Detailed Action
Notice of Pre-AIA or AIA Status
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
2. The IDS (Information Disclosure Statement) filed 3/30/23 has been entered.
3. This application is a continuation in part of application 17/584219, filed 1/25/22, now abandoned. Claims 1-13 are pending.
Claim Objections
4. Claim 1 is objected to because of the following informalities:
in line 5, after “…to zero” please delete “;” and replace with “, and then: “
lines 6-9, each beginning with “-using the…” should start indented further to the right.
These corrections clarify that the “using” steps continue to describe the swapping procedure, and that the last line “-forcing…” is after the swapping procedure. Appropriate correction is required.
Claim Rejections - 35 USC § 112
5. Claims 1-13 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Independent claim 1 line 3 recites “swapping a first value of a first qubit to a third value of a third qubit” but it is not clear what the “value” exactly means. Furthermore, a swap operation swaps the states between two qubits and it is not clear what swapping “to a third value of a third qubit” exactly means. The recitation is vague but for purposes of examination this will be interpreted as “swapping a first state of a first qubit with a third state of a third qubit .” Independent claim 11 also recites in line 3 “receiving a first value for the first qubit” and in line 11 “swapping of the first value of the first qubit to the third qubit” and the same rationale for rejection, and same interpretation for examination, applies. Dependent claims 3 and 12 validate the interpretation of “value” to mean “quantum state” but it still needs to be remedied in independent claims 1 and 11. Independent claim 1 lines 4-5 recite “forcing the second qubit to zero, and forcing the third qubit to zero” and line 11 recites “forcing the first qubit to zero” but this is unclear. If applicant means the zero state (i.e. |0> ) then this must be stated explicitly. Furthermore, it is suggested that applicant means the qubit is initialized or reset to the zero state (such as by measurement and possible NOT gate operation as necessary) and this is how the recitation will be interpreted for purposes of examination; nevertheless the claim recitation is vague and indefinite and needs to be corrected. Claim 11 line 12 has similar recitation of “forcing the first qubit to zero, and forcing the second qubit to zero” and the same rationale for rejection, and same interpretation for examination, applies.
Independent claim 11 is further vague and indefinite for the following reasons: lines 2-4 recite “a first controlled NOT gate coupled to a second qubit and coupled to a first controlled NOT gate control input to a first qubit” but this phrasing does not appear to make sense. The first CNOT (controlled NOT) is obviously coupled to itself, but to state that it is coupled to its own control input “to a first qubit” does not make sense, logically or grammatically, and the claim is vague and indefinite. For purposes of examination, this will be interpreted to mean that first CNOT is coupled to a second qubit while its control input is coupled to a first qubit. The second, third, and fourth CNOT limitations have the same issue regarding their respective CNOT gate control input coupling, but these will be interpreted in the same way as follows: the second CNOT is coupled to the first qubit and its control input is coupled to the output of the first CNOT, aka the second qubit; the third CNOT is coupled to a third qubit and its control input is coupled to the second qubit; the fourth CNOT is coupled to the second qubit and its control input is coupled to the output of the third CNOT, aka the third qubit. Appropriate correction is still required.
The dependent claims do not remedy the issues of the independent claims and are thus vague as well, including for the further reasons:
Dependent claim 4 line 2 recites “swapping said first value of said third qubit to said first qubit” and lines 3-4 and 10 recites the “forcing” recitation.
Dependent claim 8 lines 2-3 recites “receiving of the first value of the first qubit via an input switch coupled to the first qubit” but this is unclear. In addition to the vagueness of what it is meant by “value” of the qubit, even if “value” is interpreted as the quantum state, it is also not clear what it means for the quantum state to be received via the input switch. For purposes of examination, this will be interpreted to mean the switch applies the CNOT gate to the qubit thereby affecting the quantum state.
