Dual qubit gate between flux tunable multimode qubits

Abstract

The electronic structure may include a first superconducting quantum interference device (SQUID) coupled between a first electrode slice and a second electrode slice of a first tunable coupler qubit (TCQ) having a first qubit, and a first Josephson junction (JJ) coupled between the second electrode slice and a third electrode slice of the first TCQ. The electronic structure may include a second SQUID coupled between the first electrode plate and the second electrode plate of a second TCQ having a second quantum bit, and a second JJ coupled between the second electrode plate and the third electrode plate of the second TCQ. The second electrode sheet of the first TCQ may be coupled to the second electrode sheet of the second TCQ. The first TCQ may be coupled to a first drive line, and the second TCQ may be coupled to a second drive line.

Description

Background Art

[0001] The present disclosure relates to quantum circuits, and more particularly, to two-qubit gates between flux-tunable multi-mode qubits. Summary of the Invention

[0002] The following presents a summary of the invention to provide a basic understanding of one or more embodiments of the disclosed subject matter. This summary is not intended to identify key or important elements, nor is it intended to delineate any scope of the specific embodiments or any scope of the claims. Its sole purpose is to present concepts in a simplified form as a prelude to the more detailed description that is presented later. In one or more embodiments described herein, systems, devices, structures, methods, apparatuses, and / or computer program products are introduced that can facilitate the creation and / or utilization of two-qubit gates between flux-tunable multimode qubits.

[0003] According to one embodiment, a system may include a first superconducting quantum interference device (SQUID) coupled between a first electrode pad and a second electrode pad of a first tunable coupler qubit (TCQ). The first TCQ may also include a first Josephson junction (JJ) coupled between a second electrode pad and a third electrode pad of the first TCQ. Additionally, the system may include a second SQUID coupled between a first electrode pad and a second electrode pad of the second TCQ. The second TCQ may include a second JJ coupled between a second electrode pad and a third electrode pad of the second TCQ. Additionally, the second electrode pad of the first TCQ may be coupled to a second electrode pad of the second TCQ. The first TCQ may be coupled to a first drive line, and the second TCQ may be coupled to a second drive line.

[0004] According to another embodiment, a system may include a first driver line that can be coupled to a first TCQ including a first qubit. The system may also include a second driver line that is coupled to a second TCQ including a second qubit. A first flux can be applied to the first TCQ via the first driver line, and a second flux can be applied to the second TCQ via the second driver line, such that a controlled phase gate can be coupled between the first TCQ and the second TCQ.

[0005] According to yet another embodiment, a method for coupling a plurality of multimode qubits may include longitudinally coupling a first tunable coupler qubit (TCQ) with a second TCQ by operating a first TCQ with a first flux via a first drive line and operating a second tunable coupler qubit (TCQ) with a second flux via a second drive line to form a ZZ connection therebetween, wherein the first TCQ and the second TCQ may have direct capacitive coupling between a first middle electrode piece of the first TCQ and a second middle electrode piece of the second TCQ.

[0006] Advantages of the system may include: the system may enhance (e.g., increase, improve, or optimize) connectivity between quantum components (e.g., qubits or other quantum components), may enhance the layout of electronic elements or quantum components of a quantum circuit, may reduce the number of drive lines coupled to TCQ components (e.g., such that one drive line is coupled to each TCQ or qubit), and may enhance management of interactions or couplings between quantum components, which may include mitigation or suppression of increased undesirable interactions, couplings, and entanglement between quantum components.

[0007] In some embodiments, the elements described in association with the disclosed system may be embodied in different forms, such as apparatus, method, or other forms.

[0008] These and other features will become apparent from the following detailed description of exemplary embodiments, which is to be read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A block diagram illustrating an exemplary non-limiting system that can include a pair of quantum components and a drive line that can manage interactions or couplings between the quantum components in accordance with various aspects and embodiments of the disclosed subject matter is shown.

[0010] Figure 2 Block diagram depicting an exemplary non-limiting pattern structure of patterns for quantum components in accordance with various aspects and embodiments of the disclosed subject matter.

[0011] Figure 3A A diagram depicts an exemplary non-limiting system that can include a pair of quantum components that can manage interactions or couplings between qubits in accordance with various aspects and embodiments of the disclosed subject matter.

[0012] Figure 3B A diagram of exemplary non-limiting graphs illustrating tuning magnetic fields for various modes of a system in a first state, which can include a pair of quantum components that can manage interactions or couplings between qubits, is presented in accordance with various aspects and embodiments of the disclosed subject matter.

[0013] Figure 3C A diagram is presented of exemplary non-limiting diagrams illustrating magnetic fields tuning various modes of a system in a second state that can include a pair of quantum components that can manage interactions or couplings between qubits, according to various aspects and embodiments of the disclosed subject matter.

[0014] Figure 3DA diagram is presented of exemplary non-limiting graphs showing magnetic fields tuning various modes of a system in a third state that can include a pair of quantum components that can manage interactions or couplings between qubits, according to various aspects and embodiments of the disclosed subject matter.

[0015] Figure 4 A diagram is presented of an exemplary, non-limiting graph illustrating the interaction between three TCQs associated with various modes when one of the TCQs can be flux tuned to transition to an on state while the other TCQs can remain in an off state, in accordance with various aspects and embodiments of the disclosed subject matter.

[0016] Figure 5 A diagram is presented of an exemplary non-limiting graph illustrating the interaction between three TCQs associated with various modes when two of the TCQs can be flux tuned to an on state, in accordance with various aspects and embodiments of the disclosed subject matter.

[0017] Figure 6 A flow chart illustrating an exemplary non-limiting method that can employ a pair of drive lines and a TCQ to control interaction, coupling, or gating between the TCQs, according to various aspects and embodiments of the disclosed subject matter.

[0018] Figure 7 A block diagram illustrating an exemplary non-limiting operating environment that can facilitate one or more embodiments described herein is shown. DETAILED DESCRIPTION

[0019] The following detailed description is merely illustrative and is not intended to limit the embodiments and / or applications or uses of the embodiments. Furthermore, there is no intention to be bound by any express or implied information presented in the previous background or summary sections or in the detailed description section.

[0020] One or more embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals refer to like elements throughout the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a more thorough understanding of one or more embodiments. However, in various cases, it will be apparent that one or more embodiments may be practiced without these specific details.

[0021] A quantum computer can include a set of qubits, which can perform quantum operations on data. In a quantum circuit that includes qubits, couplers can be used to enable qubit-qubit interaction, or coupling, between a pair of qubits to create quantum logic gates. Couplers can also be used to enable interaction, or coupling, between other types of electronic components in a quantum circuit.

[0022] With respect to interactions, couplings, and gates, to facilitate description of various aspects and embodiments of the disclosed subject matter, the following may provide definitions and / or context that may be relevant to the disclosed subject matter. An entanglement gate may include an operation in which an external field (e.g., a microwave pulse) may be applied to a quantum processor comprising qubits to create an entangled state between two or more individual qubits. A controlled phase (CPHASE) gate may be a specific type of entanglement gate in which a qubit may acquire a phase shift if and only if both qubits are in their first excited state.

[0023] A ZZ interaction can be a type of interaction between two qubits or modes in which the excitation of one qubit can shift the transition frequency of another qubit or mode. Thus, a ZZ interaction can represent a way to entangle two different qubits and create a CPHASE gate, since the state-dependent shift in the qubit frequency can be equivalent to a state-dependent phase shift. A ZZ interaction can sometimes be referred to as longitudinal coupling, or can be denoted as chi or 2-chi. A static ZZ interaction can be a type of ZZ interaction that can exist between two qubits or modes in the absence of any external microwave drive (e.g., microwave pulses). A static ZZ interaction can be an "always on" interaction that can be undesirable (e.g., unwanted) and harmful to the qubit system by inhibiting independent control of each qubit and by creating undesirable entanglement.

[0024] An exchange interaction is a type of interaction between quantum systems that allows for the exchange of energy. If present between two qubits, applying a microwave pulse to one qubit could potentially excite the other qubit, an interaction that could be an undesirable form of crosstalk that could harm the quantum system.

[0025] In some existing quantum circuits and couplers, there can be an always-on interaction (e.g., static ZZ interaction) between two qubits or modes even in the absence of any external microwave drive. This always-on interaction can be undesirable and harmful to the qubit system because it can inhibit the independent control of each qubit and can generate undesirable (e.g., unwanted) entanglement between qubits.

[0026] It is desirable to enhance (e.g., increase, improve, or optimize) the efficiency, reliability, and performance of coupler components, enhance connectivity between qubits (or other quantum components), and enhance the layout of electronic components of quantum circuits. It is also desirable to enhance the management of interactions and couplings between qubits (or other quantum components), including mitigating or suppressing undesirable interactions, couplings, and entanglement between qubits (or other quantum components).

