Grid architecture for controlling large-scale quantum processors

Abstract

A controller for a set of superconducting qubits includes a parametrically driven variable coupler coupled to each superconducting qubit in a set of three or more superconducting qubits, a flux pump coupled to the parametrically driven variable coupler, a first control line coupled to the flux pump, and a second control line coupled to the flux pump. The parametrically driven variable coupler creates a parametric single superconducting qubit drive for a single superconducting qubit within the set of superconducting qubits, or creates a parametric resonant interaction between a pair of superconducting qubits within the set of superconducting qubits, when one or more first frequency signals on the first control line and one or more second frequency signals on the second control line satisfy certain conditions.

Description

[Technical Field]

[0001] Statement regarding research funded by the federal government Not applicable.

[0002] This disclosure relates to processors in general, and more particularly to grid architectures for controlling large-scale quantum processors. [Background technology]

[0003] Current methods for achieving complete control of all individual superconducting qubits and the couplings between them require individual physical control lines to address each superconducting qubit and each coupling between two superconducting qubits. Such conventional and commonly used architectures significantly increase the difficulty of creating quantum processors with low crosstalk and low error, because these quantum processors inevitably require an increasing number of control lines along with the number of superconducting qubits and couplings. For example, consider a typical square grid arrangement of N^2 superconducting qubits on a superconducting quantum processor where each superconducting qubit is directly coupled to four nearest superconducting qubits. Complete control of this quantum processor would require at least N^2 single superconducting qubit control lines for each superconducting qubit and 2*N^2-2*(4*N-4) control lines for couplings between coupled superconducting qubit pairs. Furthermore, in order to access the superconducting qubits within the N×N superconducting qubit grid in the typical example described above, the control wires, and even the superconducting qubits themselves, inevitably cross each other, thereby significantly increasing crosstalk, control errors of the superconducting qubits, and decoherence noise channels for the superconducting qubits. Sophisticated methods in microfabrication and quantum control optimization algorithms have been widely explored to mitigate such errors and noise. Not only have these mitigation methods significantly increased the difficulty of scaling quantum processors beyond current scales, but there is also further doubt as to whether such mitigation methods themselves are scalable (i.e., such methods may not be sustainable in solving the problems related to large-scale quantum processors, because scaling these methods becomes difficult as the size of the QPU increases). [Overview of the Initiative]

[0004] One embodiment of the present disclosure provides a controller for a set of superconducting qubits, comprising a parametrically driven variable coupler coupled to each superconducting qubit in the set of three or more superconducting qubits, a flux pump coupled to the parametrically driven variable coupler, a first control line coupled to the flux pump, and a second control line coupled to the flux pump. The parametrically driven variable coupler creates a parametric single superconducting qubit drive for a single superconducting qubit within the set of superconducting qubits, or creates a parametric resonant interaction between a pair of superconducting qubits within the set of superconducting qubits, when one or more first frequency signals on the first control line and one or more second frequency signals on the second control line satisfy certain conditions.

[0005] In one embodiment, a readout resonator is coupled to each superconducting qubit in a set of superconducting qubits. In another embodiment, each superconducting qubit in a set of superconducting qubits is configured to respond to a specific frequency from a parametrically driven variable coupler. In another embodiment, the set of superconducting qubits is arranged around each parametrically driven variable coupler. In another embodiment, the parametrically driven variable coupler includes a superconducting quantum interface device (SQUID). In another embodiment, a first control line and a second control line intersect at the flux control port position of the parametrically driven variable coupler. In another embodiment, a specific condition includes the sum or difference of one or more first frequency signals and one or more second frequency signals corresponding to a pair of superconducting qubits, and a specific condition includes the sum or difference of one or more first frequency signals and one or more second frequency signals and a dipole drive signal corresponding to a single superconducting qubit. In another embodiment, a pair of superconducting qubits includes Q! / (2!*(Q-2)!) pair combinations for a set of three or more superconducting qubits, where Q is the number of superconducting qubits in the set of three or more superconducting qubits. In another embodiment, a set of superconducting qubits, a parametrically driven variable coupler, and a magnetic flux pump are arranged on a first chip, and a first control line and a second control line are arranged on a second chip, and the first chip and the second chip are joined together in a flip-chip configuration.

[0006] Another embodiment of the present disclosure provides a quantum processor comprising an array of superconducting qubits arranged in sets of three or more superconducting qubits, and a controller coupled to each set of three or more superconducting qubits. The controller comprises a parametrically driven variable coupler coupled to each superconducting qubit in the set of three or more superconducting qubits, a flux pump coupled to the parametrically driven variable coupler, a first control line coupled to the flux pump, and a second control line coupled to the flux pump. The parametrically driven variable coupler creates a parametric single superconducting qubit drive for a single superconducting qubit within the set of three or more superconducting qubits, or creates a parametric resonant interaction between a pair of superconducting qubits within the set of three or more superconducting qubits, when one or more first frequency signals on the first control line and one or more second frequency signals on the second control line satisfy certain conditions.

