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 .
Claim Rejections - 35 USC § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claims 1-6, and 16-24 are rejected under 35 U.S.C. 101 because the claimed invention is directed to an abstract idea (i.e., mental processes and mathematical steps for determining an ion state by mapping state information to another ion and using probability-based evaluation of whether the mapped state changed), and the claims do not recite additional elements that integrate the abstract idea into a practical application or amount to significantly more than the judicial exception.
Step 2A, Prong One – Judicial exception (Abstract Idea)
The courts consider a mental process (thinking) that “can be performed in the human mind, or by a human using a pen and paper” to be an abstract idea. CyberSource Corp. v. Retail Decisions, Inc., 654 F.3d 1366, 1372, 99 USPQ2d 1690, 1695 (Fed. Cir. 2011). As the Federal Circuit explained, “methods which can be performed mentally, or which are the equivalent of human mental work, are unpatentable abstract ideas the ‘basic tools of scientific and technological work’ that are open to all.’” 654 F.3d at 1371, 99 USPQ2d at 1694 (citing Gottschalk v. Benson, 409 U.S. 63, 175 USPQ 673 (1972)). See also Mayo Collaborative Servs. v. Prometheus Labs. Inc., 566 U.S. 66, 71, 101 USPQ2d 1961, 1965 ("‘[M]ental processes[] and abstract intellectual concepts are not patentable, as they are the basic tools of scientific and technological work’" (quoting Benson, 409 U.S. at 67, 175 USPQ at 675)); Parker v. Flook, 437 U.S. 584, 589, 198 USPQ 193, 197 (1978) (same). Further, the courts do not distinguish between claims that recite mental processes performed by humans and claims that recite mental processes performed on a computer. As the Federal Circuit has explained, "[c]ourts have examined claims that required the use of a computer and still found that the underlying, patent-ineligible invention could be performed via pen and paper or in a person’s mind." Versata Dev. Group v. SAP Am., Inc., 793 F.3d 1306, 1335, 115 USPQ2d 1681, 1702 (Fed. Cir. 2015). See also Intellectual Ventures I LLC v. Symantec Corp., 838 F.3d 1307, 1318, 120 USPQ2d 1353, 1360 (Fed. Cir. 2016) (‘‘[W]ith the exception of generic computer-implemented steps, there is nothing in the claims themselves that foreclose them from being performed by a human, mentally or with pen and paper.’’); Mortgage Grader, Inc. v. First Choice Loan Servs. Inc., 811 F.3d 1314, 1324, 117 USPQ2d 1693, 1699 (Fed. Cir. 2016) (holding that computer-implemented method for "anonymous loan shopping" was an abstract idea because it could be "performed by humans without a computer").
In the instant case, the independent claims recite limitations that, when considered in their broadest reasonable interpretation, fall within the abstract idea of (i) mental process (concepts formed in the human mind such as observation, evaluation, and judgment) and/or (ii) mathematical concepts (relationships, comparisons, and mathematical operations such as probability analysis). For instance, the independent claim 1 recites (independent claims 18 and 24 recites similar limitations):
apply one or more conditioning operations, each of the one or more conditioning operations comprising:
i) applying a mapping operation to map a primary ion state of the primary ion on to a detection ion state of the detection ion;
ii) applying a state change operation comprising changing the detection ion state if the detection ion state has a first detection state value; and
determine a probability of the detection ion state changing in response to the application of the state change operation; and
determine the primary ion state using the determined probability or determine that the primary ion state is indeterminate using the determined probability.
These limitations collectively recite determining collecting/evaluating state information and making a determination based on a probability, which is an observation, evaluation, judgment, or mental process. The claim also recites mathematical concepts because the claims require determining probabilities. Such collection, observation and determination are fundamentally a form of data analysis and mathematical evaluation, activities that have long been performed by humans mentally or with pen and paper, and therefore can be characterized as an abstract idea.