[0027] The disclosed subject matter includes TCQ components and techniques that can have numerous advantages and overcome various drawbacks of existing TCQs and techniques. Compared to existing couplers and techniques, the disclosed TCQ components and techniques for TCQ coupling can have enhanced (e.g., increased, improved, or optimized) efficiency, reliability, and performance, can enhance connectivity between qubits (or other quantum components), can enhance the layout of electronic components of quantum circuits, can reduce the number of drive lines coupled to the TCQ components (e.g., such that a single drive line is coupled to each TCQ or qubit), and can enhance the management of interactions and couplings between qubits, including enhanced mitigation or suppression of undesirable interactions, couplings, and entanglement between qubits (or other quantum components).

[0028] To this end, various embodiments described herein relate to techniques for managing coupling between qubits. In some embodiments, a system or device may include a first tunable coupler qubit (TCQ), which may include a first mode (e.g., a first "A" mode) associated with a first frequency (e.g., a first oscillation mode) and a second mode (e.g., a first "B" mode) associated with a second frequency (e.g., a second oscillation mode). The TCQ may also be referred to as a TCQ coupler. The system or device may also include a second TCQ, which may include a third mode (e.g., a second "B" mode) associated with a third frequency (e.g., a third oscillation mode) and a fourth mode (e.g., a second "A" mode) associated with a fourth frequency (e.g., a fourth oscillation mode). The first TCQ and the second TCQ may be associated with each other (e.g., selectively connected or coupled), for example, by direct capacitive coupling, a bus component, or via a coplanar waveguide (CPW), as described herein.

[0029] The respective frequencies associated with the respective modes may be the same as or different from each other. For example, a first frequency associated with a first mode (e.g., a first "A" mode) may be the same as or different from a third frequency associated with a third mode (e.g., a second "A" mode), and a second frequency associated with a second mode (e.g., a first "B" mode) may be the same as or different from a fourth frequency associated with a fourth mode (e.g., a second "B" mode).

[0030] Respective magnetic fluxes can be applied to a first TCQ (e.g., a flux-tunable SQUID of the first TCQ) and a second TCQ (e.g., a flux-tunable SQUID of the second TCQ), which can result in a desired balance between the respective modes of the respective TCQs, and the interaction and such fluxes can suppress undesirable coupling between the first TCQ and the second TCQ. For example, ZZ interactions or coupling (including static ZZ interactions) between the first TCQ and the second TCQ can be desirably suppressed, and exchange interactions between the first TCQ and the second TCQ can be desirably suppressed over a wide range of frequencies based on mode-selective coupling (e.g., utilizing a TCQ pair, such as the first TCQ and the second TCQ).

[0031] When the corresponding modified magnetic flux is applied to the first and second TCQs to desirably adjust the tuning of the corresponding TCQs (e.g., to adjust the tuning of the corresponding SQUIDs of the corresponding TCQs), this can cause corresponding imbalances in the first and second TCQs (e.g., as described herein), which can excite corresponding modes of the first and second TCQs and, thus, create a desired coupling, wherein a ZZ interaction, an entanglement interaction and gate, and / or a controlled phase (CPHASE) gate can be created between the first and second TCQs. Coupling can be defined as a sufficiently strong interaction between two systems (e.g., between a first system containing a first qubit and / or a first TCQ and a second system containing a second qubit and / or a second TCQ) to create a multi-qubit gate (e.g., between two qubits) and / or a desired information or energy exchange between two electronic components (e.g., an electronic component, which can be a qubit, a resonator, or other desired electronic component or component).

[0032] These and other aspects and embodiments of the disclosed subject matter will now be described with reference to the accompanying drawings.

[0033] In an embodiment, such as Figure 1As shown, non-limiting system 100 can include a pair of quantum components (e.g., TCQ). System 100 can include various components and circuits (e.g., quantum components and circuits) that can be arranged to perform one or more desired functions, such as described herein. System 100 can include or be part of a multi-qubit device or multi-qubit package that can have dimensions (e.g., an integrated circuit (IC) chip on which system 100 can be located can have dimensions), and the dimensions can vary, wherein the length of the device or package can vary, for example, from millimeters to tens of millimeters, the width of the device or package can vary, for example, from millimeters to tens of millimeters, and the thickness can vary, for example, from about 1 millimeter (mm) to about 3 mm. It should be understood that these dimensions of the device or package are exemplary, and according to other embodiments, the device or package can have dimensions that are different (e.g., smaller or larger) than the example dimensions described herein.

[0034] In some embodiments, system 100 may include a first quantum component 102 and a second quantum component 104, which may be formed as part of a quantum circuit, which may be formed on one or more chip stacks, which may be formed on one or more die (e.g., IC chips). First quantum component 102 and second quantum component 104 may be part of a quantum component set of a quantum computer (e.g., a superconducting quantum computer). In certain embodiments, first quantum component 102 and second quantum component 104 may be flux tunable coupler qubits (TCQs). A TCQ may include, for example, one or more Josephson junctions (JJs) and a shunt capacitor that may be associated with the one or more Josephson junctions.

[0035] It is desirable (e.g., wanted, required, or appropriate) to manage (e.g., control) interactions, couplings, and / or gates between quantum components, such as first quantum component 102 and second quantum component 104. According to various embodiments, interactions and couplings between first quantum component 102 and second quantum component 104 may be enabled and managed via one or more drive lines. One or more drive lines may control and enable quantum component-to-quantum component (e.g., qubit-to-qubit) interactions (e.g., interactions between first quantum component 102 and second quantum component 104), which may allow for quantum logic gates or other desired types of interactions. In some embodiments, first quantum component 102 and second quantum component 104 may be coupled to each other using coupling capacitors, such as described in greater detail herein.

[0036] According to various embodiments, both first quantum component 102 and second quantum component 104 may be TCQs (e.g., flux-tunable TCQs). For example, first quantum component 102 and second quantum component 104 may be TCQs that may desirably tune (e.g., modify, adjust, or change) one or more parameters (e.g., frequency or other desired parameters) based on magnetic flux applied to first quantum component 102 and second quantum component 104, respectively, as described in greater detail herein.

[0037] First quantum component 102 may include JJ 110 and SQUID 112 (e.g., a flux-tunable SQUID), where SQUID 112 may include JJ 114 and JJ 116. CC 106 may also include capacitor (C) 118 (which may be a shunt capacitor associated with JJ 110 and SQUID 112), capacitor 120 associated with JJ 110, and capacitor 122 associated with SQUID 112. Second quantum component 104 may include JJ 124 and SQUID 126 (e.g., a flux-tunable SQUID), where SQUID 126 may include JJ 128 and JJ 130. The second quantum component 104 may further include a shunt capacitor 132 associated with the JJ 124 and the SQUID 126, a capacitor 134 associated with the JJ 124, and a capacitor 136 associated with the SQUID 126. Furthermore, the first quantum component 102 may store quantum information (e.g., qubit information, quantum state information, etc.) in a first oscillation mode (e.g., A-mode, first mode 138), and the second quantum component 104 may store quantum information in a third oscillation mode (e.g., A-mode, third mode 142). In this manner, the first quantum component 102 (e.g., first TCQ) and the second quantum component 104 (e.g., second TCQ) may function as qubits by utilizing the first mode 138 and the third mode 142 to store quantum information.

[0038] In the first quantum component 102, the JJ 110 and the SQUID 112 can be structured, designed, and / or arranged relative to each other in a quantum circuit so that multiple oscillation modes can be created, where the multiple modes can include a first oscillation mode 138 (e.g., an "A" mode) and a second oscillation mode 140 (e.g., a "B" mode). The first oscillation mode 138 can be associated with a first frequency, and the second oscillation mode 140 can be associated with a second frequency. The second frequency associated with the second mode 140 can generally be higher than the first frequency associated with the first mode 138. The second mode 140 can also be referred to as a dark mode because it generally can have no net dipole moment. The first mode 138 and the second mode 140 can be two different modes that can correspond to symmetric and antisymmetric combinations of excitations associated with the JJ 110 and the SQUID 112.

[0039] Similarly, in the second quantum component 104, the JJ 124 and the SQUID 126 can be structured, designed, and / or arranged relative to each other in the quantum circuit so that multiple oscillation modes can be created, where the multiple modes can include a third oscillation mode 142 (e.g., another "B" mode) and a fourth oscillation mode 144 (e.g., another "A" mode). The third mode 142 can be associated with a third frequency, which can be different from or the same as the second frequency associated with the second mode 140. The fourth mode 144 can be associated with a fourth frequency, which can be different from or the same as the first frequency associated with the first mode 138. The third frequency associated with the third mode 142 can generally be higher than the fourth frequency associated with the fourth mode 144. The third mode 142 can also be referred to as a dark mode because it can generally have no net dipole moment. The third mode 142 and the fourth mode 144 can be two different modes that can correspond to symmetric and antisymmetric combinations of excitations associated with the JJ 124 and the SQUID 126.