Dependent claim 9 lines 1-2 recites “after opening the input switch is closed within a time period…” but it is not clear whether something else is being closed after the input switch is opened, or whether something else is opened before closing the input switch, or whether the switch is opened and then closed within the time period. Thus, this claim is vague and indefinite. Additionally, claim 9 lines 2-3 also recite “the first value of the first qubit” which is vague for the reasons mentioned above for claim 1, and would need to be remedied as well. For purposes of examination, this will be interpreted to mean the input switch is opened and then closed within a time period less than a feedback loop time period for the quantum state of the first qubit to be teleported to the third qubit and back again.
Claim Rejections - 35 USC § 103
6. 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.
7. Claim(s) 1-5 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vogt et al “Vogt” (US 2025/0013904 A1) and Bataille, Quantum Circuits of CNOT Gates, 12/16/2020 “Bataille”.
8. Regarding claim 1, Vogt shows a method of mitigating decoherence in a quantum computing device (para 3, 9 shows maintaining quantum coherence in a quantum device) comprising: swapping a first value of a first qubit to a third value of a third qubit by the help of a second qubit (para 53-55 show SWAP operations between two qubits using another ancillary qubit. It need not matter which one is labeled “first”, “second”, or “third”), wherein the swapping is started by forcing the second qubit to zero and forcing the third qubit to zero (see also the 112 rejection. Para 48, 55 show initializing the ancillary/second qubit and receiving/third qubit to zero); furthermore para 50 shows that at the end of the swapping procedure the first qubit that had the state which was transferred, and the ancillary (second) qubit, are now reset/initialized to the zero state (aka forcing/resetting the first qubit to zero and forcing/resetting the second qubit to zero as recited at the end of claim 1). Vogt does not explicitly show the circuit using the first qubit to perform a controlled NOT gate on the second qubit, using the second qubit to perform a controlled NOT gate on the first qubit, using the second qubit to perform a controlled NOT gate on the third qubit, using the third qubit to perform a controlled NOT gate on the second qubit, whereby the first qubit has the third value and the third qubit has the first value; and forcing the first qubit to zero, and forcing the second qubit to zero, but Vogt para 48, 55 do show using CNOT (controlled NOT) gates among three qubits in performing the SWAP operation, and para 55, 56, 60 show various CNOT rearrangement and manipulation. Furthermore, note that this particular circuit of four CNOT gates, as well as equivalent variants that rearrange some of the CNOT gates, is common in the art as a “quantum move/transfer” circuit to transfer the state from one qubit to another. Bataille Figure 15 shows the CNOT operations in a circuit using the first qubit to perform a controlled NOT gate on the second qubit, using the second qubit to perform a controlled NOT gate on the first qubit, using the second qubit to perform a controlled NOT gate on the third qubit, and using the third qubit to perform a controlled NOT gate on the second qubit - see the second composer circuit from the bottom. Note that qubits 4, 5, 6 correspond to qubits 1, 2, 3 of claim 1. See also page 20 lines 1-14, Figure 14 (bottom), page 22 line 12 – page 23 line 3 and note by identity the rearranging of CNOT gates. The last four CNOT gates yield the same result as this CNOT sequence in claim 1, when the second and third qubits are initialized to the zero state:
a|000> + b|100> [Wingdings font/0xE0] a|000> + b|001> (assume a and b normalized)
thus effectively swapping the first and third qubits such that the first qubit has the third value/state (namely |0>) and the third qubit has the first value/state (namely a|0> + b|1>), as recited in claim 1. Vogt as noted above indeed does initialize the second (here ancillary) and third qubits to the zero state. Therefore, it would have been obvious to a person with ordinary skill in the art before the effective filing date of the claimed invention to use the CNOT circuit of Bataille, in the CNOT based swapping procedure of Vogt, thereby effectuating the circuit using the first qubit to perform a controlled NOT gate on the second qubit, using the second qubit to perform a controlled NOT gate on the first qubit, using the second qubit to perform a controlled NOT gate on the third qubit, and using the third qubit to perform a controlled NOT gate on the second qubit, because it would provide an efficient way to transfer the quantum state from a first qubit to a third qubit using a second ancillary qubit, in a scenario in which the second and third qubits are initialized to zero. Doing so would allow a permutation of CNOT gates to efficiently swap states between qubits (Bataille page 14 lines 13-26, page 17 lines 1-10).
