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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 04/16/2024 and 05/07/2024 was filed. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
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 1-9 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.
Claim 1 recites that the confinement device implements a Hamiltonian of a particular extended formula derived from Hamiltonian forces, cat state amplitude, and different photon annihilation operators, but the meaning or scope of “implements” is unclear in the context of the recited Hamiltonian. For example, “Hamiltonian forces” are quantum mechanical parameter weights that dictate how aggressively the confinement device exchanges and manipulates pairs of photons, rather than being literal, macroscopic mechanical forces (note the Specification does not define or explain what they are). The photon annihilation operators as well are abstract mathematical concepts. Thus it is not clear whether a device “implements” the recited Hamiltonian if the Hamiltonian is merely theoretically associated with the confinement device, or if it arises under certain driven conditions, or if the physical system actually exhibits the recited Hamiltonian as an effective interaction. Furthermore, the claim does not identify operational or structural features that distinguish a device that implements the recited Hamiltonian from a device that does not. Thus the recitation is vague and indefinite. Dependent claims 2-9 are also rejected because they inherit the deficiencies of the independent claim.
Additionally, claim 6 recites a “Zeno type Hamiltonian” but it is not clear exactly how similar or distinct this is from a Zeno Hamiltonian (which has a definite meaning in the literature and art). The term "Zeno-type" Hamiltonian is commonly used in physics literature to describe any Hamiltonian that mimics, produces, or governs behavior resembling the quantum Zeno effect, even if the formal mathematical conditions of a true Zeno projection are not met. Thus it is further unclear how the cat qubit oscillator is driven as recited in this claim.
Additionally, claim 7 recites “a control cat qubit having a first cat qubit oscillator” and “a target cat qubit having a second cat qubit oscillator,” and then recites “a nonlinear coupler connecting the first cat qubit oscillator of the control cat qubit and the second cat qubit oscillator of the control cat qubit.” It is unclear whether the recited second cat qubit oscillator is intended to be the oscillator of the target cat qubit previously recited in the claim, or a second oscillator associated with the control cat qubit, and this even more so renders the claim vague and indefinite.
Appropriate corrections are 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, 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.
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 1-9 are rejected under 35 U.S.C. 103 as being unpatentable over Lescanne et al (US Published Patent Application NO. 20210234086, "Lescanne"), in view of Puri et al (US Published Patent Application No. 20210125096, "Puri").
In regard to claim 1, Lescanne teaches A confinement device for cat qubit comprising: a two-photon exchanger; (Lescanne, paragraph 0054, “In particular, the ATS may be implemented for engineering a two-to-one photon exchange interaction between two microwave resonators.”)
a low quality factor buffer oscillator; and (Lescanne, paragraph 0055, “With reference to FIG. 3, the ATS dipole is shunted with a capacitive device 13, thus forming a resonant mode 20. This nonlinear resonator 20 dubbed the buffer is capacitively coupled 14 to a linear resonator 30 called the storage mode, which is modelled by an LC-circuit (inductance 15, capacitor 16).”)
a high quality factor anharmonic buffer oscillator, (Lescanne, paragraph 0009, “Another focus of superconducting circuits is to realize highly anharmonic modes, the energy level structure of which resembling that of an atom. Thus, quantum information can be encoded into two specifically addressable energy levels that form a qubit.”)
the low quality factor buffer oscillator and the high quality factor anharmonic buffer oscillator being connected to the two-photon exchanger such that, when they are both driven at their respective resonance frequency (wI, wh) and the two-photon exchanger is connected to a cat qubit oscillator, (Lescanne, paragraph 0007, “As an example, a conversion between two frequencies coa and cob, with coa <cob, may be considered, in a process that destroys a photon at frequency coa and creates a photon at frequency cob. This is a two-wave mixing process, but it is not resonant. To make this dynamics energy preserving, a three-wave mixing process should be used instead by adding a third electromagnetic tone called a pump with frequency cop =cob-co a that provides the missing energy. These kinds of relations are also called frequency matching conditions. This new process destroys one photon at frequency co a and one photon of the pump to create one photon at frequency cob, which overall leads to the desired conversion dynamics.” and paragraph 0056, “The ATS is pumped at a frequency wP =2wa-wb, where wa,b are the frequencies of the storage resonator 30 and the buffer resonator 20, respectively. This parametric pumping mediates a two-to-one photon exchange interaction between the two modes.”)