[0040] Go to Figure 2 (Together with Figure 1 ), Figure 2 A block diagram depicts an exemplary, non-limiting mode structure 200 of modes of quantum components (e.g., first quantum component 102 and second quantum component 104) according to various aspects and embodiments of the disclosed subject matter. Mode structure 200 can include an “A” mode structure 202 of an “A” mode (e.g., first mode 138) and a “B” mode structure 204 of a “B” mode (e.g., second mode 140) of first quantum component 102.

[0041] JJ 110 and SQUID 112 of first quantum component 102 (e.g., flux-tunable TCQ) can be associated with (e.g., connected to) corresponding capacitor electrodes (e.g., capacitor plates) of corresponding capacitors of first quantum component 102, such as capacitor electrodes 206, 208, and 210. As shown in "A" mode structure 202, in the "A" mode of first quantum component 102, charge can flow from capacitor electrode 210 to capacitor electrode 208 (as shown at reference numeral 212), and charge can also flow from capacitor electrode 208 to capacitor electrode 206 in the same direction (as shown at reference numeral 214). Therefore, there is no net charge accumulation in capacitor electrode 208, and the first quantum component (e.g., SQUID 112) can be symmetric or antisymmetric, depending on how the direction of charge is defined. As shown in the “B” mode structure 204 , in the “B” mode of the first quantum assembly 102 , charge can flow from the capacitor electrode pad 208 to the capacitor electrode pad 206 and the capacitor electrode pad 210 (shown at reference numerals 216 and 218 , respectively).

[0042] Further references Figure 1 In some embodiments, first quantum component 102 can be selectively coupled to second quantum component 104 by applying flux to SQUID 112 and SQUID 126 via one or more drive lines such that a ZZ interaction can form a CPHASE gate between first mode 138 (e.g., the A mode of first quantum component 102) and third mode 142 (e.g., the A mode of second quantum component 104).

[0043] Using respective SQUIDs 112 and 126 , first quantum component 102 and second quantum component 104 can be desirably tuned to facilitate excitation or non-excitation of their respective modes (e.g., 138 , 140 , 142 , 144 ), which can result in controlled interactions, couplings, and gates between first quantum component 102 and second quantum component 104 .

[0044] To facilitate tuning first quantum component 102 and second quantum component 104, system 100 may include a first coil assembly 146 (e.g., connected to a first drive line 146′), which may be associated with and proximate to first quantum component 102 and / or SQUID 112, and a second coil assembly 148 (e.g., connected to a second drive line 148′), which may be associated with and proximate to second quantum component 104 and / or SQUID 126. First coil assembly 146 may be used to apply a desired magnetic field or flux to first quantum component 102 (e.g., to SQUID 112) based on a current supplied to first coil assembly 146 via first drive line 146′. The second coil assembly 148 can be used to apply a desired magnetic field or magnetic flux to the second quantum component 104 (e.g., to the SQUID 126) based on a current supplied to the second coil assembly 148 via a second drive line 148'. The magnetic field created and applied by the second coil assembly 148 can be different from or the same as the magnetic flux created and applied by the first coil assembly 146, depending in part on the respective properties of or associated with the respective components (e.g., JJ, SQUID, or other components) of the first quantum component 102 and the second quantum component 104 (e.g., JJ, SQUID, or other components). In addition, the first coil assembly 146 can apply a first magnetic flux to the SQUID 112 via the first drive line 146', and the second coil assembly 148 can apply a second magnetic flux to the SQUID 126 via the second drive line 148'. The first magnetic flux applied by the first drive wire 146 ′ can be substantially the same as or substantially different from the second magnetic flux applied by the second drive wire 148 ′.

[0045] Under certain magnetic fluxes applied to first quantum component 102 and second quantum component 104, the corresponding modes (e.g., 138, 140, 142, 144) can remain in a non-excited state or transition to a non-excited state, which can suppress coupling between first quantum component 102 and second quantum component 104 and / or suppress interaction or coupling between corresponding components of system 100 (e.g., between first quantum component 102 and second quantum component 104).

[0046] For example, first coil assembly 146 may apply a first amount of magnetic flux to SQUID 112 of first quantum component 102 via first drive wire 146′, which may cause a critical current of SQUID 112 to be close to, equal to, or substantially similar to a critical current of JJ 110 of first quantum component 102, and thus cause a first energy associated with SQUID 112 (e.g., a first Josephson energy) to be close to, equal to, or substantially similar to a second energy (e.g., a second Josephson energy) associated with JJ 110. Additionally, second coil assembly 148 may apply a second amount of magnetic flux to SQUID 126 of second quantum component 104, which may cause a critical current of SQUID 126 to be close to, equal to, or at least substantially similar to a critical current of JJ 124 of second quantum component 104, and thus cause a third energy (e.g., a third Josephson energy) associated with SQUID 126 to be close to, equal to, or at least substantially similar to a fourth energy (e.g., a fourth Josephson energy) associated with JJ 124. As a result, the first energy and the second energy associated with first quantum component 102 can be balanced, and the third energy and the fourth energy associated with second quantum component 104 can be balanced, which can provide and / or force a desired mode-selective coupling associated with first quantum component 102 and second quantum component 104, and which can thereby cause or produce a desired suppression (e.g., suppression) of an interaction or coupling (e.g., ZZ, static ZZ, and / or exchange interaction or coupling) between first quantum component 102 and second quantum component 104, i.e., a substantially or approximately zero interaction or coupling.

[0047] If the magnetic flux applied to SQUID 112 and SQUID 126 by first coil assembly 146 and second coil assembly 148 is modified (e.g., changed or adjusted) to certain corresponding amounts of magnetic flux to adjust the tuning of first quantum component 102 and second quantum component 104 (e.g., adjust the tuning associated with SQUID 112 and SQUID 126), the corresponding modes (e.g., 138, 140, 142, 144) can transition to excited states, which can allow for desired interaction or coupling between first quantum component 102 and second quantum component 104 (as well as interaction or coupling between first mode 138, second mode 140, third mode 142, and / or fourth mode 144 to store and / or transfer quantum / qubit information).

[0048] For example and without limitation, by applying a first modified amount of magnetic flux via first drive line 146′ and a second modified amount of magnetic flux via second drive line 148′ (e.g., such that the energies of SQUID 112 and SQUID 126 can be changed), a ZZ interaction can be activated between first quantum component 102 and second quantum component 104. Additionally, by applying a second modified amount of magnetic flux to second quantum component 104 via second drive line 148′ to reduce a third energy (e.g., the Josephson energy, E) of SQUID 126, the ZZ interaction can be activated between first quantum component 102 and second quantum component 104. J ), ZZ interaction can be activated between the first quantum component 102 and the second quantum component 104. Applying the second modified amount of magnetic flux can reduce the third energy from about 13.13 GHz to about 9.75 GHz. Reducing the third energy of the SQUID 126 can reduce the frequency of the third oscillation mode 142 and the fourth oscillation mode 144 and change the spatial configuration (e.g., as Figure 4 、 Figure 5 and Figure 6 10). By applying a first modified amount of magnetic flux to the first quantum assembly 102 via the first drive wire 146' to reduce the first energy of the SQUID 112, the ZZ interaction can be further activated between the first quantum assembly 102 and the second quantum assembly 104. For example and without limitation, applying the first modified amount of magnetic flux can reduce the first energy to a value of approximately 10.5 GHz (e.g., this can be achieved by varying the Josephson energy E within a desired scan range). J (as shown in FIG. 3 ). Applying the second modifying amount of magnetic flux in conjunction with the first modifying amount of magnetic flux can increase the ZZ interaction between first quantum component 102 (e.g., first TCQ) and second quantum component 104 (e.g., second TCQ) to a value greater than about 3 MHz, while the ZZ interaction between the coupled additional quantum component and second quantum component 104 (e.g., as shown in FIG. 3 ) can be less than about 10 kHz. Furthermore, the enhanced ZZ interaction between first quantum component 102 and second quantum component 104 can allow for the implementation / generation of a CPHASE gate therebetween.

[0049] Next turn Figure 3A , Figure 3AA diagram illustrates an exemplary, non-limiting system 300 that can include a first TCQ, a second TCQ, and a third TCQ (e.g., a third spectator TCQ / qubit relative to the first and second TCQs) in accordance with various aspects and embodiments of the disclosed subject matter. System 300 can include a first TCQ 302, a second TCQ 304, and a third TCQ 306, which can be formed as part of a quantum circuit, which can be formed on one or more chip stacks formed on one or more die (e.g., IC chips). First TCQ 302 can be coupled to second TCQ 304 via direct capacitive coupling (e.g., electrode-to-electrode) or a CPW resonator (e.g., coupling element 308 in an electrode-to-wire-to-electrode coupling arrangement). Similarly, second TCQ 304 can be coupled to third TCQ 306 via direct capacitive coupling (e.g., electrode-to-electrode) or a CPW resonator (e.g., coupling element 310 in an electrode-to-wire-to-electrode coupling arrangement).

