DETAILED ACTION
This action is in response to the application filed on 10/20/2023. Claims 1-20 are pending in the application and have been examined.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries 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.
Claims 1-3; 9-11; 17-18 are rejected under 35 U.S.C. 103 as being unpatentable by Hermans et al. (“Entangling remote qubits using the single-photon protocol: an in-depth theoretical and experimental study” [18 January 2023], hereinafter “Hermans”) in view of Matthews et al. (“Heralded Entanglement for Quantum Enhanced Measurement with Photons” [2010]).
Regarding Claim 1,
Hermans discloses A method, comprising: performing an optically heralded entanglement process to entangle states of a first data quantum bit and a second data quantum bit into an entangled state of computational basis states comprising a ground state and a first excited state, wherein performing the optically heralded entanglement process comprises: (Hermans [Figure 1];
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Wherein the entangled heralded state is comprised in part of the excited state |e as well as the ground states |0 and |1)
performing a first optically heralded entanglement process to determine whether the entangled state of the first data quantum bit and the second data quantum bit excludes a state in which both the first data quantum bit and the second data quantum bit can be in the ground state; (Hermans [Figure 1];
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Wherein the resulting heralded state being the joint measurement of the photonic states comprising some combination of the ground states and excited states thus reads on embodiments of the resulting heralded state comprising at least one excited state qubit (thus implying determining the exclusion of states in which both qubits are grounded))
and performing a … optically heralded entanglement process to determine whether the entangled state of the first data quantum bit and the second data quantum bit excludes a state in which both the first data quantum bit and the second data quantum bit can be in the first excited state (Hermans [Figure 1];
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Hermans does not disclose but Matthews discloses performing a second optically heralded entanglement process (Matthews [Figure 1];
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Wherein part a) of Figure 1 demonstrates the optically heralded entanglement process comprising a first and second optically heralded entanglement process to entangle states of a first and second data quantum bit)
It would have been obvious to modify Hermans’ method of performing an optically heralded entanglement process for determining the exclusivity of the entangled states of the first and second quantum bits to be done across Matthews’ two separate optical heralds. One would have been motivated to do so because “To achieve these non-linear entangling inter actions additional photons and photon detection can be used: a particular detection event heralds the success of a given process. In this way it is possible to generate multi photon entangled states and indeed to efficiently perform universal, fault tolerant quantum computing” (Matthews [Page 1 Paragraph 1]).
Regarding Claim 2,
Hermans/Matthews teaches the method of Claim 1 (and thus the rejection of Claim 1 is incorporated). Hermans/Matthews already discloses wherein performing the optically heralded entanglement process comprises: performing a single-quantum bit gate operation on each of the first data quantum bit and the second data quantum bit to place the first data quantum bit and the second data quantum bit into respective superposition states (Hermans [Section 2];
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Wherein the superposition projection of each of the qubits is obtained through a unitary single-quantum bit gate operation performed upon each of the two qubits)
and performing a controlled two-quantum bit gate operation to conditionally flip a state of a first interface quantum bit based on the superposition state of the first data quantum bit; (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the embodiments of the protocol directed to state-selective optical excitation of a two-level qubit subspace through qubit flipping based on the projected superposition states thus reads on controlled two-quantum bit gate operation to conditionally flip a state of a first interface quantum bit (of the two-level qubit subspace) based on the superposition state of the first data quantum bit)
and performing a controlled two-quantum bit gate operation to conditionally flip a state of a second interface quantum bit based on the superposition state of the second data quantum bit; (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the embodiments of the protocol directed to state-selective optical excitation of a two-level qubit subspace through qubit flipping based on the projected superposition states thus reads on controlled two-quantum bit gate operation to conditionally flip a state of a second interface quantum bit (of the two-level qubit subspace) based on the superposition state of the second data quantum bit)
wherein the first optically heralded entanglement process is performed based on the state of the first interface quantum bit and the state of the second interface quantum bit (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.”
