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 .
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 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.
Disposition of the Claims
Claims 1-20 are pending.
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.
Claim 13 is rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor regards as the invention. It is not clear or definite to one of ordinary skill in the art as to whether the claim recites a range of states or a pair of states. Clarification is required.
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 of this title, 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 2, 5, 8-10, and 12-15 are rejected under 35 U.S.C. 103 as being unpatentable over Kok1.
Regarding claim 1, Kok teaches a linear optical CZ-gate (p. 8, Fig. 6, conditional phase gate) comprising:
an A1 optical channel comprising an A1 input end and an A1 output end (id., the top channel);
an A2 optical channel comprising an A2 input end and an A2 output end (id., the second channel from the top),
a B1 optical channel comprising a B1 input end and a B1 output end (id., the third channel from the top); and
the A2 optical channel and the B1 optical channel converge at a common optical channel (id., wherein A2 and B1 converge to two common channels after the first beam splitter in Fig. 6, the common channel being any one of the upper or bottom channels comprising the non-linear sign NS gates; note Fig. 7, describing the NS gates);
a nonlinear sign gate optically coupled to the common optical channel (id., the non-linear sign NS gates); and
a B2 optical channel comprising a B2 input end and a B2 output end (id., the bottom channel).
Kok does not explicitly show wherein a first quantum memory is optically coupled to the A2 optical channel, or wherein a second quantum memory is optically coupled to the B1 optical channel, or the common optical channel being downstream the first quantum memory and the second quantum memory.
However, Kok explicitly indicates that “all linear optical quantum computer proposals need some kind of quantum memory” (p. 32, last two paragraphs continued onto p. 33 which discloses some concrete implementations, e.g. delay lines). Kok’s disclosed component being a gate, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have utilized a quantum memory and any of the input or output ports for the purpose of having information available to process or read thus realizing the inherent purposes of quantum computing.
Regarding claim 2, the modified Kok teaches the linear optical CZ-gate of claim 1, and further discloses wherein the A2 optical channel and the B1 optical channel diverge from the common optical channel downstream the nonlinear sign gate (Fig. 6).
Regarding claim 5, the modified Kok teaches the linear optical CZ-gate of claim 1, and further discloses further comprising:
a first optical coupler optically coupled to the A2 optical channel and the B1 optical channel at a location between the A2 input end and the first quantum memory and between the B1 input end and the second quantum memory (Fig. 6, first pi/4); and a second optical coupler optically coupled to the A2 optical channel and the B1 optical channel at a location between the nonlinear sign gate and the A2 output end and between the nonlinear sign gate and the B1 output end (Fig. 6, second pi/4).
Regarding claim 8 and 9, the modified Kok teaches the linear optical CZ-gate of claim 1, and further discloses wherein the nonlinear sign gate (detailed in Fig. 7 of Kok) comprises:
a first ancilla channel (one channel for each of |Psi>, |0>, and |1>, the latter being ancillae) comprising a first input end optically coupled to an ancilla photon source and a first output end optically coupled to a first photon detector (p. 9, “The input states for the ancillæ are the vacuum and a single-photon, and the gate succeeds when the detectors D1 and D2 measure zero and one photons, respectively”);
a second ancilla channel comprising a second input end and a second output end, wherein the second output end is optically coupled to a second photon detector (id.); and
a central optical coupler optically coupled to the first ancilla channel and the common optical channel between the ancilla photon source and the first photon detector (eta1, eta2, eta3 providing coupling between each of the channels and the “1” and “0” detectors).
Regarding claim 10, the modified Kok teaches the linear optical CZ-gate of claim 8, and further discloses wherein the ancilla photon source comprises a single photon source and the first photon detector and the second photon detector each comprise a single photon detector (sequitur as the ancillae are vacuum and single photon vis-a-vis so are the detectors).