[0050] In some embodiments, the first TCQ 302 may include a JJ 314 and a SQUID 312, which may be associated with (e.g., connected to) the JJ 314. The first TCQ 302 may include a first electrode pad 330, a second electrode pad 332 (e.g., a middle electrode pad), and a third electrode pad 334. The SQUID 312 may be coupled between the first electrode pad 330 and the second electrode pad 332, and the JJ 314 may be coupled between the second electrode pad 332 and the third electrode pad 334. The second TCQ 304 may include a JJ 318 and a SQUID 316, which may be associated with (e.g., connected to) the JJ 318. The second TCQ 304 may include a first electrode pad 336, a second electrode pad 338 (e.g., a middle electrode pad), and a third electrode pad 340. The SQUID 316 may be coupled between the first electrode pad 336 and the second electrode pad 338, and the JJ 318 may be coupled between the second electrode pad 338 and the third electrode pad 340. The third TCQ 306 may include a JJ 322 and a SQUID 320, which may be associated with (e.g., connected to) the JJ 322. The third TCQ 306 may include a first electrode pad 342, a second electrode pad 344 (e.g., a middle electrode pad), and a third electrode pad 346. The SQUID 320 may be coupled between the first electrode pad 342 and the second electrode pad 344, and the JJ 322 may be coupled between the second electrode pad 344 and the third electrode pad 346.

[0051] In some embodiments, SQUID 312 of first TCQ 302 can be coupled to first drive wire 350. First drive wire 350 can terminate at a coil substantially adjacent to SQUID 312, such that current flowing through first drive wire 350 can generate a local magnetic field around SQUID 312. First drive wire 350 can provide a current that can tune the magnetic flux enclosed by SQUID 312. By varying the Josephson energy of SQUID 312 via first drive wire 350, first drive wire 350 can change the energy level and symmetry of the associated qubit state (e.g., such that quantum information can be stored within the A-mode of first TCQ 302, second TCQ 304, and / or third TCQ 306).

[0052] In some embodiments, the SQUID 316 of the second TCQ 304 can be coupled to a second drive wire 352. The second drive wire 352 can terminate at a coil substantially adjacent to the SQUID 316, such that current flowing through the second drive wire 352 can generate a local magnetic field around the SQUID 316. The second drive wire 352 can provide a current that can tune the magnetic flux enclosed by the SQUID 316. By changing the Josephson energy of the SQUID 316 via the second drive wire 352, the second drive wire 352 can change the energy level and symmetry of the associated qubit state (e.g., such that quantum information can be stored within the A-mode of the first TCQ 302, the second TCQ 304, and / or the third TCQ 306).

[0053] Furthermore, in an embodiment, the SQUID 320 of the third TCQ 306 can be coupled to a third drive wire 354. The third drive wire 354 can terminate at a coil substantially adjacent to the SQUID 316, such that current flowing through the third drive wire 354 can generate a local magnetic field around the SQUID 320. The third drive wire 354 can provide a current capable of tuning the magnetic flux enclosed by the SQUID 320. By altering the Josephson energy of the SQUID 320 via the third drive wire 354, the third drive wire 354 can change the energy level and symmetry of the associated qubit state (e.g., such that quantum information can be stored in the A-mode of the first TCQ 302, the second TCQ 304, and / or the third TCQ 306).

[0054] In an embodiment, the first TCQ 302 may include a first pattern 360 associated with a first frequency (e.g., an "A" pattern) and a second pattern 362 associated with a second frequency (e.g., a "B" pattern). The second TCQ 304 may include a third pattern 364 associated with a third frequency (e.g., another "A" pattern) and a fourth pattern 366 associated with a fourth frequency (e.g., another "B" pattern). The third TCQ 306 may include a fifth pattern 368 associated with a fifth frequency (e.g., another "A" pattern) and a sixth pattern 370 associated with a sixth frequency (e.g., another "B" pattern).

[0055] Using examples, such as Figure 3B 、 Figure 3C and Figure 3D As generally shown, the system 300 can be in a first state, a second state, or a third state. The first state can correspond to an "off" state, wherein the first modified amount of magnetic flux and the second modified amount of magnetic flux are not applied to the first TCQ 302 or the second TCQ 304 (e.g., Figure 3B 360, third mode 364, and fifth mode 368 may not couple with any additional quantum components or with each other, resulting in negligible crosstalk between the modes (first mode 360, third mode 364, and fifth mode 368).

[0056] In addition, Figure 3C In the illustrated embodiment, the second state may correspond to an "intermediate" state, wherein a second modified amount of magnetic flux may be applied to the second TCQ 304 (e.g., SQUID 316) and the first modified amount of magnetic flux may be prevented from being applied to the first TCQ 302 (e.g., SQUID 312). Applying the second modified amount of magnetic flux to the second TCQ 304 (e.g., SQUID 316) may cause the E of the SQUID 316 to decrease. JThe spatial configuration of the third mode 364 and the fourth mode 366 of the second TCQ 304 may be changed. When the system 300 is in the second state, the change in the spatial configuration of the second TCQ 304 may cause the second mode 362 (e.g., of the first TCQ 302) to include an exchange interaction with the third mode 364 and the fourth mode 366 (e.g., of the second TCQ 304), such as Figure 3C Applying the second modified amount of magnetic flux to the second TCQ 304 can reduce the frequency and energy of the third mode 364 and the fourth mode 366 (eg, the A mode and the B mode of the second TCQ 304).

[0057] In a further embodiment, Figure 3D As generally shown, the third state may correspond to an "on" state, wherein a second modified amount of magnetic flux may be applied to the second TCQ 304 and a first modified amount of magnetic flux may be applied to the first TCQ 302. Applying the magnetic flux via the first drive line 146' and the second drive line 148' may enhance the ZZ interaction between the first mode 360 ​​(the A mode of the first TCQ 302) and the third mode 364 (the A mode of the second TCQ 304), thereby implementing a CPHASE gate between the first mode 360 ​​and the third mode 364. Furthermore, the first drive line 146' may apply the first modified amount of magnetic flux, which may be determined by applying sufficient magnetic flux such that a third frequency (e.g., the frequency of the A mode of the second TCQ 304) is substantially the same as the frequency of the transition from the first state to the second excited state of the first TCQ 302 (e.g., substantially the same as the exchange coupling frequency, within about 100 MHz or more or less). For example, one or more JJs of system 300 may include ports and deactivated inductors, from which variables such as s-parameters and impedances may be calculated. Furthermore, Josephson energies may be assigned to various JJs, and system 300 may be quantized (e.g., by evaluating system 300 as a quantum mechanical system) to determine energy levels and ZZ coupling between various modes of the TCQ.

[0058] In an example, when the system 300 is in the third state, the frequency shift of the first TCQ 302 may result in additional exchange interactions with the first mode 360 ​​and the second mode 362 (e.g., of the first TCQ 302). As a result, the first mode 360 ​​may include exchange interactions with the third mode 364 and the fourth mode 366. Additionally, the second mode 362 may include exchange interactions with the third mode 364 and the fourth mode 366. The first mode 360 ​​may include exchange interactions with the fourth mode 366.

[0059] refer to Figure 4 , Figure 4A diagram illustrates an example graph 400 associated with coupling a first TCQ 302 with a second TCQ 304 (which in turn is coupled to a third TCQ 306) over a desired scan range, the coupling being by direct capacitive coupling or a CPW connection, in accordance with various aspects and embodiments of the disclosed subject matter. Coupling can be defined as a sufficiently strong interaction between two systems (e.g., between a first system including the first TCQ 302 and a second system including the second TCQ 304) to create a multi-qubit gate (e.g., between two qubits stored in the A-mode of the first TCQ 302 and the second TCQ 304) and / or a desired information or energy exchange between two electronic components (e.g., qubits, resonators, or other desired electronic components or components).