Hermans [Figure 1];
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Wherein the optically heralded entanglement process is performed based on the first and second qubits of the qubit subspace)
Regarding Claim 3,
Hermans/Matthews teaches the method of Claim 2 (and thus the rejection of Claim 2 is incorporated). Hermans/Matthews already discloses wherein performing the first optically heralded entanglement process comprises: transferring the state of the first interface quantum bit to a first quantum transducer that is configured to generate an optical photon based on the state of the first interface quantum bit; transferring the state of the second interface quantum bit to a second quantum transducer that is configured to generate an optical photon based on the state of the second interface quantum bit; (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the individual excitation of the two qubits to generate their respective emitted photons thus read on the transfer of states of a first and second interface quantum bit into respective individual transducers to generate respective generated optical emitted photons)
utilizing an optical beam splitter to perform a photon interference based on optical photons output from the first quantum transducer and the second quantum transducer; and detecting for a presence of an optical photon output from the optical beam splitter, as a result of the first optically heralded entanglement process (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the emitted optical photons being led o a beam splitter read on utilization of an optical beam splitter to perform a photon interference based on the optical photons output; wherein the two photon detectors read on detection of presence of an optical photon output from the optical beam splitter)
Claims 9-11 recite a system configured to execute the exact method of Claims 1-3 respectively. Thus, Claims 9-11 are rejected for reasons set forth in the rejection of Claims 1-3 respectively.
Regarding Claim 17,
Hermans discloses A system, comprising: a first quantum system comprising a first data quantum bit, a first interface quantum bit coupled to the first data quantum bit, and a first quantum transducer coupled to the first interface quantum bit; (Hermans [Figure 1];
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Wherein the entangled heralded state is comprised in part of the excited state |e as well as the ground states |0 and |1
Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the individual excitation of the two qubits to generate their respective emitted photons thus read on the transfer of states of a first and second interface quantum bit into respective individual transducers to generate respective generated optical emitted photons)
an optical beam splitter having input ports that are optically coupled to respective output ports of the first quantum transducer and the second quantum transducer; a photon detector device coupled to output ports of the optical beam splitter; (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.”)
and a control system configured to perform an optically heralded entanglement process to entangle states of the first data quantum bit and the second data quantum bit into an entangled state of computational basis states comprising a ground state and a first excited state, wherein in performing the optically heralded entanglement process, the control system is configured to: utilize the first and second interface quantum bits, the first and second quantum transducers, the optical beam splitter, and the photon detector device to perform a first optically heralded entanglement process to determine whether the entangled state of the first data quantum bit and the second data quantum bit excludes a state in which both the first data quantum bit and the second data quantum bit can be in the ground state; (Hermans [Figure 1];
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Wherein the resulting heralded state being the joint measurement of the photonic states comprising some combination of the ground states and excited states thus reads on embodiments of the resulting heralded state comprising at least one excited state qubit (thus implying determining the exclusion of states in which both qubits are grounded))
and utilize the first and second interface quantum bits, the first and second quantum transducers, the optical beam splitter, and the photon detector device to perform a second optically heralded entanglement process to determine whether the entangled state of the first data quantum bit and the second data quantum bit excludes a state in which both the first data quantum bit and the second data quantum bit can be in the first excited state (Hermans [Figure 1];
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Wherein the resulting heralded state being the joint measurement of the photonic states comprising some combination of the ground states and excited states thus reads on embodiments of the resulting heralded state comprising at least one ground state (thus implying determining the exclusion of states in which both qubits are excited))
Hermans does not disclose but Matthews discloses a second quantum system comprising a second data quantum bit, a second interface quantum bit coupled to the second data quantum bit, and a second quantum transducer coupled to the second interface quantum bit. (Matthews [Figure 1];
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Wherein part a) of Figure 1 demonstrates the optically heralded entanglement process comprising a first and second optically heralded entanglement process to entangle states of a first and second data quantum bit)
It would have been obvious to modify Hermans’ method of performing an optically heralded entanglement process for determining the exclusivity of the entangled states of the first and second quantum bits to be done across two separate quantum systems with their own respective separate optical heralds. One would have been motivated to do so because “To achieve these non-linear entangling inter actions additional photons and photon detection can be used: a particular detection event heralds the success of a given process. In this way it is possible to generate multi photon entangled states and indeed to efficiently perform universal, fault tolerant quantum computing” (Matthews [Page 1 Paragraph 1]).