Step 2A, Prong Two – Integration into a Practical Application
The claims are not integrated into a practical application because in practice, executing all of the steps is indistinguishable from: (i) mere data acquisition from a conventional instrument environment, and (ii) generic computer implementation of the abstract analysis. That is to say that integration into a practical application is lacking where, as here, the abstract idea has no effect on the material world or the execution of the process.
Although the claims include additional elements, such as the ion trap, controller, detection ion, primary ion, readout system, initialization system, and quantum logic system, the additional elements are recited at a high level and merely provide a technological environment for performing the abstract determination. The claims do not require a particular physical gate sequence, pulse structure, field generator, detector structure, or specific improvement to ion trapping or quantum logic spectroscopy. Rather, the claims broadly cover the desired result of mapping ion state information, evaluating whether the detection ion state changed, and determining the primary ion state using probability. The recited physical components are used as generic tools to obtain state information and apply the abstract probability-based decision process, and therefore amount to no more than field-of-use limitations and insignificant extra-solution activity.
Therefore, the claims as a whole are directed to an abstract idea.
Step 2B– Significant More (Inventive Concept)
The claims do not include additional elements, either individually or as an ordered combination, that amount to significant more than the abstract idea. The independent claims recite a quantum logic spectroscopy system, an ion trap, primary ion, detection ion, and controller at a high level, but these elements are used only as generic tools for carrying out the abstract state-mapping and probability-based state determination. Claim 2 merely recites maintaining the detection-ion state for a second state value, which is part of the same abstract state-evaluation logic. Claims 3, 4, 16, and 17 merely specify that the primary-ion state corresponds to magnetic quantum number values and particular probability relationships, which further define the information being evaluated and the mathematical relationship used, but do not add an unconventional physical implementation. Claims 5, 6, 21, and 22 merely recite updating the probability through repeated operations until convergence, a 1/0 result, or a threshold number of repetitions, which is still probability updating and decision-making. Claims 18, 20, and 23 recite the apparatus, readout system, initialization system, and quantum computer environment at a generic level, without adding a specific improvement to the ion trap, detector, controller, or quantum-computer hardware.
Considering the claim elements individually and as an ordered combination, the claims merely use generic quantum-logic spectroscopy components to implement the abstract probability-based determination of an ion state. The claims do not recite a specific unconventional gate sequence, pulse structure, field generator, detector structure, or hardware arrangement that improves the operation of the ion trap or quantum-logic spectroscopy system. Accordingly, the claims do not recite an inventive concept sufficient to transform the abstract idea into patent-eligible subject matter.
Taken alone or as ordered combination, claims 1-6, and 16-24 fail to recite patent eligible subject matter.
Claim Objections
Claims 3, 17, and 22 are objected to because of the following informalities:
Claim 3 recites “a second quantum magnetic number value,” should be “a second magnetic quantum number value.”
Claim 17 recites “the primary has state is the second magnetic quantum number value,” should be “the primary ion state is the second magnetic quantum number value
Claim 22 recites “The apparatus of claim 21, wherein: determining the probability comprises: ii) updating the probability for each subsequent conditioning operation until…”, contains a formatting error since the limitation begins with “ii)” without a preceding “i)”.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 5-6, 17, and 21-22 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.
Claims 5 and 21 each recite “updating the probability for each subsequent conditioning operation until: i) the probability converges.” Claims 6 and 22 each further recites convergence “to a 1 or a 0.” However, the claims do not specify an objective criterion for determining when convergence has occurred. In view of the disclosed probabilistic operations and possible non-zero error, the scope of the claims is unclear as to how close to 1 or 0 the probability must be, or what statistical threshold determines convergence.
Claim 17 recites “the probability will be 1 if, and only if, the primary ion state is the first magnetic quantum number value… and the probability will be 0 if, and only if, the primary has state is the second magnetic quantum number value.” The specification describes the relevant mapping and state-change operations as probabilistic and having a non-zero probability of being unsuccessful (see Spec. Page 11|17-23). Thus, it is unclear whether the claim requires an actual probability exact equal to 1 or 0, or a measured/estimated probability that converges towards 1 or 0 after repeated conditioning operations.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-2, 5-6, and 18-24 are rejected under 35 U.S.C. 103 as being unpatentable over Hume, D., et al., (2007). High-Fidelity Adaptive Qubit Detection through Repetitive Quantum Nondemolition Measurements. Physical Review Letters, 99(12) [hereinafter Hume2007].