Regarding claim 12, Kok teaches a method of operating a linear optical CZ-gate (p. 8, Fig. 6, having first and second quantum states |Phi1> and |Phi2> that are potentially interfered at the Pi/4 intersection, sign flipped by the non-linear sign gates NS, and recombined at the second Pi/4 intersection), the method comprising:
the linear optical CZ-gate further comprising:
an A1 optical channel comprising an A1 input end and an A1 output end (id., the top channel);
an A2 optical channel comprising an A2 input end and an A2 output end (id., the second channel from the top),
a B1 optical channel comprising a B1 input end and a B1 output end (id., the third channel from the top); and
the A2 optical channel and the B1 optical channel converge at a common optical channel (id., either onto the first Pi/4 beamsplitter where potential interference occurs, and/or wherein A2 and B1 converge to two common channels after the first beam splitter in Fig. 6, the common channel being any one of the upper or bottom channels comprising the NS gates);
a nonlinear sign gate optically coupled to the common optical channel (id., the non-linear sign NS gates); and
a B2 optical channel comprising a B2 input end and a B2 output end (id., the bottom channel).
Kok does not explicitly show absorbing, using a first quantum memory of the linear optical CZ-gate, a first quantum state received by the first quantum memory, wherein a first quantum memory is optically coupled to the A2 optical channel, or wherein a second quantum memory is optically coupled to the B1 optical channel, or the common optical channel being downstream the first quantum memory and the second quantum memory, or absorbing, using the second quantum memory, a second quantum state received by the second quantum memory, releasing the first quantum state from the first quantum memory into the nonlinear sign gate, or performing a sign flip function in the nonlinear sign gate using the first quantum state, or releasing the second quantum state from the second quantum memory into the nonlinear sign gate, or performing the sign flip function in the nonlinear sign gate using the second quantum state.
Regarding the addition of quantum memory to the channel terminals, Kok explicitly indicates that “all linear optical quantum computer proposals need some kind of quantum memory” (p. 32, last two paragraphs continued onto p. 33 which discloses some concrete implementations). Kok’s disclosed component being a gate as detailed above, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have utilized a quantum memory at any of the input or output ports for the purpose of having information available to process or read thus realizing the inherent purposes of quantum processing of information.
The modified Kok does not explicitly show absorbing, using a first quantum memory of the linear optical CZ-gate, or absorbing, using the second quantum memory, a second quantum state received by the second quantum memory, releasing the first quantum state from the first quantum memory into the nonlinear sign gate, or performing a sign flip function in the nonlinear sign gate using the first quantum state, or releasing the second quantum state from the second quantum memory into the nonlinear sign gate, or performing the sign flip function in the nonlinear sign gate using the second quantum state.
These features amount to the operational details of the supplying the quantum states to quantum memories interacting with Kok’s CZ gate, which performs sign flipping by nonlinear sign gates as the first and second quantum states |Phi1> and |Phi2> interact with the gate. Analogously, Buckley explicitly shows supplying photon beams (304a, 304b, … 304N) to be absorbed by delay lines (320a, 320b, … 320N, which as noted by Kok on p. 32 and cited above are operable as quantum memories; see also ¶86, indicating that optical fiber is non-linear and therefore inherently absorptive, and ¶113, indicating the delay line introduce may delay by fiber stretching) to be multiplexed into nonlinear elements (308a, 308b, … 308N).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have operated the CZ gate of Kok in the manner of Buckley using the quantum memories known to be necessary for gate operation, and thus achieved the claimed quantum processing of information.
Regarding claim 13, the modified Kok teaches the method of claim 12, and further discloses further comprising [by straightforward operation of the disclosed CZ gate of Fig. 6]:
directing an A1 quantum state into the A1 input end of the Al optical channel (Fig. 6, see also the truth table (24) indicating that |Phi1> and |Phi2> are in terms of single photon and vacuum states |0> and |1>);
directing an A2 quantum state into the A2 input end of the A2 optical channel, wherein the A1 and A2 quantum states define a first logical qubit (Fig. 6, |Phi1> shown entering the A1 and A2 channels, i.e. a dual rail logical qubit);
directing a B1 quantum state into the B1 input end of the B1 optical channel (Fig. 6 see also the truth table (24) indicating that |Phi1> and |Phi2> are in terms of single photon and vacuum states |0> and |1>); and
directing a B2 quantum state into the B2 input end of the B2 optical channel, wherein the B1 and B2 quantum states define a second logical qubit (Fig. 6, |Phi2> shown entering the B1 and B2 channels, i.e. a dual rail logical qubit), wherein:
a first optical coupler is optically coupled to the A2 optical channel and the B1 optical channel at a location between the A2 input end and the first quantum memory and between the B1 input end and the second quantum memory (Fig. 6, such that the pi/4 couplers are in the correct position when receiving the necessary memory at the ends as discussed supra);
a second optical coupler is optically coupled to the A2 optical channel and the B1 optical channel at a location between the nonlinear sign gate and the A2 output end and between the nonlinear sign gate and the B1 output end (Fig. 6, such that the pi/4 couplers are in the correct position when receiving the necessary memory at the ends as discussed supra);
the first quantum state is one of the A1-B2 quantum states (Fig. 6); and
the second quantum state is one of the A1-B2 quantum states (Fig. 6).