Regarding Claim 18,
Hermans/Matthews teaches the method of Claim 17 (and thus the rejection of Claim 17 is incorporated). Hermans/Matthews already discloses wherein when performing the optically heralded entanglement process: a state of the first interface quantum bit is entangled with a state of the first data quantum bit, and the state of the first interface quantum bit is consumed by the first quantum transducer to generate an optical photon that represents a state of the first data quantum bit; and a state of the second interface quantum bit is entangled with a state of the second data quantum bit, and the state of the second interface quantum bit is consumed by the second quantum transducer to generate an optical photon that represents a state of the second data quantum bit (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the individual excitation of the two qubits to generate their respective emitted photons thus read on the transfer of states of a first and second interface quantum bit into respective individual transducers to generate respective generated optical emitted photons)
Claims 4-8; 12-16; are rejected under 35 U.S.C. 103 as being unpatentable by Hermans et al. (“Entangling remote qubits using the single-photon protocol: an in-depth theoretical and experimental study” [18 January 2023], hereinafter “Hermans”) in view of Matthews et al. (“Heralded Entanglement for Quantum Enhanced Measurement with Photons” [2010]) further in view of Munro et al. (US 20070252081 A1, hereinafter “Munro”)
Regarding Claim 4,
Hermans/Matthews teaches the method of Claim 3 (and thus the rejection of Claim 3 is incorporated). Hermans/Matthews already discloses and in response to detecting the presence of an optical photon output from the optical beam splitter as a result of the first optically heralded entanglement process, determining that the entangled states of the first data quantum bit and the second data quantum bit exclude the state in which both the first data quantum bit and the second data quantum bit can be in the ground state (Hermans [Figure 1];
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Wherein the resulting heralded state being the joint measurement of the photonic states comprising some combination of the ground states and excited states thus reads on embodiments of the resulting heralded state comprising at least one excited state qubit (thus implying determining the exclusion of states in which both qubits are grounded))
Hermans/Matthews does not disclose but Munro discloses wherein: in response to not detecting the presence of an optical photon output from the optical beam splitter as a result of the first optically heralded entanglement process, restarting the optically heralded entanglement process (Munro [0031]; “ Errors due to dark counts in detectors 154 and 156 can generally be controlled as noted above by restricting photon measurements to short time intervals, making the probability of dark counts low. However, some types of detectors have relatively higher probabilities of dark counts. If the first measurement signal from step 230 falsely indicated one photon when no photons where emitted, two photons should be measured during the second pass. In which case, process 200 branches from step 250 back to step 210 to restart the entanglement operation. However, the difficulty of distinguishing two photons from one photon with a photomultiplier-based detector can result in both measurements from step 230 including errors, which reduces the fidelity of entanglement process 200. In accordance with a further aspect of the invention, immunity to a dark count errors may be further improved using third or subsequent passes where successful entanglement is heralded by detection of a single photon during every pass.”)
It would have been obvious to conditionally perform Munro’s extra “restart” passes of Hermans/Matthews’ optically double-heralded entanglement process when optical photon outputs are not detected. One would have been motivated to do so because “immunity to a dark count errors may be further improved using third or subsequent passes” (Munro [0031]).