However, Lescanne does not explicitly teach an exchange of two photons from the cat qubit oscillator with one photon from the low quality factor buffer oscillator and an exchange of two photons from the cat qubit oscillator with one photon from the high quality factor anharmonic buffer oscillator respectively take place, and
the confinement device implements a Hamiltonian of formula g2h((a2_-a2)bht+(a2-a2)tbh)+g21((a2-a2)tbl+(a2-a2)blt) where g2h and g21 are Hamiltonian forces, a is a photon annihilation operator of the cat qubit oscillator, a is an amplitude of the cat state, bh is a photon annihilation operator of the high quality factor anharmonic buffer oscillator, bi is the a photon annihilation operator of the low quality factor buffer oscillator.
Puri teaches an exchange of two photons from the cat qubit oscillator with one photon from the low quality factor buffer oscillator and an exchange of two photons from the cat qubit oscillator with one photon from the high quality factor anharmonic buffer oscillator respectively take place, and (Puri, paragraph 0069, “In either the embodiments using a transmon, as illustrated in FIG. 3, or a SNAIL, as illustrated in FIG. 4, the superconducting circuit element coupled to a cavity forms a Kerr-nonlinear oscillator, which may be used as the data qubit and/or the ancilla qubit. In some embodiments, a two-photon pump, received from the microwave field generator 150, may be used to create a two-component cat state: I C~,)~N ~'(li3)±1-i3)), where N 13 ±=1/V 2(1±e-21131\ and ~ is the complex amplitude associated with the coherent state I~) associated with the cat state. The cat state I C 13 +) and the cat state I C 13 - ) are degenerate and orthogonal eigenstates of the Kerr-nonlinear oscillator being pumped by the two-photon driving field.”)
the confinement device implements a Hamiltonian of formula g2h((a2_-a2)bht+(a2-a2)tbh)+g21((a2-a2)tbl+(a2-a2)blt) where g2h and g21 are Hamiltonian forces, a is a photon annihilation operator of the cat qubit oscillator, a is an amplitude of the cat state, bh is a photon annihilation operator of the high quality factor anharmonic buffer oscillator, bi is the a photon annihilation operator of the low quality factor buffer oscillator. (Please also note the 112 rejection). (Puri, paragraph 0074, “In some embodiments, a Kerr-nonlinear oscillator implemented, for example, using the hardware described above, may be driven by a two-photon drive with a frequency equal to twice a resonance frequency of the oscillator. When driven by such a microwave field, the oscillator is referred to as a pumped-cat oscillator (PCO) and the Hamiltonian in the rotating wave approximation is: Hpco~-Kat2a2+P(at2+a2 ), where at and a are the photon creation and annihilation operators of the PCO, K is the strength of the Kerr nonlinearity, and P is the strength of the two-photon drive field. Rewriting the PCO Hamiltonian in terms of the coherent state amplitude,”)
Lescanne and Puri are related to the same field of endeavor (i.e. quantum information processing). In view of the teachings of Puri, it would have been obvious for a person with ordinary skill in the art to apply the teachings of Puri to Lescanne before the effective filing date of the claimed invention in order to allow for more efficient procedures. (Puri, paragraph 0045, “Second, the techniques may be used for new, more efficient error correcting codes and procedures. Third, the techniques may be used to create bias-preserving gates, such as a controller-NOT (CNOT) gate.”)
In regard to claim 2, Lescanne and Puri teach the device of claim 1.