[0007] In one embodiment, the array of superconducting qubits has N × M superconducting qubits, but the total number of first and second control lines is N + M. In another embodiment, a readout resonator is coupled to each superconducting qubit in a set of three or more superconducting qubits. In another embodiment, each superconducting qubit in a set of three or more superconducting qubits is configured to respond to a specific frequency from a parametrically driven variable coupler. In another embodiment, the parametrically driven variable couplers are arranged in a square, rectangular, rhombic, hexagonal, or rhombic lattice with three or more superconducting qubits arranged around each parametrically driven variable coupler. In another embodiment, the parametrically driven variable coupler includes a superconducting quantum interface device (SQUID). In another embodiment, the first and second control lines intersect at the flux control port position of the parametrically driven variable coupler. In another embodiment, a specific condition includes the sum or difference of one or more first frequency signals and one or more second frequency signals corresponding to a pair of superconducting qubits, and a specific condition includes the sum or difference of one or more first frequency signals and one or more second frequency signals and a dipole drive signal corresponding to a single superconducting qubit. In another embodiment, a pair of superconducting qubits includes Q! / (2!*(Q-2)!) pair combinations for a set of three or more superconducting qubits, where Q is the number of superconducting qubits in the set of three or more superconducting qubits. In another embodiment, a set of superconducting qubits, a parametrically driven variable coupler, and a magnetic flux pump are disposed on a first chip, and a first control line and a second control line are disposed on a second chip, and the first chip and the second chip are joined together in a flip-chip configuration.

[0008] Another embodiment of the present disclosure provides a parametrically driven variable coupler coupled to each superconducting qubit in the set of superconducting qubits, a flux pump coupled to the parametrically driven variable coupler, a first control line coupled to the flux pump, and a second control line coupled to the flux pump; transmitting one or more first frequency signals on the first control line and one or more second frequency signals on the second control line; and, when one or more first frequency signals and one or more second frequency signals satisfy certain conditions, using the parametrically driven variable coupler to create a parametric single superconducting qubit drive for a single superconducting qubit within the set of superconducting qubits, or to create a parametric resonant interaction between a pair of superconducting qubits within the set of superconducting qubits.

[0009] In one embodiment, the set of superconducting qubits includes three or more superconducting qubits. In another embodiment, a readout resonator is coupled to each superconducting qubit in the set of superconducting qubits. In another embodiment, each superconducting qubit in the set of superconducting qubits is configured to respond to a specific frequency from a parametrically driven variable coupler. In another embodiment, the set of superconducting qubits is arranged around each parametrically driven variable coupler. In another embodiment, the parametrically driven variable coupler includes a superconducting quantum interface device (SQUID). In another embodiment, a first control line and a second control line intersect at the flux control port position of the parametrically driven variable coupler. In another embodiment, a specific condition includes the sum or difference of one or more first frequency signals and one or more second frequency signals corresponding to a pair of superconducting qubits, and a specific condition includes the sum or difference of one or more first frequency signals and one or more second frequency signals and a dipole drive signal corresponding to a single superconducting qubit. In another embodiment, a pair of superconducting qubits contains Q! / (2!*(Q-2)!) pair combinations for a set of three or more superconducting qubits, where Q is the number of superconducting qubits in the set of three or more superconducting qubits.

[0010] For a more complete understanding of the features and benefits of this disclosure, the following references are made to the detailed description of this disclosure, along with the accompanying drawings. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows a quantum processor according to one embodiment of the present disclosure. [Figure 2] Figure 1 shows a micrograph of two superconducting qubits, a readout resonator for one superconducting qubit, and two parametrically driven variable couplers inside a quantum processor according to one embodiment of the present disclosure. [Figure 3] This figure shows an enlarged view of the set of superconducting qubits inside the quantum processor shown in Figure 1, according to one embodiment of the present disclosure. [Figure 4]A diagram showing an enlarged view of a parametrically driven variable coupler inside the quantum processor of FIG. 1 according to an embodiment of the present disclosure. [Figure 5] A diagram showing an enlarged view of a set of superconducting qubits inside the quantum processor of FIG. 1 according to an embodiment of the present disclosure. [Figure 6] A diagram showing a flip-chip configuration according to an embodiment of the present disclosure. [Figure 7A] FIGS. 7A and 7B are diagrams showing a parametric single superconducting qubit drive according to an embodiment of the present disclosure. [Figure 7B] FIGS. 7A and 7B are diagrams showing a parametric single superconducting qubit drive according to an embodiment of the present disclosure. [Figure 8A] FIGS. 8A and 8B are diagrams showing a parametric interaction of two superconducting qubits according to an embodiment of the present disclosure. [Figure 8B] FIGS. 8A and 8B are diagrams showing a parametric interaction of two superconducting qubits according to an embodiment of the present disclosure. [Figure 9A] FIGS. 9A and 9B are diagrams showing a quantum processor having a set of three superconducting qubits according to an embodiment of the present disclosure. [Figure 9B] FIGS. 9A and 9B are diagrams showing a quantum processor having a set of three superconducting qubits according to an embodiment of the present disclosure. [Figure 10] A diagram showing a method for controlling a set of superconducting qubits according to an embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0012] Exemplary embodiments of the system of the present application are described below. For the sake of clarity, not all features of the actual implementation are described in this specification. It will of course be understood that in the development of any such actual implementation, many implementation-specific decisions must be made in order to achieve the specific goals of the developer, such as compliance with system-related and business-related constraints that will vary from implementation to implementation. Furthermore, although such development efforts are complex and may be time-consuming, it will be understood that they should be routine work for those skilled in the art who benefit from the present disclosure.