[0060] Utilizing an embodiment, graph 400 may include, for a system in a second state (“intermediate” state), frequencies (F) (in GHz) associated with the modes of TCQ (e.g., 360, 362, 364, 366, 368, 370) and the Josephson energy E as a function of the TCQ. j (in GHz). Graph 400 may also include a graph of the mode as a function of the Josephson energy E j A graph 404 is shown relating the ZZ interaction (in kHz) between the TCQ (e.g., 302, 304, 306) as a function of TCQ (in GHz). The ZZ interaction between the first mode 360 ​​and the third mode 364 is shown by curve 410. Additionally, a similar ZZ interaction can be seen between the third mode 364 and the fifth mode 368, as shown by curve 412; and the ZZ interaction between the fifth mode 368 and the first mode 360 ​​can be shown by curve 414. Figure 4 As can be seen, graph 404 and curve 414 illustrate the lack of coupling between first TCQ 302 and third TCQ 306 due to selective coupling controlled by the flux applied by first drive line 146′ and second drive line 148′ to SQUID 312 and SQUID 316. Additionally, first line segment 416 indicates E of second TCQ 304 when system 100 is in a first state (e.g., an “off” state). J The second line segment 418 indicates the E of the second TCQ 304 when the system 100 is in the second state (the "intermediate" state). J As shown, a second modified amount of magnetic flux may be applied to the second TCQ 304 via the second drive line 148', which may cause the E of the SQUID 316 to J From about 13.13 GHz to about 9.75 GHz or more or less.

[0061] In an embodiment, Figure 5A diagram of an exemplary graph 500 is shown relating to coupling the first TCQ 302 with the second TCQ 304 within a desired sweep range in a third state (the "ON" state) in accordance with various aspects and embodiments of the disclosed subject matter. The graph 500 may include, for the system in the third state (the "ON" state), frequency (F) (in GHz) associated with the modes of the TCQs (e.g., 360, 362, 364, 366, 368, 370) and the Josephson energy E as a function of the frequency (F) associated with the modes of the TCQs (e.g., 360, 362, 364, 366, 368, 370). j (in GHz). Graph 400 may also include a graph 502 of the mode as a function of the Josephson energy E j Graph 404 shows the ZZ interaction (in kHz) between the TCQs (e.g., 302, 304, 306) as a function of Hz (in GHz). The ZZ interaction between the first mode 360 ​​and the third mode 364 is shown by curve 510. Additionally, a similar ZZ interaction can be seen between the third mode 364 and the fifth mode 368, as shown by curve 512; and the ZZ interaction between the fifth mode 368 and the first mode 360 ​​can be shown by curve 514. A third line segment 516 indicates the E of the first TCQ 302 when the system is in a first state (e.g., an "off" state). J The fourth line segment 518 indicates the E of the first TCQ 302 when the system is in the third state (the “ON” state). J As shown, a first modified amount of magnetic flux may be applied to the first TCQ 302 via the second drive wire 148', which may increase the E of the SQUID 312. J The first modified amount of magnetic flux may be reduced by approximately 10.5 GHz or more or less. Applying the first modified amount of magnetic flux may increase the ZZ interaction between the first TCQ 602 and the second TCQ 604 to a value greater than approximately 3 MHz, while the ZZ interaction between the second TCQ 604 and the third TCQ 606 may be less than approximately 10 kHz. Quantum information (e.g., qubit information) may then be stored in the first mode 360 ​​and the third mode 364 without being disturbed by the fifth mode 368 and / or the sixth mode 370.

[0062] Figure 6 A flow chart illustrates an exemplary, non-limiting method 600 for coupling a first TCQ with a second TCQ such that quantum information can be stored in a first mode of the first TCQ and in a third mode of the second TCQ, according to various aspects and embodiments of the disclosed subject matter. The method 700 can be performed, for example, by a system including a pair of TCQs or any number of TCQs. For the sake of brevity, repetitive descriptions of similar elements employed in other embodiments described herein are omitted or may be omitted.

[0063] At 602, method 600 may include longitudinally coupling a first TCQ with a second TCQ to form a ZZ connection therebetween by operating the first TCQ with a first magnetic flux via a first drive line and operating the second TCQ with a second magnetic flux via a second drive line, wherein the first TCQ and the second TCQ have direct capacitive coupling between a first middle electrode piece of the first TCQ and a second middle electrode piece of the second TCQ.

[0064] In some embodiments, the first TCQ may include a first mode (A mode, a first oscillation mode) and a second mode (B mode, a second oscillation mode); and similarly, the second TCQ may include a third mode (a second A mode, a third oscillation mode) and a fourth mode (a second B mode, a fourth oscillation mode). The first TCQ may include a first SQUID and a first JJ; and the second TCQ may include a second SQUID and a second JJ. The first drive line may apply a first magnetic flux to the first SQUID of the first TCQ such that the sum of the critical currents of the first SQUID (e.g., the two JJs within the SQUID) is substantially similar to the critical current of the first JJ (e.g., substantially similar may be equal to or close to such that the second mode and the fourth mode of the first TCQ and the second TCQ can be coupled under zero flux). Similarly, the second driving line can apply a second magnetic flux to the second SQUID of the second TCQ, so that the sum of the critical currents of the second SQUID (e.g., the two JJs within the SQUID) is substantially similar to the critical current of the second JJ (e.g., substantially similar can be equal to or close to the critical current of the second JJ, so that the second mode and the fourth mode of the first TCQ and the second TCQ can be coupled under zero flux). By applying flux to the first SQUID and the second SQUID via the first driving line and the second driving line, the first TCQ can be selectively coupled to the second TCQ, so that the ZZ interaction can form a CPHASE gate between the first mode and the third mode.

[0065] Method 600 may include tuning the first TCQ and the second TCQ by applying flux to the first SQUID and the second SQUID. The first SQUID and the second SQUID can tune (e.g., by applying flux) the first TCQ and the second TCQ to promote excitation or non-excitation of their respective modes, which can result in controlled interaction, coupling, and gating between the first TCQ and the second TCQ. The first coil assembly can apply a first magnetic flux to the first SQUID via a first drive line, and the second coil assembly can apply a second magnetic flux to the second SQUID via a second drive line. The first magnetic flux and the second magnetic flux can be substantially the same or substantially different. The first coil assembly can apply a first amount of magnetic flux to the first SQUID that can make the critical current of the first SQUID, and therefore the first energy associated with the first SQUID, equal to or at least substantially equal to the critical current of the first JJ and the second energy associated with the first JJ. The second coil assembly can apply a second amount of magnetic flux to the second SQUID, which can cause the critical current of the second SQUID, and therefore the third energy associated with the second SQUID, to be equal to or at least substantially equal to the critical current of the second JJ and the fourth energy associated with the second JJ. Method 600 can include balancing the first and second energies associated with the first TCQ and balancing the third and fourth energies associated with the second TCQ, which can provide desired mode-selective coupling between the first and second TCQs. Furthermore, this energy balancing can result in desired suppression of interaction or coupling between the first and second TCQs.

[0066] At 604, method 600 may include coupling the second oscillation mode of the first TCQ with the fourth oscillation mode of the second TCQ at zero flux. For example and without limitation, the B modes of the first TCQ and the second TCQ may be coupled to each other (e.g., coupled to an adjacent TCQ via an intermediate electrode sheet).

[0067] At 606, method 600 may include storing quantum information (qubit information) in a first oscillation mode (A-mode) of the first TCQ and in a third oscillation mode (A-mode) of the second TCQ. In this manner, the TCQs can be used as qubits within the system (e.g., as first and second qubits), thus not requiring connection to a coupler element for additional control. Furthermore, coupling the first drive line to the first SQUID and the second drive line to the second SQUID may have the advantage of allowing the system to utilize a single drive line (e.g., flux line) for state manipulation and coupling per qubit (e.g., TCQ).

[0068] At 608, method 600 may include applying a second modified amount of magnetic flux to the first SQUID of the first TCQ via the second drive line to reduce the frequency of the third oscillation mode and the fourth oscillation mode of the second TCQ. The second modified amount of magnetic flux may be to reduce the frequency of the E of the second TCQ. J The amount of decrease from a value of about 13.13 GHz to a value of about 9.75 GHz (eg, decrease in energy level, decrease in frequency, and change in spatial configuration).

[0069] At 610, method 600 may include applying a first modified amount of magnetic flux to a first SQUID of a first TCQ via a first drive line such that a frequency of a first oscillation mode of the first TCQ is substantially similar to a transition frequency of a second TCQ. J Applying the first amount of magnetic flux to the first TCQ may increase the ZZ interaction between the first TCQ and the second TCQ to a value greater than about 3 MHz (or more or less).

[0070] At 612, method 600 may include coupling a controlled phase gate between the first TCQ and the second TCQ. Furthermore, the ZZ interaction between the first oscillation mode and the third oscillation mode may be significantly enhanced, which may enable a CPHASE gate. Furthermore, the application of flux via the first drive line and / or the second drive line may be removed / prevented to disable the ZZ interaction between the first oscillation mode and the third oscillation mode.