Lescanne further teaches wherein the two- photon exchanger comprises a first two-photon exchanger disposed between the low quality factor buffer oscillator and the cat qubit oscillator, and a second two-photon exchanger disposed between the high quality factor anharmonic buffer oscillator and the cat qubit oscillator. (Lescanne, paragraph 0056, “The ATS is pumped at a frequency wP =2wa-wb, where wa,b are the frequencies of the storage resonator 30 and the buffer resonator 20, respectively. This parametric pumping mediates a two-to-one photon exchange interaction between the two modes.”)
In regard to claim 3, Lescanne and Puri teach the device of claim 1.
Lescanne further teaches wherein the two- photon exchanger and the high quality factor anharmonic buffer oscillator are formed by an Assymetrically Threaded SQUID (ATS) circuit with asymmetric junction Josephson energies, (Lescanne, paragraph 0056, “The ATS is pumped at a frequency wP =2wa-wb, where wa,b are the frequencies of the storage resonator 30 and the buffer resonator 20, respectively. This parametric pumping mediates a two-to-one photon exchange interaction between the two modes.”)
which is driven resonantly at the frequency wh and to which are applied two radiofrequency flux pumps with respective frequencies 2wa-wh and 2wa-wt, wa being the resonance frequency of the cat qubit oscillator mode, w1 is the resonance frequency of the low quality factor buffer oscillator, and wh is the resonance frequency of the high quality factor anharmonic buffer oscillator, the ATS circuit being coupled to the low quality factor buffer oscillator, driven resonantly at the frequency w1, the low quality factor buffer oscillator being coupled to a dissipative bath. (Lescanne, paragraph 0056, “The ATS is pumped at a frequency wP =2wa-wb, where wa,b are the frequencies of the storage resonator 30 and the buffer resonator 20, respectively. This parametric pumping mediates a two-to-one photon exchange interaction between the two modes.” and paragraph 0008, “Superconducting circuits are a great physical platform to manipulate microwave photons and experiment with such mixing dynamics at the quantum level. Superconductivity endows the circuit with very small dissipation resulting in long-lived electromagnetic modes that are used to trap microwave photons and enhance the interactions. The mixing capabilities are provided by a loss-less non-linear element: the Josephson junction. It consists of a thin insulating layer separating two superconducting leads.”)
In regard to claim 4, Lescanne and Puri teach the device of claim 1.
Lescanne further teaches wherein the two- photon exchanger and the low quality factor buffer oscillator are formed by an Assymetrically Threaded SQUID (ATS1 circuit with symmetrical junction Josephson energies, (Lescanne, paragraph 0052, “In the embodiment of FIG. 2, the shunt inductance 4 separating the two loops each containing a Josephson junction 2, 3 is formed of a chain or array of 5 Josephson junctions (represented by the 5 crosses centred between the pair of identical Josephson junctions 2, 3 forming the SQUID). The left and right flux lines 10, 11 are connected to the same input through an on-chip hybrid (not represented).”)
which is driven resonantly at the frequency w1 and to which are applied two radio frequency flux pumps with respective frequencies 2wa-wh and 2wa-w1, wa being the resonance frequency of the cat qubit oscillator mode, w1 is the resonance frequency of the low quality factor buffer oscillator, and wh is the resonance frequency of the high quality factor anharmonic buffer oscillator, the ATS circuit being coupled to a high quality factor anharmonic buffer oscillator, driven resonantly at the frequency wh, and to a dissipative bath. (Lescanne, paragraph 0056, “The ATS is pumped at a frequency wP =2wa-wb, where wa,b are the frequencies of the storage resonator 30 and the buffer resonator 20, respectively. This parametric pumping mediates a two-to-one photon exchange interaction between the two modes.” and paragraph 0008, “Superconducting circuits are a great physical platform to manipulate microwave photons and experiment with such mixing dynamics at the quantum level. Superconductivity endows the circuit with very small dissipation resulting in long-lived electromagnetic modes that are used to trap microwave photons and enhance the interactions. The mixing capabilities are provided by a loss-less non-linear element: the Josephson junction. It consists of a thin insulating layer separating two superconducting leads.”)