9. Regarding claim 2, Vogt para 2, 7, claim 1, 7 show the (first) state/value of the qubit after the operations and thus including that of the third qubit, is used in a calculation. Para 12 shows the states/values from all the qubits in general are used in any gate calculation.
10. Regarding claim 3, Vogt para 12, 30 lines 7-12 show that the (first) value or information content of the (first) qubit is a quantum state.
11. Regarding claim 4, in addition to that mentioned for claim 1, please note that this recites the same swapping procedure of claim 1, only in reverse to swap the state from the third qubit to the first qubit. Thus, if the recitation for claim 4 simply switched the labels “the third” and “the first” on those qubits, this would be the same features as that in claim 1. Vogt para 52, 55 indeed shows reversing the procedure, effectively swapping the first and third qubits, so as to swap the state back to the first qubit. Given this, the reversed procedure would follow the same CNOT circuit as in claim 1 and so claim 4 is then rejected for the same reasons as claim 1.
12. Regarding claim 5, Vogt para 2, 7, claim 11 show the (first) state/value of the qubit after the operations and thus including that of the third qubit, is used in a calculation. Para 12 shows the states/values from all the qubits in general are used in any gate calculation.
13. Claim(s) 6-7 and 11-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vogt and Bataille and Jacak et al “Jacak” (US 2023/0205490 A1).
14. Regarding claim 6, in addition to that mentioned for claim 4, although Vogt para 52, 55 show reversing the swapping procedure to bring the state back to the first qubit, nevertheless Vogt and Bataille do not explicitly show passing the first value/state back and forth between the first and third qubits alternately by repeating the swapping procedure steps in claim 1 and back steps in claim 4. However, Jacak para 116 show a quantum repeater system which does perform a swap procedure to transfer a state from one qubit node to another and then back again, in an alternate back and forth manner. Jacak para 116 show this quantum repeater mechanism helps prevent decoherence in a quantum memory because the state is sent back to the other qubit before it decoheres in the current qubit. It would have been obvious to a person with ordinary skill in the art before the effective filing date of the claimed invention to pass the state back and forth via a swapping and return/reverse swapping procedure as is done in Jacak, in the swapping method of Vogt especially as modified by Bataille, because it provide and efficient way to use the swapping and reverse swapping procedures to mitigate decoherence in a quantum computing device.
15. Regarding claim 7, in addition to that mentioned for claim 6, Jacak show a cycle period for said alternately repeating (the swapping back and forth) is less than a decoherence time of said first qubit, said second qubit, and said third qubit (para 116 shows the time to swap back and forth is less than the time of the qubits (including the first and third and any ancillary second needed in the swapping mechanism) to decohere. It would have been obvious to a person with ordinary skill in the art before the effective filing date of the claimed invention to have this in the swapping method of Vogt especially as modified by Bataille, because it provide and efficient way to use the swapping and reverse swapping procedures to mitigate decoherence in a quantum computing device.