[0071] For ease of explanation, method and / or computer-implemented method are depicted and described as a series of actions. It is to be understood and appreciated that the disclosed subject matter is not limited to the actions shown and / or the order of the actions, for example, the actions can occur in various orders and / or simultaneously, and with other actions not introduced and described herein in various orders and / or simultaneously. In addition, not all of the actions shown need to be used to implement computer-implemented methods according to the disclosed subject matter. In addition, it will be understood and appreciated by those skilled in the art that the computer-implemented method can alternatively be represented as a series of interrelated states via state diagrams or events. In addition, it should be further appreciated that the computer-implemented methods disclosed herein subsequently and throughout the specification can be stored on an article of manufacture, so that such computer-implemented methods can be transmitted and transferred to a computer. The term "article of manufacture" as used herein is intended to encompass a computer program accessible from any computer-readable device or storage medium.

[0072] Next turn Figure 7 , provides the Figure 1-6 A detailed description of additional context for one or more embodiments described in

[0014]

[0073] Figure 7 The following discussion is intended to provide a general description of a suitable computing environment 700 in which the present invention may be implemented. Figure 1-6 Various aspects of the present disclosure are described, for example, by narrative text, flow charts, block diagrams of computer systems, and / or block diagrams of machine logic included in computer program product (CPP) embodiments. With respect to any flow chart, depending on the technology involved, the operations may be performed in an order different from that shown in a given flow chart. For example, two operations shown in successive flow chart blocks may be performed in a reverse order, as a single integrated step, simultaneously, or in a manner that at least partially overlaps in time, again depending on the technology involved.

[0074] Computer program product embodiments ("CPP embodiments" or "CPP") are terms used herein to describe any collection of one or more storage media (also referred to as "media") that are collectively included in a collection of one or more storage devices, the collection of one or more storage devices collectively comprising machine-readable code corresponding to instructions and / or data for performing the computer operations specified in a given CPP claim. A "storage device" is any tangible device that can retain and store instructions for use by a computer processor. Without limitation, a computer-readable storage medium can be an electronic storage medium, a magnetic storage medium, an optical storage medium, an electromagnetic storage medium, a semiconductor storage medium, a mechanical storage medium, or any suitable combination of the foregoing. Some known types of storage devices that include these media include floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), compact disc read-only memory (CD-ROM), digital versatile disk (DVD), memory sticks, floppy disks, mechanical encoding devices (such as punched cards or pits / bumps formed on a major surface of a disk), or any suitable combination of the foregoing. The term "computer-readable storage medium" as used herein should not be construed as storage in the form of transient signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides, light pulses transmitted through fiber optic cables, electrical signals communicated through wires, and / or other transmission media. As will be understood by those skilled in the art, during normal operation of a storage device, data is moved at some occasional points in time, such as during access, defragmentation, or garbage collection, but this does not make the storage device transient because the data is not transient when it is stored.

[0075] The computing environment 700 includes an example of an environment for executing at least a portion of computer code related to performing the inventive method, such as translation of the original source code based on the configuration of the target system by quantum circuit measurement readout code 780. In addition to the block 780, the computing environment 700 also includes, for example, a computer 701, a wide area network (WAN) 702, an end-user device (EUD) 703, a remote server 704, a public cloud 705, and a private cloud 706. In this embodiment, the computer 701 includes a processor set 710 (including processing circuitry 720 and cache 721), a communication fabric 711, volatile memory 712, persistent storage 713 (including an operating system 722 and block 780, as described above), a peripheral device set 714 (including a user interface (UI) device set 723, storage 724, and an Internet of Things (IoT) sensor set 725), and a network module 715. The remote server 704 includes a remote database 730. The public cloud 705 includes a gateway 740 , a cloud orchestration module 741 , a host physical machine set 742 , a virtual machine set 743 , and a container set 744 .

[0076] Computer 701 may take the form of a desktop computer, laptop computer, tablet computer, smartphone, smartwatch or other wearable computer, mainframe computer, quantum computer, or any other form of computer or mobile device now known or developed in the future that is capable of running programs, accessing a network, or querying a database (such as remote database 730). As is well known in the art of computer technology, and depending on the technology, the execution of the computer-implemented method may be distributed among multiple computers and / or among multiple locations. On the other hand, in the introduction to this computing environment 700, the detailed discussion focuses on a single computer, specifically computer 701, to keep the introduction as simple as possible. Computer 701 may be located in the cloud, even if it is not in the cloud. Figure 7 On the other hand, the computer 701 need not be located in the cloud unless it can be positively indicated otherwise.

[0077] Processor set 710 includes one or more of any type of computer processor now known or developed in the future. Processing circuitry 720 may be distributed across multiple packages, such as multiple coordinated integrated circuit chips. Processing circuitry 720 may implement multiple processor threads and / or multiple processor cores. Cache 721 is a memory located within the processor chip package and typically used for quickly accessing available data or code for threads or cores running on processor set 710. Cache memory is typically organized into multiple levels based on relative proximity to the processing circuitry. Alternatively, some or all of the processor set's caches may be located "off-chip." In some computing environments, processor set 710 may be designed to work with quantum bits and perform quantum computations.

[0078] Computer-readable program instructions are typically loaded onto the computer 701 to cause the processor set 710 of the computer 701 to perform a series of operating steps to implement a computer-implemented method, such that the instructions executed thereby will instantiate the method specified in the flowcharts and / or narrative descriptions of the computer-implemented method included in this document (collectively, the "inventive method"). These computer-readable program instructions are stored in various types of computer-readable storage media, such as cache 721 and other storage media discussed below. The processor set 710 accesses the program instructions and associated data to control and direct the execution of the inventive method. In the computing environment 700, at least some of the instructions for executing the inventive method may be stored in a block 780 in the persistent storage 713.

[0079] Communications fabric 711 is the signal conduction path that allows the various components of computer 701 to communicate with each other. Typically, the fabric is made of switches and electrical conduction paths, such as those that constitute a bus, a bridge, physical input / output ports, etc. Other types of signal communication paths may be used, such as fiber optic communication paths and / or wireless communication paths.

[0080] Volatile memory 712 is any type of volatile memory now known or to be developed in the future. Examples include dynamic random access memory (RAM) or static RAM. Typically, volatile memory is characterized by random access, but this is not required unless explicitly stated. In computer 701, volatile memory 712 is located in a single package and is internal to computer 701, but alternatively or additionally, volatile memory can be distributed across multiple packages and / or located externally relative to computer 701.

[0081] Persistent storage 713 is any form of non-volatile memory for computers that is now known or will be developed in the future. The non-volatility of this storage means that the stored data is maintained regardless of whether power is supplied to the computer 701 and / or directly to the persistent storage 713. Persistent storage 713 can be a read-only memory (ROM), but typically at least a portion of the persistent storage allows data to be written, deleted, and rewritten. Some familiar forms of persistent storage include magnetic disks and solid-state storage devices. Operating system 722 can take a variety of forms, such as various known proprietary operating systems or operating systems of the open source portable operating system interface type that employs a kernel. The code included in box 780 typically includes at least some of the computer code involved in executing the inventive method.

[0082] Peripheral device set 714 includes a collection of peripheral devices of computer 701. Data communication connections between peripheral devices and other components of computer 701 can be implemented in various ways, such as Bluetooth connections, near field communication (NFC) connections, connections made by cables (such as universal serial bus (USB) type cables), plug-in connections (e.g., secure digital (SD) cards), connections made through local area communication networks, and even connections made through wide area networks (such as the Internet). In various embodiments, UI device set 723 can include components such as displays, speakers, microphones, wearable devices (such as goggles and smart watches), keyboards, mice, printers, touchpads, game controllers, and haptic devices. Storage 724 is an external storage device such as an external hard drive, or a plug-in storage device such as an SD card. Storage 724 can be persistent and / or volatile. In some embodiments, storage 724 can take the form of a quantum computing storage device for storing data in the form of quantum bits. In embodiments where computer 701 is required to have a large amount of storage (e.g., where computer 701 locally stores and manages a large database), the storage may be provided by a peripheral storage device designed to store large amounts of data, such as a storage area network (SAN) shared by multiple geographically distributed computers. IoT sensor set 725 consists of sensors that can be used in IoT applications. For example, one sensor may be a thermometer and another sensor may be a motion detector.

[0083] The network module 715 is a collection of computer software, hardware, and firmware that allows the computer 701 to communicate with other computers via the WAN 702. The network module 715 may include hardware such as a modem or a Wi-Fi signal transceiver, software for packetizing and / or depacketizing data for transmission over a communication network, and / or web browser software for communicating data over the Internet. In some embodiments, the network control function and the network forwarding function of the network module 715 are executed on the same physical hardware device. In other embodiments (e.g., embodiments utilizing software-defined networking (SDN)), the control function and the forwarding function of the network module 715 are executed on physically separate devices, such that the control function manages multiple different network hardware devices. Computer-readable program instructions for executing the inventive method can typically be downloaded to the computer 701 from an external computer or external storage device via a network adapter card or network interface included in the network module 715.

