupling between nuclear spins of
adjacent 31P donor atoms. The quantum state of 250 is the direction of the nuclear spin of the 31P donor atom. An alternative to using 31P as a donor atom includes the use of 29Si, which is an example of a spin 1/2 particle.
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify Betz by Lidar because this would help implement the capability to perform many quantum logical operations in parallel.
Claims 8-9 and 14-17 are rejected under 35 U.S.C. 103 as being unpatentable over Betz in view of Schenkel as applied to claims 1 and 12 above, and further in view of Kane (USPN 6472681 B1, hereinafter “Kane”).
In regards to claims 8 and 9, Betz discloses all limitations of claim1 above but silent about the quantum dot electron wavefunction diameter is less than around 50nm; and the quantum dot electron wavefunction diameter is less than or equal to 15nm.
Kane while disclosing a quantum computer teaches (See, for example, Col. 5 lines 59-67) the quantum dot electron wavefunction diameter is less than around 50nm (100-200Å = 10nm -20 nm); and the quantum dot electron wavefunction diameter is less than or equal to 15nm (10nm -20nm, See, Col. 5 lines 59-67).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify Betz by Kane because this would help implement the capability to perform many quantum logical operations in parallel.
In regards to claim 14, Betz discloses all limitations of claim 13 above except that storing information in the qubit comprises: applying the signal to store information in the electron spin of the quantum dot; and swapping this information from the electron spin to the nuclear spin of the group IV atom.
Kane discloses applying the signal to store information in the electron spin of the quantum dot; and swapping this information from the electron spin to the nuclear spin of the group IV atom (See, for example, Col. 1 line 39 thru Col. 2 line 17).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify Betz by Kane because this would help implement the capability to perform many quantum logical operations in parallel.
In regards to claim 15, Betz as modified above discloses transporting quantum information from a first processing element of the plurality of processing elements to a second processing element of the plurality of processing elements (Col. 4 lines 50-55, Kane).
In regards to claim 16, Betz as modified above discloses transporting information from the first processing element to the second processing element comprises:
swapping the quantum information from the nuclear spin of the group IV atom of the first processing element to the electron spin of the first processing element (See, for example, Col. 6 lines 56-67, Kane); and
transporting the electron spin from the first processing element to the quantum dot of the second processing element (Col. 4 lines 50-55, Kane);
causing the transported electron spin to entangle with the nuclear spin of the group IV atom of the second processing element (See, for example, Col. 5 lines 27-36, Kane); and
swapping the quantum information from the transported electron spin to the nuclear spin of the group IV atom of the second processing element (Col. 8 lines 18-34, Kane).
In regards to claim 17, Betz as modified above discloses the electron spin of the first processing element is transported to the quantum dot of the second processing element via spin shuttling or exchange mediated coupling between the quantum dots of the first and second processing elements (See, for example, Col. 1:57 thru Col. 2 line 17; Col. 4 lines 50-55, and Col. 5: lines 27-36, Kane).
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Betz in view of Schenkel as applied to claim 1 above, and further in view of Awschalom et al. (Awschalom et al. “Quantum Technologies with optically interfaced solid-state spins”, Nature Photonics 12, pp. 516-527 (2018), hereinafter “Awschalom”).
In regards to claim 10, Betz discloses all limitations of claim1 above except that the nuclear spin of the group IV atom is entangled with the electron of the quantum dot via a hyperfine interaction between 100KHz-1MHz.
Awschalom while disclosing quantum technologies teaches the nuclear spin of the group IV atom is entangled with the electron of the quantum dot via a hyperfine interaction between 100KHz-1MHz (See, for example, Page 517, “For samples with natural isotope abundance, strongly coupled nuclei typically occur within 1 nm from the electron and have hyperfine couplings from 300 KHz…”, right column, the first 10 lines))
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify Betz by Awschalom because this would help increase speeds for interfacing quantum memories and enable high-throughput multiplexed versions of entanglement protocols.
Allowable Subject Matter
Claims 18 is allowed over prior art of record.
The following is an examiner' s statement of reasons for allowance:
See applicant’s remarks filed on 4/10/2025, pp. 9-11.
Claims 19-20, and 24-26 are also allowed as being dependent of the allowed independent base claim.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Response to Arguments
Applicant's arguments filed on 05/20/2026 have been fully considered but they are not persuasive.
Applicant makes the following arguments: 1. “Schenkel teaches qubit operations that are exclusively based on the donor electron and the quantum do electron … Therefore, Schenkel die not discloses “controlling a quantum property of the quantum dot and controlling the nuclear spin to operate a qubit”” (Remarks pp. 8-9)
This mischaracterizes Schenkel. The nuclear spin is not a passive bystander in Schenkel; it is the memory element of the architecture, and Schenkel expressly teaches controlling it through the same hyperfine coupled electron and gate structure that Applicant uses. Shenkel states that the architecture relies on “a single donor nuclear spin memory coupled to the donor electron spin through the contact hyperfine interaction for storage and retrieval of quantum information” (See Par [0017]; See also Par [0019]), that “Electrostatic gates facilitate transfer of quantum information from nuclear to electron spins and between electron spins, by modulating the contact hyperfine interaction (A-gates)”, See Par [0006], that “the control of single electron and nuclear spin states has been observed”, See Par [0006], that “Ionizing the donor protects the nuclear spin from de-coherence through uncontrolled interaction with the donor electron, if coherence can be preserved in the recombination step that is necessary to retrieve the quantum information from the nuclear spin and transfer it back to the donor electron spin”, See Par [0023], and that “Inter-dot coupling can effectively entangle donor nuclear spins”, See Par [0023]. Storing information in a nuclear spin, retrieving it, transferring it to and from an electron spin, and entangling nuclear spins are each control of the nuclear spin to operate as a qubit.