[0013] The present disclosure paves the way for scaling up quantum processors by significantly reducing the number of control lines required, because while the prior art needs to scale the control lines approximately O(N) (where N is the total number of superconducting qubits), the present disclosure

[0014]

Number

[0015] only requires one. Due to such fundamental scaling advantages, furthermore, the need for sophisticated microfabrication techniques and advanced quantum control optimization algorithms for implementing and operating large-scale (with a large number of superconducting qubits) quantum processors with high connectivity (high coordination number) is significantly reduced. Large-scale quantum processors and their control will bring about so-called quantum supremacy in computational solutions to major problems in the discovery / creation of new materials, drugs, AI, etc. The present disclosure may, in some cases, be key to accelerating the unlocking of the next evolution of information technology and a new era with rich market opportunities by providing an architecture scalable to large-scale quantum processors.

[0016] Various embodiments of this disclosure offer several advantages. Conventional methods for controlling N×M superconducting qubits with coordination number c in an N×M grid require approximately N*M + c*N*M / 2 control lines to accommodate all superconducting qubits and their couplings, whereas the architecture disclosed herein simplifies this by scaling the number of control lines to N+M. This advantage significantly reduces the requirements for microfabrication and quantum control algorithm optimization, and mitigates errors and noise arising from intersecting control lines and superconducting qubits. This disclosure enables direct and high-fidelity handling of high connectivity (coordination number) in large N*M superconducting qubit arrays in an N×M rectangular grid. The architecture disclosed herein improves the scalability of superconducting quantum processors.

[0017] Referring next to Figure 1, a quantum processor 100 according to one embodiment of the present disclosure is shown. Furthermore, referring to Figures 2 and 3, various details of the quantum processor 100 are shown. The quantum processor 100 includes an array of superconducting qubits arranged in a set of three or more superconducting qubits (e.g., 102). In this example, there are four superconducting qubits Q1, Q2, Q3, and Q4 in the set of superconducting qubits 102. An example of a set of superconducting qubits having three superconducting qubits is shown in Figures 9A and 9B. A set of superconducting qubits may contain three or more superconducting qubits. A parametrically driven variable coupler 104 is coupled to each of the superconducting qubits Q1, Q2, Q3, and Q4 in the set of superconducting qubits 102 via connectors 1061, 1062, 1063, and 1064. More specifically, the parametrically driven variable couplers 104 inside the quantum processor 100 are arranged in a square lattice with three or more superconducting qubits positioned around each parametrically driven variable coupler 104. Note that a rectangular lattice, rhombic lattice, hexagonal lattice, rhombic lattice, or other geometric lattices may be used. The parametrically driven variable couplers 104 include flux pumps 702a, 702b coupled to a first control line 108 and a second control line 110 that cross the flux control port position 704 (see Figures 7A and 8A). In this example, the first control line 108 is a vertical control line (Y-Ctrl), and the second control line 110 is a horizontal control line (X-Ctrl). As shown in Figure 6, the control lines 108 and 110 may be mounted on a separate silicon chip "wire chip" so that the qubit chip die is flip-chip bonded to the wire chip. For an N×M superconducting qubit array, since there are N×M qubits in the array, the total number of first control lines 108 and second control lines 110 is N+M (i.e., half a circumference of the array), which is a considerable improvement compared to the scaling of conventional techniques for N×M (i.e., the total number of qubits in the array). In addition to the advantages of the scaling laws described, more or fewer first and second control lines 108, 110 may be used depending on the actual requirements of a particular design.Each of the superconducting qubits Q1, Q2, Q3, Q4 includes superconducting qubit readout resonators 1121, 1122, 1123, 1124. The parametrically driven variable coupler 104 creates a single parametric single superconducting qubit drive for a single superconducting qubit within the set 102 of superconducting qubits when one or more first frequency signals on the first control line 108 and one or more second frequency signals on the second control line 110 meet certain conditions (see FIGS. 7A and 7B), or creates a parametric resonance interaction between a pair of superconducting qubits within the set 102 of superconducting qubits (see FIGS. 8A and 8B). In this example, a pair of superconducting qubits can be one of six pair combinations: Q1-Q2, Q1-Q3, Q1-Q4, Q2-Q3, Q2-Q4, Q3-Q4. In other embodiments, a pair of superconducting qubits is Q! / (2!*(Q-2)!) pair combinations for a set of three or more superconducting qubits, where Q is the number of superconducting qubits in a set of three or more superconducting qubits.