Regarding claim 14, the modified Kok teaches the method of claim 13, and further discloses wherein: when the A1 quantum state comprises a single photon and the A2 quantum state comprises zero photons, the first logical qubit is in a 0-state (see Fig. 6, implied that |Phi1> and |Phi2> are in terms of |0> or |1>, where interference occurs only where both quantum states are in |1>, see the truth table (24) reproduced below); when the A1 quantum state comprise zero photons and the A2 quantum state comprises a single photon, the first logical qubit is in a 1-state (id.); when the B1 quantum state comprise a single photon and the B2 quantum state comprises zero photons, the second logical qubit is in a 1-state (id.); and when the B1 quantum state comprise zero photons and the B2 quantum state comprises a single photon, the second logical qubit is in a 0-state (id., see also p. 8, Truth Table for CZ gate operation, reproduced below, and p. 9, first paragraph of the second column, providing evidence that |0> and |1> is defined by the presence or absence of single photons: “The input states for the ancillæ are the vacuum and a single-photon, and the gate succeeds when the detectors D1 and D2 measure zero and one photons, respectively”).
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Regarding claim 15, the modified Kok teaches the method of claim 12, and further discloses wherein performing the sign flip function on the first quantum state (“The fact that two NS
gates can be used to create a CZ gate was first realizedby Knill, Laflamme, and Milburn (2001). Their probabilistic NS gate is a 3-port device, including two ancillary modes the output of which is measured with perfect photon-number discriminating detectors (see Fig. 7). The input states for the ancillæ are the vacuum and a single-photon, and the gate succeeds when the detectors D1 and D2 measure zero and one photons, respectively. For an arbitrary input state α|0 +β|1 +γ|2 , this occurs with probability pNS = 1/4.”) comprises:
directing an ancilla photon from an ancilla photon source of the nonlinear sign gate into a first input end of a first ancilla channel of the nonlinear sign gate (Fig. 7), the nonlinear sign gate further comprising: a first photon detector (“1”) optically coupled to a first output end of the first ancilla channel (Fig. 7);
a second ancilla channel comprising a second input end and a second output end (Fig. 7);
a second photon detector (“0”) optically coupled to the second output end (Fig. 7);
a central optical coupler optically coupled to the first ancilla channel and the common optical channel between the ancilla photon source and the first photon detector (Fig. 7, couplers eta1, eta2, eta3);
a first ancilla optical coupler optically coupled to the first ancilla channel and the second ancilla channel between the ancilla photon source and the central optical coupler (Fig. 7, couplers eta1, eta2, eta3); and
a second ancilla optical coupler optically coupled to the first ancilla channel and the second ancilla channel between the central optical coupler and the second photon detector (Fig. 7, couplers eta1, eta2, eta3);
receiving the first quantum state at the central optical coupler (Fig. 7);
detecting a single photon at the first photon detector (Fig. 7, at “1”); and
detecting zero photons at the second photon detector (Fig. 7, at “0”).
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over the modified Kok as applied to claim 1 above, and further in view of Buckley (US 20210044353 A1).
Regarding claim 7, the modified Kok teaches the linear optical CZ-gate of claim 1, but does not explicitly show wherein the first quantum memory is configured to absorb a photon representing a quantum state and release a photon comprising the quantum state of the received photon toward the nonlinear sign gate.
Buckley explicitly shows supplying photon beams (304a, 304b, … 304N) to be absorbed by delay lines (320a, 320b, … 320N, which as noted by Kok on p. 32 and cited above are operable as quantum memories; note ¶86, indicating that optical fiber is non-linear and therefore inherently absorptive, and ¶113, indicating the delay line introduce may delay by fiber stretching) to be multiplexed into nonlinear elements (308a, 308b, … 308N).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have operated the CZ gate of Kok in the manner of Buckley using the quantum memories known to be necessary and thus achieved the claimed quantum processing of information.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over the modified Kok as applied to claim 1 above, and further in view of Shringarpure2 (of record).