Regarding Claims 1, 18, and 24:
Hume 2007 teaches:
a quantum logic spectroscopy system for an ion trap configured to trap a primary ion and a detection ion (Abstract and Page 1: “Using two trapped ion species (27Al+ and 9Be+) as primary and ancillary systems, we implement qubit measurements based on the repetitive transfer of information and quantum nondemolition detection”; “The Al+ ions form the primary quantum system and a single Be+ ancilla is used for sympathetic laser cooling and state detection”), the quantum logic spectroscopy system configured to:
an apparatus comprising: a quantum logic spectroscopy system; and an ion trap configured to trap a primary ion and a detection ion (Page 1: “We apply these ideas to high-fidelity measurements of one and two-qubit systems in an ion trap”); wherein: the quantum logic spectroscopy system is configured to:
a method of controlling a quantum logic spectroscopy system for an ion trap configured to trap a primary ion and a detection ion (Abstract: “we implement qubit measurements based on the repetitive transfer of information and quantum nondemolition detection”), the method comprising:
apply one or more conditioning operations (Page 2: “A series of laser pulses transfers the information in the Al+ system first to the collective motional state then to the Be+ internal state followed by Be+ detection”; the experimental steps include “Doppler cooling,” “Raman cooling,” “Be+ preparation,” “Interaction between Al+ and Be+,” and “Be+ state detection”), each of the one or more conditioning operations comprising:
i) applying a mapping operation to map a primary ion state of the primary ion on to a detection ion state of the detection ion (Page 2: “First, a π-pulse on the |↓⟩Al|0⟩m → |3P1⟩Al|1⟩m sideband transition inserts a motional quantum into the mode dependent on the ion being in the |↓⟩Al state. The information in the motional state is then transferred to the internal state of Be+ using a π-pulse on the |↓⟩Be|1⟩m → |↑⟩Be|0⟩m transition.” Thus, Al+ primary-ion state information is first mapped to the motional state and then mapped to the Be+ detection-ion internal state);
ii) applying a state change operation comprising changing the detection ion state if the primary ion state has a first detection state value (Page 2: Be+ is prepared in |↓⟩Be. Hume2007 teaches that, when Al+ is in the |↓⟩Al state, a motional quantum is inserted into the mode by the transition |↓⟩Al|0⟩m → |3P1⟩Al|1⟩m. Hume2007 then applies a π-pulse on the Be+ transition |↓⟩Be|1⟩m → |↑⟩Be|0⟩m, such that Be+ changes from |↓⟩Be to |↑⟩Be when the mapped motional quantum exists. As shown in equation (4), the resulting operation produces the α branch, where Al+ was originally in |↓⟩Al and Be+ ends in |↑⟩Be, and the β branch, where Al+ was in |↑⟩Al and Be+ remains in |↓⟩Be); and
determine a probability of the detection ion state changing in response to the application of the state change operation (Page 2: “Detection of the Be+ state relies on state-dependent resonance fluorescence from the |↓⟩Be → ... cycling transition,” and “For the jth cycle of the measurement procedure, a number of photons nj is scattered from the Be+ ion and collected in a photomultiplier tube. The entire measurement yields a series of photon counts, {nj}, that are used to determine the Al+ state.” Since Be+ is initially prepared in |↓⟩Be, a bright/high photon count indicates Be+ likely remained in |↓⟩Be and did not change, while a dark/low photon count indicates Be+ likely changed to |↑⟩Be. Hume2007 further teaches that “Imperfect cooling and transfer pulses give rise to a single-cycle detection error of approximately 15%. However, the fidelity can be improved by repeating the procedure,” and determines probabilities from the repeated photon-count series using “P({nj}|i) = Πj P(nj|i)” and Bayes’ rule); and
determine the primary ion state using the determined probability or determine that the primary ion state is indeterminate using the determined probability (Page 2: “The probability, P(n|i), of observing n photons given state |i⟩ of the Al+ system is determined based on histograms continuously updated from previous measurements”; “Applying Bayes’ rule ... yields the probability of a particular state |i⟩ given the observed series of photon counts”; and “This procedure provides both the most likely state of Al+, |imax⟩, and also the probability of measurement error.” Hume2007 further teaches repeating detection cycles “only until the aggregate detection reaches a desired error probability,” thereby determining the Al+ primary ion state when the probability is sufficient, or continuing/withholding determination when the probability is insufficient).
