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 statements (IDS) were submitted on 06/28/2024 The submission are 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 § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-12 & 14-21 are rejected under 35 U.S.C. 102(a) (1) as being anticipated by Lescanne Raphael et al. ("Exponential suppression of bit-flips in a qubit encoded in an oscillator", NATURE PHYSICS, vol. 16, no. 5, 26 July 2019 (2019-07-26), Pages 1-18, hereinafter Raphael)
Regarding Claim 1, Raphael discloses a non-linear superconducting quantum circuit (Page 9, Figure S3: "circuit diagram", the two Josephson junctions E_J, 1 and E_ j, 2 imply both superconductivity and non-linearity), comprising:
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a first mode; and a second mode, wherein: each of the first mode and the second mode has a respective resonant frequency (Page 9, bottom half: "cat-qubit and buffer modes ... their resonant frequencies": resonant frequency of the buffer mode and resonant frequency of the cat-qubit mode, in view of page 9, formula S8, and of page 10, first paragraph: "first two terms of the expansions are drives ... on the buffer and cat-qubit respectively"); and
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the circuit is configured such that the resonant frequency of the second mode is substantially 2N times the resonant frequency of the first mode (Page 10, formulas S11-S12 and subsequent: the resonant frequency of the cat-qubit mode is substantially 2 times the resonant frequency of the buffer mode)
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when a predetermined current of a constant intensity is applied to the circuit,
(Page 9, top half: "DC bias the [Asymmetrically Threaded SQUID] ATS at the asymmetric flux bias point", the flux bias teaches a current intensity bias and DC teaches constancy),
the circuit thereby performing intrinsically a resonant 2N-to-1 photon exchange between respectively the first mode and the second mode, N being a positive integer (Page 2, right column, bottom half: "engineering an interaction that exchanges pairs of photon of the cat-qubit resonator with one photon of an intentionally lossy mode referred to as the buffer", with N=1 being a positive integer: The interaction Hamiltonian takes the form
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).
Regarding Claim 2, Raphael discloses the non-linear superconducting quantum circuit of claim 1, wherein the circuit has, when the predetermined current is applied to the circuit, a Hamiltonian which is a function of a set of parameters that comprises of parameters of the circuit and parameters of the predetermined current (page 2 The interaction Hamiltonian takes the form ;
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; Pages 9-10, formulae S6-S12, wherein the dependency of the circuit parameters is via the Josephson inductances and the dependency on the current bias is via the fluxes).
Regarding Claim 3, Raphael discloses the non-linear superconducting quantum circuit of claim 2, wherein the Hamiltonian is expandable into a sum between at least a dominant term of a form ℏg2Na2Nb†+ℏg*2Na†2N b and a series of subsidiary terms, where g2N is a scalar corresponding to an intrinsic coupling strength, a is an annihilation operator of the first mode, b is an annihilation operator of the second mode, and h is the reduced Planck constant (Pages 9-10, formulae S6-S10, and: "where alb are the annihilation operators of the cat-qubit and buffer modes'1).
Regarding Claim 4, Raphael discloses the non-linear superconducting quantum circuit of claim 3, wherein; the circuit has a symbolic representation which comprises at least one loop that includes one or more Josephson junctions; and the circuit is configured to perform the resonant 2N-to-1 photon exchange when the predetermined current is applied so as to induce a phase difference across the one or more Josephson junctions (see reasoning for claim 1-3; Page 9, Figure S3 for the symbolic representation wherein the buffer comprises a loop with two Josephson junctions).
Regarding Claim 5, Raphael discloses the non-linear superconducting quantum circuit of claim 4, wherein; the at least one loop includes a first Josephson junction arranged in parallel with a first inductive element and a first capacitive element comprising respective first and second extremum nodes, the symbolic representation also comprising:
second inductive element and a second capacitive element arranged in parallel, comprising respective first and second extremum nodes; a linear coupling element, the linear coupling element being either a capacitive element or an inductive element; the respective first extremum node of the loop is connected to the respective first extremum node of the second inductive element; the second capacitive element is arranged in parallel via the linear coupling element; and the respective second extremum node of the loop and the respective second extremum node of the second inductive element and the second capacitive element are arranged in parallel and are connected to a common ground (see reasoning for claim 1-4, in particular page 9, Figure S3, with the horizontal capacitor being the linear coupling element, and the ground being at the bottom of the circuit).
Regarding Claim 6, Raphael discloses the non-linear superconducting quantum circuit of claim 5, wherein:
when the predetermined current of a constant intensity is applied to the circuit, the Hamiltonian of the superconducting circuit has:
a linear term describing the first mode and the second mode of a type Hlin=ℏωaa†a+ℏωbb†b, where ωa/2π is the resonant frequency of frequency of the first mode and ωb/2π is the resonant frequency of frequency of the second mode; and at least one non-linear term of a form EJ sin(φDC)sin(φa((a+a†)+ε(b+b†) or of a form J sin(φDC)sin(ωb((b+b†)+ε(a+a†) (see reasoning for claims 1-5, in particular pages 9-10, formulae S3-S12);
wherein: EJ is an energy of the Josephson junction;
φDC is a phase difference across the Josephson junction induced by the predetermined current;
φa is a zero-point fluctuation of the phase across the Josephson junction associated to the first mode or φb is a zero-point fluctuation of the phase across the Josephson junction associated to the second mode; and
ε describes a linear coupling between the first and second mode; and
the circuit thereby having a Hamiltonian, being expandable into a sum comprising at least a dominant term which is a non-linear resonant term of a type
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(see reasoning for claims 1-5, in particular pages 9-10, formulae S3-S12).