[0018] As shown in FIG. 3, the parametrically driven variable coupler 104 provides frequency-space selectivity. The first control line 108 provides one or more first frequency signals having a non-zero amplitude f y and frequency ω y . The second control line 110 provides one or more second frequency signals having a non-zero amplitude f x and frequency ω x . The desired parametrically driven variable coupler 104 is at the intersection of certain control lines (X-Ctrl, Y-Ctrl) carrying signals of non-zero amplitude (f x , f y ). The desired interaction occurs when two control frequencies (ω x , ω y ) meet certain conditions. The parametrically driven variable coupler 104 further includes an amplitude α d,c and frequency ω d,c on either the control line 108 and / or 110It is driven by a parametric dipole drive signal having the following characteristics: The effect to be observed is an effective parametric dipole drive on a single superconducting qubit coupled to a parametrically driven variable coupler 104 when certain conditions are satisfied between three control drive signals (i.e., two control signals and a dipole drive signal (see Figure 4, 7A and 7B)).

[0019] Next, referring to Figure 4, an enlarged view of a parametrically driven variable coupler 104 inside the quantum processor 100 of Figure 1, according to one embodiment of the present disclosure, is shown. The parametrically driven variable coupler 104 may include a superconducting quantum interface device (SQUID) 402. The asymmetric SQUID 402 will introduce a driven dipole term in the dynamics of the driven variable coupler-superconducting qubit system. The dipole drive interaction is induced by flux drive signals on two intersecting control lines 108, 110 when certain conditions between the signals are satisfied.

[0020] Next, referring to Figure 5, an enlarged view of a set of superconducting qubits Q1 inside the quantum processor 100 of Figure 1, according to one embodiment of the present disclosure. Each superconducting qubit, for example Q1, includes a single Josephson junction 502 used to tune the superconducting qubit to a fixed frequency. Detailed, non-limiting examples of various embodiments of superconducting qubits are described in PCT Patent Application No. PCT / US23 / 19199, filed April 20, 2023, U.S. Patent Application No. 18 / 137,016, filed April 20, 2023, U.S. Provisional Patent Application No. 63 / 426,204, filed November 17, 2022, and U.S. Provisional Patent Application No. 63 / 333,225, filed April 21, 2022, all of which are incorporated herein by reference in their entirety.

[0021] Next is a flip-chip configuration 600 according to one embodiment of the present disclosure, with reference to Figure 6. An array of superconducting qubits and a parametrically driven variable coupler 104 are arranged on a first chip 602, and a first control line 108 and a second control line 110 are arranged on a second chip 604. The first chip 602 and the second chip 604 are integrally joined in the flip-chip configuration 600.

[0022] Referring next to Figures 7A and 7B, a parametric single superconducting qubit drive 700 according to one embodiment of the present disclosure is shown. Two-tone parametric flux pumps 702a-702b are coupled to a parametrically driven variable coupler 104 and used to create a parametric single superconducting qubit drive for superconducting qubits coupled to the coupler. In the shown embodiment, four superconducting qubits Q1, Q2, Q3, and Q4 are connected to each parametrically driven variable coupler 104. More superconducting qubits may be connected to each parametrically driven variable coupler 104. The parametric coupling process supported by one parametrically driven variable coupler 104 is activated by two orthogonal control lines 108, 110 that cross the flux control port location, which is a geometric structure above SQUID 402. The flux-controlled port position couples the drive signals from the two control lines 108 and 110 to the SQUID 402, generating a parametric drive on the parametrically driven variable coupler 104, and creating a driven parametric interaction between single superconducting qubit drives as described above. The parametrically driven variable coupler 104 is tunable by magnetic flux via the SQUID 402. These two intersecting control lines 108 and 110 should each carry one or more frequency tones such that the sum or difference between the frequency tones corresponds to an appropriate value corresponding to a single superconducting qubit drive of one desired type for one desired superconducting qubit. As described above, such a double selection rule allows for precise control of the single superconducting qubit drive to occur precisely only as intended, minimizing quantum control errors for implementing precise gates for the single superconducting qubit.

[0023] The drive composite type flux drive for the horizontal control line 110 is a magnetic flux pump 702a(f x ,ω x ) and SQUID dipole drive pump 402 (α d,c ,ω d,c) is the drive composite flux drive for vertical control line 108, magnetic flux pump 702b(f y ,ω y ), and in some cases, SQUID dipole drive pump 402 (α d,c ,ω d,c Therefore, in this example, the transition frequency is 0 to 1.