Although Hume2007 teaches that, when applying the state-change operation, the Be+ detection-ion state is changed when the Al+ primary ion has a first state value, rather than expressly when the Be+ detection ion has a first detection-state value, as claimed; however, it would have been obvious to an ordinary skilled person in the art, that the change is also based on the Be+ detection ion having the corresponding first detection state value. Hume 2007 teaches that the Al+ primary-ion state information is mapped to the Be+ detection ion through the shared motional state before Be+ detection. Therefore, after the mapping, the Be+ detection-ion state represents the Al+ primary-ion state, and a state-change operation dependent on the Al+ primary-ion state is likewise dependent on the corresponding mapped Be+ detection-ion state value.
Regarding Claims 2 and 19:
Hume2007 teaches the quantum logic spectroscopy system of claim 1 and the apparatus of claim 18, respectively. Hume2007 further teaches wherein applying the state change operation comprises maintaining the detection ion state if the primary ion state has a second detection state value (Page 2: “This sequence implements an entangling operation, (α|↓⟩Al + β|↑⟩Al)|↓⟩Be → α|3P1⟩Al|↑⟩Be + β|↑⟩Al|↓⟩Be.” Thus, the β branch, where Al+ was in |↑⟩Al, ends with Be+ remaining in |↓⟩Be, i.e., the Be+ detection ion state is maintained for the mapped state branch corresponding to the second value). As discussed in claim 1, because Hume2007 teaches mapping the Al+ primary ion state information to the Be+ detection ion state, maintaining the Be+ state for the second Al+ branch also teaches or at least renders obvious maintaining the detection ion state when the detection ion has the corresponding mapped second detection state value.
Regarding Claims 5 and 21:
Hume2007 teaches the quantum logic spectroscopy system of claim 1 and the apparatus of claim 20, respectively. Hume2007 further teaches determining the probability comprises: determining the probability for a first conditioning operation; and updating the probability for each subsequent conditioning operation until: i) the probability converges (Page 2: Hume2007 teaches that, for each measurement cycle, photon counts are collected and used to update the probability of the Al⁺ state using Bayes’ rule. Hume2007 further teaches “repeat the detection cycles only until the aggregate detection reaches a desired error probability”. Thus, Hume2007 teaches updating the probability through repeated conditioning operations until the probability reaches a sufficiently converged/confident value); or ii) a threshold number of repeated conditioning operations is exceeded.
Further, Hume 2007 teaches repeating the measurement procedure and updating the state probability until the desired error probability is reached. Thus, in light of Hume 2007’s teaching, it would have been obvious for an ordinary person in the art, to reinitializing the primary ion state when a maximum number of repeated conditioning operations is exceeded, as claimed, because exceeding the maximum number of repetitions indicates that the readout did not reach sufficient confidence, and reinitializing the primary ion state would allow the system to reset and restart the measurement rather than continue an unreliable or failed readout indefinitely.