In regard to claim 5, Lescanne and Puri teach the device of claim 4.
Puri further teaches wherein the high quality factor anharmonic buffer oscillator is a transmon. (Puri, paragraph 0051, “The data qubit 110 may be any physical or logical qubit capable of being coupled to the ancilla qubit 120. In some embodiments, the data qubit 110 may include a superconducting circuit component. For example, the data qubit 110 may include at least one Josephson junction. In some embodiments, the data qubit 110 may include a transmon.”)
Lescanne and Puri are combinable for the same rationale as set forth above with respect to claim 1.
In regard to claim 6, Lescanne and Puri teach the device of claim 1.
Puri further teaches A Z gate for a cat qubit, comprising; (Puri, paragraph 0147, “When 8=Jt/2, the ZZ(8) gate becomes a controlled-phase gate, also referred to as a CZ gate, up to local Pauli rotations and an overall phase. The ZZ(8) gate may be implemented with an interaction Hamiltonian of the form H22=-VZ1Z2 with the unitary evolution given by U 2 z(t)=exp(iVtZ1 Z2 ).”)
The confinement device according to claim 1, wherein the two-photon exchanger of the confinement device is connected to the cat qubit oscillator, wherein said gate is executed by driving the cat qubit oscillator for a chosen duration with a Zeno-type Hamiltonian whose amplitude Ez(t) satisfies the equation
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where a is the size of the cat qubit, Re() designates the real part, and T is the duration of the gate, and 8 is the angle of rotation around the axis Z. (Puri, paragraph 0069, “The cat state I C 13 +) and the cat state I C 13 - ) are degenerate and orthogonal eigenstates of the Kerr-nonlinear oscillator being pumped by the two-photon driving field. A Bloch sphere may be formed using these cat states, the orientation of the Bloch sphere being arbitrary with respect to the cat state basis states. FIG. 6 illustrates the Bloch sphere 600 used in this application.” and paragraph 0070, “Cat states of the type described above have the property that natural couplings cause only rotations around the Z axis of the Bloch sphere 600 because the pump used to create the cat states creates a large energy barrier that prevents phase rotations (i.e., rotations from the coherent state I+~) to I-~) and vice versa).”)
Lescanne and Puri are combinable for the same rationale as set forth above with respect to claim 1.
In regard to claim 7, Lescanne and Puri teach the device of claim 1.
Puri further teaches A CNOT gate for cat qubits, comprising; a control cat qubit comprising a first confinement device according to claim 1, wherein the two-photon exchanger of which the first confinement device is connected to a first cat qubit oscillator; (Puri, paragraph 0148, “On the other hand, the controlled NOT (CNOT) gate (also referred to as a CX gate) between two qubits may be implemented using the following CX Hamiltonian: with the unitary evolution given by UcxCt)=exp(iHcx1), where the control qubit and target qubit of the CNOT gate are labelled by 1 and 2, respectively. Under this evolution, the CNOT gate is realized after an interaction time duration T=it/2\7,”)
a target cat qubit comprising a second confinement device according to one of claim 1, the two-photon exchanger of the second confinement device is connected to a second cat qubit oscillator; and (Puri, paragraph 0148, “Thus, the phase-flip error in the target qubit introduces a phase-flip error in the control qubit, depending on when the phase error in the target qubit occurs. Importantly, the phase-flip of the target qubit during the CNOT gate propagates as a combination of a phase-flip error and a bit-flip error in the same qubit. Consequently, the CNOT gate reduces the bias of the noise channel by introducing bit-flips in the target qubit.”)
a nonlinear coupler connecting the first cat qubit oscillator of the control cat qubit and the second cat qubit oscillator of the control cat qubit, wherein the gate is executed by deactivating the second confinement device of the target cat qubit. (Puri, paragraph 0149, “The inventors have therefore developed a novel solution to this problem by engineering a bias-preserving CNOT gate using the same two-component cat states realized in a parametrically driven nonlinear oscillator described above.”)