[0024]

number

[0025] The single superconducting qubit drive conditions for Q1 having are

[0026]

number

[0027] This is shown in the graph of Figure 7B for interaction times in nanoseconds. In the example, the Q1 state is initialized to |1>. The even-wave mixed Hamiltonian after renormalization [1,2] of the static superconducting qubit interaction is:

[0028]

number

[0029] That is the case. The even-wave mixed Hamiltonian for the asymmetric SQUID402, which includes an asymmetric parameter d that creates a dipole drive term as the final term of the above interacting Hamiltonian, is:

[0030]

number

[0031] That is the case.

[0032] Referring next to Figures 8A and 8B, a parametric interaction of two superconducting qubits 800 according to one embodiment of the present disclosure is shown. A two-tone parametric flux pump 702 is coupled to a parametrically driven variable coupler 104 and used to create a parametric resonant interaction between a desired pair of superconducting qubits coupled to the coupler. In one embodiment, four superconducting qubits Q1, Q2, Q3, and Q4 are connected to each coupler. More superconducting qubits may be connected to each parametrically driven variable coupler 104. The parametric coupling process supported by one parametrically driven variable coupler 104 is activated by two orthogonal control lines 108, 110 that cross the flux control port location, which is a geometric structure above SQUID 402. The flux control port positions couple drive signals from two control lines 108 and 110 to the SQUID 402, generating a parametric drive on the parametric drive variable coupler 104 and creating a drive-driven parametric interaction between a pair of superconducting qubits, as described above. These two intersecting control lines 108 and 110 should each carry one or more frequency tones such that the sum or difference between the frequency tones corresponds to an appropriate value corresponding to one type of two-superconducting qubit coupling between the two superconducting qubits coupled to the shared drive-driven coupler. The pair of superconducting qubits can be one of six pair combinations: Q1-Q2, Q1-Q3, Q1-Q4, Q2-Q3, Q2-Q4, and Q3-Q4. In other embodiments, a pair of superconducting qubits is Q! / (2!*(Q-2)!) pair combinations for a set of three or more superconducting qubits, where Q is the number of superconducting qubits in the set of three or more. Thus, in summary, a desired pair of superconducting qubit gates is implemented by the spatial and spectral simultaneous selection of a desired parametric interaction between a desired pair of superconducting qubits.Such a dual selection rule allows for precise control of qubit-to-qubit interactions, ensuring that they occur precisely only as intended, and minimizing quantum control errors required to implement precise gates between superconducting qubits.

[0033] As described above, multi-tone drives are used to activate and apply desired precision quantum control for single qubits and qubit pairs. Such tones can be frequency-multiplexed on two intersecting control lines to create desired interactions and drives on superconducting qubits sharing a single coupler. Furthermore, spatial control multiplexing makes it possible to activate the interaction of two superconducting qubits along a chain by simultaneously driving several intersecting control lines.

[0034] The drive composite type flux drive for the horizontal control line 110 is a magnetic flux pump 702a(f x ,ω x ) is the drive composite flux drive for vertical control line 108, magnetic flux pump 702b(f y ,ω y Therefore, in this example, fixed frequency

[0035]

number

[0036] Q1 and fixed frequency

[0037]

number

[0038] The parametric photon exchange condition for Q2 having is,

[0039]

number

[0040] This is shown in the graph of Figure 8B for interaction times in nanoseconds. The |Q1Q2> system is initialized with |10>. The even-wave mixed Hamiltonian after renormalization [1,2] of the static superconducting qubit coupler interaction is:

[0041]

number

[0042] That is the case.

[0043] Referring next to Figure 9A, a quantum processor 900 having a set of three superconducting qubits 902 according to one embodiment of the present disclosure is shown. Parametrically driven variable couplers 104 are coupled to each of the superconducting qubits Q1, Q2, and Q3 of the set of superconducting qubits 902 via connectors. More specifically, the parametrically driven variable couplers 104 inside the quantum processor 900 are arranged in a hexagonal lattice with the three superconducting qubits Q1, Q2, and Q3 positioned around each parametrically driven variable coupler 104. The parametrically driven variable couplers 104 include a flux pump coupled to a first control line 108 and a second control line 110 that cross the flux control port locations (see Figures 7A and 8A). In this example, the first control line 108 is a vertical control line (Y-Ctrl) and the second control line 110 is a diagonal control line (D-Ctrl).

[0044] Referring next to Figure 9B, a quantum processor 950 having a set of three superconducting qubits 902 according to one embodiment of the present disclosure is shown. Parametrically driven variable couplers 104 are coupled to each of the superconducting qubits Q1, Q2, and Q3 of the set of superconducting qubits 902 via connectors. More specifically, the parametrically driven variable couplers 104 inside the quantum processor 950 are arranged in a hexagonal lattice with the three superconducting qubits Q1, Q2, and Q3 positioned around each parametrically driven variable coupler 104. The parametrically driven variable couplers 104 include a flux pump coupled to a first control line 108 and a second control line 110 that cross the flux control port locations (see Figures 7A and 8A). In this example, the first control line 108 is a vertical control line (Y-Ctrl) and the second control line 110 is a horizontal control line (X-Ctrl).