Regarding Claims 6 and 22:
Hume2007 teaches the quantum logic spectroscopy system of claim 5 and the apparatus of claim 21, respectively. Hume2007 further teaches wherein:
determining the probability comprises: updating the probability for each subsequent conditioning operation until: i) the probability converges to a 1 or a 0 (Hume2007 teaches updating the probability of the Al⁺ state based on repeated photon-count measurements and determining the most likely Al⁺ state with an associated measurement-error probability. As additional cycles are performed, the probability moves toward one state being likely and the other state being unlikely, i.e., toward a 1/0 state determination, until the desired error probability is reached); or ii) the threshold number of repeated conditioning operations is exceeded.
Regarding Claim 20:
Hume2007 teaches the apparatus of claim 18. Hume2007 further teaches a readout system comprising the quantum logic spectroscopy system and/or an initialization system for initializing the primary ion state (Page 2: Hume 2007 teaches a readout system comprising the quantum-logic spectroscopy system because Hume2007 uses the Al⁺/Be⁺ quantum-logic system to perform state detection/readout of the Al⁺ primary ion. Hume2007 also teaches initializing/preparing the ion states before readout, including preparing the Al⁺ system before measurement and initializing Be⁺ to |↓⟩Be before detection. Thus, Hume2007 teaches a readout system and an initialization system).
Regarding Claim 23:
Hume2007 teaches the apparatus of claim 18. Hume2007 further teaches wherein the apparatus is a quantum computer (Page 1: “Reliable state detection plays a central role in quantum-limited metrology and quantum information processing,” and discusses quantum computation).
Claims 3-4 are rejected under 35 U.S.C. 103 as being unpatentable over Hume2007, in
view of Hume, D. B., Chou, C. W., Leibrandt, D. R., Thorpe, M. J., Wineland, D. J., & Rosenband, T. (2011). Trapped-Ion State Detection through Coherent Motion. Physical Review Letters, 107(24) [hereinafter Hume 2011].
Regarding Claim 3:
Hume 2007 teaches the primary ion state is a magnetic quantum number having one magnetic quantum number value comprising a first magnetic quantum number value (Fig. 1 shows Al⁺ primary-ion states labeled by magnetic quantum number mF = 5/2 used in the state-transfer/detection process).
However, Hume 2007 does not specifically note that the magnetic quantum number may have a second magnetic quantum number value. Hume 2011 teaches the magnetic quantum number values comprising a first magnetic quantum number value and a second quantum magnetic number value (Page 3: “we experimentally distinguish Zeeman substates of the Al+ 1S0 ground state” and “six Zeeman levels |I, m⟩ for m = −5/2 to +5/2.” Thus, Hume 2011 teaches a primary Al+ ion state identified by a magnetic quantum number m having multiple possible values such like −5/2, −3/2, −1/2, +1/2, +3/2, or +5/2).
Hume 2007 teaches a quantum-logic readout system for indirectly determining the state of an Al⁺ primary ion using a co-trapped detection ion. Hume 2011 teaches that the same type of quantum-logic readout can be used to determine which magnetic sublevel the Al⁺ ion is in, because different magnetic sublevels produce different motion that can be read out by the detection ion. It would have been obvious for an ordinary skilled person in the art, before the effective time of filing, to apply Hume 2011’s magnetic-sublevel readout to Hume 2007’s system because different magnetic quantum number values can carry more detailed state-related information about the Al⁺ ion than a simple two-state readout, and Hume 2011 teaches that such magnetic-sublevel information can be read out using the same indirect detection approach.
Regarding Claim 4:
Hume 2007 in view of Hume 2011 teaches the quantum logic spectroscopy system of claim 3. The combined references further teaches wherein applying the mapping operation comprises: setting the detection ion state to the first detection state value if the magnetic quantum number has the first magnetic quantum number value; and setting the detection ion state to a second detection state value if the magnetic quantum number has the second magnetic quantum number value (Hume 2007 teaches setting the Be⁺ detection-ion state to different values corresponding to different Al⁺ primary-ion state branches. Hume 2011 teaches that the Al⁺ primary-ion state can be a magnetic quantum number state having different magnetic quantum number values. Thus, the combined teachings provide mapping a first Al⁺ magnetic quantum number value to a first Be⁺ detection-ion state value and mapping a second Al⁺ magnetic quantum number value to a second Be⁺ detection-ion state value).