Applicant’s reading of Par [0017] isolates the sentence about single-qubit microwave operations on electron spins and ignores the sentences of the same paragraph that define the nuclear spin as the memory coupled by hyperfine interactions. The claim does ot require that the nuclear spine be manipulated by a mechanism distinct from the electron. Applicant’s own specification controls the nuclear spin in exactly the manner Schenkel does: the gate electrode 106 controls the nuclear spin “using similar techniques to those used for electron spin resonance”, See PG Pub of the current application Par [0051], swaps information between nucleus and electron via conditional microwave/RF pulses; and reads out the nuclear state by performing ESR on the electron (See PG Pub of the current application Pars [0051], and [0056]-[0062]). A control arrangement that acts on the nucleus through the hyperfine-coupled electron therefore falls squarely within the claimed “control arrangement for controlling a quantum property of the quantum dot and the nuclear spin”.
2. “…the Office Action…Specifically, the interpretation of Schenkel advanced by the Office Action seems to incorrectly conflate the role of the exchange coupling…” (Remarks pp. 8-9)
The office Action does not conflate them; it relies on both, because Schenkel’s architecture uses both in series. Schenkel’s own summary is a two-link chain: “donor nuclear spins are coupled via donor electron spins to spins of electrons in quantum dots,”, See Par [0008]; “…the donor electron spin couples to the spin of an electron in a vertically aligned quantum dot, with a voltage gate controlling the exchange coupling. In effect, electron spins in quantum dots are coupled to a nuclear spin memory.”, See Par [0017]. The hyperfine link (Pars [0006] and [0017]) supplies the nuclear spin control; the gate tuned exchange link (Pars [0018], [0020]) supplies the motivation to integrate a nuclear spin memory with Betz’s gate defined quantum dots. Applicant’s quotation of Par [0020] “The voltage alters the overlap of …wave function …and therefore controls the exchange coupling.” confirms, rather than rebuts, the Schenkel’s control arrangement is a gate electrode that manipulates a quantum property of the dot electron that is, through the chain, coupled to the nuclear spin.
“Schenkel … does not teach …control arrangement controls the nuclear spin …as entangled with the electron(s) of the quantum dot…” (Remarks page 9)
The claim recites that the nuclear spin is “entangled with the one or more electrons,” and dependent claim 10 specifies the entanglement mechanisms as “hyperfine interaction.” Schenke’s contact hyperfine coupling between nucleus and electron (See, Pars [0006, [0017], [0019]) is the identical mechanism; Applicant identifies no other arrangement mechanism in its own disclosure. Schenkel additionally teaches that inter-dot coupling entangles the donor nuclear spins (See Par [0023]). Whether the hyperfine-coupled electron sits in a gate defined dot (Applicant, Betz) or on a donor coupled to a gate defined dot (Schenkel) is addressed by the combination, not by Schenkel alone.
“Schenkel does not disclose "controlling a quantum property of the quantum dot and controlling the nuclear spin to operate a qubit" (Remarks page 9, 11)
Claim 1 is an apparatus claim. The recitation "controlling a quantum property …to operate a qubit” is a statement of function or intended use; the prior art structure need only be capable of performing it (MPEP 2114). Schenkel’s top gate 120 and back gates 130 together with locally or globally delivered pulsed microwaves (See Par [0017]), [0018], [0020]) are the same structure Applicant discloses as its control arrangement (gate electrode 106/206 and on-chip transmission line, Pars [0048]- [0054]. Further, claim 12 continues to recite “to operate the quantum dot and/or the nuclear spin as a qubit,” So under the broadest reasonable interpretation claim 12 is satisfied where either the dot electron or nuclear spin operates as the qubit. Finally, “a quantum property of the quantum dot and the nuclear spin” reads on a single property of the coupled system; the hyperfine split spin resonance frequency is a property of both the dot electron and the nuclear spin, and Schenkel controls the spin resonance condition of its coupled donor-dot devices with gates and magnetic detuning (Par [0017]).
“Schenkel fails to remedy the deficiencies of Betz,” (Remarks page 10)
Applicant attacks Schenkel individually for features the rejection draws from the combination. Non-obviousness cannot be established by attacking references individually where the rejection is based on a combination of references (In re Keller, 642 F.2d 413, 425, 208 USPQ 871, 881 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Betz supplies the silicon MOS quantum dot at a Si/dielectric interface with a nuclear-spin-bearing ²⁹Si atom whose hyperfine field acts on the confined dot electron (Betz, Par [0101], random hyperfine fields of naturally occurring ²⁹Si atoms on each dot 17₁, 17₂; S(²⁹Si) = ½; gates 12₁, 12₂; gate dielectric 7; channel 16; microwave source 37 Par [0123]; ESR control Par [0203]). Schenkel supplies the teaching that a nuclear spin hyperfine-coupled to an electron in a gate-defined dot architecture is used and controlled as a quantum memory qubit, and the reason to do so (long nuclear coherence, ¶¶ [0006], [0023]). One of ordinary skill applying Schenkel’s nuclear-spin-memory scheme to Betz’s dot would arrive at the claimed control arrangement; the test is not whether Schenkel’s donor could be bodily incorporated into Betz’s nanowire (In re Keller).
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Correspondence
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERMIAS T WOLDEGEORGIS whose telephone number is (571)270-5350. The examiner can normally be reached on Monday-Friday 8 am - 5 pm E.S.T..
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Britt Hanley can be reached on 571-270-3042. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/ERMIAS T WOLDEGEORGIS/Primary Examiner, Art Unit 2893
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