[0045] Referring next to Figure 10, a method 1000 for controlling a set of superconducting qubits according to one embodiment of the present disclosure is shown. Block 1002 provides a parametrically driven variable coupler coupled to each superconducting qubit in a set of superconducting qubits comprising three or more superconducting qubits, a flux pump coupled to the parametrically driven variable coupler, a first control line coupled to the flux pump, and a second control line coupled to the flux pump. In block 1004, one or more first frequency signals are transmitted on the first control line, and one or more second frequency signals are transmitted on the second control line. In block 1006, when one or more first frequency signals and one or more second frequency signals satisfy certain conditions, the parametrically driven variable coupler is used to create a parametric single superconducting qubit drive for a single superconducting qubit within the set of superconducting qubits, or to create a parametric resonant interaction between a pair of superconducting qubits within the set of superconducting qubits.

[0046] In one embodiment, a readout resonator is coupled to each superconducting qubit in a set of superconducting qubits. In another embodiment, each superconducting qubit in a set of superconducting qubits is configured to respond to a specific frequency from a parametrically driven variable coupler. In another embodiment, the set of superconducting qubits is arranged around each parametrically driven variable coupler. In another embodiment, the parametrically driven variable coupler includes a superconducting quantum interface device (SQUID) having an asymmetric parameter d for realizing flux-variable coupling between superconducting qubits and generating parametric coupling between qubits as well as single superconducting qubit dipole drive. In another embodiment, a first control line and a second control line intersect at the flux control port position of the parametrically driven variable coupler. In another embodiment, a specific condition includes the sum or difference of one or more first frequency signals and one or more second frequency signals corresponding to a pair of superconducting qubits, and a specific condition includes the sum or difference of one or more first frequency signals and one or more second frequency signals and a dipole drive signal corresponding to a single superconducting qubit. In another embodiment, a pair of superconducting qubits contains Q! / (2!*(Q-2)!) pair combinations for a set of three or more superconducting qubits, where Q is the number of superconducting qubits in the set of three or more superconducting qubits.

[0047] Circuits are not limited to individual electrical and electronic components, integrated circuits, semiconductor devices, analog devices, digital devices, etc., or any combination thereof, but can be implemented together. Elements can be coupled together using any type of suitable direct or indirect connection between elements, including but not limited to wires, passages, channels, vias, electromagnetic induction, electrostatic charge, optical links, wireless communication links, etc.

[0048] It will be understood that the specific embodiments described herein are presented as examples, not as limitations of the invention. The main features of the invention can be employed in various embodiments without departing from the scope of the invention. Those skilled in the art will recognize or be able to confirm many equivalent procedures to the specific procedures described herein using experiments within the scope of everyday practice. Such equivalent procedures are considered to be within the scope of the invention and are covered by the claims.

[0049] All publications and patent applications described herein represent the state of the art for those skilled in the art to which this disclosure relates. All publications and patent applications are incorporated herein by reference to the same extent that each individual publication or patent application is shown to be incorporated by reference as if it were specifically and individually.

[0050] In this specification, when a device is shown in the accompanying drawings, references may be made to the spatial relationships between various components and the spatial orientation of various aspects of the components. However, as will be understood by those skilled in the art after a complete reading of this application, the devices, components, apparatus, etc. described herein may be arranged in any desired orientation. Accordingly, the use of terms such as “above,” “below,” “top of,” “bottom of,” or other similar terms to describe the spatial relationships between various components or the spatial orientation of aspects of such components should be understood to describe the relative relationships between components or the spatial orientation of aspects of such components, respectively, when the device described herein may be oriented in any desired direction.

[0051] The use of the words “one (a)” or “one (an)” may mean “one” when used in conjunction with the term “equipped with” in the claims and / or specification, but it also corresponds to the meanings of “one or more,” “at least one,” and “one or more.” The use of the term “or” in the claims is used to mean “and / or” unless it is explicitly indicated to refer only to alternatives, or unless the alternatives are mutually exclusive. However, this disclosure supports the definitions of alternatives only and “and / or.” Throughout this application, the term “about” is used to indicate that a value includes an intrinsic variability in the form of error with respect to the device, and the method is employed to determine the value, or the variability present between the study subjects.

[0052] When used herein and in the claims, the words “comprising” (and any other form of comprising, such as “comprise” and “comprises”), “having” (and any other form of having, such as “have” and “has”), “including” (and any other form of including, such as “includes” and “include”), or “containing” (and any other form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude any additional undescribed elements or method steps. In any embodiment of the components and methods given herein, “comprising” may be replaced with “consisting essentially of” or “consisting of”. When used herein, the phrase “consisting essentially of” requires a specific integer or step, and that does not substantially affect the nature or function of the claimed invention. As used herein, the term “exists” is used to indicate the existence of only one integer (e.g., feature, element, characteristic, trait, method / process step, or limit) or one group of integers (e.g., feature(s), element(s), characteristic(s), trait(s), method / process(s), step, or limit(s)).