Claims 7-14 are rejected under 35 U.S.C. 103 as being unpatentable over Hume2007, in view of Lee, P. J., Brickman, K-A., Deslauriers, L., Haljan, P. C., Duan, L-M., & Monroe, C. (2005). Phase control of trapped ion quantum gates. Journal of Optics B: Quantum and Semiclassical Optics, 7(10), S371–S383 [hereinafter Lee].
Regarding Claim 7:
Hume2007 teaches the quantum logic spectroscopy system of claim 1. However, Hume 2007 does not specifically note that a controller configured to apply the one or more conditioning operations by, for each of the one or more conditioning operations: i) applying a first single rotation operation to the detection ion; ii) applying a geometric phase gate to the primary ion and the detection ion; and iii) applying a second single rotation operation to the detection ion.
Lee teaches a controller configured to apply the one or more conditioning operations by, for each of the one or more conditioning operations: i) applying a first single rotation operation to the detection ion; ii) applying a geometric phase gate to the primary ion and the detection ion; and iii) applying a second single rotation operation to the detection ion (Pages 4-5: Lee teaches converting a trapped-ion phase gate into a controlled operation by applying “(1) a carrier π/2 pulse on the target qubit,” “(2) a π phase gate on two ions,” and “(3) a carrier −π/2 pulse on the target qubit.” Lee further explains that “steps (1) and (3) are carrier couplings on the target ion”, i.e., single-qubit rotations, and that spin-dependent-force gates allow the ion spin states to acquire geometric phase and produce a phase gate).
Hume 2007 teaches a quantum-logic readout system in which the Al⁺ primary-ion state is transferred through shared ion motion and mapped to the Be⁺ detection-ion state for fluorescence readout. Lee teaches that trapped-ion quantum information can be processed through collective ion motion, and that phase gates are useful entangling gates because they have a well-defined phase and can be converted into controlled operations using single-qubit rotations. It would have been obvious for an ordinary skilled person in the art, before the effective time of filing, to implement Hume2007’s detection-ion mapping/readout operation using Lee’s known trapped-ion rotation–geometric-phase-gate–rotation sequence, such that in the modified system, Lee’s rotation–geometric-phase-gate–rotation sequence is used to perform the state-dependent mapping from the Al⁺ primary ion to the Be⁺ detection ion. This would provide a known, phase-controlled trapped-ion gate implementation for predictably transferring primary-ion state information to the detection ion for readout.
Regarding Claim 8:
Hume 2007 in view of Lee teaches the quantum logic spectroscopy system of claim 7. Hume2007 further teaches: a detector configured to measure a property of the detection ion state for each of the one or more conditioning operations; wherein: determining the probability of the detection ion state changing in response to the application of the state change operation uses the measured property of the detection ion state (Page 2: Hume2007 teaches a detector measuring Be+ fluorescence/photon counts for each cycle and using the measured detection-ion property to determine probability).
Regarding Claim 9:
Hume 2007 in view of Lee teaches the quantum logic spectroscopy system of claim 8. Hume2007 further teaches wherein the measured property of the detection ion state is whether the detection ion state has changed (Page 2: Be⁺ is initially prepared in |↓⟩Be and that, after the state-transfer operation, Be⁺ either remains in |↓⟩Be or changes to |↑⟩Be. Because |↓⟩Be is bright and |↑⟩Be is dark in fluorescence detection, the measured photon count indicates whether the Be⁺ detection-ion state has changed).
Regarding Claim 10:
Hume 2007 in view of Lee teaches the quantum logic spectroscopy system of claim 7. Lee further teaches wherein the geometric phase gate is a ZZ gate (Pages 7-8: Lee teaches a σ̂z gate that is a ZZ gate, because Lee’s Eq. (27) shows a two-qubit gate and Lee’s gate applies a phase shift of i based on the shared state of both qubits: when the two qubits are anti-aligned, |↑↓⟩ and |↓↑⟩ become i|↑↓⟩ and i|↓↑⟩; when the two qubits are aligned, |↑↑⟩ and |↓↓⟩ remain unchanged).