16. Regarding claim 11, see the 112 rejection and note the interpretation of claim 11. This therefore shows the same CNOT circuit as recited in claim 1. Vogt para 48, 52 show using CNOT (controlled NOT) gates among three qubits in performing a swapping operation, and para 55, 56, 60 (last four lines) show various CNOT rearrangement and manipulation. Furthermore, para 50 shows that at the end of the swapping procedure the first qubit that had the state which was transferred, and the ancillary (second) qubit, are now reset/initialized to the zero state (aka forcing/resetting the first qubit to zero and forcing/resetting the second qubit to zero as recited at the end of claim 11). Vogt does not explicitly show the circuit using the first qubit to perform a controlled NOT gate on the second qubit, using the second qubit to perform a controlled NOT gate on the first qubit, using the second qubit to perform a controlled NOT gate on the third qubit, using the third qubit to perform a controlled NOT gate on the second qubit, whereby the first qubit has the third value and the third qubit has the first value; and forcing the first qubit to zero, and forcing the second qubit to zero. However, note that this particular circuit of four CNOT gates, as well as equivalent variants that rearrange some of the CNOT gates, is common in the art as a “quantum move/transfer” circuit to transfer the state from one qubit to another. Bataille Figure 15 shows the CNOT operations in a circuit using the first qubit to perform a controlled NOT gate on the second qubit, using the second qubit to perform a controlled NOT gate on the first qubit, using the second qubit to perform a controlled NOT gate on the third qubit, and using the third qubit to perform a controlled NOT gate on the second qubit - see the second composer circuit from the bottom. Note that qubits 4, 5, 6 correspond to qubits 1, 2, 3 of claim 1. See also page 20 lines 1-14, Figure 14 (bottom), page 22 line 12 – page 23 line 3 and note by identity the rearranging of CNOT gates. The last four CNOT gates yield the same result as this CNOT sequence in claim 11, when the second and third qubits are initialized to the zero state:
a|000> + b|100> [Wingdings font/0xE0] a|000> + b|001> (assume a and b normalized)
thus effectuating swapping the first value of the first qubit (namely a|0> + b|1>) to the third qubit, as recited in claim 11. Vogt indeed does initialize the second (here ancillary) and third qubits to the zero state (para 86, 93 lines 1-6 show initializing the ancillary/second qubit and receiving/third qubit to zero). Therefore, it would have been obvious to a person with ordinary skill in the art before the effective filing date of the claimed invention to use the CNOT circuit of Bataille, in the CNOT based swapping procedure of Vogt, thereby effectuating the circuit using the first qubit to perform a controlled NOT gate on the second qubit, using the second qubit to perform a controlled NOT gate on the first qubit, using the second qubit to perform a controlled NOT gate on the third qubit, and using the third qubit to perform a controlled NOT gate on the second qubit, because it would provide an efficient way to transfer the quantum state from a first qubit to a third qubit using a second ancillary qubit, in a scenario in which the second and third qubits are initialized to zero. Doing so would allow a permutation of CNOT gates to efficiently swap states between qubits (Bataille page 14 lines 13-26, page 17 lines 1-10).
Regarding the “active quantum memory system,” Vogt para 72-73 show the memory devices for the quantum computing system. Nevertheless, in the event that an actual quantum memory device is used, please note this is not explicitly mentioned in Vogt or Bataille. Jacak para 116 however does show the quantum memory system. Para 116 show this quantum memory system is used for swapping procedures. It would have been obvious to a person with ordinary skill in the art before the effective filing date of the claimed invention to use the quantum memory system of Jacak in the swapping procedure of Vogt, especially as modified by Bataille, because it would provide an efficient platform on which to enable the qubits.
17. Regarding claim 12, in addition to that mentioned for claim 11, Vogt para 12, 30 show that the (first) value or information content of the (first) qubit is a quantum state.
18. Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vogt and Bataille and Bombin et al “Bombin” (WO 2022159847 A1).
(Please also see the attached copy of Bombin that numbers paragraphs in the same format as that used in this Action).
19. Regarding claim 8, in addition to that mentioned for claim 4, Vogt para 29 shows the first qubit receiving the first information content/value/state, after which the CNOT circuit would be performed (and thus the value/state is received prior to performing the CNOT gate on the second qubit), but Vogt and Bataille do not explicitly show the receiving is done via an input switch coupled to the first qubit. However, Bombin para 281 shows a quantum memory system, and para 12, 18, 104 do show an input switch coupled to a first qubit by which the input content/state/value is received. It would have been obvious to a person with ordinary skill in the art before the effective filing date of the claimed invention to use an input switch for the first qubit to receive the state/value in the swapping circuit of Vogt especially as modified by Bataille, because it would provide an efficient way to reduce time for the first qubit having to be in the quantum state, and thus mitigate decoherence in the qubit and quantum device.