[0084] WAN 702 is any wide area network (e.g., the Internet) capable of transmitting computer data over non-local distances using any technology now known or developed in the future for transmitting computer data. In some embodiments, a WAN may be replaced and / or supplemented by a local area network (LAN) designed to communicate data between devices located in a local area, such as a Wi-Fi network. A WAN and / or LAN typically includes computer hardware such as copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, and edge servers.

[0085] End-user device (EUD) 703 is any computer system that can be used and controlled by an end-user (e.g., a customer of the business operating computer 701), and can take any of the forms discussed above with respect to computer 701. EUD 703 typically receives helpful and useful data from the operation of computer 701. For example, in the hypothetical scenario where computer 701 is designed to provide recommendations to an end-user, the recommendations would typically be sent from network module 715 of computer 701 via WAN 702 to EUD 703. In this manner, EUD 703 can display or otherwise present the recommendations to the end-user. In some embodiments, EUD 703 can be a client device, such as a thin client, a fat client, a mainframe computer, and / or a desktop computer.

[0086] Remote server 704 is any computer system that serves at least some of the data and / or functionality of computer 701. Remote server 704 may be controlled and used by the same entity that operates computer 701. Remote server 704 represents a machine that collects and stores helpful and useful data for use by other computers, such as computer 701. For example, if computer 701 is designed and programmed to provide recommendations based on historical data, then this historical data may be provided to computer 701 from remote database 730 of remote server 704.

[0087] Public cloud 705 is any computer system that can be used by multiple entities and provides on-demand availability of computer system resources and / or other computer capabilities, particularly data storage (cloud storage) and computing power, without requiring direct and active management by the scale. Direct and active management of the computing resources of public cloud 705 is performed by computer hardware and / or software of cloud orchestration module 741. The computing resources provided by public cloud 705 are typically implemented as virtual computing environments running on various computers comprising host physical machine set 742, which is the universe of physical computers in and / or available to public cloud 705. Virtual computing environments (VCEs) typically take the form of virtual machines from virtual machine set 743 and / or containers from container set 744. It is understood that these VCEs can be stored as images and can be transferred between various physical machine hosts either as images or after instantiation of the VCEs. Cloud orchestration module 741 manages the transfer and storage of images, deploys new VCE instantiations, and manages active VCE deployment instantiations. Gateway 740 is a collection of computer software, hardware, and firmware that allows public cloud 705 to communicate over WAN 702 .

[0088] Some further explanation of a Virtualized Computing Environment (VCE) will now be provided. A VCE can be stored as an "image". A new active instance of a VCE can be instantiated from an image. Two familiar types of VCEs are virtual machines and containers. Containers are VCEs that use operating system-level virtualization. This refers to an operating system feature where the kernel allows multiple isolated userspace instances, called containers, to exist. From the perspective of the programs running in them, these isolated userspace instances generally behave like real computers. A computer program running on a normal operating system can make use of all of that computer's resources, such as connected devices, files and folders, network shares, CPU power, and quantifiable hardware capabilities. However, a program running inside a container can only use the contents of the container and the devices assigned to the container, a feature known as containerization.

[0089] 705 . Private cloud 706 is similar to public cloud 705 , except that the computing resources are only available for use by a single enterprise. Although private cloud 706 is depicted as communicating with WAN 702 , in other embodiments, the private cloud may be completely disconnected from the internet and accessible only via a local / private network. A hybrid cloud is a combination of multiple clouds of different types (e.g., private, community, or public cloud types), typically implemented by different vendors. Each of the multiple clouds remains a separate and discrete entity, but the larger hybrid cloud architecture is tied together by standardized or proprietary technologies that enable orchestration, management, and / or data / application portability between the multiple constituent clouds. In this embodiment, public cloud 705 and private cloud 706 are both part of a larger hybrid cloud.

[0090] One or more embodiments may be systems, methods, devices and / or computer program products at any possible level of technical detail integration. A computer program product may include a computer-readable storage medium (or multiple media) having computer-readable program instructions thereon, the computer-readable program instructions being used to cause a processor to execute aspects of one or more embodiments. A computer-readable storage medium may be a tangible device that can retain and store instructions for use by an instruction execution device. A computer-readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. A more specific non-exhaustive list of computer-readable storage media may include the following: a portable computer disk, a hard disk, a RAM, a ROM, an erasable programmable read-only memory (EPROM or flash memory), an SRAM, a portable CD-ROM, a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device such as a punch card or a raised structure in a groove on which instructions are recorded, and any suitable combination thereof. As used herein, computer-readable storage media should not be interpreted as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses transmitted through fiber optic cables), or electrical signals transmitted through wires.

[0091] Computer-readable program instructions described herein can be downloaded to corresponding computing / processing equipment from computer-readable storage media, or downloaded to external computers or external storage devices via a network (for example, the Internet, local area network, wide area network and / or wireless network).The network can include copper transmission cables, optical transmission optical fibers, wireless transmission, routers, firewalls, switches, gateway computers and / or edge servers.Network adapter cards or network interfaces in each computing / processing equipment receive computer-readable program instructions from the network, and forward computer-readable program instructions for storage in the computer-readable storage media in the corresponding computing / processing equipment.The computer-readable program instructions for performing the operation of the disclosed subject can be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, configuration data of integrated circuits, or source code or object code written in one or more programming languages ​​(including object-oriented programming languages ​​such as Smalltalk, C++ and procedural programming languages ​​such as " C " programming language or similar programming languages) of any combination. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or a connection to an external computer may be established (e.g., via the Internet using an Internet service provider). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may execute the computer-readable program instructions by personalizing the electronic circuit using state information of the computer-readable program instructions to perform aspects of the disclosed subject matter.

[0092] Aspects of the disclosed subject matter are described with reference to flowchart illustrations and / or block diagrams of the methods, devices (systems) and computer program products according to embodiments of the present disclosure. It will be understood that each frame of the flowchart illustrations and / or block diagrams and the combination of frames in the flowchart illustrations and / or block diagrams can be implemented by computer-readable program instructions. These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that the instructions executed by the processor of the computer or other programmable data processing device create a method for implementing the function / action specified in one or more frames of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium, which can instruct a computer, a programmable data processing device, and / or other equipment to act in a particular manner so that the computer-readable storage medium with instructions stored therein includes an article of manufacture, and the article of manufacture includes instructions for implementing the function / action aspects specified in one or more frames of the flowchart and / or block diagram. Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational activities to be performed on the computer, other programmable apparatus, or other device to produce a computer-implemented process, such that the instructions executed on the computer, other programmable apparatus, or other device implement the functions / actions specified in one or more boxes of the flowchart and / or block diagram.

[0093] The flow charts and block diagrams in the figure illustrate the possible architecture, functions and operations of the system, method and computer program product according to the various embodiments of the disclosed subject matter. In this regard, each box in the flow chart or block diagram can represent a part of a module, segment or instruction, which includes one or more executable instructions for realizing the specified logical function. In some alternative implementations, the function pointed out in the box may not occur in the order pointed out in the figure. For example, the two boxes shown in succession can be performed substantially in parallel, or these boxes can sometimes be performed in the opposite order, depending on the functions involved. It will also be noted that each box of the block diagram and / or flow chart illustration and the combination of the boxes in the block diagram and / or flow chart illustration can be implemented by a system based on dedicated hardware that performs a specified function or action or performs a combination of dedicated hardware and computer instructions.

[0094] Although the present invention has been described in the general context of computer-executable instructions of a computer program product running on a computer and / or multiple computers, it will be appreciated by those skilled in the art that the present invention may also be implemented in combination with other program modules. Typically, a program module includes routines, programs, components, data structures, etc. that perform specific tasks and / or implement specific abstract data types. In addition, it will be appreciated by those skilled in the art that the computer-implemented methods disclosed herein may be implemented with other computer system configurations, including single-processor or multi-processor computer systems, small computing devices, mainframe computers, and computers, handheld computing devices (e.g., PDAs, phones), microprocessor-based or programmable consumer or industrial electronics, etc. The illustrated aspects may also be implemented in a distributed computing environment, in which tasks are performed by remote processing devices linked via a communication network. However, some, if not all, aspects of the present invention may be implemented on a stand-alone computer. In a distributed computing environment, program modules may be located in local and remote memory storage devices.