[0053] The term “or any combination thereof” as used herein refers to all permutations and combinations of the enumerated items preceding the term. For example, “A, B, C, or any combination thereof” is intended to include at least one of A, B, C, AB, AC, BC, or ABC, and, where the order is important in a particular context, BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing this example, obviously included are combinations that encompass one or more repetitions of items or terms, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, etc. Typically, a person skilled in the art will understand that there is no limit to the number of items or terms in any combination unless it is clearly evident from the context.

[0054] When used herein, approximate words such as “about,” “substantial,” or “effectively,” while not limited to such use, refer to conditions that, when modified in this way, are understood not necessarily complete or perfect, but should be considered close enough to assure a person skilled in the art that such conditions exist. The degree to which this description may vary will depend on the magnitude of the possible change, and a person skilled in the art will still recognize that the modified features still possess the required qualities and capabilities of the unmodified features. Generally, however, as discussed above, numerical values ​​in this specification modified by approximate words such as “about” may vary by at least ±1, 2, 3, 4, 5, 6, 7, 10, 12, or 15% from the stated values.

[0055] All devices and / or methods disclosed and claimed herein can be made and performed without excessive experimentation in view of this disclosure. While the devices and / or methods of this disclosure have been described in relation to specific embodiments, it will be apparent to those skilled in the art that variations may be applied to the components and / or methods described herein, as well as to steps of the methods or sequences of steps of the methods, without departing from the concept, spirit, and scope of the invention. All such similar alternative and modified forms that are apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the invention as defined by the appended claims.

[0056] Furthermore, no limitations other than those set forth in the following claims are intended for the details of the configuration or design shown herein. Therefore, it is clear that any particular embodiment disclosed above may be modified or altered, and all such variations are considered to fall within the scope and spirit of this disclosure. Accordingly, the protections required herein are as specified in the following claims.

[0057] The systems and apparatus described herein may be modified, added to, or omitted without departing from the scope of the invention. The components of the systems and apparatus may be integrated or separated. Furthermore, the operation of the systems and apparatus may be performed by more, fewer, or other components. The methods may include more, fewer, or other steps. Furthermore, the steps may be performed in any preferred order.

[0058] To assist the Patent Office and any reader of any patent issued in connection with this application in interpreting the claims attached herein, the applicant wishes to note that, unless the words “means for” or “steps for” are clearly used in a particular claim, they do not intend for any of the attached claims to refer to Section 112(f) of the United States Patent Act as of the filing date of this specification.

[0059] References [1] YYGao, BJLester, Y.Zhang, C.Wang, S.Rosenblum, L.Frunzio, L.Jiang, SMGirvin, RJSchoelkopf, Programmable Interface between Two Microwave Quantum Memories, Physical Review X8, 021073 (2018) DOI:10.1103 / PhsRevX.8.021073.

[0060] [2] C. Zhou, P. Lu, M. Praquin, TC Chien, R. Kaufman, X Cao, M. Xia, RSK Mong, W. Pfaff, D. Pekker, M. Hatridge, A modular quantum computer based on a quantum state router, Research Square (2022) DOI:10.21203 / rs.3.rs-1547284 / v1.

Claims

1. A controller for a set of superconducting qubits, A parametrically driven variable coupler coupled to each superconducting qubit in the set of superconducting qubits, which includes three or more superconducting qubits, A magnetic flux pump coupled to the parametrically driven variable coupler, A first control line connected to the magnetic flux pump, The magnetic flux pump is further equipped with a second control line connected to it. The parametrically driven variable coupler is a controller that, when one or more first frequency signals on the first control line and one or more second frequency signals on the second control line satisfy certain conditions, creates a parametric single superconducting qubit drive for a single superconducting qubit within the set of superconducting qubits, or creates a parametric resonant interaction between a pair of superconducting qubits within the set of superconducting qubits.

2. The controller according to claim 1, further comprising a readout resonator coupled to each superconducting qubit in the set of superconducting qubits.

3. The controller according to claim 1, wherein each superconducting qubit in the set of superconducting qubits is configured to respond to a specific frequency from the parametrically driven variable coupler.

4. The controller according to claim 1, wherein the set of superconducting qubits is arranged around each parametrically driven variable coupler.

5. The controller according to claim 1, wherein the parametrically driven variable coupler includes a superconducting quantum interface device (SQUID).

6. The controller according to claim 1, wherein the first control line and the second control line intersect at the flux control port position of the parametrically driven variable coupler.

7. The aforementioned specific conditions include the sum or difference between the one or more first frequency signals corresponding to the pair of superconducting qubits and the one or more second frequency signals, The controller according to claim 1, wherein the specific condition includes the sum or difference of the one or more first frequency signals corresponding to the single superconducting qubit and the one or more second frequency signals and a dipole drive signal.

8. The controller according to claim 1, wherein the pair of superconducting qubits comprises Q! / ((2! * (Q - 2)!))) pair combinations for the set of three or more superconducting qubits, where Q is the number of superconducting qubits in the set of three or more superconducting qubits.