Regarding Claim 5,
Hermans/Matthews/Munro teaches the method of Claim 4 (and thus the rejection of Claim 4 is incorporated). Hermans/Matthews/Munro already discloses wherein performing the optically heralded entanglement process comprises: in response to determining that the entangled states of the first data quantum bit and the second data quantum bit exclude the state in which both the first data quantum bit and the second data quantum bit can be in the ground state: performing a single-quantum bit gate operation on each of the first data quantum bit and the second data quantum bit to flip the superposition state of the first data quantum bit and to flip the superposition state the second data quantum bit; (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the embodiments of the protocol directed to state-selective optical excitation of a two-level qubit subspace through qubit flipping based on the projected superposition states thus reads on controlled two-quantum bit gate operation to conditionally flip a state of a first interface quantum bit (of the two-level qubit subspace) based on the superposition state of the first data quantum bit)
performing a controlled two-quantum bit gate operation to conditionally flip a state of the first interface quantum bit based on the flipped superposition state of the first data quantum bit; and performing a controlled two-quantum bit gate operation to conditionally flip a state of the second interface quantum bit based on the flipped superposition state of the second data quantum bit; (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the embodiments of the protocol directed to state-selective optical excitation of a two-level qubit subspace through qubit flipping based on the projected superposition states thus reads on controlled two-quantum bit gate operation to conditionally flip a state of a second interface quantum bit (of the two-level qubit subspace) based on the superposition state of the second data quantum bit)
wherein the second optically heralded entanglement process is performed based on the state of the first interface quantum bit and the state of the second interface quantum bit (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.”
Hermans [Figure 1];
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Wherein the optically heralded entanglement process is performed based on the first and second qubits of the qubit subspace
Matthews [Figure 1];
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Wherein part a) of Figure 1 demonstrates the optically heralded entanglement process comprising a first and second optically heralded entanglement process to entangle states of a first and second data quantum bit))
Regarding Claim 6,
Hermans/Matthews/Munro teaches the method of Claim 5 (and thus the rejection of Claim 5 is incorporated). Hermans/Matthews/Munro already discloses wherein performing the second optically heralded entanglement process comprises: transferring the state of the first interface quantum bit to the first quantum transducer; transferring the state of the second interface quantum bit to the second quantum transducer; (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the individual excitation of the two qubits to generate their respective emitted photons thus read on the transfer of states of a first and second interface quantum bit into respective individual transducers to generate respective generated optical emitted photons)
utilizing the optical beam splitter to perform a photon interference based on optical photons output from the first quantum transducer and the second quantum transducer; and detecting for a presence of an optical photon output from the optical beam splitter, as a result of the second optically heralded entanglement process (Hermans [Section 2]; “In this section we provide a step-by-step description of the single-photon protocol and derive the resulting two-qubit state. Figure 1(a) shows an example of the energy levels used by the protocol, in this work we employ a L-scheme for the optical excitation. We would like to emphasize that the protocol can also be executed with a Lambda (or Raman) excitation scheme. In that case, the optical excitation induces the qubit to flip [8]. Here we develop our model based on the L-scheme, as depicted in figure 1(a). We label two levels |0⟩ and |1⟩ as our qubit subspace, and we can coherently drive the transition between them to create any superposition state. Furthermore, the |0⟩ ground state is connected to an optically excited state |e⟩, allowing for state-selective excitation and qubit-photon entanglement. Figure 1(b) shows a general experimental layout, the two qubits can be individually excited and the emitted photons are led to a beam splitter. The output ports of the beam splitter are connected to two photon detectors.” wherein the emitted optical photons being led o a beam splitter read on utilization of an optical beam splitter to perform a photon interference based on the optical photons output; wherein the two photon detectors read on detection of presence of an optical photon output from the optical beam splitter)
Regarding Claim 7,
Hermans/Matthews/Munro teaches the method of Claim 6 (and thus the rejection of Claim 6 is incorporated). Hermans/Matthews/Munro already discloses wherein: in response to not detecting the presence of an optical photon output from the optical beam splitter as a result of the second optically heralded entanglement process, restarting the optically heralded entanglement process; (Munro [0031]; “ Errors due to dark counts in detectors 154 and 156 can generally be controlled as noted above by restricting photon measurements to short time intervals, making the probability of dark counts low. However, some types of detectors have relatively higher probabilities of dark counts. If the first measurement signal from step 230 falsely indicated one photon when no photons where emitted, two photons should be measured during the second pass. In which case, process 200 branches from step 250 back to step 210 to restart the entanglement operation. However, the difficulty of distinguishing two photons from one photon with a photomultiplier-based detector can result in both measurements from step 230 including errors, which reduces the fidelity of entanglement process 200. In accordance with a further aspect of the invention, immunity to a dark count errors may be further improved using third or subsequent passes where successful entanglement is heralded by detection of a single photon during every pass.”)