20. Claim(s) 9-10 and 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vogt and Bataille and Jacak and Bombin.
21. Regarding claim 9, in addition to that mentioned for claim 8, Vogt and Bataille and Jacak do not explicitly show an input switch is opened and closed within a time period less than a feedback loop time period for the first value/state of the first qubit to be swapped to the third qubit and back again to the first qubit, but Vogt para 3, 9 show the need to prevent decoherence of qubits over time during the swapping mechanisms to obtain an active quantum memory, and Jacak shows a cycle period for said alternately repeating the swapping back and forth is less than a decoherence time of the qubits (para 116 shows the time to swap back and forth is less than the time of the qubits to decohere). Furthermore, Bombin shows a quantum memory system (para 281) and shows an input switch coupled to the first qubit (para 12-13, 104, 218 show input and output switches applied between qubits and gates) and providing a feedback path to the input switch, wherein the third qubit output is provided via the output switch (para 99, 294 show the feedback path, and para 290 as well as 104, 218 show applying switches in these circuits). Therefore, it would have been obvious to a person with ordinary skill in the art before the effective filing date of the claimed invention to use the switch of Bombin to control the input in Vogt, especially as modified by Bataille and Jacak, whereby the opened switch would be closed within the time period for the swap procedure to loop around from the first qubit to the third qubit and back to the first qubit, because it would provide an efficient way to have control and maintain an active quantum memory. Closing the switch within the loop time period would allow the output quantum state to be obtained once the swap cycles the quantum state back to the first qubit.
22. Regarding claim 10, please see also the 112 rejection. In addition to that mentioned for claim 9 and noting dependency to claim 4, Vogt para 50 show after the reverse swapping procedure, resetting/initializing what now would be the second qubit (ancillary) and the third qubit (which sent the state) to the zero state. This occurs thus after the first qubit acquired its quantum state from the third qubit.
23. Regarding claim 13, in addition to that mentioned for claim 11, Vogt and Bataille and Jacak do not explicitly show the input switch coupled to the first qubit whereby the first CNOT gate is coupled to the first qubit via the input switch, and an output switch coupled to the third qubit and providing a feedback path to the input switch, wherein the third qubit output is provided via the output switch, whereby the third qubit output can be selectively used to provide a first input to the first CNOT gate. Bombin however shows a quantum memory system (para 281), and shows an input switch coupled to the first qubit whereby the first CNOT gate is coupled to the first qubit via the input switch and an output switch is coupled to the third qubit (para 12-13, 104, 218 show input and output switches applied between qubits and gates, and para 65 show the gates include CNOT gates applied to qubits) and providing a feedback path to the input switch, wherein the third qubit output is provided via the output switch, whereby the third qubit output can be selectively used to provide a first input to the first CNOT gate (para 99, 294 show the feedback path, and para 290 as well as 104, 218 show applying switches in these circuits). Bombin para 104-106 show that using the switches helps control and maintain fidelity in the circuit and para 99-104, 294 show that switching in feedback helps to stabilize the quantum state and thus maintain fidelity. It would have been obvious to a person with ordinary skill in the art before the effective filing date of the claimed invention to use switches between components and qubits in the teleportation circuit of Vogt especially as modified by Bataille and Jacak, and in particular using a switch to provide a feedback path to the input of the first qubit, because it would provide an efficient way to control stabilization of the quantum state at the first qubit, and maintain fidelity in the circuit overall.
Conclusion
24. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
a) Shin (KR 20230046839 A) shows implementing swap protocol in a quantum repeater device.
b) Lechner (WO 2022152384 A1) shows implementing swap protocol in a quantum device.
c) Girvin (CA 3004750 C) shows quantum error correction techniques in a quantum system with quantum memory, that performs qubit swapping.
d) McCarty (US 11516190 B1) shows a quantum memory system for swapping and manipulating states between qubits, using different CNOT arrangements.
e) Nickerson (WO 2019173651 A1) shows ways to prevent fidelity loss of qubits over time.
25. Any inquiry concerning this communication or earlier communications from the examiner should be directed to STEVEN PAUL SAX whose telephone number is (571)272-4072. The examiner can normally be reached Monday - Friday, 9:30 - 6:00 Est.
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/STEVEN P SAX/Primary Examiner, Art Unit 2146