Lescanne and Puri are combinable for the same rationale as set forth above with respect to claim 1.
In regard to claim 8, Lascanne and Puri teach the device of claim 7.
Puri further teaches wherein the nonlinear circuit coupler is a Josephson junction (Puri, paragraph 0051, ““The data qubit 110 may be any physical or logical qubit capable of being coupled to the ancilla qubit 120. In some embodiments, the data qubit 110 may include a superconducting circuit component. For example, the data qubit 110 may include at least one Josephson junction. In some embodiments, the data qubit 110 may include a transmon.”)
which implements a Zeno-type Hamiltonian of form
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where Ecx is the Hamiltonian amplitude, aco and a+co the photon annihilation and creation operators for the control qubit harmonic oscillator and are the photon annihilation and creation operators for the target qubit harmonic oscillator, and a is the size of the cat state, the amplitude Ecx(t) satisfying the equation
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where a is the size of the cat qubit, Re() denotes the real part, and T is the gate execution time. (Puri, (Puri, paragraph 0069, “The cat state I C 13 +) and the cat state I C 13 - ) are degenerate and orthogonal eigenstates of the Kerr-nonlinear oscillator being pumped by the two-photon driving field. A Bloch sphere may be formed using these cat states, the orientation of the Bloch sphere being arbitrary with respect to the cat state basis states. FIG. 6 illustrates the Bloch sphere 600 used in this application.” and paragraph 0070, “Cat states of the type described above have the property that natural couplings cause only rotations around the Z axis of the Bloch sphere 600 because the pump used to create the cat states creates a large energy barrier that prevents phase rotations (i.e., rotations from the coherent state I+~) to I-~) and vice versa).”)
Lescanne and Puri are combinable for the same rationale as set forth above with respect to claim 1.
In regard to claim 9, Lascanne and Puri teach the device of claim 7.
Puri further teaches wherein the Hamiltonian g2i ((a2-a2)tbl+(a2-a2)blt) of the control qubit first confinement device of the control cat qubit is always implemented, the Hamiltonian g2h((a2_2)bht+(a2-a2)tbh) of first confinement device is implemented at least during the execution of the gate, the Hamiltonian g2i((a2-a2)tbl+(a2-a2)blt) of the second confinement device of the target cat qubit is not implemented during the execution of the CNOT gate and is implemented for the rest of the time, and the Hamiltonian g2h ((a2_a2)bht+(a2-a2)tbh) of the second confinement device of the target cat qubit is not implemented during the execution of the gate. (Puri, paragraph 0166, “In some embodiments, a particular sequence of fields are applied to the control qubit 1301 and/or the target qubit 1303 during an interaction time duration T. It is during this interaction time that the execution of the CNOT gate is performed. In some embodiments, during the times outside of this interaction time duration, the amplitudes and phases take on the following fixed values: A1 =K~2, <1>1 =O, A2=Ka2, <I>2=0, A3=A4 =As=<I>3 =<I>4 =<I>s=O.” and paragraph 0170, “A third microwave field at a frequency 2w,-wc is applied to the target cavity at with a time-dependent amplitude A3 and a time-dependent phase <l>3 (t). This third microwave field realize the coupling terms proportional to a/2ac in the CNOT Hamiltonian. The changing amplitude A3 is illustrated by line 1403 in FIG. 14A and the time-dependent phase <l>3 (t) is illustrated by line 1413 in FIG. 14B. The amplitude changes as a cosine over time. In the example shown, the phase increases linearly as a function of time.”)
Lescanne and Puri are combinable for the same rationale as set forth above with respect to claim 1.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SKYLAR K VANWORMER whose telephone number is (703)756-1571. The examiner can normally be reached M-F 6:00am to 3:00 pm.
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/S.K.V./Examiner, Art Unit 2146
/STEVEN P SAX/Primary Examiner, Art Unit 2146
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