and in response to detecting the presence of an optical photon output from the optical beam splitter as a result of the second optically heralded entanglement process, determining that the entangled states of the first data quantum bit and the second data quantum bit exclude the state in which both the first data quantum bit and the second data quantum bit can be in the first excited state (Hermans [Figure 1];
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Wherein the resulting heralded state being the joint measurement of the photonic states comprising some combination of the ground states and excited states thus reads on embodiments of the resulting heralded state comprising at least one ground state (thus implying determining the exclusion of states in which both qubits are excited)))
Regarding Claim 8,
Hermans/Matthews/Munro teaches the method of Claim 1 (and thus the rejection of Claim 1 is incorporated). Hermans/Matthews/Munro already discloses wherein the optically heralded entanglement process is configured to entangle the states of the first data quantum bit and the second data quantum bit into a maximally entangled Bell state represented by 1/√2((|1⟩|0⟩+e^iϕ|0⟩|1⟩) (Hermans [Page 6 Equation 22];
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Matthews [Column 1 Paragraph 2];
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)
Claims 12-16 recite a system configured to execute the exact method of Claims 4-8 respectively. Thus, Claims 12-16 are rejected for reasons set forth in the rejection of Claims 4-8 respectively.
Claims 19-20 are rejected under 35 U.S.C. 103 as being unpatentable by Hermans et al. (“Entangling remote qubits using the single-photon protocol: an in-depth theoretical and experimental study” [18 January 2023], hereinafter “Hermans”) in view of Matthews et al. (“Heralded Entanglement for Quantum Enhanced Measurement with Photons” [2010]) further in view of Shabani et al. (US 20240005187 A1, hereinafter “Shabani”) further in view of Wavelength Opto-Electronic (“Handling and Cleaning Optical Components Application Note” [21 February 2023]) further in view of Becker et al. (US 20240171289 A1, hereinafter “Becker”).
Regarding Claim 19,
Hermans/Matthews teaches the method of Claim 17 (and thus the rejection of Claim 17 is incorporated). Hermans/Matthews already discloses optically coupled to the first and second quantum system by optical fiber cables … and optically coupled to the optical beam splitter by optical fiber cables (Matthews [Page 4 “Detection Scheme”];
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Wherein the splitters are optically coupled to the quantum system through optical fiber couplers).
Hermans/Matthews does not explicitly disclose but Shabani discloses wherein: the first quantum system is disposed in a first dilution refrigerator; the second quantum system is disposed in a second dilution refrigerator; (Shabani [0018]; “ Although current SC QPU chips include less than 100 qubits, scaling a single chip to billions of qubits would be a challenging engineering goal, at which the chip size would be about 1 meter×1 meter and would involve a large dilution refrigeration system in order to cool the chip to superconducting temperatures, typically in the range of 20 millikelvin (mK). Furthermore, large-scale SC systems can show chaotic behavior.”)
It would have been obvious to dispose of Hermans/Matthews’ quantum systems in Shabani’s refrigeration system. One would have been motivated to do so “in order to cool the chip to superconducting temperatures, typically in the range of 20 millikelvin (mK)” (Shabani [0018])
Hermans/Matthews/Shabani does not explicitly disclose but Wavelength Opto-Electronic discloses and the optical beam splitter is disposed in a room temperature environment (Wavelength Opto-Electronic [Paragraph “Handling”]; “ Proper handling methods during cleaning can decrease the frequency of handling the optic to maximize its lifetime. Ensure that the unpacking procedure of the optical components is done in clean and temperature-controlled surrounding. Avoid handling the components with bare hands as the oils from your skin may damage the optical surface quality permanently. Alternatively, you may wear gloves when handling the optics, and for smaller optical components; use optical tweezers. When holding the optical components, it is best to hold the components along the non-optical surfaces.