Regarding Claim 11:
Hume 2007 in view of Lee teaches the quantum logic spectroscopy system of claim 7. Lee further teaches wherein the controller comprises:
a control field generator configured to provide a control field to apply the first and second single rotation operations (Page 2: Lee teaches that the first and second single-rotation operations are carrier π/2 pulses applied to the target ion, and further teaches that “single-qubit rotations between hyperfine qubit levels … can be performed by applying appropriate radiation fields. For example, a resonant microwave field... Alternatively, optically stimulated Raman transitions can be employed,” both of which are provided control field) and/or a magnetic field gradient generator configured to provide a magnetic field gradient to apply the geometric phase gate.
Regarding Claim 12:
Hume 2007 in view of Lee teaches the quantum logic spectroscopy system of claim 11. Lee further teaches wherein the control field generator configured to provide a control field to: apply the first single rotation operation by applying a first π/2 pulse; and apply the second single rotation operation by applying a second π/2 pulse (Page 4: Lee teaches that the controlled-NOT gate is performed by applying “(1) a carrier π/2 pulse on the target qubit,” then a phase gate, and then “(3) a carrier −π/2 pulse on the target qubit.” Lee further teaches that steps (1) and (3) are carrier couplings on the target qubit ion. Thus, Lee teaches applying first and second π/2 control pulses to perform the first and second single-rotation operations).
Regarding Claim 13:
Hume 2007 in view of Lee teaches the quantum logic spectroscopy system of claim 11. Lee further teaches wherein the control field generator comprises a microwave field generator and the control field is a microwave field (Page 2: Lee teaches that “single-qubit rotations between hyperfine qubit levels … can be performed by applying appropriate radiation fields. For example, a resonant microwave field”).
Regarding Claim 14:
Hume 2007 in view of Lee teaches the quantum logic spectroscopy system of claim 7. Lee further teaches wherein the control field, as provided by the control field generator, oscillates at, or near, a detection ion transition frequency of the detection ion (Fig. 7 and its annotation: Lee teaches that a σz-dependent force is driven by electromagnetic fields having two frequencies separated by ων + δ, where ων is the ion vibrational mode frequency. Lee further teaches that the fields produce a differential AC Stark shift that “oscillates at ων + δ.” Thus, Lee teaches a control/electromagnetic field oscillating at or near a mode frequency of the two-ion chain); and/or the magnetic field gradient, as provided by the magnetic field gradient generator, oscillates at, or near, a mode frequency of the ion chain comprising the primary ion and the detection ion.
Claims 15-17 are rejected under 35 U.S.C. 103 as being unpatentable over Hume2007 in view of Hume 2011, and further in view of Lee.
Regarding Claim 15:
Hume 2007 in view of Lee teaches the quantum logic spectroscopy system of claim 14. However, the combined references do not specifically note that the detection ion transition frequency and a transition frequency of the primary ion are unequal. Hume 2011 teaches wherein the detection ion transition frequency and a transition frequency of the primary ion are unequal (Page 2: “All laser beams overlap both ions but because the Al+ and Mg+ wavelengths are substantially different, each beam interacts with only one species.” Hume 2011 also identifies Al+ 3P1 laser beams at about 267 nm and Mg+ detection light at about 280 nm. Thus, Hume2011 teaches unequal transition frequencies/wavelengths for the primary Al+ ion and the detection Mg+ ion).