9. The set of superconducting qubits, the parametrically driven variable coupler, and the magnetic flux pump are arranged on a first chip. The first control line and the second control line are arranged on the second chip. The controller according to claim 1, wherein the first chip and the second chip are integrally bonded in a flip-chip configuration.

10. An array of superconducting qubits arranged within a set of three or more superconducting qubits, A quantum processor comprising a controller coupled to each set of three or more superconducting qubits, wherein the controller is A parametrically driven variable coupler coupled to each superconducting qubit in the set of three or more superconducting qubits, A magnetic flux pump coupled to the parametrically driven variable coupler, A first control line connected to the magnetic flux pump, The magnetic flux pump is further equipped with a second control line connected to it. A quantum processor comprising a parametrically driven variable coupler that, when one or more first frequency signals on the first control line and one or more second frequency signals on the second control line satisfy certain conditions, creates a parametric single superconducting qubit drive for a single superconducting qubit within the set of three or more superconducting qubits, or creates a parametric resonant interaction between a pair of superconducting qubits within the set of three or more superconducting qubits.

11. The quantum processor according to claim 10, wherein the array of superconducting qubits has N × M superconducting qubits, and the total number of the first control line and the second control line is N + M.

12. The quantum processor according to claim 10, further comprising a readout resonator coupled to each superconducting qubit in the set of three or more superconducting qubits.

13. The quantum processor according to claim 10, wherein each superconducting qubit in the set of three or more superconducting qubits is configured to respond to a specific frequency from the parametrically driven variable coupler.

14. The quantum processor according to claim 10, wherein the parametrically driven variable couplers are arranged in a square lattice, rectangular lattice, rhombic lattice, hexagonal lattice, or rhombic lattice, with the three or more superconducting qubits arranged around each parametrically driven variable coupler.

15. The quantum processor according to claim 10, wherein the parametrically driven variable coupler includes a superconducting quantum interface device (SQUID).

16. The quantum processor according to claim 10, wherein the first control line and the second control line intersect at the flux control port position of the parametrically driven variable coupler.

17. The aforementioned specific conditions include the sum or difference between the one or more first frequency signals corresponding to the pair of superconducting qubits and the one or more second frequency signals, The quantum processor according to claim 10, wherein the specific condition includes the sum or difference of one or more first frequency signals corresponding to the single superconducting qubit, one or more second frequency signals, and a dipole drive signal.

18. The quantum processor according to claim 10, wherein the pair of superconducting qubits comprises Q! / (2! * (Q - 2)!) pair combinations for the set of three or more superconducting qubits, where Q is the number of superconducting qubits in the set of three or more superconducting qubits.

19. The set of superconducting qubits, the parametrically driven variable coupler, and the magnetic flux pump are arranged on a first chip. The first control line and the second control line are arranged on the second chip. The quantum processor according to claim 10, wherein the first chip and the second chip are integrally joined in a flip-chip configuration.

20. A method for controlling a set of superconducting qubits, To provide a parametrically driven variable coupler coupled to each superconducting qubit in the set of superconducting qubits, which includes three or more superconducting qubits; a magnetic flux pump coupled to the parametrically driven variable coupler; a first control line coupled to the magnetic flux pump; and a second control line coupled to the magnetic flux pump. Transmitting one or more first frequency signals on the first control line and transmitting one or more second frequency signals on the second control line, A method comprising, when the one or more first frequency signals and the one or more second frequency signals satisfy certain conditions, using the parametrically driven variable coupler to create a parametric single superconducting qubit drive for a single superconducting qubit within the set of superconducting qubits, or to create a parametric resonant interaction between a pair of superconducting qubits within the set of superconducting qubits.

21. The method according to claim 20, further comprising a readout resonator coupled to each superconducting qubit in the set of superconducting qubits.

22. The method according to claim 20, wherein each superconducting qubit in the set of superconducting qubits is configured to respond to a specific frequency from the parametrically driven variable coupler.

23. The method according to claim 20, wherein the set of superconducting qubits is arranged around each parametrically driven variable coupler.

24. The method according to claim 20, wherein the parametrically driven variable coupler includes a superconducting quantum interface device (SQUID).

25. The method according to claim 20, wherein the first control line and the second control line intersect at the flux control port position of the parametrically driven variable coupler.

26. The aforementioned specific conditions include the sum or difference between the one or more first frequency signals corresponding to the pair of superconducting qubits and the one or more second frequency signals, The method according to claim 20, wherein the specific condition includes the sum or difference of the one or more first frequency signals corresponding to the single superconducting qubit and the one or more second frequency signals and the dipole drive signal.

27. The method according to claim 20, wherein the pair of superconducting qubits comprises Q! / (2! * (Q - 2)!) pair combinations for the set of three or more superconducting qubits, where Q is the number of superconducting qubits in the set of three or more superconducting qubits.

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