For holographic or ruled gratings, you should never touch them with your bare hands or any optical handling instruments. Their first surface is unprotected with metallic mirrors and pellicle beam splitters. These optical components are very sensitive and any form of physical contact will damage the components. Crystals are temperature sensitive and can break if exposed to thermal shock. Hence, you should always allow the package to come into thermal equilibrium before unpacking. Crystals are also much softer, unlike conventional optics, and thus, require more careful handling when cleaning.”)
It would have been obvious to modify Hermans/Matthews/Shabani’s optical beam splitter to be disposed particularly in Wavelength Opto-Electronic’s recommended equilibrium temperature-controlled surrounding. One would have been motivated to do so because “Crystals are temperature sensitive and can break if exposed to thermal shock” (Wavelength Opto-Electronic [Paragraph “Handling”]).
Hermans/Matthews/Shabani/Wavelength Opto-Electronic does not explicitly disclose but Becker discloses the photon detector device is disposed in a cryogenic environment (Becker [0042]; “ The QuIC 40 can be in the same cryogenic environment as the superconducting qubit system, which will enable the use of cryogenic low-loss coaxial cables (NbTi inner and outer conductor) to transfer the microwave quantum state of the superconducting qubits to the microwave resonators within the QuIC”)
It would have been obvious to modify Hermans/Matthews/Shabani/Wavelength Opto-Electronic’s optical beam splitter to be disposed particularly in Becker’s cryogenic environment. One would have been motivated to do so because the “cryogenic environment … will enable the use of cryogenic low-loss coaxial cables … to transfer the microwave quantum state of the superconducting qubits” (Becker [0042]).
Regarding Claim 20,
Hermans/Matthews/Shabani/Wavelength Opto-Electronic/Becker teaches the method of Claim 17 (and thus the rejection of Claim 17 is incorporated). Hermans/Matthews/Shabani/Wavelength Opto-Electronic/Becker already discloses a third quantum system comprising a third data quantum bit, a third interface quantum bit coupled to the third data quantum bit, and a third quantum transducer coupled to the third interface quantum bit; a second optical beam splitter; and a second photon detector device coupled to output ports of the second optical beam splitter; wherein the second quantum system comprises a fourth quantum transducer coupled to the second interface quantum bit; wherein the second optical beam splitter comprises input ports that are optically coupled to respective output ports of the third quantum transducer and the fourth quantum transducer (Matthews [Figure 1];
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Wherein part a) of Figure 1 demonstrates the optically heralded entanglement process comprising a plurality of quantum bits across several quantum bit systems (wherein each optical beam splitter DC and its associated 2-qubit inputs and outputs thus reads on a plurality of sub-systems) associated with a plurality of DC optical beam splitters; wherein such optical beam splitters are being optically coupled to respective output ports beam splitters (see DC3, DC4 coupled to DC2 coupled to output nodes j and k); wherein the superposition of inputted qubits while preserving quantum information before input into beamsplitters implicitly reads on at least a plurality of transducers coupled to the plurality of interface bits input into the beamsplitter))
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
“Optically Heralded Entanglement of Superconducting Systems in Quantum Networks” (US 20220215281 A1) which discloses optically heralded entanglement comprising superposed quantum bits and optical beam-splitting.
“Controlling Interaction Between Coupled Superconducting Quantum Bits” (US20230401476A1) which discloses superconducted quantum bits coupled through interference quantum bits in entanglement bit-wise gate operations.
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/JONATHAN J KIM/Examiner, Art Unit 2141
/MATTHEW ELL/Supervisory Patent Examiner, Art Unit 2141
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