Regarding claim 11, the modified Kok teaches the linear optical CZ-gate of claim 1, but does not explicitly show wherein the nonlinear sign gate is the one and only one nonlinear sign gate in the linear optical CZ-gate.
Shringarpure explicitly shows an analogous CZ gate having only a single NS gate (Fig. 4, “Implementation of a destructive controlled-phase gate that only requires a single nonlinear sign gate labelled NS.”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have utilized the implementation of Shringarpure for the purpose of achieving logical operations using fewer components, e.g. reducing complexity, failure points, etc.
Allowable Subject Matter
Claim 19 and 20 are allowed.
Regarding claim 19, Kok teaches a linear optical CZ-gate (p. 8, Fig. 7) comprising:
an A1 optical channel comprising an A1 input end and an A1 output end (top channel);
an A2 optical channel comprising an A2 input end and an A2 output end (second channel from the top), a B1 optical channel comprising a B1 input end and a B1 output end (third channel from the top), a B2 optical channel comprising a B2 input end and a B2 output end (fourth channel from the top), a nonlinear sign gate optically coupled to the common optical channel (NS gate); wherein;
Kok does not explicitly show the A2 optical channel comprises a first A2 channel arm extending from the A2 input end to a first optical switch and a second A2 channel arm extending the from a second optical switch to the A2 output end; and a first quantum memory is optically coupled to the first A2 channel arm; the B1 optical channel comprises a first B1 channel arm extending from the B1 input end to the first optical switch and a second B1 channel arm extending the from the second optical switch to the B1 output end; a second quantum memory is optically coupled to the first B1 channel arm; and a first optical coupler optically coupled to the first A2 channel arm and the first B1 channel arm upstream the first and second quantum memories; a common optical channel extending from the first optical switch to the second optical switch.
The prior art when taken alone or in combination does not remedy these deficiencies. Therefore the claim is allowable over the prior art.
Regarding claim 20, the dependent claim depends from an allowable claim and is therefore allowable.
Claims 3, 4, 6, and 16-18 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Regarding claim 3, the modified Kok teaches the linear optical CZ-gate of claim 1, but does not explicitly show further comprising:
a first optical switch optically coupled to the A2 optical channel and the B1 optical channel between the first and second quantum memories and the common optical channel; and
a second optical switch optically coupled to the A2 optical channel and the B1 optical channel between the common optical channel and the A2 output end and between the common optical channel and the B1 output end.
Regarding claim 6, the modified Kok teaches the linear optical CZ-gate of claim 1, further comprising: a third quantum memory optically coupled to the A2 optical channel between the nonlinear sign gate and the A2 output end;
a fourth quantum memory optically coupled to the B1 optical channel between the nonlinear sign gate and the B1 output end;
a fifth quantum memory optically coupled to the Al optical channel between the Al input end and the Al output end; and
a sixth quantum memory optically coupled to the B2 optical channel between the B2 input end and the B2 output end.
Regarding claim 16, the modified Kok teaches the method of claim 12, but does not explicitly show wherein: the first quantum state is directed from the first quantum memory into a first optical switch optically coupled to the A2 optical channel and the B1 optical channel between the first and second quantum memories and the common optical channel; the first optical switch is in a first position optically coupling the A2 optical channel and the common optical channel such that the first quantum state reaches the nonlinear sign gate and undergoes the sign flip function; and the method further comprises changing the first optical switch from the first position to a second position in which the B1 optical channel is optically coupled to the common optical channel, such that the second quantum state is directed from the second quantum memory into the first optical switch and thereafter into the nonlinear sign gate where the second quantum state undergoes the sign flip function.
Regarding claim 4, 17, and 18, the dependent claim depends from a claim that recites allowable subject matter therefore recites allowable subject matter.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure, and generally discloses linear optical quantum computing devices and methods.
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/COLLIN X BEATTY/Primary Examiner, Art Unit 2872
1 Pieter Kok et Al. Linear Optical Computing. arXiv:quant-ph/0512071v2 14 Mar 2006.
2 S.U. Shringarpure et Al. Destructive Controlled-Phase Gate Using Linear Optics. arXiv:2103.03711 [v1] Fri, 5 Mar 2021 14:34:58 UTC (598 KB)
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