[0095] As used herein, the terms "component", "system", "platform", "interface" and the like may refer to and / or may include computer-related entities or entities related to an operating machine having one or more specific functions. The entities disclosed herein may be hardware, a combination of hardware and software, software, or software being executed. For example, a component may be, but is not limited to, a process, a processor, an object, an executable file, an execution thread, a program, and / or a computer running on a processor. By way of illustration, both an application running on a server and a server may be a component. One or more components may reside within a process and / or an execution thread, and a component may be located on a single computer and / or distributed between two or more computers. In another example, each component may be executed from various computer-readable media having various data structures stored thereon. Components may communicate via local and / or remote processes, for example, based on signals having one or more data packets (e.g., data from a component interacts via signals with other components in a local system, a distributed system, and / or across a network having other systems such as the Internet). As another example, a component may be a device that provides a specific function by means of mechanical parts operated by electrical or electronic circuits operated by software or firmware applications executed by a processor. In this case, the processor can be located internally or externally to the device and can execute at least a portion of a software or firmware application. As another example, the component can be a device that provides a specific functionality through an electronic component without mechanical parts, where the electronic component can include a processor or other method to execute software or firmware that at least partially imparts the functionality to the electronic component. In one aspect, the component can emulate the electronic component through a virtual machine (e.g., within a cloud computing system).

[0096] In addition, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then "X employs A or B" is satisfied in any of the foregoing cases. Furthermore, unless otherwise specified or clear from the context to point to a singular form, the articles "a" and "an" should generally be understood to mean "one or more". As used herein, the terms "example" and / or "exemplary" are utilized to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited to such examples. In addition, any aspect or design described herein as "example" and / or "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it intended to exclude equivalent exemplary structures and techniques known to those of ordinary skill in the art.

[0097] As used in this subject specification, the term "processor" can refer to almost any computational processing unit or device, including but not limited to a single-core processor; a single processor with software multi-threaded execution capability; a multi-core processor; a multi-core processor with software multi-threaded execution capability; a multi-core processor with hardware multi-threading technology; a parallel platform; and a parallel platform with distributed shared memory. In addition, a processor can refer to an integrated circuit, an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), a programmable logic controller (PLC), a complex programmable logic device (CPLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. In addition, the processor can utilize nanoscale architectures such as, but not limited to, molecular and quantum dot-based transistors, switches, and gates to optimize space usage or enhance the performance of the user device. The processor can also be implemented as a combination of computational processing units. In this disclosure, terms such as "warehouse," "storage device," "data warehouse," "data storage device," "database," and almost any other information storage component related to the operation and function of the component are used to refer to a "memory component," an entity implemented in a "memory," or a component that includes a memory. It is to be understood that the memory and / or memory components described herein may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. By way of illustration and not limitation, non-volatile memory may include ROM, PROM, EPROM, EEPROM, flash memory, or non-volatile RAM (e.g., FeRAM). Volatile memory may include RAM, which may, for example, act as external cache memory. By way of illustration and not limitation, RAM comes in many forms, such as SRAM, DRAM, SDRAM, DDR SDRAM, ESDRAM, SLDRAM, DRRAM, DRDRAM, and RDRAM. In addition, the memory components of the systems or computer-implemented methods disclosed herein are intended to include, but are not limited to, these and any other suitable memory types.

[0098] What has been described above include simple examples of systems and computer-implemented methods. Of course, it is not possible to describe all conceivable combinations of components or computer-implemented methods for the purposes of describing the present disclosure, but one of ordinary skill in the art will recognize that many further combinations and permutations are possible. In addition, where terms such as "including," "having," and "possessing" are used in the detailed description, claims, appendices, and drawings, these terms are to be interpreted as inclusive in a manner similar to how "comprising" is interpreted as a transitional word in the claims. Descriptions of various embodiments are presented for illustrative purposes, but are not intended to be exhaustive or to limit the embodiments to the disclosed embodiments. Many modifications and variations will be apparent to one of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to best explain the principles of the embodiments, practical applications of or technical improvements to technologies found in the marketplace, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. An electronic structure comprising: a first superconducting quantum interference device (SQUID) coupled between a first electrode sheet and a second electrode sheet of a first tunable coupler qubit (TCQ), and a first Josephson junction (JJ) coupled between the second electrode sheet and a third electrode sheet of the first TCQ; as well as a second SQUID coupled between the first electrode sheet and the second electrode sheet of the second TCQ, and a second JJ coupled between the second electrode sheet and the third electrode sheet of the second TCQ, The second electrode sheet of the first TCQ is coupled to the second electrode sheet of the second TCQ; the first TCQ is coupled to a first driving line; and the second TCQ is coupled to a second driving line.

2. The electronic structure of claim 1 , wherein the first TCQ is coupled to the second TCQ via direct capacitive coupling.

3. The electronic structure of claim 1 , wherein a coplanar waveguide resonator is coupled between the first TCQ and the second TCQ.

4. The electronic structure of any preceding claim, wherein the first TCQ comprises a first oscillation mode and a second oscillation mode; the second TCQ comprises a third oscillation mode and a fourth oscillation mode; and quantum information is storable in the first oscillation mode of the first TCQ and the third oscillation mode of the second TCQ.

5. An electronic structure according to any preceding claim, wherein the first SQUID is tunable via the first drive line flux and the second SQUID is tunable via the second drive line flux.

6. An electronic structure according to any of the preceding claims, wherein the first SQUID includes a first plurality of JJs; the second SQUID includes a second plurality of JJs; the sum of the first critical currents from the first plurality of JJs is substantially similar to the first critical current of the first JJs; and the sum of the second critical currents from the second plurality of JJs is substantially similar to the second critical current of the second JJs. 7 . The electronic structure according to claim 4 , wherein the second oscillation mode of the first TCQ is coupled to the fourth oscillation mode of the second TCQ.

8. The electronic structure of any preceding claim, wherein the first TCQ and the second TCQ are capable of performing controlled phase gating.

9. An electronic system comprising: a first driver line coupled to a first tunable coupler qubit (TCQ) comprising a first qubit; as well as a second driver line coupled to a second tunable coupler qubit (TCQ) comprising a second qubit, A first flux is applied to the first TCQ via the first driving line, and a second flux is applied to the second TCQ via the second driving line, such that a controlled phase gate is coupled between the first TCQ and the second TCQ.

10. The electronic system of claim 9 , wherein the first TCQ includes a first oscillation mode and a second oscillation mode; the second TCQ includes a third oscillation mode and a fourth oscillation mode; the electronic system is in a first state when the first driving line does not apply the first flux to the first TCQ and the second driving line does not apply the second flux to the second TCQ; and the electronic system is in a second state when the second flux is applied to the second TCQ such that a frequency of the third oscillation mode of the second TCQ is substantially similar to a transition frequency of the first TCQ.

11. The electronic system according to any one of claims 9 to 10, wherein when the first flux is applied to the first TCQ and the second flux is applied to the second TCQ such that a ZZ interaction exists between the first TCQ and the second TCQ, the electronic system is in a third state.

12. The electronic system according to any one of claims 9 to 11, wherein the first TCQ includes a first SQUID coupled between a first electrode sheet and a second electrode sheet of the first TCQ, and a first JJ coupled between the second electrode sheet and a third electrode sheet of the first TCQ; and the second TCQ includes a second SQUID coupled between the first electrode sheet and the second electrode sheet of the second TCQ, and a second JJ coupled between the second electrode sheet and the third electrode sheet of the second TCQ. 13 . The electronic system according to claim 11 , wherein in the third state of the first TCQ, the first oscillation mode of the first TCQ and the third oscillation mode of the second TCQ each store quantum information.

14. A method for coupling a plurality of multimode quantum bits, comprising: A first tunable coupler qubit (TCQ) is longitudinally coupled with a second tunable coupler qubit (TCQ) by operating the first TCQ with a first flux via a first drive line and operating the second TCQ with a second flux via a second drive line to form a ZZ connection therebetween, wherein the first TCQ and the second TCQ have direct capacitive coupling between a first middle electrode piece of the first TCQ and a second middle electrode piece of the second TCQ.

15. The method of claim 14, wherein the first TCQ comprises a first oscillation mode and a second oscillation mode; the second TCQ comprises a third oscillation mode and a fourth oscillation mode; and the second oscillation mode of the first TCQ is coupled to the fourth oscillation mode of the second TCQ. 16 . The method of claim 15 , wherein the first oscillation mode of the first TCQ and the third oscillation mode of the second TCQ each store quantum information.

17. The method according to any one of claims 15 to 16, further comprising: A flux is applied to the first SQUID of the first TCQ via the first driving line to reduce the frequencies of the first oscillation mode and the second oscillation mode of the first TCQ.

18. The method according to any one of claims 15 to 17, further comprising: A flux is applied to the first SQUID of the first TCQ via the first driving line to reduce the Josephson energy of the first SQUID and change the spatial configuration of the first oscillation mode and the second oscillation mode of the first TCQ.

19. The method according to any one of claims 15 to 18, further comprising: The second flux is applied to the second SQUID of the second TCQ via the second driving line such that a frequency of the third oscillation mode of the second TCQ is substantially similar to a transition frequency of the first TCQ.

20. The method of any one of claims 14 to 19, wherein a controlled phase gate is coupled between the first TCQ and the second TCQ.

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