Regarding Claim 7, Raphael discloses the non-linear superconducting quantum circuit of claim 4, wherein; the at least one loop includes a Josephson junction, a first inductive element and a second inductive element arranged in a series topology, the series topology comprising: a first inner node connecting a pole of the Josephson junction with a pole of the first inductive element; a second inner node connecting another pole of the Josephson junction with a pole of the second inductive element; and a closed-loop node connecting another pole of the first inductive element with another pole of the second inductive element; the at least one loop is connected to a common ground via the closed-loop node; and the symbolic representation also comprises a first capacitor and a second capacitor wherein: the first capacitor is connected in parallel with the first inductive element between the common ground and the first inner node of the loop; and the second capacitor is connected in parallel with the second inductive element, between the common ground and the second inner node of the loop (page 3, Figure 2, in view of page 9, Figure S3: "Equivalent circuit diagram ... recovers the circuit of Fig. 2 by replacing ... the buffer is capacitively coupled to a transmission line, the cat-qubit resonator is coupled to a transmon qubit", wherein the series loop is formed by the two loops, buffer and cat-qubit, on Figure S3 and the transmon qubit that is mentioned in Figure S3 and is displayed on Figure 2).
Regarding Claim 8, Analogous rejection as the rejection of Claim 6 applies.
Regarding Claim 9, Analogous rejection as the rejection of Claim 7 applies.
Regarding Claim 10, Analogous rejection as the rejection of Claim 8 applies.
Regarding Claim 11, Raphael discloses a device comprising: a non-linear superconducting quantum circuit, wherein:
the circuit comprises a first mode and a second mode; and each of the first mode and the second mode has a respective resonant frequency; and a current source configured to apply a predetermined current of a constant intensity to the circuit such that the resonant frequency of the second mode is substantially 2N times the resonant frequency of the first mode, wherein thereby the circuit performs an intrinsically resonant 2N-to-1 photon exchange between respectively the first mode and the second mode (see reasoning for claims 1-10; the current source is implied by the wording "We DC bias the ATS at the asymmetric flux bias point" on page 9, top half)
Regarding Claim 12, Raphael discloses the device of claim 11, further comprising:
a load; a microwave source configured to apply a microwave radiation at a frequency substantially equal to the resonant frequency of the second mode or 2N times the resonant frequency of the first mode; and a coupler configured for coupling the second mode of the circuit to the load and to the microwave source (page 9, top half: "an RF flux bias ... is applied"; page 3, Figure 2: "Readout" implies a load).
Regarding Claim 14, Method claims 14 of using the corresponding device claimed in claims 1, and the rejections of which are incorporated herein for the same reasons as used above.
Regarding Claim 15, Raphael discloses the method of claim 14, further comprising stabilizing, via said applying, a quantum manifold spanned by 2N coherent states with a same amplitude and a π/N phase difference, so as to enable encoding of quantum information in the form of a cat-qubit (Page 4, Figure 3: "The two-photon dissipation ensures that the cat-qubit resonator remains entirely in the steady state manifold spanned by [formula] and [formula 'J).
Regarding Claim 16, Raphael discloses the device of claim 12, wherein the load is a resistor (page 9, top half: "an RF flux bias ... is applied"; page 3, Figure 2: "Readout" implies a load).
Regarding Claim 17, Raphael discloses the device of claim 12, wherein the load is a matched transmission line (page 9, top half: "an RF flux bias ... is applied"; page 3, Figure 2: "Readout" implies a load).
Regarding Claim 18, Raphael discloses the device of claim 12, wherein the load is a matched waveguide (Page 3, Col. 1, cat-qubit in a circuit quantum electrodynamics architecture described in Fig 2a operated at 10 mK. It consists of a sputtered niobium film on a silicon substrate patterned into coplanar waveguide resonators.
Regarding Claim 19, Raphael discloses the device of claim 12, wherein: the device further comprises a band pass filter connected to the first and the second mode of the circuit; and the band pass filter is configured to selectively allow the coupling of the second mode to the load (Pages 9-10, the buffer input is filtered via three λ/4-stub filters. These stop-band filters are centered at the cat-qubit resonance frequency to mitigate its direct coupling to the input line of the buffer).
Regarding Claim 20, Raphael discloses the device of claim 12, wherein a geometry of the coupler is such that the coupler selectively couples to the second mode (Page 9, Figure S3: "circuit diagram", the two Josephson junctions E_J, 1 and E_ j, 2 imply both superconductivity and non-linearity).
Regarding Claim 21, Raphael discloses the device of claim 11, wherein the non-linear superconducting quantum circuit is configured to stabilize a quantum manifold spanned by 2N coherent states with the same amplitude and a π/N phase difference, so as to enable encoding of quantum information in a form of a cat-qubit (Page 4, Figure 3: "The two-photon dissipation ensures that the cat-qubit resonator remains entirely in the steady state manifold spanned by [formula] and [formula 'J).
Conclusion
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/SAMUEL D FEREJA/Primary Examiner, Art Unit 2487
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