Hume 2007 teaches a quantum-logic readout system using an Al⁺ primary ion and a co-trapped detection ion, and Lee teaches implementing the state-transfer/readout operation using known trapped-ion gate/control fields. Hume 2011 teaches a closely related Al⁺ quantum-logic spectroscopy system using a different co-trapped logic ion species, Mg⁺, and expressly teaches that the Al⁺ and Mg⁺ wavelengths are substantially different so that each beam interacts with only one species. It would have been obvious for an ordinary skilled person in the art, before the effective time of filing, to apply Hume 2011’s teaching of using unequal primary-ion and detection-ion transition frequencies in the Hume 2007/Lee system because different transition frequencies allow the control/detection beams to selectively address the primary ion and detection ion separately, thereby reducing unintended interaction with the wrong ion while preserving quantum-logic readout through the co-trapped detection ion.
Regarding Claim 16:
Hume 2007 in view of Hume 2011 teaches the quantum logic spectroscopy system of claim 3. However, the combined references do not specifically note that wherein the magnetic quantum number mf corresponds to the ground state hyperfine S manifold having one of 4I+2 possible magnetic quantum number values, where I is the nuclear spin of the primary ion.
Lee teaches wherein the magnetic quantum number mf corresponds to the ground state hyperfine S manifold having one of 4I+2 possible magnetic quantum number values, where I is the nuclear spin of the primary ion (Page 2: as shown in Fig.1 and its annotation, Lee teaches trapped-ion qubits having a ²S₁/₂ ground state. “In isotopes with non-zero nuclear spin, the ²S₁/₂ ground states are split by the hyperfine interaction” Lee’s Fig. 1 gives ¹¹¹Cd⁺ as an example, where I = 1/2 and the ²S₁/₂ ground-state hyperfine manifold includes F = 0 and F = 1 levels. The F = 0 level has one mF value (0), and the F = 1 level has three mF values (-1, 0, +1), for a total of four mF values, which equals 4I+2 when I = 1/2. Thus, Lee teaches a ground-state hyperfine S manifold having 4I+2 possible magnetic quantum number values).
Hume 2007 teaches the quantum-logic readout architecture. Hume 2011 teaches using that type of readout to determine magnetic-sublevel information of a primary ion, whose ground state is a ¹S₀ Zeeman manifold, which provides 2I+1 magnetic sublevels. Lee teaches a standard trapped-ion ²S₁/₂ ground-state hyperfine manifold, where the nonzero nuclear spin splits the ground state into hyperfine levels labeled by F and mF, providing 4I+2 total mF values. It would have been obvious for an ordinary skilled person in the art, before the effective time of filing, to use Lee’s ²S₁/₂ hyperfine-manifold states as the magnetic quantum number states in the Hume 2007/2011 quantum-logic readout system because Lee teaches that such hyperfine states are standard, controllable trapped-ion qubit states with good phase stability, and using the full hyperfine manifold provides additional magnetic-state information for readout.
Regarding Claim 17:
Hume 2011 teaches that different magnetic quantum number states of the Al⁺ primary ion produce different detection responses. Specifically, Hume 2011 teaches that the optical dipole force leaves the ions in a motional state β(m) dependent on the Al⁺ Zeeman state |I,m⟩, that the primary factor affecting β(m) is the Clebsch-Gordan coefficient, and that the measured β(m) values increase from 0.05 for the lowest m state to 2.15 for the highest m state. Hume 2011 further teaches measuring the Mg⁺ detection-ion probability P↓ after a resolved-sideband pulse to identify the Al⁺ state. Thus, Hume 2011 teaches that the detection-ion state-change probability depends on the magnetic quantum number value, with the highest and lowest m states producing substantially different detection probabilities. In light Hume 2011’s teaching, it would have been obvious for an ordinary skilled person in the art, to select/calibrate the pulse duration and normalize the probability scale so that the highest-coupled m state corresponds to substantially complete detection-ion state change (i.e., probability close to 1) and the lowest-coupled m state corresponds to substantially no detection-ion state change (i.e., probability close to 0), as recited in claim 17, because Hume 2011 teaches using the m-dependent response β(m) to distinguish the Zeeman states.
Conclusion
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/JING WANG/Examiner, Art Unit 2881
/MICHAEL J LOGIE/Primary Examiner, Art Unit 2881
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